Principles of Cardiology pages 1-61

ELECTROCARDIOGRAPHY

Prof. Samir Rafla

The electrocardiogram (ECG) is a graphic representation of the electrical activity

generated by the heart during the cardiac cycle. The electrical activity starts from the

SA node, bundle of His, right and left bundles, Purkinje fibers to stimulate the

ventricles.

Waveforms: The waveforms and intervals of the ECG are: The P wave = atrial

depolarization. The QRS complex = ventricular depolarization. The Q wave is the initial

downward deflection, the R wave is the initial upward deflection, and the S wave is the

second downward deflection. The interval from the beginning of the P wave to the

beginning of the Q wave is the PR interval.

The T wave = ventricular repolarization. The interval from the end of ventricular

depolarization to the beginning of the T wave is termed the ST segment. The interval

from the onset of ventricular depolarization to end of T is the QT interval.

STANDARD APPROACH TO THE ECG: Normally, standardization is 1.0 mV

per 10 mm, and paper speed is 25 mm/s (each horizontal small box = 0.04 sec)

Heart Rate: divide 1500 by number of small boxes between each QRS.

Rhythm: Sinus rhythm is present if every P wave is followed by a QRS, PR interval >

0.12 s, and the P wave is upright in leads I, II, and III.

Intervals: PR (0.12 - 0.20 s). QRS (0.06 - 0.10 s).

QT 0.43 s;

ST-T WAVES: ST elevation : Acute MI, coronary spasm, pericarditis (concave

upward), LV aneurysm.

ST depression: Digitalis effect, strain (due to ventricular hypertrophy), ischemia, or

nontransmural MI.

Tall peaked T: Hyperkalemia; acute MI ("hyperacute T").

Inverted T: Non-Q-wave MI, ventricular "strain" pattern, drug effect (e.g., digitalis),

hypokalemia, hypocalcemia, increased intracranial pressure (e.g., subarachnoid

bleeding).

2

FIG: The magnified ECG wave is presented with the principal time intervals indicated.

Fig: The pathways of Conduction.

3

RHEUMATIC FEVER

Introduction. Classified as a connective tissue or collagen vascular disease, rheumatic

fever (RF) is the leading cause of acquired heart disease in children and young adults.

a. In many developing countries the incidence of acute RF approaches or exceeds 100

per 100.000, whereas in the Unites States it is estimated to be less than 2 per 100.000.

b. Rheumatic fever is more common among population at high risk for streptococcal

pharyngitis, those in close contact with school age children, and persons of low

socioeconomic status. It occurs commonly between the ages of 5 and 18 years and is

rare before 5. Rheumatic fever affects both sexes equally, except for Sydenham’s

chorea, which is more prevalent in females after puberty.

The clinical manifestations of RF develop after a silent period of approximately 3 weeks

following a tonsillopharyngitis caused by a group A streptococcal infection (GAS).

Diagnostic criteria

1. The Jones criteria, are designed to aid in the diagnosis of the first episode of RF.

Rheumatic fever can be diagnosed when a previous upper airway infection with GA-

Streptococci is detected in conjunction with either two major manifestations, or one

major and two minor manifestations. Major manifestation includes arthritis, carditis,

chorea, erythema marginatum, and subcutaneous nodules.

Minor manifestations include: fever, arthralgias, history of tonsillitis 1-3 weeks before

the arthralgia, history of rheumatic heart disease;

high C-reactive protein, high erythrocyte sedimentation rate, raised antistreptolysin O

titer above 200 Todd’s units or prolonged PR interval on electrocardiogram (ECG).

Major manifestations:

1. Carditis: affecting 41% to 83% of patients. It can be defined as pancarditis affecting

the endocardium, myocardium, and pericardium: The main clinical manifestations

include increased heart rate, murmurs, cardiomegaly, rhythm disturbances, pericardial

friction rub, and heart failure. Congestive heart failure is rare in the acute phase; if

present, it usually results from myocarditis. The most characteristic component of

rheumatic carditis is a valvulitis (endocarditis) involving the mitral and aortic valves.

Pericarditis may cause chest pain, friction rubs, and distant heart sounds.

4

2. Arthritis. This is the most common manifestation of RF. It is present in around 80%

of the patients and has been described as painful, asymmetric, migratory, and transient;

it involves large joints, such as knees, ankles, elbows, wrists, and shoulders. It improves

markedly with the use of salicylates within 48 hours of treatment. Monoarthritis,

oligoarthritis, and involvement of small joints of the extremities are less common. The

arthritis of RF is benign and self- limiting (Lasting 2 to 3 weeks) and does not result in

permanent sequelae.

3. Sydenham’s chorea. This extrapyramidal disorder is characterized by purposeless and

involuntary movements of face and limbs, muscular hypotonia, and emotional lability.

4. Subcutaneous nodules.

5. Erythema marginatum.

Minor manifestations:

1. Fever is encountered during the acute phase of the disease.

2. Arthralgia is defined as pain in one or more large joints without objective findings of

inflammation on physical examination.

3. Other clinical manifestations of RF include abdominal pain, epistaxis, acute

glomerulonephritis. These are not included as diagnostic criteria for the diagnosis of

RF.

Laboratory examination and diagnostic testing.

1. Neither throat culture nor rapid antigen test, if positive; differentiate

between recent infection associated with RF and chronic carriage of

pharyngeal GAS.

2. Antistreptolysin O is the most commonly available test. Elevated or rising ASO titers

provide solid evidence for recent GAS infection. A greater than two-fold rise in ASO

titers compared with convalescent titers is diagnostic.

3. Increased sedimentation rate.

4. Increased C reactive protein CRP/

5. The most common finding in the electrocardiogram is the presence of P-R

prolongation and sinus tachycardia.

Therapy:

5

Patient with the diagnosis of rheumatic activity should initially receive a full course of

antibiotic to ensure proper eradication of the organism.

A. Arthritis: Anti-inflammatory medications are generally recommended for 3 weeks

for symptomatic relief.

1. Pain resolves within 24 hours of starting therapy with salicylates.

2. If pain persists after salicylate treatment, the diagnosis of RF is questionable.

3. The recommended dose of salicylate is 100 mg/kg per day, given in 4 divided doses.

Toxic effects such as anorexia, nausea, vomiting, and tinnitus should be avoided.

B. Carditis

1. Strenuous physical activity should be avoided.

2. Congestive heart failure should be treated with appropriate therapy.

3. In patients with significant cardiac involvement, corticosteroids are preferred over

salicylates. The recommended dose is 1 to 2 mg/kg per day, (maximum of 60 mg/day as

Prednisolone). Commonly, therapy is needed for more than one month in patients with

cardiac involvement. Therapy should be continued until there is sufficient clinical and

laboratory evidence of disease inactivity.

4. The gradual reduction in steroid doses is important to avoid relapses. Use of

salicylates (75 mg/kg per day) while tapering corticosteroids may reduce the likelihood

a relapse.

Summary: Jones Criteria of Rheumatic Fever

Major Criteria Minor Criteria

Migratory polyarthritis Fever

Carditis Arthralgia

Chorea High sedimentation rate

Subcutaneous nodules Positive C reactive protein

Erythema Marginatum Prolonged PR interval

Prevention:

The most important step in the treatment of RF is the eradication of GAS infection.

Penicillin is the agent of choice. A. best results are achieved with a single intramuscular

dose of penicillin G benzathine. b. The oral antibiotic of choice is penicillin V

(phenoxymethyl penicillin) (see Table for dosage information). Patients allergic to

6

penicillin: oral erythromycin can be used. The recommended dosage is erythromycin for

10 days. The maximal dose of erythromycin is 1 g/day.

Table: Duration of therapy for secondary prevention of rheumatic fever

Disease state Duration of therapy

RF + carditis + residual valvular

disease

At least 10 years post episode and at least

until age 40. Lifelong prophylaxis may be

required

RF + carditis without valvular

disease

10 years or beyond adulthood, whichever

is longer.

RF without carditis 5 years or until age of 21, whichever is

longer.

RF, rheumatic fever.

VALVULAR HEART DISEASE

MITRAL STENOSIS

ETIOLOGY AND PATHOLOGY: Two-thirds of all patients with mitral stenosis (MS)

are females. MS is generally rheumatic in origin. Pure or predominant MS occurs in

approximately 40% of all patients with rheumatic heart disease. The valve leaflets are

diffusely thickened by fibrous tissue and/or calcific deposits. The mitral commissures

fuse, the chordae tendineae fuse and shorten. The valvular cusps become rigid, and

these changes in turn, lead to narrowing at the apex of the funnel-shaped valve.

Other rare causes of mitral stenosis: Atrial myxoma, ball valve thrombus, congenital

and calcific-atherosclerortic disease.

PATHOPHYSIOLOGY: In normal adults the mitral valve orifice is 4 to 6 cm2. When

the mitral valve opening is reduced to 1 cm2, a left atrial pressure of approximately 25

mmHg is required to maintain a normal cardiac output. The elevated left atrial pressure,

in turn, raises pulmonary venous and capillary pressures, reducing pulmonary

compliance and causing exertional dyspnea.

Pulmonary hypertension results from (1) the passive backward transmission of the

elevated left atrial pressure, (2) pulmonary arteriolar constriction, (reactive pulmonary

7

hypertension), and (3) organic obliterative changes in the pulmonary vascular bed. In

time, the resultant severe pulmonary hypertension results in tricuspid and pulmonary

incompetence as well as right-sided heart failure.

SYMPTOMS AND COMPLICATIONS: - Dyspnea, hemoptysis. - Orthopnea and

paroxysmal nocturnal dyspnea. Pulmonary edema develops when there is a sudden

surge in flow across a markedly narrowed mitral orifice.

The cardiac cycle: Simultaneous electrocardiogram and pressure obtained from the left

atrium, left ventricle, and aorta, and the jugular pulse during one cardiac cycle.

When moderately severe MS has existed for several years, atrial arrhythmias as flutter

and fibrillation occur.

Hemoptysis results from rupture of pulmonary-bronchial venous connections

(apoplexy) secondary to pulmonary venous hypertension. Frank hemoptysis must be

distinguished from the bloody sputum that occurs with pulmonary edema, pulmonary

8

infarction, and bronchitis, three conditions that occur with increased frequency in the

presence of MS.

Recurrent pulmonary emboli, sometimes with infarction are an important cause of

morbidity and mortality late in the course of MS, occurring most frequently in patients

with right ventricular failure. Pulmonary infections, i.e., bronchitis, broncho-

pneumonia, and lobar pneumonia, commonly complicate untreated MS. Infective

endocarditis is rare in pure MS but is not uncommon in patients with combined stenosis

and regurgitation.

Summary: Causes of hemoptysis in mitral stenosis:

- Bronchitis

- Congestion

- Pulmonary edema

- Pulmonary embolism, infarction

- Pulmonary apoplexy

Thrombi and emboli: Thrombi may form in the left atrium, particularly in the enlarged

atrial appendage of patients with MS. If they embolize, they do so most commonly to

the brain, kidneys, spleen, and extremities. Embolization occurs much more frequently

in patients with atrial fibrillation. Rarely, a large pedunculated thrombus or a free-

floating clot may suddenly obstruct the stenotic mitral orifice. Such “ball valve”

thrombi produce syncope, angina, and changing auscultatory signs with alterations in

position, findings that resemble those produced by a left atrial myxoma.

PHYSICAL FINDINGS: Inspection: In advanced cases there is a malar flush. When

fibrillation is present, the jugular pulse reveals only a single expansion during systole

(c-v wave) (systolic venous pulse).

Palpation: Left parasternal lift along the left sternal border signifies an enlarged right

ventricle. In patients with pulmonary hypertension, the impact of pulmonary valve

closure can usually be felt in the second and third left intercostal spaces just left of the

sternum (Diastolic shock). A diastolic thrill is frequently present at the cardiac apex,

particularly if the patient is turned into the left lateral position.

Auscultation: The first heart sound (S1) is generally accentuated and snapping. In

patients with pulmonary hypertension, the pulmonary component of the second heart

9

sound (P2) is often accentuated, and the two components of the second heart sound are

closely split. The opening snap (OS) of the mitral valve is most readily audible in

expiration at, or just medial to, the cardiac apex but also may be easily heard along the

left sternal edge. This sound generally follows the sound of aortic valve closure (A2) by

0.05 to 0.12; that is, it follows P2; the time interval between A2 closure and OS varies

inversely with the severity of the MS. It tends to be short (0.05 to 0.07 s) in patients

with severe obstruction, and long, (0.10 to 0.12 s) in patients with mild MS. The

intensities of the OS and S1 correlate with mobility of the anterior mitral leaflet.

The OS usually precedes a low-pitched, rumbling, diastolic murmur, heard best at the

apex with the patient in the left lateral recumbent position. In general, the duration of

the murmur correlates with the severity of the stenosis. In patients with sinus rhythm,

murmur often reappears or becomes accentuated during atrial systole, as atrial

contraction elevates the rate of blood flow across the narrowed orifice (presystolic

accentuation).

Associated lesion: With severe pulmonary hypertension, a pansystolic murmur

produced by functional tricuspid regurgitation may be audible along the left sternal

border. Characteristically, this murmur is accentuated by inspiration, and should not be

confused with the apical pansystolic murmur of mitral regurgitation.

In the presence of severe pulmonary hypertension and right ventricular failure, a third

heart sound may originate from the right ventricle. The enlarged right ventricle may

rotate the heart in a clockwise direction and form the cardiac apex, giving the examiner

the erroneous impression of left ventricular enlargement. Under these circumstances, the

rumbling diastolic murmur and the other auscultatory features of MS become less

prominent or may even disappear and be replaced by the systolic murmur of functional

tricuspid regurgitation which is mistaken for mitral regurgitation. When cardiac output

is markedly reduced in a patient with MS, the typical auscultatory findings, including

the diastolic rumbling murmur, may not be detectable (silent MS).

ECG findings: The P wave is wide and may be notched which suggests left atrial

enlargement. It becomes tall and peaked in lead II and upright in lead V1 when severe

pulmonary hypertension.

10

Echocardiogram: Two-dimensional echo-Doppler echocardiography for estimation of

the transvalvular gradient and of mitral orifice size, the presence and severity of

accompanying mitral regurgitation, the extent of restriction of valve leaflets, their

thickness, and the subvalvular changes. Transthoracic and transesophageal echo are

needed to verify presence of atrial thrombi.

11

X-Ray chest: Straightening of the left border of the cardiac silhouette, prominence of

the main pulmonary arteries, dilatation of the upper lobe pulmonary veins, and

backward displacement of the esophagus by an enlarged left atrium.

Summary of signs of mitral stenosis:

- Mid-diastolic rumbling murmur with presystolic accentuation;

- Snappy first sound;

- Opening snap;

- Diastolic thrill.

DIFFERENTIAL DIAGNOSIS: The apical middiastolic murmur associated with aortic

regurgitation (Austin Flint murmur) may be mistaken for MS. However, in a patient

with aortic regurgitation, the absence of an opening snap or presystolic accentuation if

sinus rhythm is present points to the absence of MS.

Tricuspid stenosis, a valvular lesion that occurs very rarely in the absence of MS, may

mask many of the clinical features of MS.

MANAGEMENT: Penicillin prophylaxis of beta-hemolytic streptococcal infections and

prophylaxis for infective endocarditis are important. In symptomatic patients, some

improvement usually occurs with restriction of sodium intake and maintenance doses of

oral diuretics. Digitalis glycosides usually do not benefit patients with pure stenosis and

sinus rhythm, but they are necessary for slowing the ventricular rate of patients with

atrial fibrillation and for reducing the manifestations of right-sided heart failure in the

advanced stages of the disease.

Small doses of beta-blockers (e.g., atenolol 25 mg/d) may be added when cardiac

glycosides fail to control ventricular rate in patients with atrial fibrillation. Particular

attention should be directed toward detecting and treating any accompanying anemia

and infections. Hemoptysis is treated by measures designed to diminish pulmonary

venous pressure, including bed rest, the sitting position, salt restriction, and diuresis.

Anticoagulants should be administered continuously in those with atrial fibrillation.

If atrial fibrillation is of relatively recent origin in a patient who’s MS is not severe

enough to warrant surgical treatment, reversion to sinus rhythm pharmacologically or

12

by means of electrical countershock is indicated. Usually this should be undertaken

following 3 weeks of anticoagulant treatment. Conversion to sinus rhythm is rarely

helpful in patients with severe MS, particularly those in whom the left atrium is

especially enlarged or in whom atrial fibrillation is chronic.

Mitral valvotomy by balloon or surgical mitral valvotomy, is indicated in the

symptomatic patient with pure MS whose effective orifice is less than approximately

1.3 cm2 (or 0.8 cm

2 / m

2 of body surface area). Mitral valve replacement by prosthetic

valve is resorted to only if the valve is heavily calcified and associated with

incompetence.

Percutaneous balloon valvuloplasty is an alternative to surgical mitral valvuloplasty in

patients with pure or predominant rheumatic stenosis (it is now the first choice). Young

patients without extensive valvular calcification or thickening or subvalvular deformity

are the best candidates for this procedure.

Contraindications of balloon mitral valvotomy:

1. presence of left atrial thrombi,

2. presence of combined mitral incompetence and stenosis, and

3. heavily calcified mitral cusps.

MITRAL REGURGITATION

ETIOLOGY:

1- Chronic rheumatic heart disease is the cause of severe mitral regurgitation (MR).

2- MR also may occur as a congenital anomaly.

3- MR may occur in patients with infarction involving the base of a papillary muscle.

4- MR may occur with marked left ventricular dilatation.

5- Massive calcification of the mitral annulus of unknown cause, presumably

degenerative, which occurs most commonly in elderly women.

6- Systemic lupus erythematosus, rheumatoid arthritis, are less common cause.

7- Mitral prolapse.

13

Acute MR occur 1- secondary to infective endocarditis involving the cusps or chordae

tendineae, 2- in acute myocardial infarction with rupture of a papillary muscle or one of

its heads, 3- as a consequence of trauma, 4- or following apparently spontaneous

chordal rupture.

MITRAL REGURGITATION: SYMPTOMS: Fatigue, exertional dyspnea, and

orthopnea are the most prominent complaints in patients with chronic, severe MR.

Hemoptysis and systemic embolism also occur less frequently in MR than in MS.

Right-sided heart failure, with painful hepatic congestion, ankle edema, distended neck

veins, ascites, and tricuspid regurgitation, may be observed in patients with MR who

have associated pulmonary vascular disease and marked pulmonary hypertension. In

patients with acute, severe MR, left ventricular failure with acute pulmonary edema and

/or cardiovascular collapse is common.

PHYSICAL FINDINGS: Palpation: A systolic thrill is often palpable at the cardiac

apex, the left ventricle is hyperdynamic, and the apex beat is often displaced laterally.

Auscultation: The first heart sound is generally absent, soft (muffled), or buried in the

systolic murmur. A low-pitched third heart sound (S3) occurring 0.12 to 0.17 sec after

aortic valve closure, i.e. at the completion of the rapid-filling phase of the left ventricle,

is an important auscultatory feature of severe MR.

A fourth heart sound is often audible in patients with acute, severe MR of recent onset

who are in sinus rhythm. A systolic murmur of at least grade III/VI intensity is the most

characteristic auscultatory finding in severe MR. It is usually holosystolic (pansystolic).

In MR due to papillary muscle dysfunction or mitral valve prolapse, the systolic

murmur commences in midsystole. In patients with ruptured chordae tendineae the

systolic murmur may have a cooing or “sea gull” quality; in patients with a flail leaflet

the murmur may have a musical quality.

Summary: Signs of mitral incompetence:

- Harsh pansystolic murmur over apex propagated to axilla.

- Muffled first heart sound.

- Systolic thrill over apex.

14

Electrocardiogram: In patients with sinus rhythm there is evidence of left atrial

enlargement (P mitrale), but right atrial enlargement also may be present when

pulmonary hypertension is severe. Chronic, severe MR with left atrial enlargement is

generally associated with atrial fibrillation.

Echocardiogram: Doppler echocardiography and color Doppler flow echocardiography

imaging are the most accurate noninvasive techniques for the detection and estimation

of MR. The left atrium is usually enlarged. Findings which help to determine the

etiology of MR can often be identified; these include vegetations associated with

infective endocarditis, incomplete coaptation of the anterior and posterior mitral leaflets,

and annular calcification, as well as left ventricular dilation, aneurysm, or dyskinesia.

The echocardiogram in patients with mitral valve prolapse is described below.

Roentgenogram: The left atrium and left ventricle are the dominant chambers; in

chronic cases, the former may be massively enlarged and forms the right border of the

cardiac silhouette. Pulmonary venous congestion, interstitial edema, and Kerly B lines

are sometimes noted.

TREATMENT: Medical: The non surgical management of MR is directed toward

restricting those physical activities that regularly produce dyspnea and excessive

fatigue, reducing sodium intake, and enhancing sodium excretion with the appropriate

use of diuretics. Vasodilators and digitalis glycosides increase the forward output of the

failing left ventricle. Angiotensin-converting enzyme inhibitors are given in chronic

MR. The same considerations as in patients with MS apply to the reversion of atrial

fibrillation to sinus rhythm. Surgical treatment should be offered to patients with severe

MR whose limitations do not allow them to perform normal household activities despite

optimal medical management. Surgery is indicated when the end systolic diameter of

the left ventricle by echo exceeds 50 mm.

MITRAL VALVE PROLAPSE

Mitral valve prolapse (MVP), also termed the systolic click-murmur syndrome, is a

common, but highly variable, clinical syndrome. It is a frequent finding in patients who

have the typical features of the Marfan syndrome. The posterior leaflet is usually more

affected than the anterior, and the mitral valve annulus is often greatly dilated.

15

MVP may be associated with thoracic skeletal deformities.

MVP is common in females between the ages of 6 and 30 years. Most patients are

asymptomatic and remain so for their entire lives. Arrhythmia, most commonly

ventricular premature contractions and paroxysmal supraventricular and ventricular

tachycardia, have been reported and may cause palpitations, light-headedness, and

syncope. Many patients have chest pain which is difficult to evaluate.

PHYSICAL EXAMINATION: Auscultation: the most important finding is the mid-or

late (nonejection) systolic click, which occurs 0.14 s or more after the first heart sound.

Systolic clicks may be followed by a high-pitched late systolic murmur, heard best at

the apex. A useful echocardiographic definition of MVP is systolic displacement (in the

parasternal view) of the mitral valve leaflets into the left atrium > 3 mm. Thickening of

the mitral valve leaflets is present. Doppler studies are helpful in revealing and

evaluating accompanying MR.

Treatment: The management of patients with MVP consists of reassurance of the

asymptomatic patient without severe MR or arrhythmias; prevention of infective

endocarditis with antibiotic prophylaxis in patients with a systolic murmur and the relief

of the atypical chest pain by beta blockers.

AORTIC STENOSIS

Aortic stenosis (AS) occurs in one-fourth of all patients with chronic valvular heart

disease; approximately 80 percent of adult patients with symptomatic valvular AS are

male.

Etiology: 1. AS may be congenital in origin, 2. secondary to rheumatic inflammation of

the valve, 3. degenerative calcification of the aortic cusps of unknown cause.

PATHOPHYSIOLOGY: A peak systolic pressure gradient exceeding 50 mmHg or an

effective aortic orifice less than approximately 0.5 cm2/m

2 of body surface area i.e., less

than approximately one-third of the normal orifice, is generally considered to represent

critical obstruction to left ventricular outflow.

SYMPTOMS: AS is rarely of hemodynamic or clinical importance until the valve

orifice has narrowed to approximately one-third of normal, i.e., to 1 cm2 in adults.

Exertional dyspnea, angina pectoris, and syncope are the three cardinal symptoms.

Angina pectoris reflects an imbalance between the augmented myocardial oxygen

16

requirement by the hypertrophied myocardium and the un-accompanying increase in

coronary blood flow. Orthopnea, paroxysmal nocturnal dyspnea, and pulmonary edema,

i.e., symptoms of left ventricular failure, also occur only in the advanced stages of the

disease.

PHYSICAL FINDINGS: A palpable double systolic arterial pulse the so-called

bisferiens pulse, excludes pure or predominant AS and signifies dominant or pure aortic

regurgitation or obstructive hypertrophic cardiomyopathy.

Palpation: The apex beat is usually sustained and displaced laterally, reflecting the

presence of left ventricular hypertrophy. A systolic thrill is generally present at the base

of the heart in the suprasternal notch, and along the carotid arteries.

Auscultation: Harsh ejection systolic murmur over aortic area propagated to carotids.

The sound of aortic valve closure, the second sound is very weak or even absent with

tight aortic stenosis.

Frequently, a fourth heart sound is audible at the apex in many patients with severe

AS and reflects the presence of left ventricular hypertrophy and an elevated left

ventricular enddiastolic pressure; a third heart sound generally occurs when the left

ventricle dilates and fails.

The murmur of AS is characteristically an ejection systolic murmur loudest at the

base of the heart, most commonly in the second right intercostal space. It is transmitted

along the carotid arteries. Occasionally, it is transmitted downward and to the apex and

may be confused with the systolic murmur of MR.

Summary: Signs of aortic stenosis:

1. Harsh ejection systolic murmur over aortic area propagated to carotids.

2. Weak or absent second heart sound (aortic component)

3. Systolic thrill over aortic area, suprasternal notch and carotids.

4. Strong sustained apex,

Electrocardiogram: This reveals left ventricular hypertrophy in the majority of patients

with severs AS.

Echocardiogram: The key findings are left ventricular hypertrophy. The transaortic

valvular gradient can be estimated by Doppler echocardiography.

Congestive heart failure was considered to be the cause of death in one-half to two-

thirds of patients. Among adults dying with valvular AS sudden death, which

17

presumably results from an arrhythmia (ventricular tachycardia or fibrillation) occurred

in 10 to 20 percent and at an average age of 60 years.

TREATMENT: All patients with moderate or severe AS require careful periodic

follow-up. In patients with severe AS, strenuous physical activity should be avoided

even in the asymptomatic stage. Digitalis glycosides, sodium restriction, and the

cautious administration of diuretics are indicated in the treatment of congestive heart

failure, but care must be taken to avoid volume depletion.

In the majority of adults with calcific AS and critical obstruction, replacement of the

valve is necessary. Percutaneous balloon aortic valvuloplasty is an alternative to

surgery in children and young adults with congenital aortic stenosis. It is not commonly

employed in elderly with severe calcific aortic stenosis because of a high restenosis rate.

Electrocardiogram (ECG), left ventricular, and aortic pressure curves in a patient with

aortic stenosis. There is a pressure gradient across the aortic valve during systole

18

Fig. Abnormal sounds and murmurs associated with valvular dysfunction displayed

simultaneously with left atrial (LA), left ventricular (LV), and aortic pressure tracings.

AVO, aortic valve opening; E, ejection click; MVO, mitral valve opening; OS, opening

snap of the mitral valve.

.

AORTIC REGURGITATION

ETIOLOGY: Approximately three-fourths of patients with pure or predominant aortic

regurgitation (AR) are males; females predominate among patients with AR who have

associated mitral valve disease.

Causes:

1- In approximately two-thirds of patients with AR the disease is rheumatic in origin,

resulting in thickening, deformation and shortening of the individual aortic valve cusps,

changes which prevent their proper opening during systole and closure during diastole.

2- Acute AR also may result from infective endocarditis, which may attack a valve

previously affected by rheumatic disease, a congenitally deformed valve, or rarely a

normal aortic valve, and perforate or erode one or more of the leaflets.

3- Patients with discrete membranous subaortic stenosis often develop thickening of the

aortic valve leaflets, which in turn leads to mild or moderate degrees of AR.

4- AR also may occur in patients with congenital bicuspid aortic valves.

5- Aortic dilatation, i.e., aortic root disease, widening of the aortic annulus and

separation of the aortic leaflets are responsible for the AR.

6- Syphilis and ankylosing rheumatoid spondylitis may lead to aortic dilatation,

aneurysm formation, and severe regurgitation.

19

7- Cystic medial necrosis of the ascending aorta, associated with other manifestations

of the Marfan syndrome, idiopathic dilatation of the aorta, and severe hypertension all

may widen the aortic annulus and lead to progressive AR.

8- Occasionally, AR is caused by retrograde dissection of the aorta involving the aortic

annulus.

History: Patients with severe AR may remain asymptomatic for 10 to 15 years.

Sinus tachycardia during exertion may produce particularly uncomfortable palpitations.

Exertional dyspnea is the first symptom of diminished cardiac reserve. This is followed

by orthopnea, paroxysmal nocturnal dyspnea, and excessive diaphoresis. Chest pain

occurs frequently, even in younger patients, due to diminished coronary filling during

diastole.

Nocturnal angina may be a particularly troublesome symptom. The anginal episodes can

be prolonged and often do not respond satisfactorily to sublingual nitroglycerin. Late in

the course of the disease, evidence of systemic fluid accumulation, including congestive

hepatomegaly, ankle edema, and ascites, may develop.

PHYSICAL FINDINGS: Peripheral signs: Arterial pulse: A rapidly rising “water-

hammer” pulse, which collapses suddenly as arterial pressure falls rapidly during late

systole and diastole, and capillary pulsations, an alternate flushing and paling of the root

of the nail while pressure is applied to the tip of nail, are characteristic of free AR. A

booming, “pistol-shot” sound can be heard over the femoral or brachial arteries, and a to

- fro murmur is audible if the femoral artery is lightly compressed with a stethoscope.

The arterial pulse pressure is widened, with an elevation of the systolic pressure and a

depression of the diastolic pressure. The severity of AR does not always correlate

directly with the arterial pulse pressure, and severe regurgitation may exist in patients

with arterial pressures in the range of 140/60.

Palpation: The apex beat is strong and displaced laterally and inferiorly. The systolic

expansion and diastolic retraction of the apex are prominent and contrast sharply with

the sustained systolic thrust characteristic of severe AS. In many patients with pure AR

or with combined AS and AR, palpation or recording of the carotid arterial pulse reveals

it to be bisferiens, i.e., with two systolic waves separated by trough.

20

Auscultation: A third heart sound is common, and occasionally, a fourth heart sound

also may be heard. The murmur of AR is typically a high-pitched, blowing, decrescendo

early diastolic murmur which is usually heard best in the third left intercostal space.

Unless it is trivial in magnitude, the AR is usually accompanied by peripheral signs

such as a widened pulse pressure or a collapsing pulse. On the other hand, with the

Graham steel murmur of pulmonary regurgitation, there is usually clinical evidence of

severe pulmonary hypertension, including a loud and palpable pulmonary component to

the second heart sound.

A midsystolic ejection murmur is frequently audible in AR. It is generally heard best

at the base of the heart and is transmitted to the carotid vessels. This murmur may be

quite loud without signifying organic obstruction; it is often higher pitched, shorter,

than the ejection systolic murmur heard in patients with predominant AS.

A third murmur which is frequently heard in patients with AR is the Austin Flint

murmur, a soft, low-pitched, rumbling middiastolic or presystolic bruit. It is probably

produced by the displacement of the anterior leaflet of the mitral valve by the aortic

regurgitant stream. Both the Austin Flint murmur and the rumbling diastolic murmur of

MS are loudest at the apex, but the murmur of MS is usually accompanied by a loud

first heart sound and immediately follows the opening snap of the mitral valve, while

the Austin Flint murmur is often shorter in duration than the murmur of MS, and in

patients with sinus rhythm the latter exhibits presystolic accentuation.

Summary: Signs of aortic incompetence over the heart:

- Soft blowing early diastolic murmur over aortic area propagated to apex.

- Austin-Flint murmur (diastolic murmur over mitral area).

Echocardiogram: Essential for detection of severity and cause of AR.

TREATMENT: Although operation constitutes the principal treatment of aortic

regurgitation, and should be carried out before the development of heart failure, the

latter usually respond initially to treatment with digitalis, salt restriction, diuretics, and

vasodilators, especially angiotensin-converting enzyme inhibitors.

21

In patients with severe AR, careful clinical follow-up and noninvasive testing with

echocardiography at approximately 6-month intervals are necessary. Operation is to be

undertaken at the optimal time, i.e., after the onset of left ventricular dysfunction but

prior to the development of severe symptoms. Valve replacement is indicated if the LV

dilates to 50 mm in systole and 65 to 70 mm in diastole.

ACUTE AORTIC REGURGITATION: Infective endocarditis, aortic dissection, and

trauma are the most common causes of severe, acute AR.

TRICUSPID STENOSIS

It is generally rheumatic in origin and is more common in women than in men. It does

not usually occur as an isolated lesion or in patients with pure MR but is usually

observed in association with MS. Hemodynamically significant TS occurs in 5 to 10

percent of patients with severe MS; rheumatic TS is commonly associated with some

degree of regurgitation.

SYMPTOMS: Since the development of MS generally precedes that of TS, many

patients initially have symptoms of pulmonary congestion. Amelioration of the latter

should raise the possibility that TS may be developing. Fatigue secondary to a low

cardiac output and discomfort due to refractory edema, ascites, and marked

hepatomegaly are common in patients with TS and / or regurgitation.

Severe TS is associated with marked hepatic congestion, often resulting in

cirrhosis, jaundice, serious malnutrition, anasarca, and ascites. The jugular veins are

distended, and in patients with sinus rhythm there may be giant “a” waves.

On auscultation, the pulmonic closure sound is not accentuated, and occasionally, an OS

of the tricuspid valve may be heard approximately 0.06 s after pulmonic valve closure.

The diastolic murmur of TS has many of the quality of the diastolic murmur of MS, and

since TS almost always occurs in the presence of MS, the less common valvular lesion

may be missed. The murmur is augmented during inspiration, and it is reduced during

expiration.

Surgical treatment of the tricuspid valve is not ordinarily indicated at the time of

mitral valve surgery in patients with mild TS. On the other hand, definitive surgical

relief of the TS should be carried out, preferable a the time of mitral valvotomy, in

patients with moderate or severe TS who have mean diastolic pressure gradients

22

exceeding 4 to 5 mmHg and tricuspid orifices less than 1.5 to 2.0 cm2. TS is almost

always accompanied by significant tricuspid regurgitation.

TRICUSPID REGURITATION

Most commonly, tricuspid regurgitation (TR) is functional and secondary to

marked dilatation of the right ventricle and the tricuspid annulus. Functional TR may

complicate right ventricular enlargement of any cause, including inferior wall infarcts

that involve the right ventricle, and is commonly seen in the late stages of heart failure

due to rheumatic or congenital heart disease with severe pulmonary hypertension, as

well as in ischemic heart disease, cardiomyopathy, and cor pulmonale. It is in part

reversible if pulmonary hypertension is relieved. Rheumatic fever may produce organic

TR, often associated with TS. Endomyocardial fibrosis, infective endocarditis may

produce TR.

The clinical features of TR result primarily from systemic venous congestion and

reduction of cardiac output. The neck veins are distended with prominent V waves, and

marked hepatomegaly, ascites, pleural effusions, edema, systolic pulsations of the liver

and positive hepato-jugular reflux are common. A prominent right ventricular pulsation

along the let parasternal region and a blowing holosystolic murmur along the lower left

sternal margin which may be intensified during inspiration and reduced during

expiration or the Valsalva maneuver are characteristic findings; AF is usually present.

Summary: Signs of tricuspid regurgitation

- Pansystolic murmur over tricuspid area increases with inspiration.

- Systolic neck vein pulsations

Echocardiography and Doppler: for detection of severity of TR, estimation of

pulmonary pressure and search for vegetations of infective endocarditis.

Treatment of the underlying cause of heart failure usually reduces the severity of

functional TR. In patients with mitral valve disease and TR due to pulmonary

hypertension and massive RV enlargement, effective surgical correction of the mitral

valve abnormality results in lowering of the pulmonary vascular pressure and gradual

23

reduction or disappearance of the TR. Tricuspid valvuloplasy by De Vega procedure

and Carpentier ring can be done.

Pulmonary Stenosis: See congenital pulmonary stenosis

Pulmonary Regurgitation

Dilatation of the pulmonary artery in cases of pulmonary hypertension may produce

pulmonary regurgitation. This is called Graham Steel murmur. It is differentiated

from the early diastolic murmur of aortic regurgitation by the associated signs of

pulmonary hypertension, and by Doppler study.

CONGENITAL HEART DISEASE

Congenital heart malformations remain one of the most frequent birth defects, with a

live-born prevalence of about 8 per 1000 live-born infants in western countries.

Etiology of congenital heart disease:

It is generally an abnormal form of cardiac development in the first 6-8 weeks of

intrauterine life. It is either due to exposure of the fetus in this period to injurious

teratogenic factor or to abnormal chromosomal structure.

Some causes could be identified as:

1- Drugs e.g. thalidomide, excess alcohol intake, anticonvulsant drugs.

2- Exposure to radiation e.g. X-rays and gamma rays.

3- Hereditary diseases: Diseases caused by chromosomal abnormalities eg Turner

syndrome, Down syndrome or mongolism.

4- Maternal infections e.g. German measles in the first trimester of pregnancy.

Congenital heart diseases in the adults could be classified into:

I- Left or right ventricular outflow obstruction: Aortic stenosis, pulmonary stenosis,

coarctation of aorta.

II- Left to right shunts: ASD, VSD and PDA.

III- Cyanotic heart disease: Fallot’s tetralogy and other cyanotic congenital diseases.

24

LEET TO RIGHT SHUNT

When there is a congenital communication between both sides of the heart, e.g. atrial or

ventricular septal defects or patent ductus arteriosus the blood always flows from the

left side (left atrium, left ventricle or aorta) to right side (right atrium, right ventricle or

pulmonary artery). This is because the pressure in all left-sided chambers is higher than

in right-sided chambers.

EFFECTS:

1- Left to right shunt results in pulmonary plethora (increased vascularity in the lung). If

the shunt is very big heart failure may occur but this is rare.

2- In mild to moderate cases the pulmonary vessels dilate to accommodate the excessive

blood flow. Mild cases are well tolerated but if the shunt is excessive the pulmonary

vessels react by vasoconstriction. Pulmonary arteriolar vasoconstriction causes

pulmonary hypertension which results in right ventricular hypertrophy.

3- Pulmonary hypertension causes rise of pressure in the chambers of the right side of

heart. Ultimately the pressure in the right side exceeds that of the left side and the blood

starts to flow across the defect in the reverse direction, i.e. right to left shunt (reversed

shunt). The patient becomes cyanosed. Emboli originating in the venous side may be

shunted across the defect to the arterial side and settle in organs such as the brain or

limbs. This is paradoxical embolism.

Closure of the defect at this stage is useless and dangerous. This situation of a

congenital defect + reversed shunt is called Eisenmenger’s syndrome. Eisenmenger’s

syndrome is not an independent congenital heart disease. It is the end result of big left to

right shunt. At this stage the clinical picture is that of central cyanosis with severe

pulmonary hypertension.

ATRIAL SEPTAL DEFECT

In the presence of a defect in the atrial septum the right atrium receives blood both from

the normal venous return and the left atrium, the right atrium dilates. This results in:

Dilatation and hypertrophy of the right ventricle (volume overload), dilatation of the

pulmonary artery, and pulmonary plethora. If the defect is big and uncorrected

pulmonary arteriolar vasoconstriction progressively occurs and results in pulmonary

hypertension usually at age 20-30 years. When the pressure in the right atrium exceeds

25

that in the atrium the shunt becomes reversed (Eisenmenger’s syndrome) and the patient

becomes cyanosed.

Clinical features:

1- Atrial septal defect is more common in females. When the left to right shunt is very

big pulmonary plethora may predispose to repeated chest infections in infancy.

Otherwise there are no symptoms for many years. Ultimately heart failure occurs.

2- Atrial fibrillation occurs in late cases.

3- Right ventricular dilatation and hypertrophy cause a hyperdynamic impulse in the

third and fourth spaces to the left of the sternum and precordial bulge.

4- Excessive flow across the tricuspid valve may produce a third heart sound and short

mid-diastolic murmur at the tricuspid area.

5- Excessive blood flow at the pulmonary valve may produce pulsations, dullness and

an ejection systolic murmur in the pulmonary area.

6- The specific auscultatory sign of atrial septal defect is wide fixed splitting of the

second heart at the pulmonary area. The pulmonary component of the second sound is

delayed because the right ventricle takes a long time o empty the excessive volume of

blood it receives. The splitting dose not vary with respiration because: although

inspiration causes increase in venous return, yet the resulting rise in right a trial pressure

causes proportionate decrease in the left to right shunt so that the right ventricular

output is constant and the time relation between aortic and pulmonary components of

the second sound remains constant.

7- Progressive pulmonary hypertension occurs in big defects and result in Eisenmenger

syndrome. At this stage the clinical picture consists of: Central cyanosis, signs of

pulmonary hypertension, and signs or right ventricular hypertrophy.

X-RAY PICTURE:

1- Plethoric lung fields. 2- Dilatation of the right atrium, right ventricle and pulmonary

artery. 3- Marked pulsation of the pulmonary artery and its branches seen during

screening (hilar dance).

ELECTROCARDIOGRAPHIC FEATURES: The characteristic sign is incomplete right

bundle branch block with rSr' pattern in V1 lead. Signs of right ventricular hypertrophy

also appear when pulmonary hypertension develops. Atrial fibrillation occurs in late

cases.

ECHOCARDIOGRAPHY WITH DOPPLER: Must be done for every patient with

suspected congenital heart disease. In A.S.D. it shows the septal defect and dilated right

26

ventricle and abnormal movement of the interventricular septum characteristic of

volume overload on the right ventricle. Cardiac catheterization may be done in some

cases.

COMPLICATIONS:

1- Pulmonary hypertension and reversal of shunt.

2- Right ventricular failure. 3- A trial fibrillation.

TREATMENT: Small defects can be left alone. Large defects should be closed

surgically or by percutaneous insertion of occluder (device that occludes the ASD) .

VENTRICULAR SEPTAL DEFECT

1- In the presence of a defect in the septum, the right ventricle receives both the normal

venous and the shunted blood. If the defect is big right ventricular hypertrophy occurs.

2- This excessive blood flows in the pulmonary artery and the pulmonary circulation

and then returns to the left atrium and the left ventricle. This causes: Dilatation of the

pulmonary artery, pulmonary plethora, dilatation of the left atrium, dilatation and

hypertrophy of the left ventricle.

3- If the shunt is very big excessive flow may cause heart failure in infancy.

4- If the shunt is large the pulmonary vessels react by vasoconstriction causing

pulmonary hypertension and reversal of shunt (Eisenmenger syndrome).

5- Small V.S.D. does not cause pulmonary hypertension and may close spontaneously.

Clinically, the murmur is very loud (Roger’s disease).

CLINICAL PICTURE: The specific signs of V.S.D. are: 1- A characteristic

pansystolic murmur best heart in the third and fourth left intercostal spaces just lateral

to the sternum, usually accompanied by a thrill. 2- With large shunts the increased flow

across the mitral valve may cause a third sound and a mid-diastolic flow murmur at the

apex.

The clinical course depends upon the size of the defect:

1- Small ventricular septal defect: many defects close spontaneously.

2- Moderately large defect:

27

1st- Progressive pulmonary hypertension and low cardiac output e.g. fatigue,

syncope on exercise, pulsations and palpable loud second heart sound in the pulmonary

area, right ventricular hypertrophy, etc.

2nd- When the pressure in the right ventricle equals that in the left ventricle no blood

will flow across the defect and the murmur diminishes disappears. The patient becomes

cyanosed on crying.

3rd- When the shunt is reversed the patient becomes cyanosed.

X-RAY PICTURE: Is normal in cases with small defects. Large defects result in:

pulmonary plethora (overfilled large and tortuous pulmonary arteries), large main

pulmonary artery, left and right ventricular enlargement, left atrial enlargement.

ECHOCARDIOGRAPHY WITH DOPPLER: Can show the size of cardiac chambers.

The defect can sometimes be shown by two-dimensional echo. Color Doppler is very

helpful in showing the blood flow through the defect. Detection of the site of the defect,

the magnitude of the shunt and the degree of pulmonary hypertension can be assessed

by this non-invasive method.

CARDIAC CATHETERISATION AND ANGIOGRAPHY: Is done in some cases.

COMPLICATIONS: Infective endocarditis, pulmonary hypertension, and heart failure.

DIFFERENTIAL DIAGNOSIS: A pansystolic murmur at the sternal border can be

caused by tricuspid or mitral incompetence in addition to the ventricular septal defect.

Sometimes the murmur of pulmonary stenosis is heard at the third intercostal space but

it is usually ejection in type and its maximal intensity is in the second space. Other

causes of systolic murmur at left sternal border are hypertrophic obstructive

cardiomyopathy, subaortic membrane and aortic stenosis.

TREATMENT:

1- To prevent infective endocarditis all patients must receive an antibiotic prophylaxis

before performing minor procedures that may causes bacteremia, e.g. dental extraction,

delivery, etc.

2- Small ventricular septal defects should be left alone. Many of them close

spontaneously.

3- Surgical closure is indicated if the defect is moderate or large in size, provided that

the pulmonary pressure is normal or moderately elevated. Surgical closure is

contraindicated if pulmonary pressure is severe (Eisenmenger’s syndrome).

PATENT DUCTUS ARTERIOSUS

28

The ductus arteriosus is normally present in the fetus. It connects the aorta (at the

junction of the arch with the descending aorta) with the pulmonary artery (at the

junction of the main pulmonary artery with its left branch). It normally closes. During

the first month after birth:

Effects:

1- The blood flows through the duct from the aorta to the pulmonary artery, i.e. left to

right shunt.

2- As the pulmonary artery receives blood both from the shunt and the right ventricle,

pulmonary artery dilatation and pulmonary plethora occur.

3- If the shunt is big pulmonary vasoconstriction and hypertension occurs. When the

pressure in the pulmonary artery equals that of the aorta the shunt will first become

confined to the systole only and then ceases altogether. The murmur, accordingly, will

first become only systolic and finally will be completely inaudible.

5- When the pressure in the pulmonary artery exceeds that of the aorta, the shunt will be

reversed and cyanosis occurs (Eisenmenger’s syndrome).

CLINICAL FEATURES: Patent ductus arteriosus is commoner in females. Its

characteristic signs are:

1- A continuous (machinery) murmur that occupies both systole and diastole because

the pressure in the aorta exceeds that of the pulmonary artery all through the cardiac

cycle. It is best heard in the first and second left intercostal spaces. There may be

continuous thrill in the same area.

2- With large ductus, the increased flow across the mitral may cause a mid-diastolic

murmur.

When the pressure in the pulmonary artery exceeds that of the aorta, right to left shunt

occurs and cyanosis appears (Eisenmenger’s syndrome). The deoxygenated blood will

flow from the pulmonary artery across the ductus down the descending aorta. The lower

limbs will be cyanosed while the upper limbs remain pink (differential cyanosis).

X-RAY PICTURE: X-ray is normal in cases with small ductus. In moderate to large

ductus the following signs appear: Pulmonary plethora, enlargement of the left atrium,

left ventricle and the aorta. Hilar dance seen in the hilum by screening.

Differential diagnosis: Other causes of continuous murmur as aorto-pulmonary window,

in coarctation of the aorta, mammary softle, rupture sinus of Valsalva, venous hum...

29

TREATMENT: Prophylaxis against endocarditis. Closure either surgical or with a

device introduced with percutaneous, transvenous catheter.

CYANOTIC HEART DISEASE

- Tetralogy of Fallot.

- Ebstein anomaly.

- Transposition of the great arteries.

- Total anomalous pulmonary venous drainage.

- Truncus arteriosus.

- Pulmonary arterio-venous malformation.

Acquired cyanotic disease: Eisenmenger Syndrome.

FALLOT’S TETRALOGY

PATHOLOGY AND EFFECTS: Fallot’s tetralogy consists of:

1- Severe pulmonary stenosis which causes right ventricular hypertrophy. The

pulmonary stenosis is usually infundibular but sometimes it is both valvular and

infundibular.

30

2- Large ventricular septal defect which makes the pressure equal in both ventricles.

3- The origin of the aorta is abnormally deviated to the right (dextroposed, dextro =

right) so that it lies partly over the right ventricle (the aorta overrides both ventricles).

4- Due to the severe pulmonary stenosis and the large ventricular septal defect, the

pressure in both ventricles is equal. There is rush of blood across the defect and the

ventricular septal defect produces no murmur.

5- Part of the blood pumped by the right ventricle passes in the aorta (right to left

shunt) causing central cyanosis.

In summary Fallot’s tetralogy consists of four components (tetra =4).

1- Pulmonary stenosis.

2- Ventricular septal defect.

3- Dextroposed and overriding aorta.

4- Right ventricular hypertrophy.

CLINICAL FEATURES:

1- The patient is cyanosed since birth, (usually after birth by few weeks); the degree of

cyanosis depends on the severity of the pulmonary stenosis.

2- When the patient exercises, cyanosis is increased. In order to increase the blood flow

to the head and brain, the child usually squats to compress the lower limbs against the

abdomen and to deviate the blood from the lower to the upper half of the body. It also

increases the systemic arterial resistance. As the pressure in the aorta rises, more blood

will be deviated across the pulmonary stenosis to the lungs. Thus more oxygenated

blood returns to the heart.

3- Chronic cyanosis and tissue anoxia results in: Dyspnea, fatigue, angina, retarded

growth, polycythemia, clubbing of fingers.

4- Sometimes the muscle surrounding the outflow tract of the right ventricle goes into

spasm, especially after excitement and exercise. The blood flow to the lungs decreases

markedly and the oxygenation decreases resulting in attacks of severe cyanosis:

cyanotic spells. If prolonged they may lead to death.

5- The characteristic cardiac signs are:

A- Murmur of pulmonary stenosis (ejection systolic murmur in second left

space, usually accompanied by a thrill.

31

B- The second heart sound is single and consists only of the aortic component.

C- Right ventricular hypertrophy.

X-RAY PICTURE:

4. Right ventricular hypertrophy causes the apex to be displaced outwards and

becomes separated from the diaphragm.

5. Right-sided aortic arch in some cases.

6. Pulmonary oligemia (the pulmonary artery and its branches are diminished in size

due to the pulmonary stenosis. All the above factors result in a characteristic cardiac

shadow: Coeur en sabot (sabot = wooden shoe).

ELECTROACARDIOGRAPHIC FEATURES: Show moderate right ventricular

hypertrophy.

ECHOCARDIOGRAPHY WITH DOPPLER: Delineates the abnormal anatomy.

Cardiac catheterization and angiography is needed for differential diagnosis.

COMPLICATIONS:

1- Polycythemia causes increased viscosity of blood resulting in a tendency towards

thrombosis, e.g. cerebral thrombosis.

2- Infective endocarditis

3- Brain abscess results when bacterial emboli are shunted from the venous to the

arterial side and lodge in the brain (paradoxical embolism).

TREATMENT:

1- Surgical correction is indicated in all cases by: Resection of the excessive stenotic

infundibular muscle splitting of the fused pulmonary valve leaflets, and closure of the

ventricular septal defect.

2- If he patient is too young, or the condition is too severe, an anastomosis is performed

to allow blood to reach the lungs by: implanting the subclavian artery in the

corresponding pulmonary artery (Blalock-Taussig operation).

3- Cyanotic attacks result from infundibular spasm and constitute an emergency. The

are treated by: Put the patient in the squatting position or compress the flexed lower

limbs against the abdomen, sedation, propranolol (inderal) intravenously. Propranolol is

a beta-adrenergic blocker. It depresses the contractility of the infundibular muscle.

LEFT VENTRICULAR OUTFLOW TRACT OBSTRUCTION

- Valvular aortic stenosis: 70% of patients with valvular AS a malformation of the

valve (usually a bicuspid valve).

32

- Discrete subvalvular aortic membrane:

Represents 8-10% of congenital AS. The magnitude of obstruction is variable. Most

membranes are eventually associated with progressive aortic regurgitation and their

presence may be an absolute indication for excision. There is a high recurrence rate

after excision (approximately 30% and septal myotomy is often performed).

COARCTATION OF THE AORTA

Narrowing of the aorta usually just distal to the left subclavian artery. Coarctation may

affect other parts of the aorta or the renal arteries.

EFFECTS:

1- Because of the narrowing, pressure rises in the ascending aorta and the aortic arch

and its branches. This results in hypertension in the upper limbs.

2- Pressure and flow decreases in the descending aorta and its branches producing

ischemia in the abdominal organs and the limbs.

3- Ischemia of the kidneys results in release of renin which raises the blood pressure.

4- Hypertension results in left ventricular hypertrophy and it severe results in left

ventricular failure.

5- Anastomosis form between the branches of the aorta proximal and distal to the

obstruction. The most important of these connect the subclavian artery through its

internal mammary branch to the intercostal arteries which arise from descending aorta.

The intercostal arteries become enlarged and tortuous and erode the lower border of the

ribs causing rib notching. Appreciable anastomosis develops gradually by time. That is

why rib notching is not detectable except after the age of 10. Other anastomosis

develops around the scapula and another connects the superior and inferior epigastric

arteries.

CLINICAL FEATURES:

1- In the majority of cases there are no symptoms and the essential diagnostic feature of

coarctation is that the blood pressure in the upper limbs exceeds that in the lower limbs.

2- The pulse in the upper limbs, neck and suprasternal notch is strong. Pulse in the

lower limbs is weak and delayed or absent.

33

3- Hypertension in the upper half of the body may produce headache, epistaxis while

ischemia of the lower half may produce thin, underdeveloped lower limbs and

claudication in the calf.

4- Visible and palpable pulsations of dilated collateral may be felt in the intercostal

areas.

5- A late systolic murmur may be heard on the back due to blood flow in the collaterals.

The murmur is sometimes continuous.

6- The cardiac signs are nonspecific and include: left ventricular hypertrophy, an

ejection systolic murmur heard at the aortic area.

X-RAY PICTURE:

1- Signs of left ventricular hypertrophy.

2- Rib notching is the most specific sign.

ELECTROCARDIOGRAPHIC SIGNS: Left ventricular hypertrophy and strain.

COMPLICATIONS:

1- Hypertension in the upper half of the body may result in: cerebral or subarachnoid

hemorrhage, left ventricular failure, dissection of the aorta.

2- Infective endocarditis.

TREATMENT: surgical resection of the narrowed segment is indicated in moderate and

severe cases preferably during childhood. Balloon dilation with expandable stent is a

feasible method of treatment. All patients must have prophylaxis against endocarditis.

PULMONARY STENOSIS

Pulmonary stenosis may be caused by: Congenital fusion of pulmonary valve cusps

(congenital valvular pulmonary stenosis).

EFFECTS:

1- In both valvular and infundibular stenosis the pressure in the right ventricle rises,

this causes hypertrophy of the right ventricle (pressure over-load). Consequently the

right atrium hypertrophies. When the stenosis is severe the output of the right ventricle

and the cardiac output are reduced. The pulmonary blood flow is reduced, i.e.

pulmonary oligemia.

CLINICAL FEATURES:

34

1. Mild cases are as asymptomatic, in severe cases low cardiac output occurs and

results in fatigability, syncope on effort, small volume pulse, cold extremities, etc.

2. An ejection systolic murmur is caused by passage of blood through the stenosed

valve. It is best heard over the pulmonary area. It may be preceded by an ejection click.

3. The pulmonary component of the second heart sound is faint and delayed due to

prolonged contraction of the right ventricle.

4. There is usually a systolic thrill over the pulmonary area.

5. Right ventricular hypertrophy produces a sustained impulse in the third and fourth

intercostal spaces just to the left of the sternum and pulsation in the epigastrium.

Forceful right atrial contraction causes a large wave in the neck veins (the a wave).

X-RAY PICTURE: 1. Pulmonary oligemia occurs in moderate to severe cases and

results in reduced pulmonary vascular markings). 2- Right ventricular enlargement is

proportional to the severity of the stenosis. Right atrial enlargement may also occur. 3.

Post-stenosis dilatation of the pulmonary artery is seen.

ECG FEATURES: Right ventricular hypertrophy.

ECHO FEATURES: Right ventricular hypertrophy, the stenosed pulmonary valve.

TREATMENT: Either percutaneous transvenous balloon dilatation (the standard

treatment, first option) or surgical removal of the valve by open-heart surgery.

Interventions In Congenital Heart Diseases (therapeutic procedures that are used in

treatment without surgery but through catheterization):

- Pulmonary stenosis balloon dilatation.

- Aortic stenosis balloon dilatation.

- Coarctation of the aorta balloon dilatation and stent insertion.

- Atrial septal defect insertion of Amplatzer occluder through catheter.

- Patent ductus arteriosus occlusion by insertion of coil.

- Other procedures.

DIAGNOSIS AND MANAGEMENT OF SYNCOPE AND HYPOTENSION

35

Syncope is a sudden and transient loss of consciousness with associated loss of

postural tone. The occurrence of syncope is 3% in men ad 3.5% in women in the

general population. As a general role, the incidence of syncope increases with age.

Hypotension: When systolic blood pressure (SBP) is less than 90 mmHg or reduction

of SBP of 30 mmHg or more from baseline.

Patients with transient episode of altered consciousness (presyncope) and those with

complete loss of consciousness (syncope) are classified into 3 broad categories: cardiac

syncope, noncardiac syncope, and syncope of undetermined etiology. Among all

patients with syncope associated with cardiac disease, sudden cardiac death is extremely

high.

Table: Causes of Syncope

Circulatory (reduced cerebral blood flow)

A. Inadequate vasoconstrictor mechanisms

1. Vasovagal (vasodepressor)

2. Postural hypotension

3. Primary autonomic insufficiency

4. Sympathectomy (pharmacologic, due to antihypertensive medications such as

methyldopa and hydralazine, or surgical )

5. Carotid sinus syncope

6. Diseases of the central and peripheral nervous system, including autonomic nerves)

B. Hypovolemia

1. Blood loss – gastrointestinal hemorrhage.

2. Addison’s disease

C. Mechanical reduction of venous return

1. Valsalva maneuver. 2. Cough; Micturition.

3. Atrial myxoma, ball valve thrombus.

D. Reduced cardiac output

1. Obstruction to left ventricular outflow: aortic stenosis, hypertrophic subaortic

stenosis.

2. Obstruction to pulmonary flow: pulmonary stenosis, primary pulmonary

hypertension, pulmonary embolism.

3. Myocardial: massive myocardial infarction with pump failure.

4. Pericardial: cardiac tamponade

E. Arrhythmias

36

1. Bradyarrhythmias

a. Atrioventricular (AV) block (second and third degree), with Stokes-Adams attacks

b. Ventricular asystole

c. Sinus bradycardia, sinoatrial block, sinus arrest, sick sinus syndrome

d. Carotid sinus syncope

a. Tachyarrhythmias: Supraventricular tachycardia. Episodic ventricular tachycardia

Other causes of disturbances of consciousness

A. Hypoglycemia

B. Hypoxia

C. Hypoventilation

D. Transient cerebral ischemic attack

E. Emotional disturbances, anxiety attack, hysterical seizures.

Noncardiac Syncope

Neurocardiogenic syncope:

The syndrome of neurocardiogenic syncope, the common faint (also referred to as

neurally mediated hypotension, vasovagal syncope, and vasodepressor syncope), is one

of the most common causes of syncope.

This disorder is due to abnormality in the neuro-cardiovascular interactions responsible

for maintaining systemic and cerebral perfusion.

Diagnostic evaluation:

Head-up tilt (HUT) is essential for the diagnosis of neurocardiogenic syncope. Here

we change the position of the patient from the horizontal to the vertical position. HUT

at an angle of 60º to 90º for a time period of 20 to 60 min is the usual protocol.

Management of syncope:

First-line therapy includes counseling the patient to avoid dehydration, prolonged

period of standing motionless, and situations known to trigger syncope. Volume

expansion, fludrocortisone may be helpful in augmenting salt retention and volume

expansion.

Alpha-Agonists: Medodrine may prevent neurocardiogenic syncope due to

vasoconstrictor effect that may reduce venous pooling.

Orthostatic Syncope (orthostatic Hypotension):

Orthostatic hypotension is a disorder in which assumption of the upright posture is

associated with a fall in blood pressure. Therapy: is based on treatment of causes.

37

Management of hypotension: 1- Treatment of the etiology. 2- Avoid dehydration. 3-

Medodrine. 4. Mineralocorticoids as Astonin H.

Cardiac Syncope

It is due to severe diminution of the cardiac output Either due to severe obstructive

lesion as tight mitral stenosis, atrial myxoma, aortic stenosis, obstructive

cardiomyopathy or due to arrhythmia whether tachy or brady. Obstructive lesions and

arrhythmias frequently coexist; indeed, one abnormality may accentuate the other.

Common disorders associated with cardiac syncope are listed in table.

Diagnostic evaluation of syncope associated with cardiac disease:

- History & physical examination

- Echocardiography & Doppler

- Standard ECG

- Holter monitor ( 24 h. ECG continuous recording )

- Electrophysiologic study.

- Cardiac catheterization.

Treatment of cardiac syncope: Obstructive Heart Disease, for patients with syncope

caused by obstructive heart disease, cardiac surgery is often the treatment of choice.

Arrhythmic syncope, detailed discussion of therapy for cardiac arrhythmias presented

earlier. Antiarrhythmic drugs, pacemakers and ablation are available tools of

management of arrhythmia.

Syncope of undetermined cause: Despite careful diagnostic evaluation, the cause of

syncope often cannot be defined.

Sudden Cardiac Death

Definition: Sudden cardiac death describes the unexpected natural death due to cardiac

cause within a short period from the onset of symptoms.

More recent definition focused on time interval of one hour from the symptoms leading

to collapse and then to death.

Incidence: SCD accounts for 300.000 to 400.000 deaths yearly in the United States.

SCD is the most common and often the first manifestation of coronary heart disease

(CHD) and is responsible for half the deaths from cardiovascular disease.

38

Sudden Cardiac Death in the young: The most common underlying pathological

conditions in people who die of SCD in the first three decades of life are myocarditis,

hypertrophic cardiomyopathy, congenital coronary artery anomalies,

atherosclerotic coronary heart disease, conduction system abnormalities (e.g. long QT),

congenital arrhythmogenic disorders, arrhythmias associated with mitral valve

prolapse and aortic dissection. About 40% of SCD in the pediatric population occur in

patients with surgically treated congenital cardiac abnormalities.

Risk factors for Sudden Cardiac Death (SCD):

1- Left ventricular hypertrophy (by ECG)

2- Cholesterol.

3- Hypertension.

4- Cigarette smoking.

5- Diabetes.

6- Alcohol.

7- Obesity.

8- History of coronary heart disease.

9- Age.

10- Positive family history of SCD.

11- Frequent PVCs (Premature ventricular contractions, unsustained ventricular

tachycardia).

Cardiac Abnormalities Associated with Sudden Cardiac Death

I. Ischemic heart disease

A) Coronary Atherosclerosis:

- Acute myocardial infarction, - Chronic ischemic cardiomyopathy

B) Anomalous origin of coronary arteries.

II. Cardiomyopathies

A. Idiopathic dilated cardiomyopathy

B. Hypertrophic cardiomyopathy

C. Hypertensive cardiomyopathy

D. Arrhythmogenic right ventricular dysplasia

III. Valvular heart disease: Aortic stenosis

IV. Inflammatory and Infiltrative myocardial disease

39

V. Congenital heart disease.

VI. Primary Electrical Abnormality.

A. Long Q-T syndrome

B. Wolf Parkinson White syndrome (WPW).

C. Idiopathic ventricular tachycardia

D. Idiopathic ventricular fibrillation

E. Brugada syndrome (right bundle block with raised ST in V1 to V3)

VII. Drug and other toxic agents

A. Proarrhythmia (Drug induced arrhythmia)

B. Cocaine and Alcohol. C. Electrolyte abnormalities

Treatment Options for Patients at Risk of Sudden Cardiac Death (SCD)

I. Pharmacologic therapy

1- Beta blockers , Angiotensin-converting enzyme inhibitors

2- Class I antiarrhythmic drugs,

3- Class III antiarrhythmic drugs: Amiodarone, sotalol

II. Device therapy

1- Automatic implantable cardioverter Defibrillator (ICD)

2- External automatic defibrillator

III. Role of surgery: Revascularization

IV. Catheter Ablation therapy.

40

CARDIAC ARRHYTHMIAS

An arrhythmia is any disturbance in the normal sequence of impulse generation and

conduction in the heart.

Anatomy of the conduction system: The conduction system of the heart consists of the

sinus node, internodal tracts, atrioventricular node (AVN), bundle of His, bundle

branches (right and left), and Purkinje fibers.

Fig: The pathways of Conduction.

General considerations: Normal cardiac impulses arise from the automatic

(pacemaking) cells of the sinus node and are conducted through the atria to the AV

junction then the His-Purkinje system to the ventricular muscle. Normally the sinus

node discharges at a rate of 60-100/min.

41

Mechanisms of arrhythmias

A- Disturbance of impulse formation: may result from either:

1- Disturbed normal automaticity:

2- Triggered activity: Hyper-excitable focus which discharges ectopic impulses.

B- Disturbance of Impulse conduction: e.g. heart block

Classification of arrhythmia:

Clinical classification:

- Rapid, regular. Sinus tachycardia, supraventricular tachycardia, atrial flutter,

ventricular tachycardia.

- Rapid, irregular. Sinus arrhythmia, multiple ectopic beats whether atrial or

ventricular, atrial fibrillation.

- Slow, regular. Sinus bradycardia, nodal rhythm, complete heart block.

- Slow, irregular. Slow atrial fibrillation.

Disturbances in Sinus Rhythm

Sinus tachycardia

Cardiac impulses arise in the sinus node at a rate more than 100/min.

Etiology:

A- Physiological: Infancy, childhood, exercise and excitement.

B- Pharmacological: Sympathomimetic drugs such as epinephrine and isoproterenol.

Parasympatholytic drugs such as atropine. Thyroid hormones, nicotine, caffeine,

alcohol.

C- Pathological: Fever, hypotension, heart failure, pulmonary embolism, hyperkinetic

circulatory states as anemia.

Treatment: 1- Treatment of the underlying etiology. 2- Propranolol.

Sinus Bradycardia

Cardiac impulses arise in the sinus node at a rate less than 60/min.

Etiology:

A- Physiologic: Athletes, sleep, and carotid sinus compression.

B- Pharmacologic: Digitalis, propranolol, verapamil and diltiazem.

C- Pathologic: Convalescence from infections, hypothyroidism, obstructive jaundice,

rapid rise of the intracranial tension, hypothermia and myocardial infarction

(particularly inferior wall infarction).

42

Treatment:

1- Treatment of the underlying etiology is usually all that is needed.

2- If the patient is hemodynamically compromised, Atropine 0.6 – 1.0 mg IV may be

given and repeated every 3 hours (maximum 2.5 mg in two hours).

SICK SINUS SYNDROME: This term is applied to a syndrome encompassing a

number of sinus nodal abnormalities that include: 1- persistent spontaneous sinus

bradycardia not caused by drugs, and inappropriate for the physiological circumstance,

2- apparent sinus arrest or exit block, 3- combinations of SA and AV conduction

disturbances, or 4- alternation of paroxysms of rapid and slow atrial and ventricular

rates (bradycardia-tachycardia syndrome).

FIG. Normal intracardiac electrograms.

PREMATURE BEATS (EXTRASYSTOLES)

These are cardiac impulses of ectopic origin occurring earlier than expected in the

prevailing rhythm. The ectopic focus may be: 1- Atrial resulting in atrial premature

beat. 2- AV junctional (arising from bundle of His) resulting in AV junctional

premature beat. 3- Ventricular resulting in ventricular premature beat.

43

Etiology:

A- Physiological: Emotions, exercise and fatigue.

B- Pharmacological: Coffee, alcohol, tobacco, catecholamines, digitalis and hypoxia.

C- Pathological: Various infections, digestive disturbances, hyperthyroidism and all

cardiovascular disorders.

SUPRAVENTRICULAR TACHYARRHYTHMIAS

All tachyarrhythmias that originate above the bifurcation of the bundle of His are

classified as supraventricular arrhythmias (SVT). The atrial rate must be 100 or more

beats per minute for a diagnosis.

SVTs may be separated into three groups based on duration: brief paroxysms,

persistent, and chronic (permanent).

Arrhythmias that are paroxysmal in onset and offset (e.g., paroxysmal SVT due to AV

nodal reentry or WPW syndrome, paroxysmal atrial fibrillation, paroxysmal atrial

flutter) tend to be recurrent and of short duration; i.e., seconds to hours.

Persistent tachycardias (e.g., sinus tachycardia, ectopic atrial tachycardia

(nonparoxysmal), multifocal atrial tachycardia, longer episodes of PSVT or atrial flutter

or fibrillation) may persist for days or weeks.

Longstanding or chronic SVTs (chronic atrial flutter, chronic atrial fibrillation) do not

revert if untreated, often fail to revert even with attempted treatment, and if reverted will

frequently recur despite therapy.

Supraventricular tachyarrhythmias include; atrial tachycardia, atrial flutter, atrial

fibrillation and AV tachycardias.

ATRIAL FLUTTER

Atrial flutter is a rapid regular atrial tachyarrhythmia that is less common than the

PSVTs or atrial fibrillation. It is observed in the presence of underlying atrial

abnormalities such as those secondary to mitral valve disease, congenital heart disease,

cardiomyopathies, and, less frequently, coronary artery disease.

44

Untreated atrial flutter usually has atrial rates between 240 and 340 per minute,

commonly very close to 300 per minute. The ventricular rate in atrial flutter is usually a

defined fraction of the atrial rate 2: 1 conduction generating a ventricular rate of 150 per

minute and 4:1 conduction at 75 per minute.

Clinically, atrial flutter may occur in brief, persistent, or chronic forms, and therapeutic

approaches are influenced by the clinical pattern.

Electrocardiographic Features

Atrial flutter generates a defined pattern of atrial activity in the ECG. Classically, a saw-

tooth pattern is identifiable in leads II, 111, and aVF. A narrow QRS complex

tachycardia at a rate of 150 per minute should always lead to the consideration of atrial

flutter. Carotid sinus massage will not interrupt atrial flutter but nonetheless may be

very helpful in distinguishing flutter from other mechanisms, impairment of AV nodal

conduction causes an abrupt change from a rate of 150 per minute to 75 per minute or

less.

Management of atrial flutter: - If the patient is hemodynamically compromised, D.C.

cardioversion using low energies (around 50 joules) should be instituted.

- Administering a Class IA antiarrhythmic agent (i.e., quinidine, procainamide, or

disopyramide). IC antiarrhythmic drugs, flecainide and propafenone, are as effective, if

not more effective than Class IA drugs. Class III antiarrhythmic agents (i.e.,

amiodarone, sotalol) may also be quite effective. In general, atrial flutter is difficult to

suppress completely with drug therapy. - The ventricular rate is slowed by digitalis

and/or propranolol or verapamil before antiarrhythmics are instituted to avoid very rapid

rates associated with drug induced 1:1 AV conduction.

- At present, catheter ablation provides the best hope of cure.

FIG. A 12-lead ECG of a typical case of type 1 atrial flutter.

45

FIG. A 12-lead ECG of a typical case of type 1 atrial flutter.

FIG: Atrial flutter with AV block varying between 2: 1 and 4: 1.

AV Nodal Reentrant Tachycardia

Electrocardiographic Features: Paroxysmal SVT due to AV nodal reentry is

characterized by an abrupt onset and termination and usually has a narrow QRS

complex without clearly discernable P waves. The rate is commonly in the range of 150

to 250 per minute (commonly 180 to 200 bpm in adults) and with a regular rhythm.

Management of PSVT Due to AV Nodal Reentry

The acute attack: Vagal maneuvers serve as the first line of therapy. Simple procedures

to terminate paroxysmal SVT

- Carotid sinus massage: If effective the rhythm is abruptly stopped; occasionally only

moderate slowing occurs

- Cold water splash on face.

- Performance of Valsalva's maneuver (often effective).

46

Intravenous adenosine, Ca channel blockers (verapamil), digoxin or B-blockers are the

choices for managing the acute episodes.

Adenosine, 6 mg given intravenously, followed by one or two 6-mg boluses if

necessary, is effective and safe for acute treatment.

A 5-mg bolus of verapamil (isoptin) , followed by one or two additional 5-mg boluses

10 min apart if the initial dose does not convert the arrhythmia, has been an effective

regimen in up to 90 percent of patients with PSVT due to AV node reentry.

Intravenous digoxin, 0.5 mg infused over 10 min and repeated if necessary may convert

the arrhythmia.

DC cardioversion: Consider DC cardioversion before digitalis or a beta blocker is

administered.

Radiofrequency catheter ablation: Should be considered early in the management of

patients with symptomatic recurrent episodes of AV node reentry.

AV Reentrant Tachycardia

PSVT Due to Accessory Pathways (The Wolff-Parkinson-White Syndrome)

47

ELECTROCARDIOGRAPHIC RECOGNITION: Three basic features in the ECG of

patients with the usual form of WPW syndrome caused by an AV connection:

(1) Short P-R interval less than 120 msec during sinus rhythm;

(2) QRS complex duration exceeding 120 msec

(3) Slowly rising onset of the QRS in some leads (delta wave).

The most common tachycardia is characterized by a normal QRS, by ventricular rates of

150 to 250 beats/min and by sudden onset and termination.

Termination of the acute episode should be approached as for AV nodal reentry. In

many patients, particularly those with a very rapid ventricular response, electrical

cardioversion is the initial treatment of choice.

The Wolff-Parkinson-White Syndrome

ELECTRICAL ABLATION: Ablation of the accessory pathway is advisable for

patients with frequent symptomatic arrhythmias that are not fully controlled by drugs.

Atrial Fibrillation

48

The arrhythmia is characterized by multiple electric foci in the atrium causing

disorganized atrial depolarizations without effective atrial contraction. Electrical

activity of the atrium can be detected on ECG as small irregular baseline undulations,

called f waves, at a rate of 350 to 600 beats/min. The ventricular response is grossly

irregular (irregular irregularity) and is usually between 100 and 160 beats/min.

It is a common arrhythmia, occurring in 5 – 10 % of individuals over 65 years of age. It

also occurs in a paroxysmal form in younger patients.

The hemodynamic consequences of atrial fibrillation are due to two factors:

(1) The loss of atrial systole may impair ventricular function in the noncompliant

ventricle [e.g., aortic stenosis, left ventricular hypertrophy (LVH)] or the dilated

ventricle with systolic dysfunction, and

(2) A rapid ventricular rate will encroach upon the diastolic filling period of the left

ventricle and the diastolic flow time of the coronary arteries.

(3) The risk of embolism and stroke is a long-term concern of special importance. Atrial

fibrillation may occur in paroxysmal, persistent, and chronic patterns.

Clinical expression of atrial fibrillation:

Definition Duration

- Paroxysmal Minutes/hours

- Short-lasting Seconds --<1 hour

- Long-lasting >1 hour; -- < 48 hours

- Persistent Two days -- weeks

- Permanent (Chronic) Months / years

Table: Causes of atrial fibrillation

With structural heart disease

- Rheumatic mitral valve disease

- Ischemic heart disease

- Hypertension

- Cardiomyopathy: Dilated, Hypertrophic

- Atrial septal defect, - Constrictive pericarditis, Myocarditis

Without structural heart disease

49

- Alcohol. Thyrotoxicosis

- Acute pericarditis. Pulmonary embolism

- Sick sinus syndrome, Lone atrial fibrillation

Atrial Fibrillation

Clinical picture

Onset and offset are sudden in paroxysmal cases.

Symptoms: Paroxysmal AF produces symptoms similar to those of supraventricular

tachycardia. Established AF (persisting for more than two weeks) is better tolerated than

the paroxysmal variety. Congestive heart failure may occur if the attack is prolonged,

the ventricular rate is very rapid, or the underlying heart disease is severe.

Signs:

1- Arterial pulse:

a- Rate is usually 100-150/min. Slower rates may be encountered in old age and in

patients receiving digitalis or beta-blockers.

50

b- Rhythm shows marked (irregular) irregularity. c- Force is irregular. d- Pulsus deficit:

The radial pulse rate is less than the cardiac rate counted at the apex beat. This is due to

inability of the week ventricular contractions following short diastolic periods to open

the aortic valve.

2- Neck veins show systolic expansion; no “a” waves are seen.

3- Auscultation reveals varying intensity of S1.

4- Exercise increases the pulse irregularity and deficit.

Electrocardiogram: The P waves are replaced by irregular f waves. The QRS

complexes are normal in shape but irregularly spaced.

Complications: 1- Atrial thrombosis due to stagnation of blood in the fibrillating atria.

The formed thrombi may embolize in the systemic and pulmonary circulations. 2- Heart

failure due to loss of the atrial contribution to contractility and the cardiac output.

Atrial fibrillation (AF) progressed to ventricular fibrillation (VF)

Treatment of Atrial Fibrillation

Pharmacologic Management of Patients with Recurrent Persistent or Permanent AF:

- Recurrent Persistent AF:

A) Minimal or no symptoms: Anticoagulation and rate control as needed.

B) Disabling symptoms in AF:

1- Anticoagulation and rate control

2- Antiarrhythmic drug therapy

51

3- Electrical cardioversion as needed, continue anticoagulation as needed and therapy

to maintain sinus rhythm

- Permanent AF: Anticoagulation and rate control as needed.

AF management

Antiarrhythmic Drug Therapy to Maintain Sinus Rhythm in Patients with

Recurrent Paroxysmal or Persistent AF:

A) No or minimal heart disease:

1- Flecainide, propafenone, sotalol

2- Amiodarone, dronedarone, dofetilide, Disopyramide, procainamide, quinidine

3- Consider non-pharmacological options (ablation).

B) Heart disease present:

a- Heart failure: Amiodarone, dofetilide

1- Coronary artery disease: Sotalol, Amiodarone, dofetilide

2- Dronedarone is allowed only in HF class I or II with precaution.

3- Vernakalant I.V. for aute AF of less than 7 days duration, with many precautions

and contraindications.

C) Hypertension: With

1- With LVH (septum greater than or equal to 1.4 cm): Amiodarone

2- Without this degree of LVH: - Flecainide, propafenone.

52

Drugs for Pharmacologic Cardioversion of AF (Rhythm

control)

Drug Route of Admin. And Dosage

Amiodarone Oral: 1.2 to 1.8 g /day then 200 to 400 mg /d maintenance.

IV: 1.2 g /d IV continuous or in divided doses, then 200 to 400

mg /d maintenance

Dofetilide Oral: Creatinine clearance > 60 ml/min: 500 mcg BID

Flecainide Oral 200 to 300 mg

IV: 1.5 to 3 mg /kg over 10 to 20 min

Propafenone Oral: 450 to 600 mg

IV: 1.5 to 2 mg per kg over 10 to 20 min

Orally Administered Pharmacological Agents for Heart

Rate Control in Patients with AF

Drug Maintenance dose

Digoxin 0.125 to 0.375 mg daily

Metoprolol* 25 to 100 BID

Propranolol 80 to 360 mg daily in divided doses

Verapamil 120 to 360 mg daily in divided doses

Diltiazem 120 to 360 mg daily in divided doses

Anticoagulation of Patients with Atrial Fibrillation: Indications

Rheumatic mitral valve disease with recurrent or chronic atrial fibrillation.

Dilated cardiomyopathy with recurrent persistent or chronic atrial fibrillation.

Prosthetic valves.

Prior to (>3 weeks) elective cardioversion of persistent or chronic atrial fibrillation, and

also for 3 weeks after cardioversion (because of atrial stunning).

53

Coronary heart disease or hypertensive heart disease with recurrent persistent or chronic

atrial fibrillation

Atrial fibrillation in thyrotoxicosis (while awaiting long-term control; elective

cardioversion)

Chronic or persistent lone atrial fibrillation, age >60 years

Controversial; or limited data

Coronary or hypertensive heart disease with normal left atrial size, after first episode of

paroxysmal atrial fibrillation

Elective cardioversion of atrial fibrillation of short duration (2-3 days) with normal left

atrial size

Chronic or persistent lone atrial fibrillation, age <60 years

Not indicated

Lone atrial fibrillation, short paroxysms (<48 h)

Most clinical settings associated with short paroxysms (minutes to hours)

Relative contraindications

Difficulty controlling prothrombin times. Dementia

Malignancies, especially associated with bleeding risk

Prior major bleeding events. Uncontrolled hypertension

Treatment of Cardiac Arrhythmias with Catheter Ablative Techniques

Radiofrequency ablation destroys tissue by controlled heat production. Catheter ablation

is used to treat patients with four major tachyarrhythmias: atrial flutter/fibrillation, AV

nodal reentry, accessory pathways and ventricular tachycardia.

VENTRICULAR TACHYCARDIA

Specific Forms of Ventricular Tachycardia

Duration: Salvo (3-5 impulses)

Nonsustained VT: (6 impulses, up to 29 seconds)

Sustained VT: (>30 seconds)

The electrocardiographic diagnosis of ventricular tachycardia is suggested by the

occurrence of a series of three or more bizarrely shaped premature ventricular

complexes whose duration exceeds 120 msec, with the ST-T pointing opposite to the

major QRS deflection.

54

The rates range from 70 to 250 beats/min. Ventricular tachycardia can be sustained,

defined arbitrarily as lasting longer than 30 sec or requiring termination because of

hemodynamic collapse, or nonsustained (Unsustained), when it stops spontaneously in

less than 30 sec.

Ventricular tachycardia (Wide QRS tachycardia)

Management: Intravenous lidocaine or amiodarone, followed by an infusion of the

successful drug. If the arrhythmia does not respond to medical therapy, electrical DC

cardioversion can be employed.

Ventricular tachycardia in a patient with right ventricular dysplasia.

55

CONGENITAL LONG QT INTERVAL SYNDROME

The normal QT interval is .43 sec. The congenital long QT interval syndrome, which is

present persistently from childhood, is characterized by the presence of long QT

intervals on the standard 12-lead ECG. The affected patients are prone to episodes of

torsade de pointes (ventricular tachycardia with special polymorphic

configuration), which may cause transient light-headedness or syncope or sudden

cardiac death. Arrhythmias may occur at rest, under emotional stress, or with exercise.

ACQUIRED LONG QT INTERVAL SYNDROME

Causes: Antiarrhythmic drugs as quinidine. There is a growing list of other drugs that

may prolong the QT interval, and establish susceptibility to torsade de pointes. These

include the phenothiazines, certain antibiotics, pentamidine, cocaine, and terfenadine,

among others.

Management of Congenital Long QT Interval Syndrome: Long-term therapy includes

B-adrenergic blockade. Placement of an ICD should be considered for patients with

resistant arrhythmias.

CARDIOVERSION AND DEFIBRILLATION

Differences between cardioversion and defibrillation:

Cardioversion Defibrillation

Elective Emergency

Synchronized Non-synchronized

For AF, A. flutter, SVT, VT For V. fibrillation

50, 100, 150, 200 Joules Start by 200 Joules

Need sedative first Patient is unconscious

VENTRICULAR FLUTTER AND FIBRILLATION

MANAGEMENT: Immediate nonsynchronized DC electrical shock using 200 to 360

joules is mandatory treatment for ventricular fibrillation. Cardiopulmonary resuscitation

is employed only until defibrillation equipment is ready. Time should not be wasted

with cardiopulmonary resuscitation maneuvers if electrical defibrillation can be done

promptly.

56

The Implantable Cardioverter Defibrillator (ICD)

Apparatus (pacemaker) that gives electric shock if the patient develops ventricular

fibrillation. The pacemaker is inserted in the sub-pectoral area.

ICD indications

A. Cardiac arrest not due to acute ischemia or infarction or reversible causes.

B. Documented sustained VT with hemodynamic compromise.

C. Syncope of unknown origin in structural heart disease patients with inducible

sustained VT.

D. Cardiomyopathy ischemic or non-ischemic with ejection fraction 30% or lower

(MADIT II results).

AV HEART BLOCK

Heart block is a disturbance of impulse conduction that can be permanent or transient,

owing to anatomical or functional impairment.

The conduction disturbance is classified by severity in three categories.

During first degree heart block, conduction time is prolonged but all impulses are

conducted (P-R interval > 0.2 sec.).

Second degree heart block occurs in three forms:

Mobitz type I (Wenckebach) and type II; and persistent 2:1 block.

Mobitz Type I heart block is characterized by a progressive lengthening of the

conduction time until an impulse is not conducted (Fig).

Mobitz Type II heart block denotes occasional (Mobitz II) or repetitive sudden block of

conduction of an impulse without prior measurable lengthening of conduction time.

When no impulses are conducted, complete or third degree block is present.

Mobitz type I (Wenckebach) block

57

Mobitz Type II second degree heart block

COMPLETE AV BLOCK

ELECTROCARDIOGRAPHIC RECOGNITION: Complete AV block occurs when no

atrial activity conducts to the ventricles and therefore the atria and ventricles are

controlled by independent pacemakers. Thus, complete AV block is one type of

complete AV dissociation.

The ventricular focus is usually located just below the region of block, which can be

above or below the His bundle bifurcation. The ventricular rate of acquired complete

heart block is less than 40 beats/min but may be faster in congenital complete AV

block.

CLINICAL FEATURES. Block proximal to the His bundle generally exhibits normal

QRS complexes and rates of 40-60 beats/min because the escape focus that controls the

ventricle arises in or near the His bundle.

Causes: Surgery, electrolyte disturbances, endocarditis, tumors, Chagas' disease,

rheumatoid nodules, calcific aortic stenosis, myxedema, polymyositis, infiltrative

processes (such as amyloid, sarcoid, or scleroderma). In the adult, drug toxicity,

coronary disease, and degenerative processes appear to be the most common causes of

AV heart block.

COMPLETE AV BLOCK

MANAGEMENT: Temporary or permanent pacemaker insertion is indicated in patients

with symptomatic bradyarrhythmias. Vagolytic agents such as atropine (novatropine 15

drops every 8 hours) are useful, while catecholamines such as isoproterenol (Allupent

syrup 5 ml every 8 hours) can be used transiently to treat patients who have heart block.

The use of transcutaneous pacing is preferable.

58

ELECTROPHYSIOLOGIC STUDY

EP study is an invasive procedure in which intracardiac electrode catheters are used to

evaluate cardiac arrhythmias and to select various therapeutic options.

Indications of EPS:

Diagnostic:

Aborted SCD (sudden cardiac death). - Syncope of undetermined cause.

Recurrent WCT (wide complex tachycardia). - Ventricular tachycardia.

Recurrent tachycardia with WPW syndrome.

Symptomatic refractory NCT (narrow complex tachycardia).

Therapeutic:

Catheter ablation for AVNRT (AV nodal reentrant tachycardia), WPW (Wolff

Parkinson White syndrome), VT (Ventricular Tachycardia), Atrial fibrillation.

Acute termination of hemodynamically unstable tachycardias.

CARDIAC PACEMAKERS

Cardiac pacemakers are devices either implanted permanently or inserted temporarily,

consisting of a pulse generator and an electrode catheter that is placed transvenously

into the right ventricle and/or atrium. Small electrical impulses, generated by the pulse

generator and delivered via the electrode catheter depolarize the heart. Pacemakers are

widely used for treating bradyarrhythmias but can also be useful for treatment of some

tachyarrhythmias.

Temporary pacing is indicated for symptomatic second or third degree heart block

caused by transient drug intoxication or electrolyte imbalance in the setting of an acute

MI, CHB, or Mobitz II second degree AV Block. Symptomatic sinus bradycardia, AF

with a slow ventricular response.

Indications for permanent pacemaker implantation:

Symptomatic bradycardia, due to either sinus node dysfunction or AV nodal block, in

absence of a reversible cause, constitutes a class I indications for permanent pacing.

Asymptomatic conditions that are also considered class I indications for permanent

pacing include:

1- 3rd degree AV Block .

59

2- Persistent advanced 2nd degree or 3rd degree AVB after acute MI with

demonstrated block in His-Purkinje system (BBB).

3- Chronic bifascicular or trifascicular block with intermittent type II second or third

degree AV Block.

Pacing modalities: a four-letter alphabetic code is used to identify pacing modalities.

The first initial defines the chamber that is paced (V: ventricle, A: atrium, D: dual

chamber). The second identifies the chamber that is sensed (V, A, D), the third

indicates the response to sensed event (I: inhibited, T: triggered, D: dual function), and

the fourth when present, denotes, R: rate responsive node. VVI & DDD modes are used

most commonly. VVI units pace and sense ventricle and a sensed (native) event

inhibits the ventricular stimulus. DDD units, pace and sense both chambers, events

sensed in the atrium inhibit the atrial stimulus and trigger a ventricular response after

an appropriate interval, where as ventricle-sensed events inhibit ventricular and atrial

outputs.

Antiarrhythmic Drugs

Class Mode of

Action

Drugs Indication Dose Side Effects

Class

IA

Reduces

rate of

entry of

sodium

into the

cell

Quinidine

(Quinidine)

For

supraventricular

and ventricular

arrhythmias

including

conversion of AF or

A flutter, SVT, VT

600 – 1000

mg/day

Prolongation of QT

interval, risk of

Torsade de pointes.

Quinidine syncope,

quinidine induced

sudden death.

Diarrhea, vomiting

Procainamide

(Pronestyl)

Is effective

against

supraventricular

and ventricular

arrhythmias

2-6

mg/min

IV. 350-

1000 mg q

6 h PO

SLE like

syndrome,

prolonged QT,

nausea, rash,

myalgia,

Disopyramid

e (Norpace)

Is effective

against

supraventricular

and ventricular

arrhythmias

100-400

mg q 8 h

Worsening of

heart failure,

anticholinergic

actions as urine

retention. Avoid

in pts with

60

glaucoma

Class

IB

Lidocaine

(Zylocain)

Ventricular

arrhythmias only

1-4 mg/min

IV (50-150

mg IV

loading

dose)

Confusion,

convulsions

Mexiletine

(Mexitil)

Ventricular

arrhythmias only

150-300

mg q 6-8 h

Confusion,

tremor,

bradycardia,

hypotension

Class

IC

Flecainide

(Tambocor)

Is very effective

for ventricular

and

supraventricular

tachycardias

100-200

mg q 12 h

PO

Aggravation of

arrhythmia

(proarrhythmia),

negative inotropic

effect, depression

of sinus node

Propafenone

(Rytmonorm)

Has a rule in

treatment of many

types of

arrhythmias

including

supraventricular

arrhythmias

150-300 mg

q 8-12 h

Negative inotropic

effect

Class

II

Beta

adrenergi

c

blockers

e.g.

Propranolol

(Inderal),

Atenolol,

Bisoprolol,

Carvedilol

For premature

beats atrial and

ventricular, for

torsade de

pointes,

10-200 mg

q 8 h PO

Bradycardia,

hypotension, heart

failure, intermittent

claudication,

worsening of

asthma, impotence

Class

III

Prolong

action

potential

duration

Amiodarone

(Cordarone)

Life-threatening

ventricular

arrhythmias,

conversion and

slowing of atrial

fibrillation,

AVNRT,

tachycardias

associated with

WPWs

200-400

mg q 6-8 h

Corneal deposits,

photosensitivity,

skin pigmentation,

thyroid

disturbances (hypo

& hyperfunction),

alveolitis, liver

enzyme elevation

Sotalol

(Betacor)

Effective in

supraventricular

80-160 mg

x 2-3 PO

Torsade de

pointes,

61

and ventricular

arrhythmias

bronchospasm in

asthmatic patients

Class

IV

Calcium

antagonis

ts

Verapamil

(Isoptin)

Diltiazem

Slow the

ventricular rate in

AF or flutter, treat

and prevent

AVNRT

0.1 Mg/kg

IV 40-160

mg q 6-8 h

PO

60-120 mg

q 6-8 h PO

Constipation,

edema of LL,

negative inotropic

effect

Unclas

sified

Activates

K+

channels

Adenosine

(Adenocore)

Is very effective

for the acute

conversion of

paroxysmal SVT

6-18 mg

IV rapidly

Contraindicated

in sick sinus s., or

2nd

or 3rd˚

heart

block. Antidote is

theophylline

Enhances

central

and

periphera

l vagal

tone

Digoxin

(Lanoxin)

Slow ventricular

rate in AF, flutter

0.5 – 1 mg

IV or

0.125 –

0.25 mg /d

PO

Bradycardias and

tachycardias

(atrial, junctional,

vent.

tachycardia),

nausea, vomiting

Note: there are new two important antiarrhythmic drugs: Dronedarone (Multaq), and

Vernakalant.