1

Cardiac Arrhythmias

Co-assistenten 2014-2015

Dr. L. Al tmimi

Department of anaesthesia

University Hospitals Leuven

2

Cardiac Arrhythmias

The normal ECG

• Regular narrow-complex rhythm

• Rate 60-100 bpm

• Each QRS complex is proceeded by a P wave

• P is upright in lead II & down going in lead aVR

3

Cardiac Arrhythmias

The normal ECG

• P wave: the sequential activation of the right & left atria.

• QRS complex: right & left ventricular depolarization

• ST-T wave: ventricular repolarization

• U wave: origin for this wave is not clear - but probably

represents "after depolarizations" in the ventricles

4

Cardiac Arrhythmias

The normal ECG

5

Cardiac Arrhythmias

The normal ECG

• PR interval: time from onset of atrial depolarization to onset of

ventricular depolarization.

• QRS duration: duration of ventricular muscle depolarization.

• QT interval: duration of ventricular depolarization &

repolarization

• RR interval: duration of ventricular cardiac.

• PP interval: an indicator of atrial rate.

6

Cardiac Arrhythmias

The normal ECG

• PR Interval: 0.12 - 0.20 sec

• QRS Duration: 0.06 - 0.10 sec

• QT Interval (QT < 0.40 sec at HR = 70)

• Poor Man's Guide to upper limits of QT: For HR = 70 bpm,

QT<0.40 sec; for every 10 bpm increase above 70 subtract

0.02 sec, and for every 10 bpm decrease below 70 add 0.02

sec. For example: QT < 0.38 @ 80 bpm QT < 0.42 @ 60

bpm

• Frontal Plane QRS Axis: +90° to -30° (in adult)

7

Cardiac Arrhythmias

The normal ECG

8

Cardiac Arrhythmias

The Sinoatrial node (SA node)

• Is the primary pacemaker of the heart

• These cells lies on the wall of the right atrium near superior

vena cave entrance

9

Cardiac Arrhythmias

Other cells exhibit automaticity are found in

• Along the sulcusterminalis

• In the coronary sinus ostium

• Within the AV junction

• In purkinje system

10

Cardiac Arrhythmias

The atrioventricular node (AV node)

• Specialized tissue lies between the atria and the ventricles

near the opening of coronary sinus.

• Conduct impulse from atria to ventricles.

11

Cardiac Arrhythmias

12

Cardiac Arrhythmias

Mechanism of arrhythmia

• Abnormal automaticity

• Abnormal cardiac conduction

• Or both

13

Cardiac Arrhythmias

Causes of arrhythmia in operation room

are not always possible to determine because of :

• Physiologic imbalance

• Effects of multiple drugs

• Underlying myocardial disease

14

Cardiac Arrhythmias

Mechanism of arrhythmia

15

Cardiac Arrhythmias

Causes or risk factors of abnormal rhythm

• Ischemia

• Hypoxia

• Myocardial injury

• Sever hypothermia

• Excessive catecholamine exposure

• Acute electrolytes imbalance

• Drug toxicity

• Endocrine disease e.g. thyroid

• Others

16

Cardiac Arrhythmias

Sinus rhythms

• Sinus bradycardia

• Sinus tachycardia

• Sinus arrhythmia

17

Cardiac Arrhythmias

Sinus bradycardia

• pulse : <60/min; rhythm: regular

• P wave: normal, QRS : normal

• If the HR<40 mostly not good tolerated

• Treatment:

• according to the causes

• Atropine, Isoprenaline, P.M.

18

Cardiac Arrhythmias

Sinus bradycardia

19

Cardiac Arrhythmias

Causes of bradycardia

• medication e.g. neostigmin, myoplegin , etc.

• diseases e.g. hypothyroidism, after MI

• hypothermia & hypoxia

• halothane or gas anaesthesia in children

• vagal stimuli

• increased intracranial pressure

• others

20

Cardiac Arrhythmias

Sinus tachycardia

• Heart rate >100 to 180/min

• Rhythm is regular

• P wave is normal

• QRS is also : normal

• Treatment depends on the causes

• Beta blocker

21

Cardiac Arrhythmias

Causes of sinus tachycardia

• light anaesthesia, hypovolemia

• pain, anxiety

• hyperthyroidism

• medication e.g. atropine

• fever & anaemia

• etc.

22

Cardiac Arrhythmias

Sinus arrhythmia

• Normal increase in HR occurs during inspiration, more seen

in children

• Rhythm is irregular

• Normal QRS after each wave

• No treatment is required

23

Cardiac Arrhythmias

Atrial rhythms

• Premature atrial complexes

• Atrial flutter

• Atrial fibrillation

• Supraventricular tachycardia & nodal rhythm

• Wolff-Parkinson-White (WPW)

24

Cardiac Arrhythmias

Premature atrial complexes

• Occur as single or repetitive events and have unifocal or

multifocal origins.

• The ectopic P wave is often hidden in the ST-T wave of the

preceding beat.

25

Cardiac Arrhythmias

Atrial flutter

• Atrial rate between 250-350 bpm

• A saw-tooth appearance (F waves) is in leads II, III, aVF &V1.

• Variable degrees of AV block is

26

Cardiac Arrhythmias

Atrial flutter

• Usually results from a re-entrant circuit located totally within

the atrial wall.

• It is generally associated with heart disease - e.g. rheumatic

heart disease (with mitral stenosis).

• Hemodynamic compromise may warrant electrical

cardioversion.

27

Cardiac Arrhythmias

Atrial flutter treatment

• Digoxine

• Synchronal defibrillation

• Beta-blocker

• Verapamil

• Amiodarone

28

Cardiac Arrhythmias

Atrial fibrillation (AF)

• Most common arrhythmia; risk increases with age.

• Irregular fibrillating atrial waves at a rate of 300-600 bpm,

best seen in leads II, III, aVF &V1.

• Absence of P waves

• Fibrillation is may caused by numerous microentry circuits

within the atrial muscle.

• Ventricular rate is irregularly irregular with AV block

29

Cardiac Arrhythmias

Atrial fibrillation (AF)

30

Cardiac Arrhythmias

Clinical significance of AF

• AF is usually associated with chronic heart disease.

• Also in hyperthyroidism, pulmonary embolism & COPD

• DC may be required in the acute cases with hemodynamic

compromise.

• Anticoagulation is always necessary

31

Cardiac Arrhythmias

AF Differential diagnosis includes

• Atrial flutter with an irregular ventricular response

• Multifocal atrial tachycardia which is usually irregular

Rx:

• Digoxine

• Amiodarone

• Beta-blocker

• Verapamil

• Synchronal defibrillation

32

Cardiac Arrhythmias

Supraventricular tachycardia (SVT)

• Is a rapid rhythm of the heart in which the origin of the

electrical signal is either the atria or the AV node.

33

Cardiac Arrhythmias

Possible symptoms of SVT

• Pulse rate of 140 – 200/ min or faster.

• Palpitations & Angina may be triggered by an episode of SVT.

• Dizziness & Dyspnoea

Treatment

• Verapamil, beta blocker, or even Amiodarone

• Synchronic defibrillation in some occasion

34

Cardiac Arrhythmias

Junctional rhythm

• HR : variable, 40 tot 180/min

• Rhythm : regular

• P wave: High nodal before QRS

Mid nodal in QRS

Low nodal after QRS

• QRS : normal

35

Cardiac Arrhythmias

Junctional tachycardia

• The AV node initiates electrical activity in the heart.

• An ECG of a Junctional rhythm commonly presents with an

inverted "P" wave due AV nodal origin of electrical signal

36

Cardiac Arrhythmias

Treatment of junctional rhythm

• No treatment is usually needed unless low cardiac output

• Atropine or isoprenaline if junctional bradycardia

• Deeping of the anaesthesia

• Beta-blocker in nodal tachycardia

37

Cardiac Arrhythmias

Wolff-Parkinson-White (WPW) syndrome

• Is a congenital abnormality.

• Presence of abnormal conductive tissue between the atria

and the ventricles.

• Is often associated with supraventricular tachycardia (SVT).

38

Cardiac Arrhythmias

Wolff-Parkinson-White (WPW) syndrome

39

Cardiac Arrhythmias

Wolff-Parkinson-White (WPW) syndrome

• Presence of a short PR interval (<120 ms)

• A wide QRS complex of longer than 120 milliseconds with a

slurred onset of the QRS waveform producing a delta wave in

the early part of QRS

• Secondary ST-T wave changes

40

Cardiac Arrhythmias

Treatment of WPW

• Asymptomatic patients with the WPW shown are not treated.

Drug therapy: according to the arrhythmia associated with WPW.

Digoxine is contraindicated in WPW with AF. Amiodarone or

procainamide may help.

Electrical ablation

• Symptomatic tachyarrhythmias

• Occupations in which the development of symptoms would put

themselves or others at risk (e.g. truck drivers or airline pilots

• Selected asymptomatic patients

Surgical ablation

41

Cardiac Arrhythmias

Ventricular arrhythmias

• Ventricular extrasystole

• Ventricular tachycardia

• Ventricular fibrillation

42

Cardiac Arrhythmias

Ventricular extrasystole

• Also called premature ventricular contraction (PVC) or

ventricular premature beat (VPB)

• Is a form of irregular heart beat in which the ventricle

contracts prematurely

43

Cardiac Arrhythmias

Possible triggers for ventricular extrasystole ( PVC )

• Anxiety/Stress

• Chocolate ,Caffeine, Cocaine or other stimulant

• Calcium/magnesium imbalance

• Dehydration , Exercise, Hormonal imbalance

• Hypercapnia (CO2 poisoning)

• Hyperstimulation of the Vagus nerve

• Lack of sleep/exhaustion

44

Cardiac Arrhythmias

What is this arrhythmia?

Ventricular tachycardia

usually caused by reentry, and most commonly seen in

patients following myocardial infarction.

45

Cardiac Arrhythmias

Ventricular tachycardia

• HR : 100 tot 300/min

• Rhythm: regular

• P top : through VT

• QRS :wide complex

46

Cardiac Arrhythmias

Ventricular tachycardia

• VT can be monomorphic or polymorphic with prolong QT

interval (torsade de pointes )

47

Cardiac Arrhythmias

Ventricular tachycardia (VT) treatment

• Synchronous defibrillation

• Xylocaïne

• Bretyllium

• Amiodarone

• Beta-blocker

48

Cardiac Arrhythmias

Ventricular arrhythmias: “ Torsade de pointes” Rx:

• Withdrawal of any offending drugs and correction of

electrolyte abnormalities

• Intravenous magnesium sulfate

• Potassium repletion to 4.5 to 5 mmol/liter

• Beta blockers combined with cardiac pacing as acute therapy

for patients with TdP and sinus bradycardia

• Intravenous lidocaine

• Non-synchronous defibrillation

49

Cardiac Arrhythmias

Ventricular tachycardia

50

Cardiac Arrhythmias

Ventricular fibrillation

• Ventricular fibrillation has been described as "chaotic

asynchronous fractionated activity of the heart" (Moe et al.

1964).

• No cardiac output

• Treatment is : CPR

51

Cardiac Arrhythmias

Rhythms Produced by Conduction Block

• AV Block (relatively common)

– 1st degree AV block

– 2nd degree AV block Type 1

– 2nd degree AV block Type 2

– 3rd degree AV block

• SA Block (relatively rare)

52

Cardiac Arrhythmias

1st Degree AV Block

• Prolongation of the PR interval, which is constant.

• All P waves are conducted

53

Cardiac Arrhythmias

2nd Degree AV Block: Mobitz I or Wenckebach block

• Progressive prolongation of the PR interval until a P wave is

not conducted.

54

Cardiac Arrhythmias

2nd Degree AV Block: Mobitz II

• Constant PR interval with intermittent failure to conduct

55

Cardiac Arrhythmias

3rd Degree (Complete) AV Block

• No relationship between P waves and QRS complexes

• Relatively constant PP intervals and RR intervals

• Greater number of P waves than QRS complexes

56

Cardiac Arrhythmias

Bundle branch block

57

Cardiac Arrhythmias

Right bundle branch block

58

Cardiac Arrhythmias

Left bundle branch block

59

Cardiac Arrhythmias

Left bundle branch block

60

Cardiac Arrhythmias

Left bundle branch block

Patient with LBBB in whom a PA catheter is being placed

may need availability of transcutaneous PM because of the risk

of inducing Right BBB & thus complete heart block during

passage of the PA catheter

61

Cardiac Arrhythmias

success