HEART DISEASE IN PREGNANCY

Cardiac output begins to rise in the first trimester and continues as steady increase to peak at 32 weeks gestation by 30% to 50% of pre pregnancy level.

Causes for increased cardiac output are 1. Increases in stroke volume (early pregnancy) 2. Increase in heart rate (late pregnancy) 3. Decreased peripheral resistance 4. Decreased blood viscosity

The fall in the peripheral resistance is about 20-30% at 21-24 weeks & returns to normal at term. This fall is due to

1. Due to the trophoblastic erosion of endometrial vessels, the placental bed serves as a large arteriovenous shunt causing lowered systemic vascular resistance

2. There is physiological vasodilatation which is believed to be secondary to endothelial prostacyclin and circulating progesterone.

Table 1: Normal Hemodynamic Changes During Pregnancy

Hemodynamic Parameter

Change During Normal Pregnancy

Change During Labor and Delivery

Change During Postpartum

Blood volume ↑ 40%-50% ↑ ↓ (auto diuresis)Heart rate ↑ 10-15 beats/min ↑ ↓

Cardiac output ↑ 30%-50% above baseline ↑ Additional 50% ↓

Blood pressure ↓ 10mmHg ↑ ↓

Stroke volume↑ First and second

trimesters; ↓ third trimester

↑ (300-500mL/contraction)

↓

Systemic vascular resistance ↓ ↑ ↓

The clinical features in a normal pregnancy which can mimic a cardiac disease are

1.    Dyspnea - due to hyperventilation, elevated diaphragm..2.    Pedal Edema 3.    Cardiac impulse- Diffused and shifted laterally from

elevated diaphragm.4.    Jugular veins may be distended and JVP raised.5.     Systolic ejection murmurs along the left sternal border

occur in 96% of pregnant women and are believed to be caused by increased flow across the aortic and pulmonary valves.

Table 2: Predictors of Maternal Risk for Cardiac Complications

Criteria Example Points *

Prior cardiac eventsHeart failure, transient ischemic

attack, stroke before current pregnancy

1

Prior arrhythmiaSymptomatic sustained

tachyarrhythmia or bradyarrhythmia requiring treatment

1

NYHA III or IV or cyanosis 1

Valvular and outflow tract obstruction

Aortic valve area < 1.5 cm2, mitral valve area < 2 cm2, or left ventricular outflow tract peak gradient > 30 mm Hg

1

Myocardial dysfunctionLVEF < 40%, restrictive

cardiomyopathy, or hypertrophic cardiomyopathy

1

*Maternal cardiac event rates for 0, 1, and >1 points are 5%, 27%, and 75%, respectively.LVEF, left ventricular ejection fraction; NYHA, New York Heart Association.Adapted from Siu SC, Sermer M, Colman JM, et al: Prospective multicenter study of pregnancy outcomes in women with heart disease. Circulation 2001;104:515-521.

The New York Heart Association (NYHA) Grading of functional capacity of the heart:

CLASS INo functional limitation of activity

Symptoms with extra ordinary physical work.

CLASS II Mild limitation of physical activity.  

Symptoms with ordinary physical work

CLASS IIIMarked limitation of physical activity

Symptoms with less than ordinary physical work

CLASS IV Severe limitation of physical activity

Symptoms at rest

Mortality associated with specific cardiac lesions;1. Low risk of maternal mortality (less than 1%). (a) Septal defects. (b) New York Heart Association classes I and II. (c) Patent ductus arteriosus. (d) Pulmonary / tricuspid lesions.2. Moderate risk of maternal mortality (5-15%). (a) NYHA classes III and IV mitral stenosis. (b) Aortic stenosis. (c) Marfan’s syndrome with normal aorta. (d) Uncomplicated coarctation of aorta. (e) Past history of myocardial infarction. 3. High risk of maternal mortality (25-50%). (a) Eissenmenger’s syndrome. (b) Pulmonary hypertension. (c) Marfan’s syndrome with abnormal aortic root. (d) Peripartum cardiomyopathy.

Prognosis depending on the functional status

v   In general, women in NYHA classes I and II lesions usually do well during pregnancy and have a favorable prognosis with a mortality rate of <1%. v   Patients in NYHA classes III and IV may have a mortality rate of 5% to 15%. These patients should be advised against becoming pregnant.

Physiological changes during labour and puerperium. 1.First stage. Cardiac output increases by15%. Uterine contractions increases venous return , causing increase in cardiac output & can cause reflex bradycardia.

2.Second stage Increase in intra abdominal pressure (valsalva’s) causes decrease in venous return and cardiac output. 3.Third stage Normal blood loss during delivery (around 250-350 ml). It leads to a. Decrease blood volume b. Decrease cardiac output.

• Criteria to diagnose cardiac disease during pregnancy:

1.Presence of diastolic murmurs.

2.Systolic murmurs of severe intensity (grade 3).

3.Unequivocal enlargement of heart (X-ray).

4.Presence of severe arrythmias, atrial fibrillation or flutter

Box 1: Maternal Cardiac Lesions and Risk of Cardiac Complications During Pregnancy

Low Risk

1. Atrial septal defect 2. Ventricular septal defect 3. Patent ductus arteriosus 4. Asymptomatic AS with low mean gradient (<50 mm Hg) and normal LV

function (EF > 50%) 5. AR with normal LV function and NYHA Class I or II 6. MVP (isolated or with mild or moderate MR and normal LV function) 7. MR with normal LV function and NYHA Class I or II 8. Mild or moderate MS (MVA > 1.5 cm2, mean gradient < 5 mm Hg) without

severe pulmonary hypertension 9. Mild or moderate PS 10.Repaired acyanotic congenital heart disease without residual cardiac

dysfunction

Intermediate Risk

1. Large left to right shunt 2. Coarctation of the aorta 3. Marfan syndrome with a normal aortic root 4. Moderate or severe MS 5. Mild or moderate AS 6. Severe PS

High Risk

1. Eisenmenger's syndrome 2. Severe pulmonary hypertension 3. Complex cyanotic heart disease (TOF, Ebstein's anomaly, TA, TGA, tricuspid

atresia) 4. Marfan syndrome with aortic root or valve involvement 5. Severe AS with or without symptoms 6. Aortic or mitral valve disease, or both (stenosis or regurgitation), with

moderate or severe LV dysfunction (EF < 40%) 7. NYHA Class III or IV symptoms associated with any valvular disease or with

cardiomyopathy of any cause 8. History of prior peripartum cardiomyopathy

AR, aortic regurgitation; AS, aortic stenosis; EF, ejection fraction; LV, left ventricular; MVP, mitral valve prolapse; MS, mitral stenosis; MVA, mitral valve area; NYHA, New York Heart Association; PS, pulmonary stenosis; TOF, tetralogy of Falot; TA, truncus arteriosus; TGA, transposition of the great arteries.

The indications for Termination of pregnancy. Because of high maternal risks, MTP is indicated in:

1.Eisenmenger’s syndrome.2.Marfan’s syndrome with aortic involvement3.Pulmonary hypertension.4.Coarctation of aorta with valvular involvement.

Termination should be done before 12 weeks of pregnancy.

Warfarin use in first trimester can be teratogenic and can cause fetal embryopathy(15 to 25 % ) which includes :

– Nasal cartilage hypoplasia, – Stippling of bones,– IUGR and – Brachydactyly

Risk factors for cardiac failure during pregnancy

Infection Anemia Obesity Hypertension Hyperthyroidism Multiple pregnancy

Antibiotic prophylaxis consists of

a.     2 gm ampicillin IV/plus b.     1.5mg per kg gentamicin /IV prior to the procedure , followed by one more dose of ampicillin 8 hours later.

In the event of penicillin allergy 1 gm vancomycin IV can be substituted.

Contraception1.    OC pills are not ideal as they can cause thrombo embolism. 2.    IUCD can cause infection- endocarditis.3.    Barrier contraceptives – Have high failure rates.4.    Progestin only pills or Long acting injectable progesterone are better

PILL - DesogestrelINJECTABLES a. Medroxy progesterone 150mg IM every 3 months. b. Norethisterone.200 mg every 2 months

5. Sterilization is best.

Thank You