Heart failure related to pregnancy,
peripartum or postpartum cardiomyopathy
Peripartum or postpartum cardiomyopathy is type of dilated cardiomyopathy, that though is a rare condition, but is the most common cardiomyopathy occurring in pregnancy and majority of these cases are diagnosed postpartum hence named so.
it is a life-threatening idiopathic cardiomyopathy presenting with left ventricular dysfunction and heart failure in last month of pregnancy or within five months after delivery. It is a rare condition that can have mild or severe symptoms. Although the left ventricle may not be dilated, the ejection fraction is reduced to 45%. It is diagnosis of exclusion and excludes the women who have left ventricular dilation early in pregnancy and the cardiac issues related to eclampsia, pre-eclampsia and other conditions.
The disease is more prevalent in Asia and Africa. In America, it is common in African Americans and it is low in Hispanics.
The exact cause is not known, however several factors are considered important in playing a role in its pathogenesis. Few of these are as under,
- viral infection caused by coxsackievirus, herpes virus, Ebstein Barr virus, parvovirus B19 and cytomegalovirus.
- Prolactin effect on heart
- Estrogen and progesterone effect
- Malnutrition causing selenium deficiency
- Familial predisposition
- Chimerism: Cells from the fetus take up residence into mother or vice versa resulting in an immune response
- Abnormal hemodynamic response
- Apoptosis and inflammation
- Placental angiogenic factors
- Patients with high parity
- Increased maternal age
- Pre-eclampsia and eclampsia
- Obesity among pregnant women
- Black women
It presents as symptoms of cardiac failure including dyspnea, dizziness, pedal edema, orthopnea and paroxysmal nocturnal dyspnea. These symptoms are usually seen in pregnancy and thus may be missed to be noticed leading to delayed diagnosis and increased mortality rate. It may also present as thromboembolism or cardiac arrhythmias. If the edema and other symptoms may develop suddenly in pregnancy, it should be taken seriously and investigated properly.
The diagnostic criteria includes:
- Cardiac failure developing in last month of pregnancy or within five months after delivery
- No cardiac disease before the last month of pregnancy
- No other identifiable cause of cardiac failure
- Ejection fraction of less than 45% or combination of an M-mode fractional shortening of less than 30% and end-diastolic dimension greater than 2.7 cm/m2
ECG shows non-specific changes like sinus tachycardia and interventricular delay. Echocardiography shows ventricular dilatation of variable consistency, left ventricular systolic dysfunction, atrial enlargement, tricuspid regurgitation and pulmonary hypertension along with the above mentioned criteria. It is most useful technique to diagnose this condition due to non-exposure of any rays in pregnant lady. Cardiac magnetic resonance imaging (MRI) can be used as complementary tool. It may be used to measure exact ejection fraction, and differentiate the underlying mechanisms. MRI with 1.5 Tesla is considered safe to be used in pregnancy but use of gadolinium for contrast studies is discouraged to use in pregnancy due to its ability to cross placenta and teratogenic effects.
Digoxin, beta-blockers and loop diuretics are used during pregnancy
ACE inhibitors and ARBs are used mainly. Their use in pregnancy is contraindicated because of their teratogenic effects. In addition, diuretics, digoxin and beta-blockers are also used.
Among all types of cardiomyopathies, peripartum cardiomyopathy has relatively better prognosis. About fifty percent cases recover. 25% cases develop complications and other patients die within the course of disease. Patients with improved ejection fraction can undergo pregnancy with regular monitoring however the risk of relapse of peripartum cardiomyopathy is there in subsequent pregnancy. A gap of 5 years after the improved ejection fraction is usually recommended. However if the ejection fraction has not improved then next pregnancy is not recommended as it is associated with increased mortality.
This is rare but life-threatening condition which has the chances of being under-diagnosed so awareness regarding it is important for the health professionals as well as in patients.
Dr Saadia Hafeez