Postpartum Cardiomyopathy

Postpartum cardiomyopathy (peripartum cardiomyopathy) is heart failure with a left ventricular ejection fraction below 45 percent, appearing in the last month of pregnancy or within 5 months of birth, with no other cause. It is linked to prolactin fragments, inflammation, oxidative stress and genetic factors, and it is uncommon, affecting roughly 1 in 1000 to 1 in 4000 births, more often in women of African descent. It matters because it causes heart failure, thromboembolism and death, but about half of women recover heart function within 6 months.

• Risk factors: age above 30 years, multiparity, multiple pregnancy, preeclampsia, hypertension, African ancestry, obesity, anaemia, prolonged tocolytic use, family history.
• Diagnosis of exclusion after other causes of heart failure.
• Recovery is less likely with ejection fraction below 30 percent at diagnosis.

Women have breathlessness on effort or lying flat, waking at night breathless, cough, fatigue, ankle swelling, palpitations and chest discomfort. They may be mistaken for normal late pregnancy or postpartum tiredness.

• Tachycardia, displaced apex beat, third heart sound, raised jugular venous pressure, basal crackles, hepatomegaly, pedal oedema.
• Low blood pressure and cool peripheries in severe cases.
• Differential diagnosis: pulmonary embolism, pneumonia, preeclampsia with pulmonary oedema, rheumatic valve disease, congenital heart disease, myocarditis, severe anaemia, thyrotoxicosis, amniotic fluid embolism, ischaemic heart disease, aortic dissection.
• Complications: cardiogenic shock, arrhythmias, left ventricular thrombus, stroke, pulmonary embolism, sudden cardiac death, chronic heart failure, relapse in later pregnancy.

The approach is echocardiography with exclusion of other causes of heart failure.

• Echocardiography: left ventricular ejection fraction below 45 percent, dilated ventricle, thrombus.
• ECG (sinus tachycardia, ST and T changes, arrhythmia); chest X-ray (cardiomegaly, pulmonary congestion); brain natriuretic peptide or NT-proBNP (raised); troponin.
• Full blood count, urea, creatinine, electrolytes, liver enzymes, thyroid function, HIV test, malaria test.
• Cardiac MRI or genetic testing where available; coronary assessment if there is chest pain and risk factors.

The principle is standard heart failure treatment that is safe in breastfeeding, anticoagulation for low ejection fraction, and bromocriptine in selected women.

• Supportive: sit upright; oxygen for saturation below 94 percent; fluid restriction to 1.5 litres daily and sodium restriction; daily weights; rest then gradual activity; treat anaemia and infection; avoid NSAIDs; breastfeeding may continue on the drugs given, with the option of stopping when the woman is severely ill.
• Pharmacological: acute congestion: furosemide 40 mg IV, repeated every 6 to 12 hours to relieve congestion, then 20 to 80 mg oral once or twice daily; hypotension or shock: dobutamine 2.5 to 10 micrograms/kg/minute IV infusion, with noradrenaline 0.05 micrograms/kg/minute IV titrated to a mean arterial pressure of 65 mmHg or more; long term: enalapril 2.5 mg oral twice daily increased every 1 to 2 weeks to 10 mg twice daily (maximum 20 mg twice daily) with potassium and creatinine checked at 1 and 2 weeks; carvedilol 3.125 mg oral twice daily increased every 2 weeks to 25 mg twice daily (50 mg twice daily above 85 kg), started when congestion is controlled; bisoprolol 1.25 mg oral once daily increased to 10 mg once daily as an alternative; spironolactone 25 mg oral once daily (potassium below 5.0 mmol/L); hydralazine 25 mg oral 8-hourly increased to 75 mg 8-hourly with isosorbide dinitrate 20 mg oral 8-hourly to 40 mg 8-hourly if ACE inhibitor is not tolerated; digoxin 0.125 mg oral once daily for atrial fibrillation or severe failure (maintain level below 1.0 nanograms/mL); anticoagulation for ejection fraction below 35 percent, atrial fibrillation or thrombus: enoxaparin 1 mg/kg subcutaneous 12-hourly, then warfarin 5 mg oral once daily to INR 2.0 to 3.0 for at least 3 months and until ejection fraction recovers; bromocriptine 2.5 mg oral twice daily for 2 weeks then 2.5 mg once daily for 6 weeks, given only with anticoagulation and stopping lactation.
• Procedures: implantable defibrillator after 6 months of treatment if ejection fraction stays at or below 35 percent; mechanical circulatory support or heart transplant in refractory cases at a referral centre.
• Special groups: breastfeeding women use enalapril, captopril, carvedilol, bisoprolol, furosemide and warfarin, avoiding sacubitril-valsartan, angiotensin receptor blockers and bromocriptine while breastfeeding; women who are not breastfeeding may use angiotensin receptor blockers (losartan 25 mg oral daily increased to 100 mg) if ACE inhibitor causes cough; a later pregnancy is high-risk if the ejection fraction has not recovered to 50 percent and is contraindicated if it stays below 30 percent, so counselling is given before pregnancy, with contraception using the levonorgestrel intrauterine system, implant or copper intrauterine device and avoidance of oestrogen.
• Red flags: breathlessness at rest, systolic blood pressure below 90 mmHg, syncope, sustained arrhythmia, ejection fraction below 25 percent, signs of embolism, rising creatinine, potassium above 5.5 mmol/L.
• Follow-up: review at 1 and 2 weeks after starting drugs; echocardiography at 3 and 6 months and then yearly; continue drugs for 12 to 24 months after recovery of ejection fraction, tapering one drug at a time with monitoring; counselling about relapse in future pregnancy.