161 THIEME Review Article Heart Failure in Pregnancy Asha Mahilmaran 1 1 Senior Interventional Consultant Cardiologist, Apollo Hospitals, Greams Lane, Chennai, Tamil Nadu, India Address for correspondence Asha Mahilmaran, MD, DNB, DM, IFESC, FCSI, FACC, 21/7A, Thandavarayan Mudali Street, Washermanpet, Chennai 600021, Tamil Nadu, India (e-mail: drashamahil@gmail.com). Cardiovascular mortality remains an important cause of maternal mortality other than the obstetric direct causes. Most cardiovascular deaths occur due to heart failure. Rheumatic heart diseases (RHD) account for more than two-thirds of heart diseases in pregnancy in low–middle income countries. Among RHD patients, 49% of patients with severe mitral stenosis, 31% with moderate mitral stenosis, and 23% with moderate to severe mitral regurgitation present with heart failure during pregnancy. In the U.K. registry, 25% of patients had heart failure due to cardiomyopathy. Congenital heart diseases such as atrial septal defect with severe pulmonary hypertension, significant atrioventricular valve regurgitation, peripartum, or dilated cardiomyopathy are less common causes of heart failure in pregnancy. Coronary artery diseases usually present as acute coronary syndromes during pregnancy, and heart failure as presentation is a rare occurrence. Preeclampsia and chronic hypertension can lead to increased vascular resistance, diastolic dysfunction, acute pulmonary edema, and acute heart failure. Two-thirds of heart diseases are diagnosed during the antepartum period itself. Preconception counseling, optimal medical therapy and avoidance of teratogens, and planning interventional or surgical therapies in patients with severe or moderate valvular diseases and congenital heart diseases will enable patients to enter the pregnancy well compensated. During pregnancy and postpartum, close surveillance and a multidisciplinary approach involving the obstetrician, cardiologist, physician, and anesthetist will lead to better maternal and fetal outcomes. Abstract Keywords ► mitral stenosis ► mitral regurgitation ► peripartum cardiomyopathy ► rheumatic heart disease Indian J Cardiovasc Dis Women-WINCARS 2018;3:161–166 DOI https://doi.org/ 10.1055/s-0038-1676911 ©2018 Women in Cardiology and Related Sciences Introduction Heart failure (HF) is a common cause of maternal mortality and morbidity. Cardiac disorders are an indirect cause of maternal mortality that contributes to about 25% of the total mortality during pregnancy. Congenital heart diseases (CHDs) are the leading cause of cardiac mortality in developed countries. Rheumatic heart diseases (RHDs) are the dominant cause of HF and cardiac death in underdeveloped and developing nations. There is an increasing prevalence of diabetes, hypertension, and obesity in younger women, and women with advanced age are getting into pregnancy due to cultural changes and assisted reproductive technologies offered to older women. Combination of these two factors is likely to result in increased cardiac events due to coronary artery disease (CAD). Physiologic Changes during Pregnancy There is an increase in cardiac output, decrease in systemic vascular resistance (SVR), and tachycardia during pregnancy, all of which can jeopardize the delicate balance in a previously compromised patient and precipitate overt HF and result in increased morbidity and mortality. Cardiac output increases by 30 to 50%. The increase starts in the first trimester and peaks toward the end of the second trimester. Both the ventricles increase in mass and volume during pregnancy. During delivery, there is an increase in heart rate (HR), blood pressure, and SVR with each uterine contraction that places enormous stress on a failing heart. Postpartum, there is a sudden increase in preload due to decompression of the inferior vena cava by the uterus and emptying of placenta into the maternal circulation. 1