A 38-year-old woman comes to the office due to worsening shortness of breath over the past 4 weeks. She has no chest pain or lightheadedness but has noticed some ankle puffiness. The patient can hardly do chores without having to stop to catch her breath. Medical history is unremarkable. She delivered a healthy child 2 months ago without complications. The patient is a lifetime nonsmoker and does not use alcohol. She has no family history of early heart disease or sudden cardiac death. Blood pressure is 96/60 mm Hg and pulse is 92/min and regular. The apical impulse is palpated along the anterior axillary line, and S3 is heard at the apex. There are no heart murmurs. Which of the following best describes the left ventricular changes in this patient?

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11ec160b_38ca_d150_9249_395077c52a24_MD0001_00 This patient with progressive dyspnea and peripheral edema, as well as a laterally displaced point of maximal impulse and S3 on physical examination, likely has heart failure due to peripartum cardiomyopathy. Peripartum cardiomyopathy is relatively uncommon and manifests as a dilated cardiomyopathy that occurs during the last month of pregnancy or within 5 months after delivery. The pathogenesis of the condition is poorly understood, but it may be related to impaired function of angiogenic growth factors (eg, vascular endothelial growth factor) during the peripartum period. In addition, certain individuals may have genetic mutations affecting cardiac structural proteins that predispose to the development of peripartum cardiomyopathy. In dilated cardiomyopathy, myocardial dysfunction causes an increase in left ventricular end-diastolic volume, which is compensated for by eccentric hypertrophy to maintain cardiac output. The dilation of the left ventricle allows for increased compliance to accommodate the increase in end-diastolic volume. Eventually, however, overwhelming wall stress leads to left ventricular failure with reduced ejection fraction and symptomatic heart failure. (Choice B) Normal compliance with decreased ejection fraction may occur in neurogenic shock due to impaired sympathetic stimulation resulting in decreased myocardial contractility. (Choice C) Decreased compliance with normal (or increased) ejection fraction (diastolic heart failure) is seen with left ventricular hypertrophy due to long-standing hypertension. (Choice D) Increased compliance with relatively normal ejection fraction occurs during the compensated period of eccentric hypertrophy, before overwhelming wall stress leads to systolic failure. (Choice E) Normal compliance and ejection fraction describes a heart that is without underlying pathology. Educational objective: Peripartum cardiomyopathy is a relatively uncommon cause of dilated cardiomyopathy that may be related to impaired function of angiogenic growth factors. Dilated cardiomyopathy involves compensatory eccentric hypertrophy, which increases ventricular compliance and also allows for temporary maintenance of cardiac output. Over time, overwhelming wall stress leads to left ventricular failure with reduced ejection fraction and symptomatic heart failure. __________ References: Peripartum cardiomyopathy: current state of knowledge, new developments and future directions. (http://www.ncbi.nlm.nih.gov/pubmed/24646160) Current state of knowledge on aetiology, diagnosis, management, and therapy of peripartum cardiomyopathy: a position statement from the Heart Failure Association of the European Society of Cardiology Working Group on peripartum cardiomyopathy. (http://www.ncbi.nlm.nih.gov/pubmed/20675664) Cardiac angiogenic imbalance leads to peripartum cardiomyopathy. (http://www.ncbi.nlm.nih.gov/pubmed/22596155)

A 38-Year-Old Woman Comes to the Office Due to Worsening