Heart failure Quiz: Ace Your Exams

A 70-year-old woman comes to the emergency department due to a three week history of worsening fatigue, dyspnea on exertion, and lower extremity swelling. Her past medical history is significant for hypertension and hyperlipidemia, but notes no recent travel, sick contacts, or illnesses. She recalls one episode of nausea and diaphoresis while she was lifting boxes at home approximately one month ago, but she does not recall any chest pain or shortness of breath at that time. She is a life-time non-smoker and reports drinking one glass of wine every night with dinner. Her temperature is 37.2°C (98.9° F), pulse is 75/min, respirations are 18/min, and blood pressure is 142/82 mmHg. Physical examination shows 2+ pitting edema of the lower extremities and prominent jugular veins. An additional heart sound is heard just after S2, and faint bibasilar crackles are heard on auscultation of the lungs. Transthoracic echocardiography demonstrates a dilated left ventricle and increased end-diastolic volume, and wall motion abnormalities are noted along the anterolateral heart border. Ejection fraction by visualization is estimated at 34%. Which of the following best describes the underlying cause of this patient’s symptoms?