Drug misuse, intoxication and withdrawal Quiz: Ace Your Exams

A 48-year-old man comes to the emergency department to evaluate progressive, worsening shortness of breath. The patient cannot walk from his bed to the bathroom without becoming short of breath. He also reports worsening abdominal distension and leg swelling for the past several months. Past medical history is unremarkable, and the patient does not take any medications. The patient has been smoking two packs of cigarettes per day for the past 15 years and drinks 10-12 beers daily. Temperature is 37.5°C (99.5°F), pulse is 94/min, respirations are 17/min, and blood pressure is 130/90 mmHg. Physical examination demonstrates a laterally displaced and enlarged apical impulse. The patient has moderate abdominal distension and pitting edema to the knees. Bibasilar rales are appreciated on pulmonary auscultation. Laboratory results are demonstrated below. Chest x-ray demonstrates an enlargement of the cardiac silhouette and pulmonary vascular congestion. Transthoracic echocardiography shows a dilated left ventricle with an increased ventricular cavity size; left ventricular ejection fraction is 23%. Coronary angiography is within normal limits. Which of the following is the most likely etiology of this patient’s clinical condition?