A 56-year-old man has experienced increased fatigue and decreased exercise tolerance for the past 2 years. On physical examination, his temperature is 37deg C, pulse is 75/min, respirations are 17/min, and blood pressure is 115/75 mm Hg. On auscultation, diffuse crackles are audible. The abdomen is distended with a fluid wave, and there is bilateral pitting edema to the knees. A chest radiograph shows pulmonary edema, pleural effusions, and marked cardiomegaly. An echocardiogram shows mild tricuspid and mitral regurgitation and reduced right and left ventricular wall motion, with an ejection fraction of 30%. He experiences cerebral, renal, and splenic infarctions over the next year. Chronic use of which of the following substances has most likely produced these findings?
High-Yield Explanation
The findings point to dilated cardiomyopathy (DCM) with both right-sided and left-sided heart failure. The most common toxin-producing DCM is alcohol, and individuals with chronic alcoholism are more likely to have DCM than to have ischemic heart disease. Acetaminophen ingestion can be associated with hepatic necrosis and analgesic nephropathy. Cocaine can produce ischemic effects on the myocardium. Lisinopril is an angiotensin-converting enzyme inhibitor that is used to treat hypertension. Nicotine in cigarette smoke is a risk factor for atherosclerosis. Propranolol is a b-blocker that has been used to treat hypertension, and it may exacerbate bradycardia and congestive heart failure.