A 49-year-old man presents to the cardiologist as an outpatient with a month-long history of progressively worsening shortness of breath, orthopnea, fatigue, and leg swelling. He denies any fever, nausea, vomiting, palpitations, angina, diaphoresis, or loss of consciousness over this period. Past medical history is significant for hyperlipidemia and gout. Current medications include atorvastatin, and allopurinol which are both taken consistently at appropriate doses. He drinks 25-30 beers per week which has been relatively consistent for the past 30 years. He has smoked 1 pack of cigarettes daily across this time as well. Vital signs are temperature 37.1° C (98.6° F), blood pressure 135/82 mmHg, pulse 105 beats/min, respirations 15/min and oxygen saturation 98% on room air. On physical examination, he has jugular venous distension, bilateral rales over the lower lung field on auscultation, and 2+ pitting edema to the shins bilaterally. A transthoracic echocardiogram shows an ejection fraction of 30% with left ventricular dilation and no significant valvular abnormalities. The ejection fraction is reduced from 55% measured 2 years ago.
Which of the following is the most likely underlying mechanism contributing to this patient’s condition?
- A) Alcohol use
- B) Aortic stenosis
- C) Chronic hypertension
- D) Hemochromatosis
- E) Ischemia
A) Alcohol use
This patient has evidence of heart failure with reduced ejection fraction (HFrEF) along with signs of fluid overload such as lower extremity edema. Long-term excessive alcohol consumption is a leading cause of acquired dilated cardiomyopathy. Left ventricular dysfunction and alcohol-induced cardiomyopathy are related to the mean daily alcohol intake and the duration of alcohol consumption, though the pathogenesis is not fully understood. Chronic alcohol consumption may impair myocardial contractility due to the effects of ethanol and its metabolites.
Answer choice B: Aortic stenosis, is incorrect. While Aortic stenosis can lead to heart failure, this is usually due to concentric hypertrophy, secondary to increased pressure in the left ventricle. The echocardiogram findings in this patient show left ventricular dilation and reduced ejection fraction, which would more likely be seen with aortic regurgitation.
Answer choice C: Chronic hypertension, is incorrect. Chronic hypertension would also present with concentric hypertrophy as opposed to dilation, which is due to eccentric hypertrophy.
Answer choice D: Hemochromatosis, is incorrect. Hemochromatosis is an iron overload disorder that can lead to dilated cardiomyopathy. However, this condition is usually accompanied by systemic symptoms such as diabetes and skin changes.
Answer choice E: Ischemia, is incorrect. While ischemic heart disease can lead to dilated cardiomyopathy, this patient does not have symptoms of ischemia or a history of myocardial infarction. it is likely accompanied by a history of myocardial infarction which this patient does not have. With an extensive history of alcohol use and associated sequelae such as gout, alcohol is a more likely cause of his symptoms.
Key Learning Point
Chronic excessive alcohol consumption is a leading cause of dilated cardiomyopathy.
