LAUSR

Introduction The heart oxidizes fatty acids for its energy production. However, excessive accumulation of lipids due to various processes such as obesity, diabetes, heart failure (HF), myocardial ischemia, or infarction can result in damage to the heart tissue, also known as cardiolipotoxicity. Case A 69-year-old gentleman with a history of non-ischemic cardiomyopathy, right ventricle failure, permanent atrial fibrillation, ventricular tachycardia and cardiac cirrhosis presented to the hospital with exertional dyspnea, orthopnea, and decreased functional capacity. Physical exam was pertinent for elevated jugular venous distension, bibasilar rales, and bilateral pitting pedal edema. Laboratory findings were significant for brain type natriuretic peptide 1641 pg/ml, hemoglobin A1c 6.1%, total cholesterol 79 mg/dl, triglyceride 84 mg/dl, low density lipoprotein (LDL) 53 mg/dl, and high density lipoprotein (HDL) 9 mg/dl. Chest x-ray demonstrated mild pulmonary vascular congestion. Electrocardiogram showed atrial fibrillation and right bundle branch block. Transthoracic echocardiogram showed normal left ventricular systolic function with ejection fraction of 55%, severely dilated right ventricle with severely reduced systolic function and markedly dilated right and left atrium. Right heart catheterization showed findings consistent with mild pulmonary hypertension from diastolic HF and severe tricuspid regurgitation. Endomyocardial biopsy showed intracellular accumulation of significant amorphous material in most cardiac myocytes. Electron microscopy revealed fat lobules and inclusion bodies within the myocytes, consistent with cardiolipotoxicity (figure 1). Guideline directed medical management of HF was initiated and patient was subsequently discharged home. Discussion Due to various stressors such as HF, myocardial ischemia, infarction or atrophy, there is increased expression of genes involved in glucose metabolism rather than fatty acid oxidation. This leads to increased accumulation of lipids in the failing myocardium, thereby leading to cardiolipotoxicity. Increased lipid accumulation causes cardiac steatosis thereby leading to ER dysfunction, contractile dysfunction, and cell death. Our case describes a distinct metabolic phenotype of myocardial dysfunction for which no definite cause or treatment has been identified. Further research is required to advance our knowledge on cardiac metabolism in normal myocardium as well as in patients with HF, which could result in development of novel therapeutic interventions and strategies in these patients.