Cardiac Beriberi After Gastrectomy Presenting With Peripheral Neuropathy and Mimicking Tachycardia-Induced Cardiomyopathy: A Case Report.

Cardiac beriberi, a manifestation of thiamine deficiency, is an uncommon but reversible cause of heart failure that can mimic other forms of cardiomyopathy, such as dilated or tachycardia-induced cardiomyopathies. It is likely underrecognized or misdiagnosed. We report an elderly man with neurological symptoms and globally reduced left ventricular (LV) function in the context of prior gastrectomy, chronic alcohol consumption, and prolonged malnutrition. Early empiric thiamine administration led to rapid improvement in pulse rate, left ventricular function, and neurological symptoms, and the diagnosis was confirmed by a low thiamine level. This case underscores the importance of considering cardiac beriberi in the differential diagnosis of newly diagnosed heart failure, particularly in patients with nutritional risk factors or a history of gastrointestinal surgery. Early recognition and treatment are crucial to preventing adverse outcomes.