[A rare cause of reversible dilated cardiomyopathy: hypocalcemia].

Hypocalcaemia is a rare cause of reversible heart failure. We present a 27-year-old man who had severe heart failure unresponsive to medical therapy. He had vitamin D-resistant rickets for which he had received replacement therapy with vitamin D and calcium until age 20, but he discontinued treatment for the past seven years. Severe hypocalcemia was detected. Echocardiography showed left ventricular dilatation, global hypokinesia (ejection fraction 25%), and mitral and tricuspid regurgitation of grades 3 and 2, respectively. After calcium and vitamin D supplementation, his symptoms showed rapid improvement. At nine months, myocardial dysfunction improved fully. Hypocalcemia should be considered among the causes of heart failure unresponsive to medical treatment.