Reversible heart failure and subsequent bradyarrhythmia during long-term follow-up in a patient with chronic hypocalcemia: a case report

Chronic hypocalcemia is an uncommon, potentially reversible cause of heart failure. Existing reports have mainly described recovery of ventricular function with calcium correction, whereas long-term rhythm outcomes after clinical improvement remain poorly characterized. We report the case of a 74-year-old man with a history of hypocalcemia for more than 40 years and coronary artery disease for 19 years, who was admitted for acute decompensated heart failure. He was ultimately diagnosed with hypocalcemic cardiomyopathy. Following calcium and calcitriol supplementation together with heart failure therapy, his dyspnea resolved, the corrected QT interval shortened, and echocardiography demonstrated improvement in left ventricular ejection fraction. However, 11 months after discharge, he developed persistent atrial fibrillation with a slow ventricular response and intermittent third-degree atrioventricular block, subsequently underwent permanent pacemaker implantation after clinical evaluation. This case highlights the importance of long-term rhythm surveillance after recovery from hypocalcemic cardiomyopathy, while recognizing that late arrhythmic events may be influenced by multiple contributing factors.