Hypocalcaemia, long QT interval and atrial arrhythmias.

Calcium has diverse roles in neuromuscular mechanisms. Within the cardiovascular system, hypocalcaemia is known to both impair myocardial contractility and prolong the QT interval, predisposing to ventricular arrhythmias. We present a case of chronic hypocalcaemia with prolonged QT interval associated with an atrial arrhythmia. Recent studies of congenital long QT syndrome suggest there is also a predisposition to atrial arrhythmias. Our case raises the hypothesis that acquired causes of long QT cause similar repolarisation abnormalities that predispose to atrial arrhythmias.