Magnesium deficiency during lactation as a precipitant of ventricular tachyarrhythmias.

A young ICD recipient with a history of syncope and idiopathic polymorphic ventricular tachycardia/ventricular fibrillation presented after an ICD discharge. She had delivered her first child 8 days prior to the event and she had been lactating. Numerous short runs of polymorphic ventricular tachycardia/ventricular fibrillation resolved with aggressive replacement of magnesium and elimination of breast-feeding.