Verapamil and ventricular tachycardias

In the absence of myocardial ischaemia, ventricular tachycardias occurring in patients with structural heart disease rarely respond to calcium antagonists like verapamil. In contrast, verapamil is markedly effective in the acute management of "supraventricular" tachycardias. Thus, intravenous verapamil has often been used for therapeutic and diagnostic purposes in patients with wide QRS complex tachycardias. This report details two unusual cases of ventricular tachycardia that are verapamil-sensitive. They highlight two major categories of "idiopathic" ventricular tachycardia, namely fascicular tachycardia and catecholamine-mediated ventricular tachycardia. The risks of verapamil administration for wide complex tachycardias are also reviewed.