Rapidly Recurring Supraventricular Tachycardia

or digitalis and quinidine, prevented tachyeardia in five patients and slowed it in one. Our cases suggest the following: (1) Recurrent supraventricular tachycardia in patients without the WPW syndrome may frequently be caused by a reciprocal mechanism. (2) The diagnosis of reciprocating tachycardia should be suspected when (a) the tachycardia recurs within minutes of its termination, (b) the onset follows prolongation of the P-R or R-P interval, (c) the P wave during the tachycardia is superiorly directed and different from the P wave which initiates the tachycardia, and (d) at least one other criterion for the diagnosis is met. (3) Propranolol is the drug of choice for the treatment of recurrent supraventricular tachycardias which satisfy the criteria for reciprocating tachycardia.