Mechanisms of supraventricular tachycardia.

Programmed electrical stimulation of the heart in combination with intracardiac recordings has contributed a wealth of new information on the mechanisms and pathways of supraventricular tachycardia in humans. This knowledge has resulted in better treatment approaches to these patients. Questions still remain, however, about the mechanisms of atrial flutter and fibrillation and of some types of atrial tachycardia. The location of the circuit in paroxysmal atrioventricular nodal tachycardia also continues to puzzle investigators. The use of refined mapping techniques during cardiac surgery should provide answers to these questions in the near future.