Arrhythmias Involving the Atrioventricular Junction.

The atrioventricular junction has a central role in electrophysiology, responsible for reentrant and automatic forms of supraventricular tachycardia. During atrioventricular nodal reentry tachycardia, the circuit involves 2 electrophysiologically separate pathways located in the vicinity of the atrioventricular node. Atrioventricular reentry tachycardia is caused by the presence of an accessory pathway located almost anywhere along the atrioventricular groove; the macroreentrant circuit involves the atrioventricular node, the accessory pathway and necessarily portions of atria and ventricles. Junctional tachycardia is a rare form of nonparoxysmal supraventricular tachycardia, secondary to enhanced automaticity or triggered activity. By analyzing a 12-lead electrocardiogram during sinus rhythm and tachycardia, it is possible to accurately diagnose the specific type of supraventricular tachycardia.