Atrial Rhythm in Ventricular Tachycardia Occurring During Cardiac Catheterization

Abstract

The atrial rhythm was studied in 38 patients during runs of tachycardia of five or more beats in sequence which occurred during cardiac catheterization and whose ventricular site of origin could be established with considerable confidence. Simultaneous esophageal and other leads were recorded. The most frequent mechanism was retrograde conduction to the atria with varying degrees of V-A (ventriculo-atrial) block which occurred in 26 of the 38 patients. Runs of ventricular tachycardia with one-to-one V-A conduction occurred in 13 patients. Runs with an independent atrial rhythm (A-V dissociation) occurred in nine patients. Varying atrial mechanisms during different runs of tachycardia occurred in 11 patients. The minimum QRS-to-retrograde P intervals in 24 of 35 patients with V-A conduction were within 0.03 sec of P-R interval. The briefest QRS-to-retrograde P interval observed was 0.09 sec. Reciprocal beats occurred in eight of 35 patients with V-A conduction.