A new method for evaluating the effect of antiarrhythmic drugs on atrioventricular nodal conduction.

Electrophysiological variables were studied in 19 patients before and after one of three commonly used antiarrhythmic agents. The pacing rate at which alternating Wenckebach periods appeared in eight patients was significantly reduced by intravenous digoxin (0.01 mg/kg body weight).

Electrophysiology of tiapamil in humans.

Electrophysiological properties of tiapamil, a new calcium antagonist, were studied in 15 patients. His bundle recordings were obtained during sinus rhythm and following atrial and ventricular pacing. Studies were performed before and 20 min after slow injection of tiapamil (1 mg/kg).