Management of cardiac arrhythmias with tiapamil

37 patients with either chronic atrial fibrillation (AF), atrial premature beats (APBs) or ventricular premature beats (VPBs) received tiapamil as antiarrhythmic treatment. Tiapamil reduced A-V conduction by an average 20% in the group with AF (10 patients), the magnitude of response being dependent on the initial ventricular rate. In 3 of the 7 patients with APBs, the frequency of ectopic beats was reduced following a single i.v. injection of 1 mg/kg tiapamil. In patients with VPBs (n = 20), tiapamil (i.v. injection of 1 mg/kg followed by 4-hour i.v. infusion of 50 micrograms/kg/min in 10 patients) reduced ectopic beats by 30-50% in 6 cases, these all being patients who had not responded to previous antiarrhythmic therapy. The antiarrhythmic effect was maintained by i.v. infusion of 50 micrograms/kg/min for 4 h. The antiarrhythmic effect of tiapamil consists essentially in slowing A-V conduction and reducing chronic VPBs.