A double-blind randomized study was performed to compare the efficacy of intravenous verapamil with saline in 28 patients with a rapid ventricular rate and atrial fibrillation or atrial flutter. Conversion of atrial fibrillation to sinus rhythm occurred in none of 14 patients after saline and in 3 of 20 patients (15%) 7 to 160 min after verapamil. The ventricular rate in atrial fibrillation was slowed greater than or equal to 15% in 2 of 14 patients (14%) by saline, in 17 of 20 patients (85%) by 1 dose of verapamil (p less than 0.001), and in 19 of 20 patients (95%) by 1 or 2 doses of verapamil (p less than 0.001). Conversion of atrial flutter to sinus rhythm occurred in none of 4 patients after saline and in 1 of 7 patients (14%) 105 min after verapamil. The ventricular rate in atrial flutter was slowed greater than or equal to 15% in none of 4 patients by saline, in 4 of 7 patients (57%) by 1 dose of verapamil, and in 7 of 7 patients (100%) by 1 or 2 doses of verapamil (p less than 0.001).

Verapamil and placebo were compared in patients with stable, effort-induced angina. Single-blind dose titration (240, 360 and 480 mg/day) preceded a double-blind crossover. Among the 18 patients who completed graded exercise stress tests with reproducible pretreatment effort-limiting angina, exercise duration increased from 348 +/- 127 seconds (SD) before treatment to 494 +/- 182 seconds after verapamil (p less than 0.001), but did not change after placebo. Compared with placebo, verapamil reduced the weekly number of anginal episodes from 4.54 +/- 5.03 to 2.44 +/- 3.30 (p less than 0.05) and reduced nitroglycerin consumption from 3.46 +/- 5.30 to 1.55 +/- 2.89 tablets per week (p less than 0.05). Of 26 patients who completed the single-blind dose titration, 16 were improved (greater than 1 minute) at a dosage of 240 or 360 mg/day. No patient improved (greater than 1 minute) on 480 mg/day who had not already improved on a lower dose, but side effects requiring reduction in dosage occurred in seven patients receiving 480 mg of verapamil per day. Verapamil is an effective antianginal drug that appears most efficacious at a dose of 360 mg/day, but side effects are common at a dose of 480 mg/day.

A double-blind, randomized study comparing the efficacy of intravenous acebutolol with propranolol on frequent premature ventricular complexes (PVCs) in 24 patients is reported. Frequent PVCs were abolished or reduced by 75% or more in 10 of 12 patients (83%) given acebutolol and in 10 of 12 patients (83%) given propranolol. The therapeutic effect of acebutolol lasted for at least 1 hr in 4 of 12 patients (33%), for at least 3.5 hr in 3 of 12 patients (25%), and for at least 4 hr in 2 of 12 patients (17%). The effect of propranolol lasted for at least 1 hr in 6 of 12 patients (50%), for at least 3.5 hr in 4 of 12 patients (33%), and for at least 4 hr in 4 of 12 patients (33%). Hence, intravenous acebutolol and propranolol were equally effective.

Eight patients who improved their exercise duration to angina or marked fatigue (greater than or equal to 25%) on timolol 10 to 30 mg twice daily over that on placebo 8 to 14 mo previously were subjects in a double-blind, randomized, crossover 4-wk study of the effect of timolol on exercise duration 2 and 12 hr after medication. One patient was discontinued from the study because unstable angina developed on placebo. Mean exercise duration on timolol over control was increased at 12 hr (p less than 0.02) and at 2 hr ( p less than 0.001) after drug. There was an increase in exercise duration greater than or equal to 25% on timolol over control compared with placebo in three of seven patients (43%) 12 hr after drug and in seven of seven (100%) 2 hr after drug. Timolol 10 to 30 mg twice daily prolongs exercise duration to angina or marked fatigue at 2 hr after drug and in some responders at 12 hr after drug.