Rate Control for Atrial Fibrillation: What Is the Best Drug to Use?

Summary and Comment

In a small, randomized crossover trial of four commonly prescribed beta- and calcium-channel blockers, diltiazem emerged the winner.

Current guidelines recommend either a beta-blocker or a calcium-channel blocker as first-line rate-control treatment for atrial fibrillation (AF). However, head-to-head trials of the agents in current use are lacking. To compare the effects of four once-daily drug regimens on heart rate and AF-related symptoms in patients with permanent, rapidly conducted AF, investigators in Norway conducted a prospective, randomized, investigator-blind, crossover study. Sixty adults (mean age, 71; 18 women) with permanent AF and without congestive heart failure or ischemic heart disease received, in randomized order, diltiazem, 360 mg; verapamil, 240 mg; metoprolol, 100 mg; and carvedilol, 25 mg. Each drug was given for 3 weeks to ensure steady-state plasma concentration and adequate washout of the prior treatment. Before the first treatment and on the last day of each treatment protocol, 24-hour Holter recordings were obtained, and patients completed questionnaires on symptom frequency and severity.
The 24-hour mean heart rate was significantly reduced from baseline with all four treatments and was significantly lower with diltiazem than with any other drug:

• Baseline, 96 beats per minute (bpm)
• Diltiazem, 75 bpm
• Verapamil, 81 bpm
• Metoprolol, 82 bpm
• Carvedilol, 84 bpm

Compared with baseline, diltiazem treatment significantly reduced both the frequency and severity of symptoms. Verapamil significantly reduced symptom frequency only, and metoprolol and carvedilol improved neither frequency nor severity. Reported symptoms were more frequent and more severe in women than in men, both at baseline and during all drug treatments.
Comment: Deciding which drug to prescribe for heart-rate control in patients with atrial fibrillation is a common clinical challenge. In this small, single-center study, diltiazem, at 360 mg per day, appeared to be the best choice. However, these results need confirmation in larger clinical trials and in different populations before any definitive recommendation can be made.
— Joel M. Gore, MD
Published in Journal Watch Cardiology January 30, 2013