Calcium Channel Blockers associated with less bradycardia risk compared to beta Blockers in AF Patients

A recent study delving into the disparities in heart rate control strategies for individuals with non-permanent atrial fibrillation (AF) has unveiled intriguing findings published in Heart Journal regarding the use of non-dihydropyridine calcium channel blockers versus beta-blockers.

The study drew data from the 'A Comparison of Rate Control and Rhythm Control in Patients with Atrial Fibrillation' (AFFIRM) trial shed light on the impact of these drugs on heart rate during AF and sinus rhythm.

In this comprehensive analysis, 4060 participants from the AFFIRM trial were meticulously evaluated. Their mean age was 70±9 years, with women constituting 39% of the cohort. Focusing on the subset of 1112 patients who began the trial in sinus rhythm and were prescribed either calcium channel blockers or beta-blockers for rate control, the study scrutinized heart rate effects during follow-up.

Surprisingly, the findings unveiled that while both classes of drugs achieved similar success rates (92%) in attaining a resting heart rate below 110 beats per minute during AF, a distinct differentiation emerged during sinus rhythm. Notably, bradycardia, a condition characterized by an unusually slow heart rate, was significantly less frequent among patients on calcium channel blockers compared to those on beta-blockers. The occurrence of bradycardia during sinus rhythm was 17% in calcium channel blocker users, whereas it escalated to 32% in beta-blocker users.

Upon controlling for baseline patient characteristics, the study affirmed that calcium channel blockers displayed a notable advantage in reducing the likelihood of bradycardia during sinus rhythm. The odds ratio stood at 0.41, emphasizing the substantial clinical impact of this discovery. Interestingly, the average age of patients on calcium channel blockers was slightly higher than those on beta-blockers (70±8 vs. 68±8, p=0.003).

This investigation holds paramount importance as it accentuates the necessity of personalized medication selection in managing non-permanent AF. Although both calcium channel blockers and beta-blockers demonstrated efficacy in controlling heart rate during AF, calcium channel blockers surfaced as the more favorable choice in terms of avoiding bradycardia during sinus rhythm.

Source:

Koldenhof, T., Van Gelder, I. C., Crijns, H. J., Rienstra, M., & Tieleman, R. G. (2023). Rate control in atrial fibrillation, calcium channel blockers versus beta-blockers. In Heart (p. heartjnl-2023-322635). BMJ. https://doi.org/10.1136/heartjnl-2023-322635