Lower risk of bradycardia with calcium channel blockers compared to beta-blockers in AF patients: Study

Netherlands: A recent study published in Heart (British Cardiac Society) has compared calcium channel blockers versus beta-blockers for rate control in atrial fibrillation (AF). The study found differences in heart rate outcomes between non-dihydropyridine calcium channel blockers and beta-blockers in patients with non-permanent atrial fibrillation.

The researchers revealed that calcium channel blockers instituted for rate control were linked with less bradycardia during sinus rhythm versus beta-blockers in these patients. 

Atrial fibrillation, a common heart rhythm disorder, can lead to an irregular heartbeat and increase the risk of stroke and other cardiovascular complications. In the AFFIRM trial, patients were randomly assigned to receive either rate or rhythm control for their AF management.

● The study focused on 1,112 patients from the AFFIRM trial who were in sinus rhythm at baseline and were prescribed either non-dihydropyridine calcium channel blockers or beta-blockers for rate control.

● Among this group, 474 patients experienced AF during the follow-up period while continuing to use the same rate control drugs, with 218 (46%) on calcium channel blockers and 256 (54%) on beta-blockers.

● The mean age of patients using calcium channel blockers was 70±8 years, while those using beta-blockers were slightly younger at 68±8 years (p=0.003). Both groups had a similar percentage of women, with 42% in the calcium channel blocker group and 39% in the beta-blocker group.

● During episodes of AF, the study found that a resting heart rate of less than 110 beats per minute was achieved in 92% of patients using calcium channel blockers and 92% of patients using beta-blockers (p=1.00).

● The occurrence of bradycardia (an abnormally slow heart rate) during sinus rhythm was notably different between the two groups. Patients using calcium channel blockers experienced bradycardia at a rate of 17%, while 32% of patients using beta-blockers had bradycardia (p<0.001).

● To validate the findings, the researchers performed multivariable logistic regression analysis, adjusting for various patient characteristics.

● The results confirmed that calcium channel blockers were associated with a significantly lower risk of bradycardia during sinus rhythm compared to beta-blockers (odds ratio 0.41, 95% confidence interval 0.19 to 0.90).

The study's findings suggest that in patients with non-permanent AF, calcium channel blockers used for rate control may be a preferable option over beta-blockers due to their reduced risk of bradycardia during sinus rhythm. Bradycardia can lead to symptoms such as dizziness, weakness, and fainting, making it an essential consideration when choosing medications for AF management.

As more data is accumulated and analyzed, healthcare professionals can better tailor their approach to managing AF and preventing complications, ultimately improving the quality of life for patients with this common heart rhythm disorder.

Reference:

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. Heart (British Cardiac Society), heartjnl-2023-322635. https://doi.org/10.1136/heartjnl-2023-322635