Rate control with calcium channel blockers versus betablockers in patients with paroxysmal and persistent atrial fibrillation - data from the AFFIRM trial

Abstract Funding Acknowledgements Type of funding sources: None. Purpose To investigate whether there are differences between nondihydropyridine calcium channel blockers and beta blockers on heart rate in patients with paroxysmal and persistent atrial fibrillation (AF). Methods In present analysis of the AFFIRM trial, the effect of rate control drugs on heart rate was evaluated during first reported AF-episode as well as the last recorded sinus rhythm episode prior to AF. Patients who used both rate control drugs or switched rate control drugs between the last sinus rhythm and the first AF episode were excluded. Results A total of 1195 patients were in sinus rhythm at baseline and used either betablockers (603, 50%) or non-dihydropyridine channel blockers (592, 50%). Of the total, 513 had at least one episode of AF while remaining on the same rate control drug, 257 (50%) of them using calcium channel blockers and 256 (50%) of them using betablockers. Mean age of patients treated with a calcium channel blocker was 70±8 years versus 68±8 for the betablocker treated patients (p=0.014). Forty-four percent were women, 31% with paroxysmal AF, and 69% with persistent AF. A resting heart rate <110 bpm during AF (lenient rate control) was achieved in 92% of patients using beta blockers and 93% of patients using calcium channel blockers (P= 0.724). Bradycardia during sinus rhythm (<60 bpm) occurred significantly less often in patients using calcium channel blockers (19%) versus betablockers (32% , P = 0.001). After adjusting for differences in patient characteristics, the association between calcium channel blockers and a reduction in sinus bradycardia remained statistically significant (OR = 0.40, 95% CI = 0.10-0.68). Conclusion In patients with persistent or paroxysmal AF included in the AFFIRM trial, nondihydropyridine calcium channel blocker as rate control treatment was associated with less bradycardia during sinus rhythm compared to betablockers. Resting heart rates <110 bpm during AF were achieved similarly in those treated with calcium channel blockers and betablockers.