How much should the resting heart rate be controlled in patients with atrial fibrillation and coronary heart disease?

Background Current guidelines recommend maintaining a resting heart rate below 100-110 beats per minute (bpm) for patients with atrial fibrillation (AF). However, there is a lack of research on various treatment approaches for patients with both atrial fibrillation and coronary heart disease (AF&CHD). We have discussed the primary therapeutic options for controlling resting heart rate in patients with AF&CHD. Methods We conducted a post hoc analysis of the AFFIRM (Atrial Fibrillation Follow-up Investigation of Rhythm Management) trial. Our study included 3986(98.2%) participants with AF, of which 1522 had AF&CHD. The primary outcome was all-cause mortality. We utilized the chi-squared test to identify significant differences in categorical variables. Multivariate Cox regression analysis was performed to compare the risk of death by standard deviation of heart rate visit to visit variability quartile. Results Compared to the AF group, a higher proportion of patients in the AF&CHD group had histories of smoking, hypertension, diabetes, heart failure, cardiomyopathy, valvular heart disease, peripheral vascular disease, bradycardia, hepatic or renal disease, pulmonary disease, and stroke (all P < 0.001). Additionally, patients with AF&CHD were more likely to undergo coronary artery bypass grafting (CABG) and pacemaker surgeries than those with AF alone. After adjusting for multiple clinical variables, patients with AF&CHD had a significantly higher risk of all-cause mortality compared to the AF group (RR = 1.79, 95% CI: 1.49-2.60; P < 0.01). Nonlinear multivariate curve-fitting analysis identified an optimal resting heart rate of 70 bpm for patients with AF&CHD (P < 0.001). Subgroup analysis revealed that patients with a resting heart rate below 70 bpm had lower all-cause mortality than those with a resting heart rate above 70 bpm (P < 0.001). Conclusions For resting heart rates below 70 bpm, our results suggest an inverse causal relationship between genetically determined resting heart rate and all-cause mortality in patients with AF&CHD.