Associations between heart rate, deformational echocardiographic parameters and clinical outcomes in patients with atrial fibrillation

Abstract Background The relationship between baseline heart rates and cardiac function in patients with atrial fibrillation (AF) remains unknown, as does its impact on long-term outcomes. Methods Patients with newly diagnosed AF and available echocardiography images were included. Conventional echocardiography measurement and myocardial deformation analyses using two-dimensional speckle-tracking echocardiography were performed during AF. Clinical endpoints included first-time hospitalization for ischemic stroke, heart failure (HF), all-cause mortality, and composite endpoint. Results Patients were categorized into groups according to baseline heart rates: 40-59, 60-69, 70-79, 80-89, 90-99, 100-109, 110-119, and ≥120 beats per minutes (bpm). As heart rates increased, there was a stepwise decrease of peak atrial longitudinal systolic strain (PALS: 14.6 ± 5.3%, 14.7 ± 5.5%, 14.1 ± 4.6%, 13.4 ± 4.7%,12.6 ± 4.9%, 12.1 ± 4.5%, 11.2 ± 5.2% and 10.8±4.1% in 40-59, 60-69, 70-79, 80-89, 90-99, 100-109, 110-119, and ≥120 bpm groups, respectively; P < 0.001)) and LV strain (-13.8 ± 3.9%, -14.5 ± 4.0%, -13.4 ± 3.4%, -13.4 ± 3.6%, -12.5 ± 3.6%, -11.9 ± 3.8%, -10.3 ± 3.8%, and -10.2 ± 3.8%, in 40-59, 60-69, 70-79, 80-89, 90-99, 100-109, 110-119, and ≥120 bpm groups, respectively; P < 0.001)(Figure). The lowest risk of composite endpoint was observed for patients whose heart rate between 60 to 69 bpm (Figure). Compared to the 60-69 heart rate group, faster heart rates were associated with increased risk of ischemic stroke (adjusted hazard ratios [aHR] 4.448 in the ≥120 bpm group), HF (aHR 1.909 in the ≥120 bpm group), mortality (aHRs 2.487, 2.810, 4.569, 4.760 in the 90-99, 100-109, 110-119, and ≥120 bpm groups, respectively), and composite endpoint (aHRs 2.034, 2.349, 3.492 in the 100-109, 110-119, and ≥120 bpm groups, respectively) (all P < 0.05). Conclusion In patients with AF, heart rate is closely linked to cardiac function and plays a pivotal role in long-term prognosis. Faster heart rates were associated with worse LA/LV functions and increased risk of clinical events. Favorable outcomes were found at heart rates below 100 bpm, with even better LA/LV function noted at heart rates below 80 bpm.