Prognostic Implications of Reductions in Heart Rates in Patients With Acute Heart Failure and Atrial Fibrillation

Abstract

Background: Atrial fibrillation (AF) is a common arrhythmia in patients with acute heart failure (AHF). Heart rate (HR) also changes significantly over time. However, the association between changes in HR in AF patients and prognosis is uncertain. Methods and Results:We investigated the association between HR reduction in AF achieved within 48 h of admission and 60-day mortality in patients with AHF from the REALITY-AHF study. The percentage HR (%HR) reduction was calculated as (baseline HR-HR at 48 h) / baseline HR × 100. The primary endpoint was 60-day all-cause mortality. In 468 patients with confirmed AF at both admission and 48 h after admission, the median HR at these time points was 105±31 and 84±18 beats/min, respectively. The median %HR reduction was 15.4% (interquartile range 2.2-31.4%). During the 60 days of admission, 39 deaths (8.3%) were recorded, and the %HR reduction within 48 h was significantly associated with 60-day mortality in the unadjusted model (hazard ratio [HR] 0.85; 95% confidence interval [CI] 0.77-0.95; P=0.005) and after adjusting for other covariates (HR 0.81; 95% CI 0.68-0.96; P=0.016). Furthermore, the %HR reduction was associated with a significant reduction in 60-day mortality in patients with higher baseline HR.Conclusions: %HR reduction is associated with a better short-term prognosis in patients with AHF presenting with AF, particularly in those with a rapid ventricular response.

Resting heart rate and risk of atrial fibrillation in Chinese general population: Kailuan prospective cohort study

“…First, regulation of heart rate is the result of the combined effect of vagal weakness and sympathetic activation 11 24 25. A lower RHR extends the time limit of vagal tone, leading to increased activation of vagal, which reduces the action potential duration of atria to medicate AF 26 27. Furthermore, a higher RHR may be associated with increased sympathetic activity, which could accelerate the automaticity of atrial muscle and shorten the atrial effective refractory period, leading to re-entrant excitation of the atria.…”