Relationship between 24-h Holter recordings and clinical outcomes in patients with permanent atrial fibrillation

SummaryObjectivesThis study aimed to test the hypothesis that the range of 24-h total heart beats (24 h-tHB) correlates with cardiac outcomes (cardiac death and incidence of hospitalization with heart failure) in patients with permanent atrial fibrillation (AF).Methods and resultsWe divided 252 consecutive outpatients with permanent AF into 4 groups according to their 24 h-tHB and examined clinical outcomes. Initial 24 h-tHB at enrollment was significantly associated with patient characteristics including age, sex, presence of structural heart diseases, and left ventricular ejection fraction (EF). The cumulative incidence of heart failure was high in the lowest 24 h-tHB group compared with other groups and significantly different from the highest one (23.9% vs. 7.2% at 5 years, p = 0.0074). Multivariate analysis showed that 24 h-tHB < 100,000 was associated with cardiac events [hazard ratio, 2.45; 95% confidence interval (CI), 1.09–5.49; p = 0.03), along with structural heart disease (hazard ratio, 9.81; 95% CI, 3.34–28.83; p = 0.0001) and EF (hazard ratio, 0.97; 95% CI, 0.94–0.99; p = 0.002).ConclusionsSurprisingly, low but not high heart rate was significantly associated with higher incidence of heart failure in Japanese patients. This finding should be further evaluated in future prospective studies.