Heart rate during sinus rhythm predicts paroxysmal atrial fibrillation on 30-day mobile cardiac telemetry monitoring

Abstract

Abstract Background Low mean heart rate at ambulatory ECG monitoring and low resting heart rate are both predictors of later incident atrial fibrillation (AF). The aim of this study is to determine whether mean heart rate at ambulatory ECG is a predictor of paroxysmal AF that can be detected with extended ambulatory ECG registration. Methods We included all patients who recorded 2–30 full days of ambulatory ECG using a full disclosure mobile cardiac telemetry device in USA 2019–2020, and without AF on the first full day of registration (n=18,220, mean age 64.4 years, 57.2% women). The association between mean heart rate on the first day and the occurrence of paroxysmal AF (≥30 seconds duration) during subsequent up to 30 day ECG recording was analysed using logistic regression models adjusted for age, sex and duration of ECG recording, according to tertiles of mean heart rate (39–66, 67–76 and >77 beats per minute) as well as modelled using restricted cubic splines. Results During a median registration duration of 16 days there were 1,290 cases of paroxysmal AF (7.1%). More paroxysmal AF occurred in the lower tertiles of mean heart rate (11.2% in tertile 1, 6.2% in tertile 2, and 4.4% in tertile 3). After adjustment, low mean heart rate was associated with a higher risk of AF (OR 1.69, 95% CI 1.47–1.93 p<0.001 for tertile 1 vs tertile 2, and OR 1.84, 95% CI 1.58–2.15, p<0.001 for tertile 1 vs tertile 3). Cubic spline curves indicated that lowest risks of AF were seen among subjects with a mean heart rate ≈80 beats per minute. Conclusion Low mean heart rate at 24hECG predicts detection of paroxysmal AF during extended ≤30 day ambulatory ECG monitoring. Funding Acknowledgement Type of funding sources: Foundation. Main funding source(s): Swedish Heart Lung foundationSwedish Society for Medical Research