Introduction: Atrial fibrillation (AF) is the most common sustained arrhythmia. The characteristics of AF relating to the duration, frequency, and burden of paroxysmal AF remains unclear. These characteristics have not been explored in a large real-world population free of implantable devices.
Hypothesis: There is wide inter-individual heterogeneity in the characteristics of paroxysmal AF events.
Methods: We analyzed the results from 13,350 de-identified individuals documented to have paroxysmal AF during clinically-indicated continuous rhythm monitoring with a wearable, single-lead ECG patch monitor.
Results: The median duration of monitoring was 12.3 days [IQR 7.3-13.6]. A total of 3,711,422 discrete episodes of AF were documented, with a median of 2.9 episodes/day [IQR 0.7-12.5]. The median duration of all episodes of AF was 6 seconds [IQR 3-39], whereas the median (IQR) duration of the episode of maximal duration for each individual was 7.0 hours [IQR 2.3-17.3]. The median overall proportion of time in AF was greater in men than in women (10.4% vs. 7.8%, p=1.4 x 10-14) and increased with age in women (p=0.01), but not in men (p=0.24). Forty percent (40%) of individuals showed nominally significant (p<0.05) differences in AF duration variance compared to the population as a whole (p<2.2 x 10-16); 61% of these individuals demonstrated lower inter-individual variation (p<2.2 x 10-16). Across all individuals, the number of total AF episodes was inversely associated with maximum episode duration (p=7.4 x 10-14) suggesting at least two patterns or subtypes of the disease: one characterized by many short episodes and the other by fewer, longer episodes.
Conclusions: Individuals with paroxysmal AF exhibit a wide range of duration, frequency, and burden of AF. Multiple subtypes of the disease, related to these characteristics, are likely to exist. Understanding the characteristics of paroxysmal AF and relationship to adverse outcomes may be important for improved clinical care.