Non-sustained atrial tachyarrhythmia episodes as predictors of atrial fibrillation: should they be ignored?

Introduction

Non-sustained atrial tachyarrhythmias (ATAs) lasting less than 30 seconds have traditionally been considered clinically insignificant. However, recent evidence suggests that even these brief episodes may serve as markers of electrophysiological instability and predictors of progression to atrial fibrillation (AF).

Objective

To determine the predictors of prolonged AF episodes (>30 seconds) among patients with non-sustained paroxysms of ATAs.

Methods

From a total of 450 patients who underwent 24-hour ECG monitoring, 85 patients were selected for the study. Patients were divided into two groups: group 1 — non-sustained ATAs lasting <30 sec (n = 58 (68.2%), and group 2 — paroxysmal AF lasting >30 sec (n = 27 (31.8%). A comparative analysis of clinical and electrophysiological indicators was performed. Additionally, a combined risk index for AF progression (0–3 points) was developed based on the results of ROC analysis.

Results

Patients with ≥5 paroxysms of non-sustained ATAs per day were more likely to have sustained AF episodes compared to those with 1–2 episodes (p < 0.05).

Patients with AF lasting >30 sec had a longer QTc interval compared with the <30 sec group (460 ± 21 ms vs. 440 ± 20 ms, p < 0.05).

They also had higher BMI values (30.5 ± 7.2 vs 28.4 ± 5.2 kg/m2), greater prevalence of obesity (14 (53%) vs. 23 (39%), lower circadian index (CI) (1.21 ± 0.10 vs. 1.25 ± 0.15), and a higher number of supraventricular premature beats (SPBs) (9800 ± 4100/day vs. 7500 ± 3900/day, p < 0.05).

The combined index, which included BMI >30 kg/m2, CI <1.15, and SPBs >5000/day, demonstrated an AUC of 0.75 in ROC analysis. The incidence of sustained AF episodes among patients with scores 0 and 1 was 11% (4/35) and 24% (10/41), respectively, confirming the prognostic significance of even a single clinical and electrophysiological risk factor. Patients with scores 2 were not included in the analysis due to the small sample size (n = 9).

Conclusion

Non-sustained ATAs lasting <30 seconds have clinical and prognostic significance. These episodes are associated with markers of electrophysiological instability, including prolonged QTc interval, obesity, reduced CI, and increased burden of supraventricular ectopy.

Patients with ≥5 brief episodes per day are more likely to progress to sustained AF. A combined risk index includes: BMI >30 kg/m2, CI <1.15, and SPBs >5000/day allows for effective risk stratification for AF progression and may support personalized clinical assessment and management strategies.