Background: Nonsustained atrial fibrillation (NS-AF) lasting longer than 30 seconds on ambulatory electrocardiogram(ECG) monitoring is considered a potential risk factor for future persistent or permanent AF and stroke. However, the clinical significance of NS-AF episodes shorter than 30 seconds, as detected on 24-hour Holter monitoring, remains unclear, as does their potential impact on stroke risk.

Methods: A total of 6117 Holter recordings were analyzed after excluding patients with AF, valvular heart disease, and a history of thromboembolic events. A total of 133 patients with NS-AF lasting less than 30 seconds and 113 controls with no detected arrhythmias were included. Both groups were followed for a mean of 65.84 ± 6.38 months.

Results: In 133 patients (2.17%), NS-AF episodes were detected. During follow-up, the stroke rate was significantly higher in the NS-AF group [21 (15.78%) vs. 5 (4.42%), P = .004]. After excluding 20 patients through propensity matching and adjusting for other risk factors, both NS-AF (OR = 3.930, 95% CI: 1.235-12.510, P = .021) and CHA2DS2-VA score (OR = 1.819, 95% CI: 1.204-2.748, P = .004) were identified as independent predictors of ischemic stroke. In the NS-AF group, the prevalence of stroke increased with advancing CHA2DS2-VA score. Furthermore, in the NS-AF group, a CHA2DS2-VA score ≥2 demonstrated a sensitivity of 85.7%, a specificity of 56.6%, a positive predictive value of 26.8%, and a negative predictive value of 95.5% for predicting stroke (area under the curve [AUC]: 0.76; 95% CI: 0.65-0.86.6; P < .001).

Conclusion: Stroke risk is increased in patients with NS-AF of less than 30 seconds detected on 24-hour ambulatory ECG monitoring with a CHA2DS2-VA score ≥2. Close follow-up should be considered for these patients to evaluate the need for anticoagulation.