Nonsustained atrial fibrillation in ambulatory ECG recording and thromboembolic events in long-term follow-up

Abstract

Background: Short-lasting (<30 s), nonsustained episodes of atrial fibrillation (NS-AF) are frequently observed in ambulatory ECG monitoring. Although they are considered as a risk factor for future persistent/permanent AF and stroke, real-life data on the indence of thromboembolic events in these patients are limited. This study aimed to examine whether NS-AF detected in Holter monitoing increases the risk of thromboembolic events. Methods: A total of 6,117 Holter monitorings were evaluated after excluding patients with paroxysmal/persistant/permenant atrial fibrillation, valvular heart diseases and known thrombembolic events. The control group consisted of 114 patients without any detected arrhythmia. Both groups were followed-up for a mean of 5.5 years, and new onset thromboembolic events were recorded. Results: NS-AF episodes were detected in 134 patients (2.2%). Twenty-one subjects (15.7%) in NS-AF group experienced stroke and 9 (6.7%) deceased during the follow-up period, whereas the corresponding numbers were 5 (4.4%) and 2 (1.8%) in controls respectively (p=0.004 and p=0.069). After adjusting for baseline risk factors, both NS-AF and CHADS-VASc were associated with stroke (HR: 3.58; 95% confidence interval [CI]: 1.26 to 10.16) and HR: 1.77; 95% CI: 1.34 to 2.24). In ROC analysis of the NS-AF group, a CHADs-VASc score ≥2 had a sensitivity of 91%, a specificity of 38%, a postive predictivity of 21% and a negative predictivity of 95% to predict stroke (AUC 0.74; 95% CI 0.63–0.85; p=0.001). Conclusions: NS-AF is associated with an increased risk of stroke, and especially in NS-AF patients with a CHADS-VASc ≥2 oral anticoagulation should be considered.