Usefulness of Short-Lasting Episodes of Supraventricular Arrhythmia (Micro-Atrial Fibrillation) as a Risk Factor for Atrial Fibrillation.

According to the present European Society of Cardiology's guidelines for atrial fibrillation (AF), the definition of AF contains a 30-second time criterion, based on consensus. The aim of this cohort study is to evaluate whether very short-lasting episodes of AF, micro-AF, are risk factors for developing AF and to compare AF detection between continuous and intermittent ECG recordings applied in parallel. All participants, n = 102, were identified from the STROKESTOP study, a Swedish mass-screening study for AF. Participants were divided into 2 groups depending on results in the STROKESTOP study: a micro-AF group (with abrupt onset episodes of ≥4 consecutive supraventricular beats, irregular rate-to-rate intervals, absence of regular p waves, lasting for <30 seconds), n = 54, and a control group, n = 48. After a follow-up period participants who were clinically free of AF were invited to undergo repeat AF screening during a 2-week period, using continuous ECG recording and 30 seconds intermittent recordings simultaneously. After 2.3years of follow-up, significantly more participants in the micro-AF group had developed AF, 27 of 54 (50%), compared with the control group, 5 of 48 (10%), p < 0.001. Among the 94 participants not already diagnosed with AF who underwent AF-screening, 25 of 25 (100%) AF cases were detected with help of continuous monitoring whereas 10 of 25 (40%) AF cases were found with intermittent ECGs. In conclusion, micro-AF seems to be an important risk factor for the development of AF in an elderly population. The detection of AF was significantly higher using 2 weeks of continuous ECG monitoring compared with intermittent 30-second ECG recordings twice daily for 2 weeks.