Journal of electrocardiology | 2019
Advanced interatrial block: A predictor of covert atrial fibrillation in embolic stroke of undetermined source.
Abstract
AIMS\nOne third of ischemic strokes are of unknown etiology. Interatrial block (IAB) is a marker of atrial electromechanical dysfunction that may predispose to the development of atrial fibrillation (AF). We hypothesized that IAB, especially in its advanced form, could be a marker of covert AF in patients with embolic stroke of undetermined source (ESUS).\n\n\nMETHODS\nWe reviewed a single center cohort of ESUS patients with no prior history of AF. According to P-wave analysis of baseline ECG we distinguished 3 groups: normal P-wave duration (P-wave\xa0<\xa0120\xa0ms), partial IAB (P-IAB, P-wave\xa0≥\xa0120\xa0ms) and A-IAB (A-IAB, P-wave\xa0≥\xa0120\xa0ms with biphasic morphology in inferior leads). Follow-up was done 1, 6 and 12\xa0months after discharge; then every 6\xa0months. AF episodes, frequent premature atrial contractions (PACs) (>1%) and atrial tachyarrhythmias (runs of >3 consecutive PACs) were detected on 24\xa0h Holter. The primary endpoint was new-onset AF detection on follow-up by any means.\n\n\nRESULTS\nA high prevalence of both P-IAB (n\xa0=\xa030, 40%) and A-IAB (n\xa0=\xa023, 31%) was found in 75 ESUS patients. After a 521\xa0day mean follow-up, 14 patients (19%) were diagnosed of AF. A-IAB independently predicted AF diagnosis (p\xa0=0.042) on follow-up. 24\xa0h Holter analysis showed greater frequency of PACs and atrial tachyarrhythmia episodes in patients with IAB (p\xa0=\xa00.0275).\n\n\nCONCLUSIONS\nIn this hypothesis-generating study, A-IAB in the setting of ESUS is an independent risk predictor of covert AF. Although additional randomized clinical trials are warranted, A-IAB identifies ESUS patients with advanced atrial disease that could potentially benefit from early oral anticoagulation in secondary prevention.