Guiomar Mendieta1, Eduard Guasch2, Danilo Weir3, David Aristizabal3, Luis Alberto Escobar-Robledo3, Laura Llull4, Lluis Mont2, Antonio Bayés de Luna3, Marta Sitges2. 1. Cardiovascular Institute, Hospital Clínic, IDIBAPS, University of Barcelona, Spain. Electronic address: lgmendieta@clinic.cat. 2. Cardiovascular Institute, Hospital Clínic, IDIBAPS, University of Barcelona, Spain; CIBERCV, Spain. 3. Cardiovascular Research Foundation, Cardiovascular ICCC-Program, Research Institute Hospital de la Santa Creu i Sant Pau, IIB-Sant Pau, Barcelona, Spain. 4. Comprehensive Stroke Center, Department of Neurology, Hospital Clinic, IDIBAPS, University of Barcelona, Spain.
Abstract
AIMS: One 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). METHODS: We 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 < 120 ms), partial IAB (P-IAB, P-wave ≥ 120 ms) and A-IAB (A-IAB, P-wave ≥ 120 ms with biphasic morphology in inferior leads). Follow-up was done 1, 6 and 12 months after discharge; then every 6 months. AF episodes, frequent premature atrial contractions (PACs) (>1%) and atrial tachyarrhythmias (runs of >3 consecutive PACs) were detected on 24 h Holter. The primary endpoint was new-onset AF detection on follow-up by any means. RESULTS: A high prevalence of both P-IAB (n = 30, 40%) and A-IAB (n = 23, 31%) was found in 75 ESUS patients. After a 521 day mean follow-up, 14 patients (19%) were diagnosed of AF. A-IAB independently predicted AF diagnosis (p =0.042) on follow-up. 24 h Holter analysis showed greater frequency of PACs and atrial tachyarrhythmia episodes in patients with IAB (p = 0.0275). CONCLUSIONS: In 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.
AIMS: One 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). METHODS: We 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 < 120 ms), partial IAB (P-IAB, P-wave ≥ 120 ms) and A-IAB (A-IAB, P-wave ≥ 120 ms with biphasic morphology in inferior leads). Follow-up was done 1, 6 and 12 months after discharge; then every 6 months. AF episodes, frequent premature atrial contractions (PACs) (>1%) and atrial tachyarrhythmias (runs of >3 consecutive PACs) were detected on 24 h Holter. The primary endpoint was new-onset AF detection on follow-up by any means. RESULTS: A high prevalence of both P-IAB (n = 30, 40%) and A-IAB (n = 23, 31%) was found in 75 ESUS patients. After a 521 day mean follow-up, 14 patients (19%) were diagnosed of AF. A-IAB independently predicted AF diagnosis (p =0.042) on follow-up. 24 h Holter analysis showed greater frequency of PACs and atrial tachyarrhythmia episodes in patients with IAB (p = 0.0275). CONCLUSIONS: In 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.