Fibrillatory wave amplitude and thromboembolic risk in non-anticoagulated patients with atrial fibrillation

Abstract

Background The benefit of oral anticoagulation in atrial fibrillation (AF) is well established for patients at elevated stroke risk, but less clear for those at intermediate risk. We investigated whether analysis of electrocardiogram (ECG) derived fibrillatory waves (F-waves) could help identify patients at risk for stroke and systemic embolism (SSE). Methods The Finnish Cardioversion (FinCV) study included patients not on permanent anticoagulation therapy who underwent cardioversion for an acute AF episode. We identified 739 individuals with a valid ECG and complete follow-up data. The maximum amplitudes of the F-waves in leads II and V1 were manually measured from the pre-procedure ECG. Patients were categorized into fine and coarse F-wave groups. The optimal lead and amplitude threshold for grouping were found in an events per person-years analysis. SSE were identified from the patient medical records until either anticoagulation was prescribed, AF was deemed chronic, the patient had deceased, or the end of follow-up. Results Overall 37 (5.0%) patients suffered SSE during the median follow-up time of 5.4 years (1.9–10.8). Measured from lead V1 the SSE rates per 100 person-years were 1.5 and 0.7 in fine and coarse F-wave groups, respectively. Fine F-waves were observed in 112 (15.2%). Baseline characteristics were similar between the groups. Fine F-wave predicted SSE in a competing risk analysis (SHR 2.34, 95%CI 1.12–4.87, p = .023). Analyses from lead II did not provide significant results. Conclusion Electrocardiographic F-wave amplitude may provide additional information on stroke risk in patients with paroxysmal AF and borderline indications or contraindications for anticoagulation.