CORRELATION OF SIGNAL-AVERAGED P-WAVE WITH ELECTROPHYSIOLOGICAL TESTING FOR ATRIAL VULNERABILITY IN STROKES OF UNEXPLAINED ETIOLOGY

Atrial fibrillation is considered the main cause of cardioembolic strokes. After detailed investigations, about 30 % of ischemic strokes remain unexplained. A percentage of these ischemic attacks may result from asymptomatic episodes of paroxysmal atrial fibrillation (PAF). Previous studies have demonstrated that electrophysiological testing and signal-averaged P wave (SAPW) ECG are useful to detect patients with PAF. Methods and Results: Twenty patients with unexplained ischemic strokes had electrophysiological studies (EPS) to determine atrial vulnerability and SAPW recordings. At EPS, patients were classified in group I (10 patients) if they had a latent atrial vulnerability index < 2 and/or more than 1 minute of sustained atrial arrhythmia. Otherwise they were classified in group II (10 patients). In group I; the filtered P wave duration was greater: 142 versus 120 msec (P = 0.03) and RMS 30 tended to be lower: 2.54 versus 4.13 mu V (P = 0.11) than in group II, A filtered P wave duration, 125 msec associated with a RMS 30 < 3 mu V had a positive predictive value of 78 % and a negative predictive value of 88 % for the detection of patients with abnormal atrial vulnerability at EPS. Conclusions: SAPW may be useful to identify patients at risk of PAF who may be candidates for EPS.