ATRIAL ELECTROPHYSIOLOGICAL STUDIES IN UN EXPLAINED ISCHEMIC CEREBROVASCULAR STROKES

The aim of this study was to search for the presence of atrial vulnera bility by programmed atrial stimulation in patients with unexplained i schaemic cerebrovascular strokes and to evaluate the effects of intrav enous flecainide acetate on the electrophysiological parameters and on the induction of atrial arrhythmias. Thirty-eight patients (20 men, 1 8 women) with a mean age of 38.4 +/- 11 years were investigated. Progr ammed atrial pacing triggered a sustained (> 1 min) atrial arrhythmia with 1 or 2 extrastimuli in 23 of the 38 patients (61 %). in these pat ients, there was a significant shortening of the effective refractory periods (ERP : 193 +/- 23 vs 218 +/- 30 ms; p < 0.02) and of the funct ional refractory periods (FRP : 228 +/- 25 vs 253 +/- 27 ms; p < 0.01) with lengthening of the A2 auriculogramme (99.7 +/- 22 vs 76.1 +/- 16 ms; p < 0.05). A combined study of the refractory periods and conduct ion defects provides a means of calculating an index of latent vulnera bility which is greatly shortened when an atrial arrhythmia is induced (2 +/- 0.5 cm vs 3 +/- 0.6 cm; p < 0.001). Atrial arrhythmias could n ot be initiated after intravenous 3 mg/kg of flecainide acetate in 4 s ubjects (17 %) with initially positive atrial stimulation tests. This study confirms the high frequency of atrial vulnerability in patients with unexplained ischaemic cerebrovascular strokes. In their populatio n, the authors observed a low efficacy of flecainide acetate in the pr evention of reinduction of atrial arrhythmias. The indication of long- term antiarrhythmic drugs in these patients are questionnable and shou ld be assessed by a prospective long-term multicentre trial.