[Atrial electrophysiological study of unexplained ischemic cerebrovascular disorders].

The aim of this study was to search for the presence of atrial vulnerability by programmed atrial stimulation in patients with unexplained ischaemic cerebrovascular strokes and to evaluate the effects of intravenous flecainide acetate on the electrophysiological parameters and on the induction of atrial arrhythmias. Thirty-eight patients (20 men, 18 women) with a mean age of 38.4 +/- 11 years were investigated. Programmed atrial pacing triggered a sustained (> 1 min) atrial arrhythmia with 1 or 2 extrastimuli in 23 of the 38 patients (61%), in these patients, there was a significant shortening of the effective refractory periods (ERP: 193 +/- 23 vs 218 +/- 30 ms; p < 0.02) and of the functional 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 conduction defects provides a means of calculating an index of latent vulnerability 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 not be initiated after intravenous 3 mg/kg of flecainide acetate in 4 subjects (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 population, the authors observed a low efficacy of flecainide acetate in the prevention of reinduction of atrial arrhythmias. The indication of long-term antiarrhythmic drugs in these patients are questionnable and should be assessed by a prospective long-term multicentre trial.