• E Somody, J F Albucher, M Delay, F Chollet, J P Bonnet, J Fourcade, B Guiraud-Chaumeil, and J Puel.
• Service de cardiologie, CHU Toulouse Purpan, Toulouse.
• Arch Mal Coeur Vaiss. 1996 Nov 1; 89 (11): 1365-73.

AbstractThis study searched for abnormalities of the atrial electrophysiological substrate in young subjects with unexplained ischaemic cerebrovascular accidents. Thirty-seven patients (18 to 45 years) underwent programmed atrial stimulation at 2 sites in the right atrium after an unexplained ischaemic cerebrovascular accident. Seventeen of them underwent repeat study at 6 months. The following parameters were analysed: indices of atrioventricular conduction and sinus node automaticity; indices related to atrial hyperexcitability: effective refractory period; adaptation of the refractory periods to heart rate, intraatrial conduction and the index of latent vulnerability; the inducibility test by the extrastimulus technique. The following results were obtained: 54% of patients had an inducible atrial arrhythmia; the effective refractory periods and index of latent vulnerability were lower (204 +/- 21 ms and 2.25 +/- 0.7) in the inducible patients than in the non-inducible patients (232 +/- 28 ms and 3.4 +/- 1.1) (p < 0.001 and p < 0.002 respectively); 76% of patients had latent atrial vulnerability indicating and underlying arrhythmogenic substrate; this substrate was still present 6 months later in 80% of these cases; in patients with an abnormality of the interatrial septum, there was an abnormality of the electrophysiological investigation in 85% of cases compared with 65% in those with normal transoesophageal echocardiography. These results confirm the presence of an arrhythmogenic substrate similar to that of patients with paroxysmal atrial fibrillation in over two thirds of cases. Programmed atrial stimulation is a reproducible technique. The relationship between latent atrial vulnerability and abnormalities of the interatrial septum requires confirmation in a series with a larger numbers of patients.

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