LATENT ATRIAL VULNERABILITY IN UNEXPLAINE D ISCHEMIC CEREBROVASCULAR ACCIDENTS OF THE YOUNG

This study searched for abnormalities of the atrial electrophysiologic al substrate in young subjects with unexplained ischaemic cerebrovascu lar accidents. Thirty-seven patients (18 to 45 years) underwent progra mmed atrial stimulation at 2 sites in the right atrium after an unexpl ained ischaemic cerebrovascular accident. Seventeen of them underwent repeat study at 6 months. The following parameters were analysed : ind ices of atrioventricular conduction and sinus node automaticity; indic es related to atrial hyperexcitability : effective refractory period; adaptation of the refractory periods to heart rate, intraatrial conduc tion 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 arrythmia; the effective refract ory periods and index of latent vulnerability were lower (204 +/- 21 m s and 2.25 +/- 0.7) in the inducible patients than in the non-inducibl e patients (232 +/- 28 ms and 3.4 +/- 1.1) (p < 0.001 and p < 0.002 re spectively); 76 % of patients had latent atrial vulnerability indicati ng and underlying arrhythmogenic substrate; this substrate was still p resent 6 months later in 80 % of these cases; in patients with an abno rmality of the interatrial septum. there was an abnormality of the ele ctrophysiological investigation in 85 % of cases compared with 65 % in those with normal transoesophageal echocardiography. These results co nfirm the presence of an arrhytmogenic substrate similar to that of pa tients with paroxysmal atrial fibrillation in over two thirds of cases . Programmed atrial stimulation is a reproducible technique. The relat ionship between latent atrial vulnerability and abnormalities of the i nteratrial septum requires confirmation in a series with a larger numb ers of patients.