[Brugada syndrome and supraventricular arrhythmias]. / Syndrome de Brugada et arythmies supraventriculaires. A propos d'une observation clinique.

The author reports the case of a 46-year old patient diagnosed with idiopathic ventricular fibrillation (Brugada syndrome) further to induction of class Ic antiarrhythmic therapy for the management of paroxystic ventricular fibrillation. It would appear that this diagnosis is increasingly frequent in young patients with Brugada syndrome shown to be minimal or intermittent on electrocardiograms. Atrial arrhythmia was the only rhythmic pathology objectively evidenced in this patient and the author was consequently led to reconsider its prevalence in patients presenting this syndrome both in the literature and according to his personal experience.

[Simplified approach to ablation in atrial flutter using a single catheter electrode. Based on 70 cases]. / Approche simplifiée de l'ablation du flutter auriculaire par un seul cathéter muni d'électrodes. A propos de 70 observations.

The object of this study was to assess the feasibility, efficacy and risks of ablation of common atrial flutter using a single catheter electrode. Recent studies have shown that radiofrequency ablation is effective for interrupting atrial flutter but with a variable rate of recurrence. Therefore, the search for a conduction block in the isthmic region has become the reference method for reducing the incidence of recurrence but this requires the use of costly material. The necessity of single usage has incited research to find a less costly method without compromising efficacy. The authors reviewed the results in 70 consecutive patients with common atrial flutter resistant to anti-arrhythmic medication. The site of ablation was located using anatomical landmarks and electrophysiological criteria. The anatomic site was situated either on a lateral isthmus or, to a variable degree, a septal isthmus; the electrophysiological criterion was an endocavitary auriculogramme, the amplitude of which had to decrease by more than 2/3 after application of the radiofrequency. The technique was interrupted not after the interruption of the flutter but after obtaining a microvoltage atrial activity along the isthmus. Radiofrequency energy of 10 to 50 W was delivered at each site for 90 seconds. Atrial flutter was interrupted in all 70 patients (100%). The average number of applications to interrupt the flutter was 12.67 and to create a microvoltage barrier 14.58. The average duration of the radiofrequency procedure was 50.43 minutes. After an average of six months' follow-up, the recurrence rate was 13%: 9 patients, 5 of whom underwent a second session of radiofrequency ablation. There were no immediate complications after this method of ablation.

[Effort-induced atrioventricular block. Apropos of 62 cases]. / Blocs auriculo-ventriculaires d'effort. A propos de 62 cas.

Based on a retrospective study, we report the clinical and electrophysiological characteristics of 62 cases of effort-induced atrio-ventricular block (AVB). The diagnosis of effort-induced AVB was established by stress test and/or Holter ECG. This series consisted of 18 women and 44 men with a mean age of 64 +/- 13 years. AVB presented in the form of poor adaptation to effort in 41 patients (66%), fainting and/or presyncope suggestive of Stokes-Adams attacks in 20 patients (32%), associated with poor adaptation to effort, except in 5 patients. 48 patients (77%) did not have any underlying heart disease. The ECG was normal in 25 patients (40%) or abnormal, demonstrating a 1st degree AVB and/or an intraventricular conduction disorder. On electrophysiological investigation, the AVB was type II (Mobitz II) in 48 patients (77%), generally 2/1. The block was infranodal, either in or below the His bundle, in 56 patients (90%). When it was situated above the His bundle, it was organic and degenerative, situated at the AV node, at the node-His junction, or even proximally in the His bundle. Effort-induced AVB implies DDD atrioventricular stimulation. The presence of this anomaly should be investigated in patients with poor adaptation to effort, but also when the clinical picture is dominated by Stokes-Adam attacks.

[Supraventricular tachycardia due to simultaneous conduction in the rapid and slow nodal pathways. Treatment by ablation of the slow pathway]. / Tachycardie supraventriculaire due à une conduction simultanée dans la voie nodale rapide et lente. Traitement par ablation de la voie lente.

The authors report the case of a 70 year old woman with frequent attacks of supraventricular tachycardia resistant to antiarrhythmic therapy. The tachycardia was irregular with predominantly normal QRS complexes. Electrophysiological investigation showed dual conduction in the atrioventricular node and tachycardia was induced by atrial extrastimulus. However, reentrant tachycardia could not be induced, the refractory period of the slow pathway being much longer than that of the rapid pathway. The mechanism of the tachycardia was simultaneous conduction of the sinus rhythm through the two nodal conduction pathways. This was successfully treated by radiofrequency ablation of the slow pathway.

[Tilt test in the etiological diagnosis of syncope unexplained by electrophysiological study]. / Apport du test d'inclinaison dans le diagnostic étiologique des syncopes inexpliquées après exploration électrophysiologique.

In order to determine the role of tilt testing in the aetiological diagnosis of syncope unexplained by electrophysiological investigation, the authors retrospectively studied the results of this test in 275 patients with a mean age of 64 +/- 16 years. These 275 patients were divided into two groups: group I: 43 patients with a mean age of 50 +/- 19 years presenting with vagal syncopes, group II: 232 patients with unexplained syncope, probably vagal: group IIa (120 patients, mean age: 67 +/- 15 years), sudden syncope: group IIb (112 patients, mean age: 67 +/- 13 years). The electrophysiological investigation was inconclusive in every case. In group II, 50% of tilt tests were positive (19% under basal conditions, 31% after isoproterenol), with 61% of positive tests in group IIa, including 31% on the basal test, and 38% of positive tests in group IIb, including 11% on the basal test. In group I, 84% of tests were positive (33% on the basal test, 51% after isoproterenol), indicating a sensitivity of the test of 84%. In 96 patients with a doubtful electrophysiological investigation, the tilt test was positive in 70% of cases, allowing specific treatment or a pacemaker to be avoided in the majority of cases. 84% of vasovagal syncopes were therefore confirmed by tilt testing; 50% of syncopes unexplained by electrophysiological investigation were demonstrated to be of vasovagal origin. The author emphasize the value of tilt testing in certain discordant situations in which the clinical context is disturbing and/or electrophysiological investigation is not completely reassuring.

[Left syncopal bundle-branch block during tachycardia. A new, syndrome?]. / Bloc de branche gauche syncopal per-tachycardique. Nouveau syndrome?

The authors report four observations: three are essentially clinical cases where sustained rate dependent left bundle branch block can induce syncope, where as there is no syncope when the same supraventricular tachycardia at the same frequency has narrow QRS complexes. The fourth case demonstrates the dramatic decrease of arterial electrophysiological slowly accelerated atrial pacing in a patient investigated for a loss of consciousness of unknown origin. The hemodynamic impairment due to intermittent left bundle branch block has been demonstrated even in patients with normal ventricular function. If there are critical hemodynamic events such as during fast supraventricular rhythms occurrence of a left bundle branch block may determinate a dramatic decrease of arterial pressure with syncope. Syncope of supraventricular tachycardias might be induced not only by very fast rate but also by functional left bundle branch block. It might have some interesting applications in the diagnosis of syncope when coexist electrophysiological data of supraventricular arrhythmia substrate and frequency dependent left bundle branch block.

[Evaluation of electrophysiological properties of asymptomatic Wolff-Parkinson-White syndromes. Comparison with symptomatic Wolff-Parkinson-White syndromes]. / Evaluation des propriétés électrophysiologiques des syndromes de Wolff-Parkinson-White asymptomatiques. Comparaison avec les syndromes de Wolff-Parkinson-White symptomatiques.

The aim of this study was to compare the electrophysiologic properties of asymptomatic Wolff-Parkinson-White (WPW) syndromes with those of symptomatic WPW, and in particular the anterograde refractory period of the accessory tract and atrial vulnerability. This retrospective study involved 171 patients with WPW seen in their surface electrocardiogram, untreated, having undergone standard invasive electrophysiologic investigation. These patients were divided into two groups: group I consisting of 42 asymptomatic patients and group II consisting of 129 asymptomatic patients. 1) The mean anterograde refractory period (mean ARP) did not differ statistically between group I (330 +/- 97 msec) and group II (311 +/- 110 msec). The mean minimum interval between two preexcited complexes during atrial fibrillation (mean RR min) did not differ statistically between group I (313 +/- 80 msec) and II (300 +/- 105 msec). The mean retrograde refractory period (mean RRP) was significantly (p < 0.001) longer in group I (416 +/- 126 msec) than in group II (307 +/- 75 msec). 2) A reciprocal tachycardia was induced in 95% of cases in group II (122 patients) as compared with 9.5% of cases in group I (4 patients), with a very significant (p < 0.001) difference. Atrial fibrillation was induced in 24% of cases in group I (10 patients) and 34% of cases in group II (44 patients), the difference not being significant. 3) The incidence of potentially serious forms did not differ statistically between groups I and II. Nine patients in group I (21.4%) and 49 patients in group II (38%) had rapid anterograde conduction in the accessory tract (ARP or RR < or = 250 msec).(ABSTRACT TRUNCATED AT 250 WORDS)