[Value and limitations of programmed ventricular stimulation].

The electrocardiogramme and methods of prolonged ECG recording are sufficient for diagnosing most cardiac arrhythmias. They also provide some prognostic information and allow evaluation and follow-up of treatment. However, in some situations, endocavitary electrophysiological investigations are required when the diagnosis is uncertain, that more prognostic information is required or interventional techniques (endocavitary ablation) are envisaged.

[Ventricular extrasystoles].

Ventricular extrasystoles result from premature excitation of the heart from a site beyond the bifurcation of the bundle of His, at the level of the conductive tissue or myocardial cells. In practice they represent a daily problem for cardiologists due to their frequent occurrence. They can be detected in symptomatic patients and also in asymptomatic subjects, for example during routine health checks.

[Bidirectional ventricular tachycardias].

Bidirectional tachycardias are rare arrhythmias. Nevertheless in the sixties and seventies these arrhythmias prompted much work relating to their mechanism. Discussions about the supposed supra-ventricular origin of certain bidirectional tachycardias essentially rested on presumptive arguments based on electrocardiographic analysis.

High-flow perfusion of sheaths for prevention of thromboembolic complications during complex catheter ablation in the left atrium.

Introduction: Mechanisms for thromboembolic complications during complex ablation procedures in left atrium (LA) have not been defined. The aim of this study was to determine the effect of the perfusion rate of the transseptal sheath on the incidence of thromboembolic complications during catheter ablation for atrial fibrillation (AF) or LA macroreentrant tachycardia.

Methods And Results: We analyzed clinical and procedural data from 86 consecutive patients (153 procedures) referred for catheter ablation of AF (74 patients) or LA macroreentrant tachycardia (12 patients).

[Brugada syndrome].

The Brugada syndrome is characterised clinically by the occurrence of syncope or sudden death due to ventricular arrhythmias in patients with structurally normal hearts and electrocardiographic signs of right bundle branch block and ST elevation in the right precordial leads (V1 to V3). The transmission of the condition is autosomal dominant with variable penetration. Mutations have been identified in a gene coding for the alpha sub-unity of the sodium channel (SCN5A) on chromosome 3 in only 30% of cases.