[Endocavitary ablation for arrhythmias. New modalities of radiofrequency applications. New energy types]. / Ablation endocavitaire des arythmies. Nouvelles modalités d'application de la radiofréquence. Nouvelles énergies.

Radiofrequency remains the reference energy type for catheter ablation of rhythm disorders. In the classic indications, which are atrial flutter or tachycardia, nodal re-entry and Wolff-Parkinson-White syndrome, this energy source has the best cost-efficiency-safety ratio, subject to strict conditions of use. Some new modalities of application have further improved performance, especially active irrigation of the electrode which allows induction of deeper lesions which is very useful for the ablation of difficult atrial flutters, epicardial fascicles of Kent and ischaemic ventricular tachycardias. The only emerging alternative energy type, in the framework of classical ablation, is cold, for which the principal advantages are the homogenous and slightly thrombogenic character for the lesion involved, and the possibility of reversible applications tests which are especially useful in the ablation of structures at risk. The situation is more open-ended concerning research on ablation for atrial fibrillation or the so-called new energy types, such as ultrasound and laser, whilst recognising a renewal in interest, especially for circumferential ablation of the pulmonary veins to isolate the ectopic venous foci. Mechanical energy such as luminous energy is emitted across a catheter balloon deployed at the orifice of the vein, perpendicular to its axis, aiming to reach a continuous circumferential lesion with a minimum of applications. Equally radiofrequency has been undergoing significant evolution for this application, such as by the development of porous catheter balloons with a liquid electrode, as well as by the development of deployable circumferential catheters. Ablation is use for atrial fibrillation, by endocavity atrial segmentation remains a field of research in which radiofrequency retains an important place. It is delivered via multi-electrode catheters according to the new application modalities, either pulsed or by phase interval, which secure better efficacy by better continuity of the line of block. Research is equally underway on the use of microwaves and cold in this application.

[Role of antiarrhythmics in the treatment of paroxysmal atrial fibrillation]. / Place des antiarythmiques dans le traitement de la fibrillation auriculaire paroxystique.

Atrial fibrillation is not a homogenous entity. Numerous parameters affect its cause, its continuation, and the arrest of an attack. The presence or absence of cardiopathy and left ventricular dysfunction play a major role via the electrophysiological and haemodynamic consequences and the repercussions on the state of the autonomic nervous system, and finally on the effect of anti-arrhythmics themselves. This shows the importance of taking into account all of these parameters together in order to adapt the therapeutic approach. Equally, this underlines the difficulty in interpreting clinical studies comparing pharmacological treatments when the populations treated are poorly defined or very heterogenous. Most often, one drug is not more or less effective than another, it is more or less suited to the patients treated. The frequency of recurrences of AF despite anti-arrhythmic treatment (on average 50% to 60% at one year) means that in paroxysmal AF the goal of anti-arrhythmic treatment is relatively modest: essentially reducing the frequency, duration and severity of AF attacks, allowing an improvement in the quality of life. The consequences in daily practice are clear: one must ensure good patient compliance and minimise the risks of treatment: side effects of and pro-arrhythmic effects of anti-arrhythmics.