[Control of ventricular response in patients with atrial fibrillation]

The underlying treatment of atrial fibrillation comprises two possible options. In the best of cases, sinus rhythm obtained by cardioversion must be maintained by appropriate therapy. This solution is the best option for preventing the risks of embolism or of myocardial deterioration. In refractory cases, the remaining option is to control the ventricular response. The principle is to maintain the rhythm within acceptable limits (70 to 90/min at rest), an action which also aims to limit the response to effort. This results in a symptomatic improvement and protects myocardial function. Digitalis is the commonest drug used for controlling the ventricular response. It is usually successful at recommended therapeutic doses, but often fails to control the response to effort. Adjustment of dosage using plasma concentrations may improve the situation. Another method of improving the control of the ventricular response is to associate digitalis with beta-blockers or calcium inhibitors. The risk of this option is the induction of an excessive bradycardia but, on the other hand, the response to exercise can be reduced and the variations of ventricular response decreased over a 24 hour period. In forms resistant to pharmacological treatment, it is possible to intervene directly on the atrioventricular conduction pathways. Radio frequency current is used in this indication. Sometimes, the objective is only to alter atrioventricular conduction to reduce the ventricular response to atrial fibrillation. In fact, this is often difficult to obtain and a number of cases develops complete atrioventricular block. In general, the aim is to create complete atrioventricular block which is then associated with implantation of a pacemaker.(ABSTRACT TRUNCATED AT 250 WORDS)