[Therapeutic strategies in acute myocardial infarction: antiarrhythmic therapy].

Antiarrhythmic therapy is a special case in the therapeutic strategy of acute myocardial infarction. There are very few controlled therapeutic trials and its use is mainly based on clinical experience rather than on scientific evidence. The most common arrhythmias requiring treatment in acute myocardial infarction are atrial fibrillation, ventricular tachycardia and ventricular fibrillation. There is no evidence to support the use Class I antiarrhythmics. Lidocain may be used in some cases. Similarly, contradictory results have been reported with the use of magnesium salts and the general tendency is not to use this ion in acute myocardial infarction. The most commonly used antiarrhythmic agents are the betablockers and amiodarone. The general principles of treatment should be respected: all antiarrhythmic drugs have negative inotropic effects, apart from digitalis. All antiarrhythmics may have a proarrhythmic effect including digitalis, especially in this clinical context. Whenever possible, continuous intravenous infusions are to be preferred to bolus injections. In addition, and when possible, electrotherapy is preferable to antiarrhythmic drug therapy. Finally, a number of cardiac arrhythmias observed in acute myocardial infarction should be "respected" or treated by electrotherapy but never by antiarrhythmic drugs.