Treatment of Arrhythmias in Myocardial Infarction

More than 90% of the patients with acute myocardial infarction experience some type of arrhythmia. Premature venticular systoles occur most often, and lidocaine is preferred for initial drug therapy. For symptomatic ventricular tachycardia and for ventricular flutter or fibrillation, immediate direct current cardioversion is mandatory. The most important therapeutic aspect of supraventricular arrhythmias is control of the ventricular rate. Rapid rates must be slowed by atrial pacing, direct current cardioversion, or the administration of digitalis. Bradycardias may lead to ectopic beating and should be treated with atropine sulfate, isoproterenol hydrochloride, and artificial pacing if necessary. In patients with atrioventricular (AV) block, the differentiation between Mobitz type 1 and Mobitz type 2 is essential since the latter frequently requires transvenous pacing while the former resolves spontaneously and the problems associated with temporary transvenous pacing may be avoided.