Treatment of ventricular arrhythmias after recovery from myocardial infarction.
Demonstrated associations between postmyocardial infarction ventricular arrhythmias and a higher subsequent risk of both sudden and all-cause mortality have prompted a search for effective and safe treatment modalities. Recently completed clinical trials have provided a rationale for treatment recommendations in some specific settings. Beta-blocking therapy is recommended for postinfarction patients with frequent or complex ventricular premature beats. In contrast, calcium antagonist therapy is not helpful in these cases, and Class I antiarrhythmic therapy is actually harmful. Early indications of benefit from Class III antiarrhythmic therapies, particularly amiodarone, are under evaluation in large trials. Patients with sustained ventricular tachycardia (VT) or ventricular fibrillation (VF) occurring late after myocardial infarction require therapy. Viable therapeutic methods include individualized antiarrhythmic therapy selected by the noninvasive approach, individualized antiarrhythmic therapy selected by the invasive approach, empiric amiodarone therapy, transcatheter or surgical ablative therapy (for VT), and use of an implantable cardioverter defibrillator. Clinical trial data have yet to determine which of these approaches is most effective under which circumstances. Postinfarction patients with nonsustained VT are the focus of several ongoing treatment trials. Early data suggest that risks requiring specific therapy are reached only by those patients who also have significant left ventricular dysfunction. The presence of inducible sustained ventricular tachycardia at an electrophysiologic study may further risk stratify such patients. High-risk patients with nonsustained ventricular tachycardia, left ventricular dysfunction, and inducible sustained ventricular tachycardia should participate in ongoing clinical trials. In the absence of this opportunity, intensive treatment should be considered.