DRUGS OR IMPLANTABLE CARDIOVERTER-DEFIBRILLATORS IN PATIENTS WITH POOR LEFT-VENTRICULAR FUNCTION

Poor left ventricular function is a predictor of sudden death. Both an tiarrhythmic drugs and implantable cardioverter-defibrillators (ICDs) promise to reduce the sudden death rate in these patients and conseque ntly improve survival. In patients without spontaneous ventricular tac hyarrhythmias, only beta-blocking agents and amiodarone have been show n to reduce sudden death and improve survival in some studies, whereas class I antiarrhythmic dregs increased mortality. For patients with d ocumented ventricular tachyarrhythmias, protection against sudden deat h by serially tested class I antiarrhythmic drugs is at best moderate. There is some evidence suggesting that therapy with class III antiarr hythmic drugs, either amiodarone or dl-sotalol, may reduce sudden deat h rates and improve overall mortality in comparison to therapy with cl ass I antiarrhythmic drugs. ICDs have been shown to prevent sudden dea th reliably. In published patient cohorts in which only patients who w ere not inducible off antiarrhythmic drugs or still inducible on antia rrhythmic drugs received an ICD, the ICD seemed to improve overall sur vival in comparison to class I antiarrhythmic drugs. A small prospecti ve randomized study that compared a conventional therapy strategy to p rimary ICD implantations showed an improved outcome with ICDs as thera py of first choice. However, these studies included many patients trea ted with class I antiarrhythmic drugs considered to be less effective. In matched control studies comparing the ICD to amiodarone or dl-sota lol, less sudden deaths and an improved overall survival could be show n for the ICD in general without stratification for left ventricular f unction. Thus, in patients with hemodynamically nontolerated ventricul ar tachyarrhythmias, the ICD seems to improve survival in comparison t o class I antiarrhythmic drugs, dl-sotalol, or amiodarone. However, in patients with poor left ventricular function, therapy with ICDs seems to be less cost-effective than in patients with preserved left ventri cular function. In patients with very poor left ventricular function w ho are evaluated for cardiac transplantation, the ICD seems to change only the mode of death from sudden to a nonsudden cardiac death if tra nsplantation cannot be performed soon.