Identifying the High Risk Patient with Coronary Artery Disease—Is Ejection Fraction All You Need?

Abstract

Although the total number of deaths resulting from cardiovascular disease has decreased in the United States, the percentage of cardiac deaths that occur suddenly has increased. Over the past 10 years, a number of randomized clinical trials have evaluated the ability of antiarrhythmic therapy to reduce mortality in patients in patients with chronic coronary disease and abnormal left ventricular function that had not yet developed spontaneous sustained VT or VF. A majority of these trials have demonstrated that the implantable cardioverter-defibrillator (ICD) can reduce mortality compared to pharmacologic antiarrhythmic therapy, or no specific antiarrhythmic therapy. While, reduced left ventricular ejection fraction (EF) has been a major determinant for entry into these studies, in all but one case, it was not the sole entry requirement. These studies have demonstrated that a number of factors have prognostic significance, and therefore impact efficacy of the ICD. None of these studies was designed to evaluate the relative efficacy of various risk factors. Therefore, we lack adequate information today to determine the most cost-effective manner in which to assign use of ICDs for primary prevention. This article reviews the potential for using EF alone as a risk factor, as well as the efficacy of other variables for risk stratification.