Recent studies have emphasized the prognostic significance of left ventricular ejection fraction in patients with coronary and other types of heart disease. Ejection fraction relates as a continuous variable to mortality risk. In patients with a variety of underlying heart diseases, the lower the ejection fraction, the higher observed mortality. However, while ejection fraction is statistically associated with mortality, it is only one of multiple factors that impact on mortality. In order to assess the clinical utility of ejection fraction, it is necessary to assess the sensitivity as well as the specificity of commonly used cut points in identification of patients at mortality risk. In this manuscript, it is shown that ejection fraction lacks sensitivity, and its specificity is suspect in patients with chronic coronary artery disease. The dangers of focusing on ejection fraction are that many patients whose ejection fractions exceed commonly used cut offs experience sudden death. Finally, because ejection fraction is not specific in predicting mode of death, utilization of expensive technology such as the implantable defibrillator based solely on ejection fraction will not be very cost-effective.