Prospective assessment of a nongeometric Doppler-derived index of combined systolic and diastolic myocardial performance was performed in 64 patients with acute myocardial infarction (MI) within 1 hour after their arrival to the hospital and in 39 age-matched healthy subjects. The index is defined as the sum of isovolumetric contraction time and relaxation time divided by ejection time, and is obtained by Doppler measurement from the mitral inflow and left ventricular outflow velocity-time intervals. The index was significantly higher in patients with MI compared with healthy subjects (P <.0001). In patients with MI and in-hospital congestive heart failure (CHF), the index was significantly higher compared with patients without CHF. In a multivariate regression analysis, the index >0.45 was the strongest independent predictor of the development of CHF. This simply obtained nongeometric Doppler index, assessed in the early phase of MI, detected and graded left ventricular dysfunction and identified patients at risk for the development of CHF.