One hundred thirty patients with idiopathic-dilated cardiomyopathy were referred for heart transplantation to our center and followed for 18 months. Heart transplantation was performed on 63 patients, 17 patients died before transplantation due to heart failure, and 50 patients never had transplantation. Clinical, electrocardiographic, echocardiographic, and hemodynamic data of the 50 nontransplanted survivors and the 17 patients who died were used to identify independent risk variables with discriminant analysis. Using a statistical model based on the results of discriminant analysis, each of the remaining 63 transplanted patients were predicted as being alive or dead in absence of transplantation. The discriminant analysis identified right atrial pressure, cardiac index, and the New York Heart Association functional class as the strongest predictors of 18-month outcome. The accuracy of the model in predicting survival without transplantation in the nontransplanted group of patients, based on the concordance between actual and predicted outcome, was 85% (kappa = 0.62). Subsequent application of this model to the transplanted group of patients suggested that the decision for transplantation was appropriate in 41 of the 63 patients, and could have been premature in the remaining 22 patients predicted as alive. These results suggest that two-thirds of patients receiving transplants would have died without intervention, but the decision to transplant could have been premature in the remaining patients.