VALIDATION OF A CLINICAL-PREDICTION RULE FOR LEFT-VENTRICULAR EJECTION FRACTION AFTER MYOCARDIAL-INFARCTION IN PATIENTS GREATER-THAN-OR-EQUAL-TO-65 YEARS OLD

We sought to validate a previously described clinical prediction rule for classifying left ventricular ejection fraction (LVEF) after acute myocardial infarction (AMI). As part of the Connecticut cohort of the Cooperative Cardiovascular project (CCP) pilot study, we identified 3, 093 Medicare patients who had been admitted to hospitals throughout Co nnecticut with an AMI in 1992 and 1993. Retrospective chart review and detailed electrocardiogram interpretation were performed. Of the 1,89 1 patients with an interpretable EF, 1,378 (73%) had greater than or e qual to 1 of the rule's exclusion criteria. Of the remaining 513 patie nts, the clinical prediction rule had a positive predictive value of 8 9% (i.e., 456 of 513 patients had an EF greater than or equal to 40%). In a multivariate model, presentation >6 hours after the onset of che st pain, a history of bypass surgery, and diabetes mellitus were assoc iated with patients in whom the rule did not correctly predict an EF g reater than or equal to 40%. Excluding patients with these characteris tics from the rule increased the positive predictive value from 89% to 93% and excluded an additional 239 patients. The EF could not be pred icted among the patients who did not meet the rule's criteria. In conc lusion, a previously published clinical prediction rule for the classi fication of the EF in patients after an AMI correctly classified 8 of every 9 eligible elderly patients as having an EF greater than or equa l to 40%. Thus, while not performing as well as it did in the original study, our findings support the use of this rule in providing clinici ans with an objective method for estimating an EF greater than or equa l to 40% in a specific subset of elderly patients. (C) 1997 by Excerpt a Medica, Inc.