RELATIONS BETWEEN HEART-FAILURE, EJECTION FRACTION, ARRHYTHMIA SUPPRESSION AND MORTALITY - ANALYSIS OF THE CARDIAC-ARRHYTHMIA SUPPRESSION TRIAL

Objectives. We studied the relations between heart failure, ejection f raction, arrhythmia suppression and mortality. Background. Both left v entricular ejection fraction and functional class of heart failure are strongly associated with mortality after acute myocardial infarction. Both are also related to the presence of ventricular arrhythmias and have been identified as factors related to the ability to suppress ven tricular arrhythmias. Little has been reported about the relations bet ween these two factors and arrhythmia suppression or mortality. Method s. Baseline data from the Cardiac Arrhythmia Suppression Trial were us ed to define several categories of heart failure and to relate both th e resulting categories and ejection fraction to arrhythmia suppression and mortality using logistic and survival regression analytic methodo logies. Results. Regardless of the prospective baseline definition of heart failure used, the data consistently showed that heart failure wa s a more powerful predictor of subsequent congestive heart failure eve nts and arrhythmia suppression and was equally powerful in predicting death. However, each variable provided incremental information when in cluded in the prediction model. Heart failure and ejection fraction ap peared to be independent predictors of death. Interactions were observ ed: A low ejection fraction was more predictive of failure of arrhythm ia suppression in patients with than without evidence of heart failure before or at baseline; a low ejection fraction was more predictive of subsequent congestive heart failure events in patients without than w ith evidence of heart failure before or at baseline. Conclusions. Alth ough heart failure as a prognostic feature appears to be somewhat supe rior to ejection fraction, both are powerful predictors of arrhythmia suppression and cardiac events in patients with ventricular arrhythmia after myocardial infarction. Each provides incremental prediction.