Comparison of the predictive characteristics of heart rate variability index and left ventricular ejection fraction for all-cause mortality, arrhythmic events and sudden death after acute myocardial infarction.

Heart rate (HR) variability index and left ventricular ejection fraction (EF) were compared for the prediction of all-cause mortality, arrhythmic events and sudden death in 385 survivors of acute myocardial infarction. For arrhythmic events, where, for a sensitivity of 75%, HR variability index had a specificity of 76%, EF had a specificity of only 45%. An EF of less than or equal to 40% had a sensitivity of 42% and a specificity of 75% for arrhythmic events; for the same sensitivity an HR variability index of 20 U had a specificity of 92%. An EF less than or equal to 40% had a sensitivity of 40% and a specificity of 73% for sudden death; HR variability index had a specificity of 83% for the same sensitivity. For all cause mortality, where, for a sensitivity of 75%, HR variability index had a specificity of 52%, EF had a specificity of 40%. It is concluded that HR variability index appears a better predictor of important postinfarction arrhythmic complications than left ventricular EF, but both indexes perform equally well in predicting all-cause mortality.