DAY-TO-DAY REPRODUCIBILITY OF TIME-DOMAIN MEASURES OF HEART-RATE-VARIABILITY IN SURVIVORS OF ACUTE MYOCARDIAL-INFARCTION

To assess day-to-day reproducibility of the most commonly used time-do main indexes of heart rate (HR) variability, we compared performance o f HR variability indexes in 2 successive 24-hour predischarge ambulato ry electrocardiograms acquired from 33 clinically stable survivors of acute myocardial infarction. Analysis of relative errors showed compar able stability of time-domain indexes of HR variability except for the pNN50 parameter, the use of which should be favorably substituted by the rMSSD measure.