title: Predictive power of increased heart rate versus depressed left ventricular ejection fraction and heart rate variability for risk stratification after myocardial infarction. Results of a two-year follow-up study.
abstract: OBJECTIVE
  The aim of this study was to compare the predictive value of mean RR interval assessed from predischarge Holter recordings with that of heart rate variability and left ventricular ejection fraction for risk stratification after myocardial infarction.
  
  
  BACKGROUND
  Heart rate variability is a powerful tool for risk stratification after myocardial infarction. Although heart rate variability is related to heart rate, little is known of the prognostic value of 24-h mean heart rate.
  
  
  METHODS
  A total of 579 patients surviving the acute phase of myocardial infarction were followed up for at least 2 years. Predischarge heart rate variability, 24-h mean RR interval and left ventricular ejection fraction were analyzed.
  
  
  RESULTS
  During the first 2 years of follow-up, there were 54 deaths, 42 of which were cardiac (26 sudden). Shorter mean RR interval was a better predictor of all-cause mortality as well as cardiac and sudden death than depressed left ventricular ejection fraction. Depressed heart rate variability predicted the risk of death better than mean RR interval for sensitivities < 40%. For sensitivities > or = 40%, mean RR interval was as powerful as heart rate variability. All three variables performed equally well in predicting nonsudden cardiac death. For cardiac death prediction, a left ventricular ejection fraction < 35% had a 40% sensitivity, 78% specificity and 14% positive predictive accuracy; a mean RR interval < 700 ms had a 45% sensitivity, 85% specificity and 20% positive predictive accuracy; and a heart rate variability < 17 U had a 40% sensitivity, 86% specificity and 20% positive predictive accuracy.
  
  
  CONCLUSIONS
  Predischarge 24-h mean heart rate is a strong predictor of mortality after myocardial infarction that can compete with left ventricular ejection fraction and heart rate variability.
authors.affiliation: Department of Cardiological Sciences, St. George's Hospital Medical School, London, England, United Kingdom.
authors.forename: X
authors.initials: X
authors.lastname: Copie
authors.forename: K
authors.initials: K
authors.lastname: Hnatkova
authors.forename: A
authors.initials: A
authors.lastname: Staunton
authors.forename: L
authors.initials: L
authors.lastname: Fei
authors.forename: A J
authors.initials: AJ
authors.lastname: Camm
authors.forename: M
authors.initials: M
authors.lastname: Malik
mesh_terms: D015331:Cohort Studies; D016757:Death, Sudden, Cardiac / Q000453:epidemiology*; D015716:Electrocardiography, Ambulatory; D005260:Female; D005500:Follow-Up Studies; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis / Q000401:mortality* / Q000503:physiopathology; D011237:Predictive Value of Tests; D012372:ROC Curve; D012307:Risk Factors; D012680:Sensitivity and Specificity; D013318:Stroke Volume / Q000502:physiology; D013997:Time Factors; D016277:Ventricular Function, Left / Q000502:physiology*