title: The relationship between ventricular repolarization duration and RR interval in normal subjects and patients with myocardial infarction.
abstract: OBJECTIVE
  When either ventricular myocardium becomes ischemic or autonomic nervous system activity changes with age, the relationship between ventricular repolarization duration and RR interval will change as well. We studied the relationship between ventricular repolarization duration and RR interval among normal subjects in different age groups and between patients with myocardial infarction (MI) and age-matched healthy subjects.
  
  
  METHODS
  Ventricular repolarization duration variability (RDV) spectra were separated into RR-dependent and RR-independent components. We compared spectral measures among normal subjects in different age groups and between patients with MI and age-matched healthy subjects.
  
  
  RESULTS
  The RR-dependent component of RDV spectra, which is correlated with autonomic nervous system activity, significantly decreased with age for healthy subjects. The RR-independent component significantly increased in MI patients compared to age-matched healthy subjects.
  
  
  CONCLUSIONS
  We demonstrated the increase in RDV upon decreasing age and in the presence of MI. Our results support the idea that the RR-dependent part corresponds to the physiology-related part of the RDV spectra and the RR-independent part corresponds to the pathology-related part of the RDV spectra. Our study suggests that these spectral measures are likely to be helpful in the evaluation of a patient with MI and merit further investigation.
authors.affiliation: Department of Medicine and Center for Cardiovascular Research, University of Illinois at Chicago, Chicago, Ill., USA.
authors.forename: Yujie
authors.initials: Y
authors.lastname: Zhu
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Lee
authors.forename: Jiapu
authors.initials: J
authors.lastname: Pan
authors.forename: Harvey A
authors.initials: HA
authors.lastname: Lardin
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D001341:Autonomic Nervous System / Q000502:physiology* / Q000503:physiopathology; D016022:Case-Control Studies; D004562:Electrocardiography / Q000379:methods; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D007087:Illinois; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis / Q000503:physiopathology*; D012815:Signal Processing, Computer-Assisted; D016276:Ventricular Function / Q000502:physiology*; D055815:Young Adult