title: Correlation of modification of heart rate recovery with adaptation to myocardial ischemia in a model of sequential exercise testings.
abstract: BACKGROUND
  Heart rate recovery (HRR) has been identified as a reliable predictor of cardiac mortality, correlated with autonomic tone. In a model of sequential exercise testings, we investigated the reproducibility of HRR and the association between HRR modification and myocardial adaptation to ischemia.
  
  
  METHODS
  We studied 128 patients (mean age 62 +/- 9 years, 83% males) with angiographically documented coronary artery disease (CAD) and a first positive exercise testing, who agreed to undergo a second exercise testing after 24 hours.
  
  
  RESULTS
  HRR was increased from 25 +/- 10 beats/min at the first exercise testing to 30 +/- 13 beats/min at the second exercise testing (P < 0.001). Thereafter, participants were divided into two groups: Group I comprised 88 patients who presented augmentation of the HRR in the first compared to the second exercise testing, while group II comprised 40 patients who presented unchanged or reduced HRR. The rate-pressure product (RPP) at 1 mm ST-segment depression (ischemic threshold) at the second compared to the first exercise testing were significantly improved in group I patients (2345 +/- 3429 mmHg/min), while it was worsened in group II patients (-630 +/- 2510 mmHg/min) (P < 0.001).
  
  
  CONCLUSIONS
  In a model of sequential exercise testings, myocardial adaptation to exercise-induced ischemia was associated with favorable modification of HRR.
authors.affiliation: First Department of Cardiology, Medical School of Athens University, Hippokration Hospital, Athens, Greece. michaelides@freemail.gr
authors.forename: Andreas P
authors.initials: AP
authors.lastname: Michaelides
authors.forename: Christos A
authors.initials: CA
authors.lastname: Fourlas
authors.forename: George K
authors.initials: GK
authors.lastname: Andrikopoulos
authors.forename: Charalambos
authors.initials: C
authors.lastname: Antoniades
authors.forename: Dimitrios
authors.initials: D
authors.lastname: Soulis
authors.forename: Evangelos
authors.initials: E
authors.lastname: Chatzistamatiou
authors.forename: Christodoulos I
authors.initials: CI
authors.lastname: Stefanadis
mesh_terms: D000222:Adaptation, Physiological; D001341:Autonomic Nervous System / Q000503:physiopathology; D017023:Coronary Angiography; D005080:Exercise Test; D005260:Female; D006339:Heart Rate; D006801:Humans; D019157:Ischemic Preconditioning, Myocardial; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000503:physiopathology*