title: Heart rate variability after coronary artery bypass graft surgery: a prospective 3-year follow-up study.
abstract: BACKGROUND
  Autonomic heart rate control is impaired after CABG. The aim of this study was to establish the temporal pattern of change in the decrease of HRV observed after CABG.
  
  
  RESULTS
  Twelve patients with coronary artery disease were assessed with 24-hour Holter recordings 2 days before CABG and 1 week, 3 months, 6 months, 1 year, and 3 years after CABG. All the time-domain and frequency-domain HRV parameters decreased precipitately after CABG and were mostly recovered 3 months after CABG except mean NN, rMSSD, and pNN50. The ratio of LF to HF showed a slight decrease after surgery, recovered to preoperative values after 3 months, surpassed, and continued to increase 6 months after surgery. At 3 years of follow-up the recovery was complete. The rate of change of time-domain and frequency-domain parameters were calculated and their correlation with aortic cross-clamping time, number of vessels bypassed, the amount of cardioplegic used were sought and no statistically significant correlation was found.
  
  
  CONCLUSIONS
  The recovery of HRV regardless to the preoperative state of the patients and their postoperative course implies that the early drop of HRV after CABG was related to the acute effects of surgery. Late complete recovery of HRV may be due to resolution of ischemia or use of angiotensin-converting enzyme inhibitor.
authors.affiliation: Department of Internal Medicine, University of Istanbul, Turkey.
authors.forename: Seref
authors.initials: S
authors.lastname: Demirel
authors.forename: Vakur
authors.initials: V
authors.lastname: Akkaya
authors.forename: Hüseyin
authors.initials: H
authors.lastname: Oflaz
authors.forename: Tufan
authors.initials: T
authors.lastname: Tükek
authors.forename: Osman
authors.initials: O
authors.lastname: Erk
mesh_terms: D000328:Adult; D017677:Age Distribution; D000368:Aged; D001919:Bradycardia / Q000175:diagnosis* / Q000453:epidemiology / Q000209:etiology; D016022:Case-Control Studies; D001026:Coronary Artery Bypass / Q000009:adverse effects* / Q000379:methods; D003327:Coronary Disease / Q000601:surgery; D015716:Electrocardiography, Ambulatory / Q000379:methods*; D005260:Female; D006339:Heart Rate; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D011184:Postoperative Period; D011300:Preoperative Care / Q000379:methods; D011446:Prospective Studies; D012016:Reference Values; D012307:Risk Factors; D017678:Sex Distribution; D018709:Statistics, Nonparametric; D013610:Tachycardia / Q000175:diagnosis* / Q000453:epidemiology / Q000209:etiology