title: Heart rate variability as an assessment of acute rejection after heart transplantation.
abstract: BACKGROUND
  Orthotopic heart transplantation is currently a widely accepted treatment for end-stage heart disease. Early detection and adequate therapy of acute rejection increases the survival rate. Currently, the most reliable technique for the detection of acute cardiac rejection (ACR) is endomyocardial biopsy (EMB), which is an invasive procedure with some intrinsic problems. The purpose of this study was to assess heart rate variability (HRV) as a noninvasive procedure for frequent monitoring of ACR.
  
  
  METHODS
  Six consecutive orthotopic cardiac transplant recipients were prospectively recruited into this study. The follow-up periods ranged from seven to 359 days (median; 146 days). A precordial electrocardiograph (ECG) of 288 seconds was recorded at 5:00 PM before the patient underwent EMB. The results from the frequency domain analysis of the ECG signals were evaluated to correlate with the findings from EMB.
  
  
  RESULTS
  Of 48 EMBs, 42 (87.5%) showed no evidence of rejection, four showed mild focal ACR (EMB grade 1A), one mild diffuse ACR (1B) and one moderate plurifocal ACR (3A). There was no moderate focal ACR (2), severe diffuse ACR (3B) or severe ACR (4). Correlation between ACR (3A) and a significant increase in HRV with a corresponding 'broad-band' or bell-shaped pattern on the power spectrum was noted.
  
  
  CONCLUSIONS
  Our study in consecutive cardiac transplant recipients indicates that the changes in HRV provide clinicians with a new concept for heart transplant monitoring. Further study is needed to verify clinical utility.
authors.affiliation: Department of Physical Medicine and Rehabilitation, Veterans General Hospital-Taipei, Taiwan, ROC.
authors.forename: C L
authors.initials: CL
authors.lastname: Chou
authors.forename: N T
authors.initials: NT
authors.lastname: Kao
authors.forename: T B
authors.initials: TB
authors.lastname: Kuo
authors.forename: T J
authors.initials: TJ
authors.lastname: Liu
authors.forename: R C
authors.initials: RC
authors.lastname: Chan
mesh_terms: D000208:Acute Disease; D000328:Adult; D000368:Aged; D005260:Female; D006084:Graft Rejection; D006339:Heart Rate; D016027:Heart Transplantation / Q000276:immunology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies