title: Sex steroids and heart rate variability in patients after myocardial infarction.
abstract: BACKGROUND
  Although the relationship between sex steroid levels and coronary artery disease (CAD) has been the subject of many studies there are still controversies concerning the role of sex steroids in CAD. In patients with CAD, especially after a myocardial infarction, there is evidence for autonomic nervous system dysfunction. However, there is no data detailing the relationship between sex steroids and cicardian autonomic activity in patients with CAD. The aim of the study was to evaluate the association between sex steroids and heart rate variability (HRV) parameters in postinfarction patients.
  
  
  METHODS
  In 88 postinfarction men (aged 36-73, average 53 years), 24-hour Holter monitoring was performed to assess HRV parameters: SDNN, SDNNI, SDANN, rMSSD, pNN50, and levels of the following hormones were measured: testosterone, estradiol, free testosterone index, and estradiol/testosterone ratio. Univariate and multivariate regression analyses were used to investigate the relationship between HRV parameters and levels of tested hormones.
  
  
  RESULTS
  Increased testosterone levels were associated with increased SDNN (r = 0.38, P = 0.03), increased rMSSD (r = 0.51, P = 0.002), and increased pNN50 (r = 0.45, P = 0.007). These associations remained significance after adjustment for age, ejection fraction, and other relevant clinical covariates. There was no significant association between estradiol and HRV parameters.
  
  
  CONCLUSIONS
  In men with a history of myocardial infarction, higher levels of testosterone are associated with higher HRV measures of parasympathetic activity. These findings suggest that testosterone beneficially influences autonomic regulation of the heart.
authors.affiliation: Department of Cardiology, Medical University of Lodz, Lodz, Poland. holter@csk.am.lodz.pl
authors.forename: Jerzy Krzysztof
authors.initials: JK
authors.lastname: Wranicz
authors.forename: Marcin
authors.initials: M
authors.lastname: Rosiak
authors.forename: Iwona
authors.initials: I
authors.lastname: Cygankiewicz
authors.forename: Piotr
authors.initials: P
authors.lastname: Kula
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Kula
authors.forename: Wojciech
authors.initials: W
authors.lastname: Zareba
mesh_terms: D000328:Adult; D000368:Aged; D000728:Androgens / Q000378:metabolism; D015415:Biomarkers / Q000097:blood; D003324:Coronary Artery Disease / Q000097:blood / Q000503:physiopathology; D004452:Echocardiography; D015716:Electrocardiography, Ambulatory; D004958:Estradiol / Q000378:metabolism; D006339:Heart Rate / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009203:Myocardial Infarction / Q000097:blood* / Q000503:physiopathology*; D013223:Statistics as Topic; D013256:Steroids / Q000378:metabolism*; D013318:Stroke Volume / Q000502:physiology; D013739:Testosterone / Q000378:metabolism
chemical_list: D000728:Androgens; D015415:Biomarkers; D013256:Steroids; D013739:Testosterone; D004958:Estradiol