Effects of hormone replacement therapy on heart rate variability in postmenopausal women

Aylin Yildirir, Giray Kabakci, Hakan Yarali, Funds Aybar, Ebru Akgul, Orhan Bukulmez, Lale Tokgozoglu, Timur Gurgan, Ali Oto

Research output: Contribution to journalArticle

27 Scopus citations

Abstract

Background: Hormone replacement therapy (HRT) is associated with reduced cardiovascular risk, but the underlying mechanism(s) are not fully understood. This study investigated the effects of a 6-month course of HRT on cardiac autonomic function parameters assessed by heart rate variability (HRV) in postmenopausal women. Methods: Forty-six healthy postmenopausal women (age 48 ± 5, range 40-60) with normal baseline electrocardiogram and negative exercise testing were enrolled. HRT, which was either 0.625 mg/day conjugated equine estrogen (CEE) plus 2.5 mg/day medroxyprogesterone acetate or 0.625 mg/day CEE alone were administered depending on hysterectomy status. Power spectral analysis of HRV was performed to calculate the low frequency component in absolute (LF) and normalized units (LF nu), high frequency component in absolute (HF), and normalized units (HF nu), and the LF/HF ratio. The standard deviation of RR intervals (SDNN) was calculated from the time series of RR intervals. Results: A 6-month course of HRT did not significantly alter resting heart rate (P > 0.05). The LF/HF ratio and LF nu significantly decreased after HRT (P = 0.022 and P = 0.032), whereas a significant increase was noted in the HF component of HRV (P = 0.043), indicating an improvement in cardiac autonomic function. The SDNN value, which was 28.8 ± 11.8 ms before HRT significantly increased to 35.4 ± 16.7 ms after 6 months (P = 0.011). Conclusion: Our results indicate that a 6-month course of HRT may significantly improve cardiac autonomic function._parameters, a finding that could at least partly explain the potential cardioprotective effect(s) of HRT.

Original languageEnglish (US)
Pages (from-to)280-284
Number of pages5
JournalAnnals of Noninvasive Electrocardiology
Volume6
Issue number4
DOIs
StatePublished - Jan 1 2001

Keywords

  • Heart rate variability
  • Hormone replacement therapy
  • Menopause

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)

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