[Menopausal changes in circadian heart rate variability].
OBJECTIVE
Presence of cardiovascular symptoms in perimenopausal period is suggested to be associated with the decrease of cardiac autonomic nervous system (cANS) regulatory function.


OBJECTIVE
Aim of the study was to evaluate whether menopause affects circadian heart rate variability (HRV).


METHODS
42 healthy women were divided into two equal groups: premenopausal (age 43 +/- 7 years) and postmenopausal (age 53 +/- 3 years, 3.25 +/- 1.6 years after the last menstruation). Menopausal status was verified by plasma estradiol and FSH activities. In both groups the outpatient 24-hrs ECG recordings were carried out. The HRV parameters (SDNN, pNN50, r-MSSD, nLF, nHF) were analysed within the day-time (6 a.m. - 10 p.m.) and the night-time (10 p.m. - 6 a.m.) ECG.


RESULTS
Day-time recordings showed higher SDNN (128 +/- 23 vs. 104 +/- 36, p = 0.01), pNN50 (18 +/- 8.3 vs. 7 +/- 4.4 p < 0.001), nLF (74 +/- 11 vs. 33 +/- 5 p < 0.01) in the premenopausal patients and higher nHF in the postmenopausal women (39 +/- 3.4 vs. 26 +/- 11, p < 0.01). In the night-time recordings we observed higher pNN50 (24 +/- 20 vs. 13 +/- 10, p = 0.01) and nLF (66.5 +/- 17 vs. 37 +/- 5.8, p < 0.01) in the premenopausal patients with nHF higher in the postmenopausal group (44 +/- 5.7 vs. 31.4 +/- 17, p < 0.01). In the premenopausal women higher r-MSSD and nHF values were observed at the night time (respectively p = 0.03 and p = 0.04). Simultaneously higher night-time values of pNN50 (p = = 0.03) and nHF (p = 0.001) were noted in the postmenopausal group.


CONCLUSIONS
Lower time HRV parameters suggest decreased parasympathetic regulation of the heart. Lower nLF indicates impairment of the arterial baroreceptor reflexes, whereas the increase of nHF requests further studies.
Katedra Patofizologii, Collegium Medicum Unwersytetu Jagielloriskiego, Kraków.
Agata
A
Ryś
Andrzej
A
Ryś
Piotr
P
Kogut
Piotr J
PJ
Thor
D000328:Adult; D001145:Arrhythmias, Cardiac / Q000503:physiopathology*; D002940:Circadian Rhythm; D015716:Electrocardiography, Ambulatory; D004958:Estradiol / Q000097:blood; D005260:Female; D006329:Heart Conduction System / Q000502:physiology; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008593:Menopause / Q000502:physiology*; D008875:Middle Aged; D017697:Premenopause / Q000502:physiology
D004958:Estradiol