Cardiac autonomic modulation by estrogen in female mice undergoing ambulatory monitoring and in vivo electrophysiologic testing

Samir Saba; Vladimir Shusterman; Irmute Usiene; Barry London

doi:10.1111/j.1542-474X.2004.92535.x

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Cardiac autonomic modulation by estrogen in female mice undergoing ambulatory monitoring and in vivo electrophysiologic testing

Journal article

Open access

Cardiac autonomic modulation by estrogen in female mice undergoing ambulatory monitoring and in vivo electrophysiologic testing

Samir Saba, Vladimir Shusterman, Irmute Usiene and Barry London

Annals of noninvasive electrocardiology, Vol.9(2), pp.142-148

04/2004

DOI: 10.1111/j.1542-474X.2004.92535.x

PMCID: PMC6932571

PMID: 15084211

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Abstract

Estrogen is an important modulator of cardiovascular risk, but its mechanism of action is not fully understood. We investigated the effect of ovariectomy and its timing on the cardiac electrophysiology in mice. Thirty female mice (age 18.8 +/- 3.1 weeks) underwent in vivo electrophysiologic testing before and after autonomic blockade. Fifteen mice were ovariectomized prepuberty (PRE) and ten postpuberty (POST), 2 weeks prior to electrophysiologic testing. Five age-matched sham-operated female mice (Control) served as controls. A subset of 13 mice (5 PRE, 3 POST, and 5 Controls) underwent 24-hour ambulatory monitoring. With ambulatory monitoring, the average (668 +/- 28 vs 769 +/- 52 b/min, P = 0.008) and minimum (485 +/- 47 vs 587 +/- 53 b/min, P = 0.02) heart rates were significantly slower in the ovariectomized mice (PRE and POST groups) compared to the Control group. At baseline electrophysiologic testing, there were no significant differences among the ovariectomized and intact mice in any of the measured parameters. With autonomic blockade, the Control group had a significantly larger change (delta) in the atrioventricular (AV) nodal Wenckebach (AVW) periodicity (deltaAVW = 11.3 +/- 2.9 vs 2.1 +/- 7.3 ms, P = 0.05) and functional refractory period (deltaFRP = 11.3 +/- 2.1 vs 1.25 +/- 6.8 ms, P = 0.02) compared to the ovariectomized mice. These results were not altered by the time of ovariectomy (PRE vs POST groups). Our results suggest that estrogen modulates the autonomic inputs into the murine sinus and AV nodes. These findings, if replicated in humans, might underlie the observed clustering of certain arrhythmias around menstruation and explain the higher incidence of arrhythmias in men and postmenopausal women.

Estrogens - pharmacology

Ovariectomy

Autonomic Nervous System - drug effects

Models, Cardiovascular

Anti-Arrhythmia Agents - pharmacology

Autonomic Nervous System - physiology

Organ Size

Atropine - pharmacology

Heart Conduction System - drug effects

Mice, Inbred C3H

Uterus - anatomy & histology

Heart Rate - drug effects

Propranolol - pharmacology

Animals

Heart Conduction System - physiology

Heart Rate - physiology

Female

Models, Animal

Mice

Electrophysiologic Techniques, Cardiac

Electrocardiography, Ambulatory

Details

Title: Subtitle: Cardiac autonomic modulation by estrogen in female mice undergoing ambulatory monitoring and in vivo electrophysiologic testing
Creators: Samir Saba - Cardiovascular Institute, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania 15213, USA.savas@msx.upmc.edu
Vladimir Shusterman
Irmute Usiene
Barry London
Resource Type: Journal article
Publication Details: Annals of noninvasive electrocardiology, Vol.9(2), pp.142-148
DOI: 10.1111/j.1542-474X.2004.92535.x
PMID: 15084211
PMCID: PMC6932571
NLM abbreviation: Ann Noninvasive Electrocardiol
ISSN: 1082-720X
eISSN: 1542-474X
Publisher: United States
Language: English
Date published: 04/2004
Academic Unit: Molecular Physiology and Biophysics; Cardiovascular Medicine; Internal Medicine
Record Identifier: 9984025474502771

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