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33rd International Congress on Electrocardiology

International Society of Electrocardiology

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QT interval dynamics is modified by menstrual cycle

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  • corresponding author presenting/speaker T. Saikawa - Oita University, Yufu City, Japan
  • M. Nakagawa - Oita University, Yufu City, Japan
  • T. Ooie - Oita University, Yufu City, Japan
  • N. Takahashi - Oita University, Yufu City, Japan
  • Y. Taniguchi - Oita University, Yufu City, Japan
  • F. Anan - Oita University, Yufu City, Japan
  • H. Yonemochi - Oita University, Yufu City, Japan

33rd International Congress on Electrocardiology. Cologne, 28.06.-01.07.2006. Düsseldorf, Köln: German Medical Science; 2007. Doc06ice051

The electronic version of this article is the complete one and can be found online at: http://www.egms.de/en/meetings/ice2006/06ice051.shtml

Published: February 8, 2007

© 2007 Saikawa et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by-nc-nd/3.0/deed.en). You are free: to Share – to copy, distribute and transmit the work, provided the original author and source are credited.

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Objectives: The aim of this study was to investigate the effects of the menstrual cycle on QT interval dynamics and the autonomic tone in healthy women.

Methods: Holter ECGs were recorded in 11 healthy female wolunteers aged 18 to 32 years during the follicular- and luteal phases of their regular menstrual cycle. Two QT parameters, the interval from QRS onset to the apex (QaT) and to the end of the T wave (QeT), the interval between the apex and the end of the T wave (Ta-e), and RR intervals were measured automatically in the course of 24 hr by Holter ECGs (QT guard, GE Medical systems). The QeT/RR, QaT/RR, and Ta-e/RR relationships were evaluated in each subject. The autonomic tone was assessed by serum catecholamine level at rest and heart rate variability measured by Holter ECGs. Results: (1) The follicular and luteal phases did not differ significantly with respect to the slopes of the QeT/RR, QaT/RR, and Ta-e/RR relationships. However, QeT and QaT intervals were significantly shorter for all RR intervals in the luteal- than the follicular phase (p<0.0001). (2) The serum progesterone concentration was significantly higher in the luteal- than follicular phase (p<0.001). (3) Noradrenaline was significantly higher in the luteal- than follicular phase (p<0.05). There was no significant difference in the follicular- and luteal phase with respect to heart rate variability measurements.

Conclusions: Our results suggest that the menstrual cycle affects the QT interval dynamics. The observed shorter QT interval during the luteal- than follicular phase may be attributable to the increase in serum progesterone and sympathetic tone during the luteal phase.