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Influence of menstrual cycle on QT interval dynamics
Mikiko Nakagawa1, Tatsuhiko Ooie, Naohiko Takahashi
1Department of Cardiovascular Science, Division of Laboratory Medicine, Oita University School of Medicine, Yufu City, Oita, Japan. mikinak@med.oita-u.ac.jp
Pacing and Clinical Electrophysiology : PACE
|June 21, 2006
Summary
The menstrual cycle influences cardiac repolarization, with shorter QT intervals observed during the luteal phase. This change in QT interval dynamics is linked to increased progesterone and sympathetic activity.
Area of Science:
- Cardiology
- Reproductive Endocrinology
- Autonomic Nervous System Physiology
Background:
- The QT interval on an electrocardiogram (ECG) reflects cardiac repolarization.
- The menstrual cycle involves hormonal fluctuations that may impact cardiovascular parameters.
- Autonomic tone plays a role in regulating heart rate and cardiac electrical activity.
Purpose of the Study:
- To investigate the impact of the menstrual cycle on QT interval dynamics.
- To assess changes in autonomic tone throughout the menstrual cycle in healthy women.
Main Methods:
- 24-hour Holter ECGs were recorded in 11 healthy women during the follicular and luteal phases.
- Measurements included QT interval (QeT, QaT), T-wave apex to end (Ta-e), and RR intervals.
- Autonomic tone was assessed via serum catecholamine levels and heart rate variability (HRV).
Main Results:
- QT intervals (QeT and QaT) were significantly shorter in the luteal phase compared to the follicular phase.
- Serum progesterone and noradrenaline levels were significantly higher during the luteal phase.
- No significant differences in heart rate variability were observed between phases.
Conclusions:
- The menstrual cycle significantly affects QT interval duration.
- Shorter QT intervals in the luteal phase may be attributed to elevated progesterone and increased sympathetic nervous system activity.
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