Study of Variations in Heart Rate., QT and QTc During Different Phases of Menstrual Cycle

Aim: The present study was undertaken with the aim to investigate influence of hormonal fluctuation duringmenstrual cycle on ECG.Materials and Method: The present study was carried out on 30 healthy female medical students in theage group of 18 to 23 years with normal menstrual cycle of 27-33 days. ECG was recorded on 2nd,11th,22ndday of menstrual cycle (corresponding with menstrual phase, proliferative phase and secretory phase ofmenstrual cycle), using AD INSTRUMENT–POWERLAB®/30 Series.Results: The study revealed that Heart rate was significantly (P<0.05) increased in secretory phase(98.26±10.44) compared to menstrual phase (91.85±10.27).QT and QTc interval showed increase duringproliferative phase but not significant.Discussion: Fluctuation in both estrogen and progesterone during menstrual cycle influence not only phase-II of cardiac action potential but also autonomic tone which could have led to prolonged QTc in Proliferativephase and increase in heart rate during secretory phase in present study, which provides a screening toolto avoid morbidity due to intake of drugs which prolonged QTc interval during menstrual cycle. But QTcinterval in present study was not increased significantly as it was done during single cycle.