Grant: Project Grant

The sinus node controls heart rate, and is considered the natural pacemaker of the heart. Electrical impulses from the sinus node travel throughout the four chambers of the heart: the two upper chambers, called atria, and the lower two ventricles. Inappropriate electrical activity in the upper part of the heart (sinus node or atria), results in abnormal heart rhythms referred to as supraventricular arrhythmias. During pregnancy, there is a significant increase in the risk of cardiac arrhythmia. The increased incidence of these arrhythmias may have significant consequences on the health of the mother and the fetus. However, the mechanisms by which pregnancy increases the risk of arrhythmias have been largely unexplored. Thus, the first objective of this project is to explore the cellular and molecular mechanisms responsible for the increased incidence of arrhythmias during pregnancy. Additionally, considering that hormonal status has emerged as an important factor in the development of some types of cardiac arrhythmias, a second objective is to determine whether the major increase in estrogen levels that occur during pregnancy are implicated in these changes. The proposed studies will be realized using a combination of electrophysiological and biochemical techniques in mouse and human-derived cells. This work will provide important information related to the understanding of the influence of pregnancy on cardiac arrhythmia, and on the influence of estrogen on the electrical activity of the sinus node and atria. As comorbidity and the number of pregnancies at an advanced maternal age continue to rise, this issue is becoming even more pertinent. Ultimately, with further understanding, management of pregnancy-induced arrhythmias, and/or arrhythmias correlated with estrogen fluctuation could be significantly improved.