Michael Khoury

Children are occasionally born with severe under-development of one of the two pumping chambers of the heart, known as ventricles, rendering it non-functional. A surgery called the Fontan surgery has contributed to dramatic improvements seen in this population in recent decades. With improved early survival outcomes, more attention has been paid towards improving long-term outcomes. In the general population, low levels of physical activity are associated with impaired function of the body’s blood vessels, known as vascular dysfunction, that in turn is associated with heart attacks, strokes, heart failure, and numerous other diseases. Associations between physical activity and vascular dysfunction in the Fontan population, however, have not been established. Therefore, we intend to evaluate this association in children who have had the Fontan surgery. Vascular function will be measured using two established protocols simultaneously that utilize probes that measure blood flow to the finger-tips. Blood flow to the probe will be occluded using a blood pressure cuff. Following release of the cuff, the degree of increased blood flow to the finger-tip will be measured. A detailed questionnaire and a device known as an accelerometer will be provided to measure physical activity over the course of a week. We will include children with normal hearts to evaluate the differences between the general and Fontan populations regarding levels of, and associations between, physical activity levels and vascular function. This study will help us better understand the impact of physical activity on the vascular health of this vulnerable and important population.