Date of Award

12-2009

Degree Type

Thesis

Degree Name

Master of Science (MS)

Department

Kinesiology

Supervisor

Maureen MacDonald

Language

English

Abstract

Some individuals with coarctation of the aorta (CoA) have impaired cardiac and vascular structure and function, despite surgical intervention. Exercise training has been shown to improve cardiovascular structure and function in individuals with acquired heart disease; however, little information exists to inform exercise prescription in individuals with congenital heart abnormalities. Nine children with CoA (7 males, age: 12 ± 3 y) and 9 age and sex matched controls (7 males, age: 11 ± 3 y) completed a 20 minute bout of leg and arm cycling on two separate days at workloads which elicited exercising heart rates which were 50% above resting heart rate. Central arterial stiffness was measured using both carotid distensibility and pulse wave velocity (PWV) before exercise and at 5 and 15 minutes post exercise. At the same time points, upper limb and lower limb arterial stiffness were assessed using PWV. At rest prior to exercise, the CoA group had larger carotid lumen diameters in comparison to controls (p<0.05). Carotid distensibility was not different between the groups at any time point (p>0.05) and did not change in response to either arm or leg exercise (p>0.05). Central PWV was elevated at 5 minutes post arm cycling exercise (main effect for time, p<0.05) but was not different between groups (p>0.05). Central PWV was reduced at 5 and 15 minutes post leg cycling exercise in CoA and did not change in the controls. Non-exercised limb stiffness did not change with arm or leg exercise in either group (p>0.05). Stiffness decreased in the exercised limb following arm exercise (p<0.05) but not leg exercise (p>0.05). There was a significant group difference for slower PWV in the upper limb with arm and leg exercise in repaired CoA group in comparison to controls (p<0.05). Our findings indicate that in contrast to previous reports, children with successfully repaired CoA may not be predisposed to increased arterial stiffness in the large conduit arteries proximal to the coarctation. Furthermore, this group of children with a successful repair of CoA had similar vascular responses to moderate intensity exercise as healthy age and sex matched controls and higher intensity exercise challenges may be needed to reveal divergent vascular responses in these groups.

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