Cardiac rehabilitation (CR) exercise training, which traditionally involves the prescription of moderate intensity continuous exercise, can slow the progression of heart disease and improve cardiorespiratory fitness (CRF). Cardiac function is typically investigated using calculations of ejection fraction (EF) from echocardiography, yet EF measures do not provide information about the unique twisting motion of the heart. Novel measures of cardiac function, such as LV twist, myocardial performance index (MPI) and global longitudinal strain (GLS), may provide additional information about changes in LV mechanics associated with exercise training for individuals with coronary artery disease (CAD). The aims of this study were to investigate the changes in cardiac function, using both standard and novel measures, at baseline (0 weeks; T1), post-initial training (4 weeks; T2), and post-training (12 weeks; T3) in response to either stair climbing-based high intensity interval training (STAIR) or traditional moderate intensity continuous training (TRAD). We recruited 16 individuals with CAD (61±7years; 1W) and randomized them into TRAD and STAIR groups (n=8/group). Standard (CRF and EF), and novel (LV twist, MPI, GLS), measures of cardiovascular function were assessed at all three timepoints. CRF improved in both groups, after 4 and 12 weeks (STAIR: T1:22.1±4.2, T2:24.7±4.9, T3:25.4±5.2 and TRAD: T1:22.8±2.5, T2:25.2±4.9, T3:26.0±5.0 mL/kg/min; P<0.005) of CR exercise. We observed an increase in apical rotation (P=0.01) and LV twist (P=0.03), but no changes in either traditional (EF P=0.15), or novel (MPI P=0.19; GLS P=0.81) measures of cardiac function over time, in either group. It is possible that the relatively short training period (12 weeks) was not sufficient to result in significant changes in cardiac function, despite improvements in CRF. Future research should assess both standard and novel indices of cardiac function over longer exercise training periods to determine the ideal indices for tracking changes over time with interventions in this population. / Thesis / Master of Science (MSc) / Cardiac rehabilitation exercise is an important part of recovery after a heart attack, and it has been shown to improve heart function measured using standard ultrasound assessments. Studies have suggested that novel measures of heart function may be more sensitive in comparison to these standard ultrasound measures, yet these novel measures have not been examined in individuals completing stair-climbing based high intensity cardiac rehabilitation exercise training. This work examined the changes in both novel and standard ultrasound measures of heart function after either stair climbing-based high intensity interval training or traditional moderate intensity exercise training in individuals who have heart disease. While this study found that both stair climbing based high intensity interval training and traditional cardiac rehabilitation both resulted in increases in cardiorespiratory fitness after 12 weeks of training, no changes were observed in any of the standard measures of heart function. Supporting the concept that novel measures of heart function might be more sensitive, as some training associated changes were observed in the novel measures of heart function.
| Identifer | oai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/24917 |
| Date | January 2019 |
| Creators | Valentino, Sydney E |
| Contributors | MacDonald, Maureen J, Kinesiology |
| Source Sets | McMaster University |
| Language | English |
| Detected Language | English |
| Type | Thesis |
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