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No description available.

Studies have indicated that weight gain, and being overweight, are risk factors for the development of cardiovascular disease. Weight management is particularly intense in cardiac rehabilitation (CR) settings where the majority of participants are medically defined as overweight or obese and often have co-morbid risk factors. CR programs in Canada focus primarily on cardiovascular fitness, but have extended their program interventions to address cardiac risk factor modification, including diet management and weight loss. Health-related research has indicated that on average, CR participants show weight neutrality (no change from baseline weight) upon CR program completion. Prior to this study there was no substantive qualitative data exploring why this occurs. This doctoral study was a concurrent analysis of a larger funded qualitative study that explored the everyday practices of people with heart disease and type 2 diabetes who were participating in one of three large urban CR programs. A total of 33 participants were enrolled in the study (17 men and 16 women). Data was collected through the use of in-depth interviews, an activity journal, and field notes. Data analysis used sociologist Chris Shillings’ work related to body projects and corporeal realism in order to explore themes related to body size, diet management, and weight loss. Study results pointed to the importance of recognizing the role of social practice in health behaviour change, and the role of social discourses in determining how healthy bodies should look and act. Participants described how their social worlds shaped their eating practices, and relayed accounts of attempting to integrate their CR prescription into their daily routines. These findings suggest that a more nuanced approach to CR programming that takes into account the medical and social influences at work on CR participants while they attempt to modify health behaviours, may further inform the development of future CR weight loss and diet programming.

Studies have indicated that weight gain, and being overweight, are risk factors for the development of cardiovascular disease. Weight management is particularly intense in cardiac rehabilitation (CR) settings where the majority of participants are medically defined as overweight or obese and often have co-morbid risk factors. CR programs in Canada focus primarily on cardiovascular fitness, but have extended their program interventions to address cardiac risk factor modification, including diet management and weight loss. Health-related research has indicated that on average, CR participants show weight neutrality (no change from baseline weight) upon CR program completion. Prior to this study there was no substantive qualitative data exploring why this occurs. This doctoral study was a concurrent analysis of a larger funded qualitative study that explored the everyday practices of people with heart disease and type 2 diabetes who were participating in one of three large urban CR programs. A total of 33 participants were enrolled in the study (17 men and 16 women). Data was collected through the use of in-depth interviews, an activity journal, and field notes. Data analysis used sociologist Chris Shillings’ work related to body projects and corporeal realism in order to explore themes related to body size, diet management, and weight loss. Study results pointed to the importance of recognizing the role of social practice in health behaviour change, and the role of social discourses in determining how healthy bodies should look and act. Participants described how their social worlds shaped their eating practices, and relayed accounts of attempting to integrate their CR prescription into their daily routines. These findings suggest that a more nuanced approach to CR programming that takes into account the medical and social influences at work on CR participants while they attempt to modify health behaviours, may further inform the development of future CR weight loss and diet programming.

Problem: The risk of serious postoperative cardiovascular and respiratory complications (SPCRCs) in patients with obstructive sleep apnea (OSA) is poorly defined. Methods: In this cohort study (n = 21221), patients with clinically diagnosed OSA were matched to controls without OSA to compare the risk of postoperative death and SPCRCs in an administrative database. Results: Compared to non-OSA controls, OSA patients were at increased risk of postoperative respiratory failure both before and after diagnosis with OSA. Prior to diagnosis, OSA patients, particularly those with severe OSA, were also at increased risk of cardiac arrest and SPCRCs . After diagnosis with OSA, except for postoperative respiratory failure, the risk of SPCRC’s was not different from controls. Also, the risk of postoperative death among OSA patients after diagnosis was not different from controls. Other important predictors of SPCRCs and death included admission in an intensive care unit at the time of surgery, a history of congestive heart failure, a higher Charlson comorbidity index score and the type of surgery. Conclusions: OSA was associated with an increased risk of SPCRCs, especially prior to diagnosis and in severe disease. This suggests that screening for and treating OSA in preoperative patients would reduce the risk of SPCRCs. However, the significant influences of the type of surgery and the presence of medical comorbidities on the risks of SPCRCs and death, regardless of the presence of OSA, must be considered in planning efficient and equitable interventions to reduce these risks.

Cardiac rehabilitation (CR) is recommended for those living with heart disease, however adherence is suboptimal. The home program (HP) model of care is as clinically effective as traditional programs (TP), however little information exists about the HP’s effect on adherence. The objectives of this thesis were to 1) compare adherence of patients in a HP and TP model of CR. 2) To characterize self-regulatory self-efficacy (SR-SE) in a CR HP and 3) to explore the reasons for non-completion of a HP. Study 1 showed adherence to be similar between the TP and HP. Study 2 showed that SR-SE was high throughout the HP for completers, but dropped in those who did not complete the program. The HP is a good alternative for those unable to attend a TP; however those with low SR-SE may require further interventions to help them complete their program.

Cardiac rehabilitation (CR) is recommended for those living with heart disease, however adherence is suboptimal. The home program (HP) model of care is as clinically effective as traditional programs (TP), however little information exists about the HP’s effect on adherence. The objectives of this thesis were to 1) compare adherence of patients in a HP and TP model of CR. 2) To characterize self-regulatory self-efficacy (SR-SE) in a CR HP and 3) to explore the reasons for non-completion of a HP. Study 1 showed adherence to be similar between the TP and HP. Study 2 showed that SR-SE was high throughout the HP for completers, but dropped in those who did not complete the program. The HP is a good alternative for those unable to attend a TP; however those with low SR-SE may require further interventions to help them complete their program.

Cardiac fibrosis is the excess deposition of myocardial extracellular matrix components, which increases tissue stiffness and heterogeneity, causing impaired diastolic/systolic function and arrhythmias, and eventually leading to heart failure and death. There are no available treatments for cardiac fibrosis. Myofibroblasts mediate fibrosis, and are characterized by hypersynthesis of collagens, decreased migration, and increased α-smooth muscle actin, which is incorporated into stress fibers, imparting contractility. Scleraxis is a transcriptional regulator of collagen-rich tissues, increased in response to the same stimuli that drive the myofibroblast phenotype, such as cyclic stretch. We show that Scleraxis mediates the conversion of cardiac fibroblasts to myofibroblasts, by increasing myofibroblast marker expression and contraction, and decreasing migration. Additionally, a proximal 1500 bp human SCLERAXIS promoter is activated by stretch and is responsive to transforming growth factor-β1. Thus, Scleraxis is a specific mechanoresponsive regulator of the myofibroblast, representing a novel target for the treatment of cardiac fibrosis.

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No description available.