Thesis (M.A.)--West Virginia University, 2001. / Title from document title page. Document formatted into pages; contains ix, 60 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references (p. 29-34).

A non-invasive, in vitro method of estimating mean pulmonary artery pressure (PAP) was developed. This information was obtained by establishing a relationship between the pneumatic right drive pressure (RDP) and PAP waveforms. The RDP-PAP relationship was formalized into a series of multiple-linear regression equations for TAH cardiac cycles of known fill volume (FV). Correlation of computed estimates of PAP to actual measurements showed that these equations were greater than 92% accurate within 1.84 mmHg. In addition, while the RDP-PAP relationships were wholly dependent on FV, it was shown that they are independent of the manner in which FV was obtained. This method proved useful over the clinical operating range of the pneumatic heart driver, as well as over the normal physiological range of PAP in the human. Effectiveness of this method in vivo needs to be demonstrated.

Age is the major risk factor for cardiovascular diseases (CVD) and this is attributable in part to stiffening of large elastic arteries and development of vascular endothelial dysfunction. In contrast, regular aerobic exercise is associated with reduced risk of CVD. Swimming is an attractive form of aerobic exercise and always recommended for health promotion as well as prevention and treatment of risk factors for CVD. However, there is little scientific evidence to date indicating that swimming is equally efficacious to land-based exercise modes in reducing cardiovascular risks. Accordingly, the aim of the research was to determine the role of regular swimming exercise on both CVD traditional risk factors and vascular functions. To comprehensively address this aim, 2 different approaches were used: Study 1 (cross-sectional study) was designed to determine the potential benefit of regular swimming exercise in the primary prevention of age-related decreases in vascular function. Key measurements of vascular function were performed in middle-aged and older swimmers, runners, and sedentary controls. Central arterial compliance was higher in swimmers and runners than in sedentary controls. Study 2 (intervention study) was designed to determine whether regular swimming exercise could reverse the age-associated decline in vascular function. Middle-aged and older subjects completed either a 12-week swim training program or relaxation/ stretching exercise (attention control) program. Short-term swim training improved arterial blood pressure and vascular functions. In summary, regular swimming exercise can attenuate reductions in and partially restore the loss of vascular function including central arterial compliance and endothelial function in middle-aged and older adults. Swimming exercise exhibited typical central arterial compliance and endothelial function phenotypes that are often displayed in land-based exercise. / text

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The present study examined the hemodynamic response to recreational hockey (n= 22) in middle-aged men (53±6 yrs). Study participants were equipped with ambulatory blood pressure and heart rate monitoring equipment prior to a weekly hockey games. Participants were monitored throughout the duration of their hockey game for “On-Ice” responses and during seated bench time (“Bench”), and for a brief period afterwards. On-Ice HR’s and blood pressures were significantly higher than values obtained during maximal cycle exercise (HR 174±8.9 vs. 163±11.0 bpm) (SBP 17%; DBP 15%) (p<0.05), Blood pressures decreased throughout the duration of the game while HR increased significantly. The On-Ice endocardial viability ratio (EVR), an index of myocardial oxygen supply and demand, did not change from early (1.56±0.05) to late (1.44± 0.06) in the game. In conclusion, recreational hockey is an extremely vigorous form of interval exercise that produces cardiovascular responses exceeding intensities commonly recommended for continuous training.

The oscillometric method for blood pressure measurement has been known for over a century. It was overshadowed by the classic stethoscope and cuff method until more recently when its ease of automation became useful. It is now found in the automated blood pressure cuffs used in hospitals, doctor's offices, pharmacies, and devices sold for home use. It still challenges accurate blood pressure measurement, however, due to its difficulty in compensating for pregnancy, age, hypo-, and hypertension. Global sensitivity analysis methods were used to develop a model that focuses on the most important system parameters. The most influential biological and design parameters were identified allowing the removal or fixing of less influential parameters, and the replacement of subsystems with linear models, with minimal effect on the overall system accuracy. The developed model allows for the investigation and development of new methods for extracting parameter information from the oscillometric signals. This is illustrated by the development of a method to extract the artery's cross-sectional area from standard oscillometric output. The system design requirements for accurate measurement of blood pressure are examined and discussed with recommendations for system parameter adjustment. The model's performance and usefulness is highlighted with modelled case studies of potential real-world applications for subjects with parameters or inputs for which the oscillometric method would find it difficult to compensate. Through the use of the developed model to compensate for the system errors, the measurement error can be reduced by half. Highlighting the important system parameters allows the engineer to focus on choosing the design parameters over which she or he has control. The system model provides the ability to experiment with the cuff design choices and provides information regarding system performance under conditions that are historically difficult to measure accurately. The developed model's usefulness is illustrated by applying it to parameter extraction, and to the compensation of oscillometric blood pressure readings.

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The thesis offers the following contributions to the epidemiology of hypertension in Canada: 1.The first manuscript uses cross-sectional data from the 2007-2009 Canadian Health Measures Survey (CHMS) to compare the prevalence of controlled hypertension between people with and without diabetes. Of the 74% of Canadians with diabetes who had hypertension, 56% (95% CI: 45%-66%) had controlled blood pressure compared to 64% (95% CI: 58%-69%) of Canadians without diabetes. Among people taking medication, individuals with diabetes were less likely to have controlled hypertension (ORadjusted: 0.3; 95% CI: 0.2-0.6). 2.The objective of the second manuscript was to determine, among Canadians with hypertension, whether individuals with diabetes were less likely than those without to recall health professional advice for healthy behaviours and whether receipt of such advice influences behaviour, using cross-sectional data from the 2009 Survey on Living with Chronic Diseases in Canada (SLCDC). Canadians with diabetes were more likely than those without to recall advice to control/lose weight (81% vs. 66%), exercise (79% vs. 68%), limit alcohol (78% vs. 55%) and modify diet (70% vs. 61%) but not limit salt (65% vs. 64%). Both groups were equally likely to report following advice, with receipt of advice positively associated with engagement in healthy behaviours. 3. The third manuscript describes knowledge of blood pressure targets in Canadians with hypertension using cross-sectional data from the 2009 SLCDC. Knowledge of blood pressure targets was low, with 28% and 32% of Canadians with and without diabetes reporting having discussed a blood pressure target and reporting a target in line with clinical practice guidelines. 4.The fourth manuscript validates an existing self-reported blood pressure control question in a sample of 161 patients with hypertension in Kingston. In people with and without diabetes, the question had sensitivities of 83% ± 11% and 78% ± 10% and specificities of 30% ±19% and 58% ± 21%, respectively. 5.The final manuscript tests a method designed to account for misclassification in epidemiologic studies, using data from the CHMS. The method was found to perform inconsistently in multivariate contexts and introduced bias when minor differential misclassification was ignored. / Thesis (Ph.D, Community Health & Epidemiology) -- Queen's University, 2013-11-14 09:55:12.161

The thesis offers the following contributions to the epidemiology of hypertension in Canada: 1.The first manuscript uses cross-sectional data from the 2007-2009 Canadian Health Measures Survey (CHMS) to compare the prevalence of controlled hypertension between people with and without diabetes. Of the 74% of Canadians with diabetes who had hypertension, 56% (95% CI: 45%-66%) had controlled blood pressure compared to 64% (95% CI: 58%-69%) of Canadians without diabetes. Among people taking medication, individuals with diabetes were less likely to have controlled hypertension (ORadjusted: 0.3; 95% CI: 0.2-0.6). 2.The objective of the second manuscript was to determine, among Canadians with hypertension, whether individuals with diabetes were less likely than those without to recall health professional advice for healthy behaviours and whether receipt of such advice influences behaviour, using cross-sectional data from the 2009 Survey on Living with Chronic Diseases in Canada (SLCDC). Canadians with diabetes were more likely than those without to recall advice to control/lose weight (81% vs. 66%), exercise (79% vs. 68%), limit alcohol (78% vs. 55%) and modify diet (70% vs. 61%) but not limit salt (65% vs. 64%). Both groups were equally likely to report following advice, with receipt of advice positively associated with engagement in healthy behaviours. 3. The third manuscript describes knowledge of blood pressure targets in Canadians with hypertension using cross-sectional data from the 2009 SLCDC. Knowledge of blood pressure targets was low, with 28% and 32% of Canadians with and without diabetes reporting having discussed a blood pressure target and reporting a target in line with clinical practice guidelines. 4.The fourth manuscript validates an existing self-reported blood pressure control question in a sample of 161 patients with hypertension in Kingston. In people with and without diabetes, the question had sensitivities of 83% ± 11% and 78% ± 10% and specificities of 30% ±19% and 58% ± 21%, respectively. 5.The final manuscript tests a method designed to account for misclassification in epidemiologic studies, using data from the CHMS. The method was found to perform inconsistently in multivariate contexts and introduced bias when minor differential misclassification was ignored. / Thesis (Ph.D, Community Health & Epidemiology) -- Queen's University, 2013-11-14 09:55:12.161