Cardiology Commons^™

About Dying And Death: Thanatology's Place In Medical Curriculum, Jill Dombroski

Electronic Thesis and Dissertation Repository

This study explored how healthcare providers engage in advance care planning and end-of-life care conversations. The research explored what shapes their understanding and the extent to which concepts from thanatology they intuitively bring in, explicitly bring in, and maybe fail to recognize. To achieve this, constructivist grounded theory (CGT) methodology guided the design, data collection, analysis, and interpretation of the findings, which allowed for iteration across interviews and analysis with existing theories and data in the literature. The CGT design encouraged further engagement with the literature in an ongoing iterative fashion as well as with the analysis of the data. …

Malperfusion Syndrome In The Setting Of Type A Aortic Dissection, Karama Yaslam Karama Bayamin

Electronic Thesis and Dissertation Repository

Background: Acute Type A aortic dissection (TAAD) patients who experience malperfusion syndrome (MPS) are at the greatest risk of major morbidity and mortality. However, the appropriate timing for open proximal aortic repair in the presence of MPS is still uncertain due to variations in clinical manifestations and diverse treatment approaches.

Methods: We conducted a comprehensive literature review to understand the importance of MPS in the setting of TAAD. Then, we conducted a national survey to understand the perception of cardiovascular surgeons across Canada and their approach for those patients. Furthermore, we performed a retrospective analysis of our local data to …

Sociodemographic Factors And The Risk Of Paediatric Out-Of-Hospital Cardiac Arrest, Samina Idrees

Electronic Thesis and Dissertation Repository

Paediatric out-of-hospital cardiac arrest (POHCA) is associated with poor survival and severe neurological sequelae. This thesis aims to explore the relationship between sociodemographic factors and POHCA. The findings from our systematic review indicate that there are racial disparities in POHCA risk and in the provision of bystander cardiopulmonary resuscitation. There was little evidence of sociodemographic disparities in bystander defibrillation, survival and neurological outcome, particularly across adjusted analyses. The findings from our case-control study in Ontario, Canada, indicate that children living in marginalized areas have an elevated risk of experiencing POHCA. We also found that children living in northern urban or …

Multi-Scale Computational Modeling Of Coronary Blood Flow: Application To Fractional Flow Reserve., Jermiah Joseph

Electronic Thesis and Dissertation Repository

Introduction. Fractional flow reserve (FFR) is presently an invasive coronary clinical index. Non-invasive CT imaging combined with computational coronary flow modelling may reduce the patient’s burden of undergoing invasive testing.

Research statement. The ability to obtain information of the hemodynamic significance of detected lesions would streamline decision making in escalation to invasive angiography.

Methods. A reduced order (lumped parameter) model of the coronary vasculature was further developed. The model was used in the assessment of the roles of structure and function on the FFR. Sophisticated methods were used to elicit numerical

solutions. Further, CT imaging (n = …

Feasibility And Clinical Value Of 3-Dimensional Myocardial Deformation Analysis By Computed Tomography In Transcatheter Aortic Valve Replacement Patients, Mohamad Rabbani

Electronic Thesis and Dissertation Repository

Purpose: Multi-phase computed tomography angiography (CTA) for the pre-procedural planning of TAVR presents a unique opportunity to assess 3D myocardial biomechanics. This study aimed to assess the feasibility and predictive utility of 3D myocardial deformation analysis (3D-MDA) based principal strain to predict heart failure or death following TAVR using pre-procedural, multi-phase computed tomography angiography (CTA) datasets.

Methods: Two hundred and five patients undergoing pre-TAVR multi-phase gated CTA followed by successful TAVR were retrospectively identified. Whole heart 3D mesh chamber models were generated followed by 3D-MDA of the left ventricle (LV) to determine global LV minimum principal strain (minPS) for endocardial, …

Delineation Of Ascending Aortic Medial Degeneration Using Diffusion Tensor Imaging, Justin A. Ching-Johnson

Electronic Thesis and Dissertation Repository

Thoracic aortic aneurysms (TAAs) are a life-threatening dilation of the thoracic aorta that can lead to catastrophic dissection or rupture. In TAAs, the structure of the aortic wall is perturbed. Current imaging approaches assess lumen dimensions but lack the ability to delineate aortic wall architecture, a key determinant of aortic integrity. Diffusion tensor imaging (DTI) is an MRI modality which can reveal tissue microstructure through diffusion characteristics. In this thesis I investigated the potential for DTI to evaluate TAA architecture. A porcine model of aortic wall degeneration was developed, and DTI scans were performed on healthy and degenerated porcine ascending …

Measuring Inflammation In The Entire Myocardium In A Canine Model Of Myocardial Infarction With Hybrid Pet/Mri, Benjamin Wilk

Electronic Thesis and Dissertation Repository

Background: After myocardial infarction (MI), fibrosis and an ongoing dysregulated inflammatory response are associated with adverse cardiac remodeling. Fluorodeoxyglucose (FDG) positron emission tomography (PET) is sensitive to inflammation provided suppression protocols are implemented to restrict the uptake of glucose in myocytes. Magnetic resonance imaging can be used to determine extracellular volume, a surrogate measure of fibrosis. In some cases, patients present with markedly reduced flow in the setting of a large infarct, i.e. microvascular obstruction, restricting the delivery of FDG and contrast agents. To overcome this problem, a constant infusion was explored as an alternative to the clinical standard bolus …

Novel Imaging Tools Reveal The Dynamics Of The Myocardial Growth Hormone Secretagogue Receptor In Heart Disease And Heart Failure, Rebecca Sullivan

Electronic Thesis and Dissertation Repository

Heart disease (HD) is the leading cause of mortality worldwide. Currently, diagnosis is based on clinical features, imaging, and circulating cardiac biomarkers. Cardiac imaging technologies, such as echocardiography and cardiac magnetic resonance imaging (cMRI), enable the non-invasive detection of changes in heart function. Although these modalities can detect changes in structure and anatomy, it is usually at later stages, where prevention may not be possible. In conjunction with imaging, circulating biomarkers of heart failure (HF), notably B-type natriuretic peptide (BNP) and cardiac troponin I and T, can be detected with increased levels in the blood. These biomarkers are associated with …

Maternal Nicotine Exposure Induces Congenital Heart Defects In The Offspring Of Mice, Elizabeth Greco

Electronic Thesis and Dissertation Repository

Congenital heart defects are the most prevalent birth defect, and maternal cigarette smoking is a known risk factor. Nicotine replacement therapies are recommended to pregnant women who smoke to aid in smoking cessation, as this alternative is thought to be much safer compared to cigarette smoking. However, these products contain nicotine, and the safety of nicotine on the developing heart is not well known. In this thesis, a mouse model was used to test the hypothesis that maternal nicotine exposure (MNE) during pregnancy leads to congenital heart defects and coronary artery defects in the offspring of mice. MNE resulted in …

The Epidemiology Of Infective Endocarditis Among People Who Inject Drugs In London, Ontario., Brian Hallam

Electronic Thesis and Dissertation Repository

Infective endocarditis is an infectious disease that affects the valves of the heart. Injection drug use is currently a leading risk factor among patients with endocarditis. We conducted a prospective study using data from hospital chart records among patients with endocarditis in London, Ontario, which has a relatively high prevalence of people who inject drugs to assess the severity of the issue and the major risk factors of mortality pertaining to this population. This study had a sample size of 353 and included a review of the incidence of admissions of endocarditis, as well as a survival analysis, using both …

Antithrombotic Therapy In Patients Undergoing Coronary Artery Bypass Grafting: A Systematic Review And Network Meta-Analysis, Karla Solo

Electronic Thesis and Dissertation Repository

Comprehensive evidence on the comparative effects of various oral antithrombotic agents on the prevention of saphenous vein graft failure (SVGF) for patients undergoing coronary artery bypass is lacking. A systematic review and frequentist random-effects network meta-analysis of 18 RCTs (n=3,413 patients) comparing the effect of antithrombotic agents on SVGF and clinical outcomes was performed. Based on moderate quality evidence, among the six eligible interventions, dual-antiplatelet therapy with aspirin and clopidogrel was superior to aspirin monotherapy in reducing SVGF (OR: 0.63; 95% CI: 0.41-0.97). No statistical differences were found for major bleeding, mortality, and myocardial infarction between antithrombotic agents, owing to …

Non-Invasive Imaging For The Assessment Of Cardiac Dose And Function Following Focused External Beam Irradiation, Omar El-Sherif

Electronic Thesis and Dissertation Repository

Technological advances in imaging and radiotherapy have led to significant improvement in the survival rate of breast cancer patients. However, a larger proportion of patients are now exhibiting the less understood, latent effects of incidental cardiac irradiation that occurs during left-sided breast radiotherapy. Here, we examine the utility of four-dimensional computed tomography (4D-CT) for the accurate assessment of cardiac dose; and a hybrid positron emission tomography (PET) magnetic resonance imaging (MRI) system to longitudinally study radiation-induced cardiac effects in a canine model.

Using 4D-CT and deformable dose accumulation, we assessed the variation caused by breathing motion in the estimated dose …

Physical Exertion As A Risk Factor For Ventricular Arrhythmia: A Prospective Cohort Study, Harpreet S. Chahal

Electronic Thesis and Dissertation Repository

Episodes of physical exertion are associated with an immediately higher risk of cardiovascular events while physical activity over the long-term is cardioprotective. To assess the transient and long-term risk of ventricular arrhythmia (VA), we conducted a nested case-crossover study within a prospective cohort of 97 patients with implantable cardioverter-defibrillators (ICD). Within an hour of episodes of exertion, the risk of VA was 5.3 (95% CI 2.7 – 10.6) times greater compared to periods of rest. The association was higher among patients with aerobic fitness below the median (RR[relative risk]=17.5, 95% 5.2 – 58.5) than for patients with aerobic fitness above …

Methotrexate And Cardiovascular Events, Alpesh Shah

Electronic Thesis and Dissertation Repository

We conducted a systematic review and meta-analysis to assess the association of MTX with cardiovascular morbidity, cardiovascular mortality and all-cause mortality in patients with autoimmune disease. Our primary outcome was incident cardiovascular events. After screening 13,479 citations, we identified a total of 30 eligible studies. We synthesized adjusted risk estimates using a random effects model. MTX was significantly associated with a 25% reduction in cardiovascular events (pooled RR: 0.75, 95% CI: 0.65, 0.86, I²: 11%), a 55% reduction in cardiovascular mortality (0.45, 95% CI: 0.26, 0.80, I²: 33%) and a 40% reduction in all-cause mortality (0.60, …

Cortisol And Testosterone In Hair As Biological Markers Of Systolic Heart Failure, Justin Chan

Electronic Thesis and Dissertation Repository

Congestive heart failure (CHF) is associated with increased stress and alterations in metabolism, favoring catabolism over anabolism. Hormonal profiles of patients with heart failure have been assessed using serum and saliva as matrices, which are only point measurements and do not provide long-term information. Scalp hair is a novel matrix that allows for measurement of hormones over a period of several months. We aimed to evaluate whether levels of cortisol and testosterone and their ratio (C/T) in hair correlate with severity of heart failure. We conducted a prospective study in ambulatory male patients with a left ventricular ejection fraction (LVEF) …

Augmented Image-Guidance For Transcatheter Aortic Valve Implantation, Pencilla Lang

Electronic Thesis and Dissertation Repository

The introduction of transcatheter aortic valve implantation (TAVI), an innovative stent-based technique for delivery of a bioprosthetic valve, has resulted in a paradigm shift in treatment options for elderly patients with aortic stenosis. While there have been major advancements in valve design and access routes, TAVI still relies largely on single-plane fluoroscopy for intraoperative navigation and guidance, which provides only gross imaging of anatomical structures. Inadequate imaging leading to suboptimal valve positioning contributes to many of the early complications experienced by TAVI patients, including valve embolism, coronary ostia obstruction, paravalvular leak, heart block, and secondary nephrotoxicity from contrast use.

A …

Uwomj Volume 77, No. 2, 2008, Western University

University of Western Ontario Medical Journal

Schulich School of Medicine & Dentistry