Thesis (M.S.)--West Virginia University, 1999. / Title from document title page. Document formatted into pages; contains viii, 91 p. : ill. (some col.) Includes abstract. Includes bibliographical references (p. 67-69).

Thesis--University of Wisconsin--Madison. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 82-86).

Thesis (M.Phil.) - University of Queensland, 2006. / Includes bibliography.

Thesis (Ph.D.) - University of Queensland, 2006. / Includes bibliography.

Masters of Technology: Radiography in the Faculty of Health and Wellness Sciences at the Cape Peninsula University of Technology 2015 / Introduction: Diabetes mellitus is a chronic disease with a significant impact on personal lifestyle and wellbeing. It is associated with a high prevalence of myocardial disease, the early detection of which is important for prevention of disease progression. Although echocardiography is recognised as a leading cardiovascular imaging modality, there has been limited work on its role in the early detection of diabetes-related myocardial dysfunction. The aim of this study was therefore to evaluate the role of echocardiography in the early detection of diabetes-related myocardial disease, in a population with a high prevalence of type 2 diabetes mellitus. Methodology: A single sonographer, blinded to individual biochemical markers conducted detailed echocardiographic examinations on 407 participants from a Cape Town community with a high prevalence of diabetes mellitus. Participants were subsequently stratified by biochemical status, as normoglyceamia or hyperglycaemia. The echocardiographic features of the two groups were compared using the Pearson chi-squared and Mann-Whitney U tests. Findings: Hyperglycaemia was associated with left atrium (LA) enlargement (p ˂ 0.0014), aortic enlargement (p ˂ 0.0067) and inter-ventricular septal (IVS) thickening (p ˂ 0.0001). Conclusion: The findings suggest that echocardiography can be a useful screening tool for myocardial dysfunction in Type 2 diabetes mellitus.

No description available.

The objective of this study was to non-invasively document the changes in echocardiographic variables of left ventricular size and function during acute normovolaemic anaemia. This model was developed as a pilot study with the purpose of providing baseline information to investigate the pathophysiology, and more specifically the effect on the heart, of canine babesiosis-induced anaemia. The study group comprised of 11 mature healthy Beagle dogs that weighed between 9 and 15 kg. Severe normovolaemic anaemia was induced over a 3-4 day period by serial bleeding while maintaining normovolaemia by autotransfusing plasma and infusing crystalloids. The dogs were then allowed to recover. Pre-anaemic [mean haematocrit (Hct) 46.7%, standard deviation (SD) 2.4%)] echocardiographic variables of left ventricular size and performance were statistically compared to those in the severely [mean Hct 15.3 %, SD 1.1%], moderately [mean Hct 24.7%, SD 1.5%] and mildly [mean Hct 33.5%, SD 2.5%] anaemic states, and between the anaemic states. The following variables were measured: left atrial size; left ventricular fractional shortening, ejection fraction, end-systolic and end-diastolic ventricular volumes and their derivatives [stroke volume, stroke index, cardiac output, cardiac index]; systolic time intervals [left ventricular ejection time (LVET), pre-ejection period (PEP), velocity of circumferential shortening, LVET/PEP and LVET index (LVETI)]; and heart rate. With the exception of end diastolic volume, left atrial size, LVET/PEP and LVETI, there was a statistically significant (p < 0.05) change in all variables in the severely anaemic state versus the pre-anaemic and the mild and moderate anaemic states. In accordance with previous invasive models, this study demonstrates the hyperdynamic state of the left ventricle that develops in response to experimentally induced acute canine normovolaemic anaemia in the conscious dog, and shows promise as a non-invasive technique of evaluating the cardiac changes in dogs suffering from canine babesiosis. / Dissertation (MMedVet(Diagnostic Imaging))--University of Pretoria, 2005. / Companion Animal Clinical Studies / unrestricted

The purpose of this investigation was to compare the frequencies of normal and abnormal findings from exercise electrocardiography (ECG), post-exercise echocardiography (ECHO) and angiography studies in a series of hypertensive and normotensive individuals who underwent diagnostic testing. Data for the ECG and ECHO were obtained simultaneously and the angiography was performed either before or following the exercise stress test. Thirty-seven cases were included in this retrospective study. Records were excluded if patients had: history of myocardial infarction; valvular heart disease; ECG evidence of abnormal Q waves, left ventricular hypertrophy (LVH) with abnormal ST/T wave pattern, or left bundle branch block (LBBB); medications that would alter blood pressure responses or ECG interpretation, technically uninterpretable records; or failure to attain 85% of age-adjusted maximal heart rates during the exercise tests. Subjects were defined as hypertensive (HYP) if at least two of the following criteria were met: 1) SBP ≥ 140 mmHg or DBP ≥ 90 mmHg; 2) current use of antihypertensive medications; or 3) history of hypertension. Normotensive subjects (NORM) were defined as absence of the above criteria. Data for the ECG and ECHO variables were obtained simultaneously in association with treadmill exercise studies. In each test, ECG measures were taken at peak exercise while the ECHO data were taken within 90 seconds immediately post exercise to obtain images. ECG response was considered abnormal if the ST shifted ≥ .1 mV from baseline at J₆₀ , while the ECHO response was considered abnormal when new or worsening of pre-existing wall motion abnormalities was observed. The 2-D ECHO's were recorded with the subject in the left lateral decubitus position, and parasternal long- and short-axis apical two and four chamber views were recorded for qualitative determination of wall motion abnormalities. Eleven of the 37 subjects also underwent angiography. Chi-square analysis demonstrated that high blood pressure status did not increase the frequency of abnormal test results for the ECHO (Χ²= 0.00009, DF = 1, p>.05), the exercise ECG (Χ²= 0.07, DF = 1, p>.05) nor for the angiography (Χ²= 0.69, DF = 1, p>.05). These results indicate that resting blood pressure does not influence the occurrence of abnormal vs normal ECG and ECHO findings nor angiography findings between hypertensive and normotensive subjects. There was also no significant differences between the ECG and ECHO in the occurrence of abnormal findings for NORM subjects (Χ²=2.43E-015, DF = 1, p>.05) nor HYP subjects (Χ²=0.13, DF = 1, p>.05). The ECHO showed 80% true-positive findings and the ECG showed 60% compared to the angiography. Both the ECG and ECHO had the same percentage of true-negatives (33%) compared to the angiography results. Since there was a higher percentage of ECHO true-positive results compared to the angiography then the ECG, this may indicate that the ECHO is comparable to the angiography findings and may be a better predictor in determining disease than the ECG. However, these data warrant further evaluation studies. / Master of Science

Development of pulmonary hypertension is an independent predictor of poor outcome in dogs affected by myxomatous valvular degeneration (MMVD). Systolic pulmonary arterial pressure is routinely estimated by Doppler echocardiography applying the simplified Bernoulli equation to the velocity of tricuspid regurgitation (sPAP_D). The accuracy of this estimation is unknown in dogs with MMVD, but experimental studies suggest that the method is imperfect. In order to fill this knowledge gap we prospectively enrolled dogs affected by MMVD and cardiac remodeling - American College of Veterinary Internal Medicine (ACVIM) stages B2 and C MMVD for which treatment had been unchanged for at least one month. A flow-directed thermodilution monitoring catheter was percutaneously placed in the right jugular vein and advanced to the main pulmonary artery. Pulmonary arterial systolic pressure was recorded through this catheter connected to a pressure-transducer and data acquisition-analysis system (sPAP_C). A second operator simultaneously acquired tricuspid regurgitant velocity spectra to calculate sPAP_D. Each operator was blinded to the result of the other technique. Twenty dogs were enrolled. Technical difficulties prevented catheterization in 2 dogs. Eighteen measurement pairs were therefore used for comparison of sPAP_C and sPAP_D through Bland-Altman analysis and linear regression. A statistically significant bias between sPAP_C and sPAP_D (mean difference=0.5mmHg; Confidence interval: -6.5mmHg, +7.5mmHg) was not detected. The limits of agreement between the techniques were wide (-27.3mmHg, +28.2mmHg). Regression analysis failed to identify a significant linear association between the two techniques (r=0.11, p=0.17). In conclusion, sPAP_D poorly agrees with sPAP_C measurement in dogs affected by MMVD in ACVIM stages B2 and C. In these dogs, sPAP_D could under- or over-estimate sPAP_C by more than 20mmHg, and therefore caution should be used when interpreting PASP_D. / Master of Science / The most common heart disease of dogs is myxomatous mitral valve disease (MMVD). In many affected dogs, this disease can be complicated by the development of high pressure in the vessels of the lungs, a condition called pulmonary hypertension (PH). On average, dogs with MMVD and PH have shorter survival compared to dogs affected solely by MMVD. The pulmonary pressure in dogs is usually estimated using cardiac ultrasound (echocardiography). This technique has the advantage of being "non-invasive" but it is not a direct measurement of pressure, therefore it may not be accurate. In order to evaluate the accuracy of echocardiography in measuring pulmonary pressure, in this study we compared direct measurements of pulmonary pressure obtained through cardiac catheterization to the measurements estimated using echocardiography, in dogs affected by MMVD. We performed this on 18 dogs affected by MMVD, with one person performing the direct measurements and another performing the echocardiographic ones; the two people were not aware of the measurements obtained with the other technique. We found that the echocardiographic estimated pressures can be very different from the real pressures measured with cardiac catheterization. Particularly, echocardiography resulted both in relevant over- and under-estimation of the real pressure, in an unpredictable way. This study therefore suggests that pulmonary pressures estimated by echocardiography should be interpreted cautiously in dogs affected by MMVD.

Echocardiography has an prominent role in the era of CRT by virtue of its non-invasive nature with high feasibility and reproducibility. The clinical applications include not only quantification of the change in systolic function, hemodynamics, LV volume, or mitral regurgitation, but also assessment of systolic dyssynchrony. A number of new echocardiographic techniques were employed in this study, such as tissue Doppler imaging (TDI) and its post-processing modalities including strain, strain rate and displacement mappings, tissue synchronization imaging (TSI), as well as three-dimentional (3D) echocardiography. / For heart failure patients with wide QRS complexes who received CRT, LV volumes, cardiac function and synchronicity were shown to change acutely between CRT-on and CRT-off modes by both 2D and 3D echocardiography methods. Furthermore, the usefulness of 3D echocardiography and its accuracy in assessing volumetric changes / Systolic dyssynchrony, which illustrates discoordinated contraction of the heart, is relatively common in heart failure patients, in particular those with prolonged QRS complexes. It is caused by electromechanical delay in some regions of the failing heart and will result in further reduction of cardiac function. Cardiac resynchronization therapy (CRT) is a rapidly evolving pacing modality for advanced heart failure, characterized by implantation of the left ventricular (LV) lead through coronary sinus to the free wall region. It is recommended to patients who have refractory heart failure despite optimal medical treatment, LV dilatation with ejection fraction lower than 35%, and prolonged QRS duration on surface ECG. / The main findings were as followed: The Ts-SD was 17.0+/-7.8ms in normal control, 33.8+/-16.9ms in narrow QRS group and 42.0+/-16.5ms in wide QRS group, respectively. The prevalence of systolic dyssynchrony in heart failure population was 43% in the narrow QRS group, and 64% in the wide QRS group, when a Ts-SD of > 32.6 ms (+2 SD of normal controls) was used to define significant dyssynchrony. QRS duration does not have a linear relationship with systolic dyssynchrony. / TSI was useful to predict a reverse remodeling and gain in ejection fraction after CRT. Qualitative identification of the latest peak systolic contraction at the lateral wall was a quick and specific guide to predict a favorable reverse remodeling response while quantitative computation of "Asynchrony Index" from 12 LV segments in ejection phase was beneficial in the absence of lateral wall delay. In conclusion, the improvement of cardiac function and LV reverse remodeling after CRT is more obvious in heart failure patients with wide QRS complex and echocardiographic evidence of significant systolic dyssynchrony. Reverse remodeling is not only an objective measure of favorable responses, but also a prognosticator of disease outcomes. "Asynchrony Index" is a strong predictor of LV reverse remodeling response after CRT. Assessment of systolic dyssynchrony by various echocardiographic tools is promising, however, further studies are needed to compare the predictive values of different parameters objectively and prospectively. / We performed echocardiography with TDI in 200 subjects, including 67 patients with heart failure and narrow QRS complexes (&le; 120ms), 45 patients with heart failure and wide QRS complexes (>120ms), and 88 normal controls, which served as a polit study. Severity and prevalence of systolic dyssynchrony were assessed by the maximal difference in time to peak myocardial systolic velocity (Ts-dif-12) and the standard deviation (Ts-SD) of the 12 LV segments. / We recruited a group of seventy patients with chronic heart failure who fulfilled the established criteria and received CRT. Serial echocardiographic assessment with clinical evaluation was performed at baseline, predischarge, 1-month, 3-month, 6-month and long-term follow up. The objective was to demonstrate the improvement of cardiac function and dyssynchrony after CRT by echocardiographic parameters, in particular the reduction of LV end-systolic volume (LVESV) which is also known as reverse remodeling, and its relationship with the improvement in clinical status and prognosis. We also attempted to identify dyssynchrony parameters which are useful in predicting LV reverse remodeling after CRT. / Zhang Qing. / "October 2006." / Adviser: Yu Cheuk-Man. / Source: Dissertation Abstracts International, Volume: 68-09, Section: B, page: 5852. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references. / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract in English and Chinese. / School code: 1307.