| Summary: | 碩士 === 國立臺灣大學 === 獸醫學研究所 === 99 === Myxomatous mitral valve disease (MVD) is characterized by vavular myxomatous degeneration and is the most common heart disease in small breed dogs. The affected valves result in leakage of mitral valves (mitral regurgitation). As the severity of mitral regurgitation progresses, dogs with MVD eventually develop dilation of left ventricle and atrium, impairment of the systolic and diastolic function, and may cause congestive heart failure (CHF). In this study, small breed dogs with MVD were classified into two groups: MVD with CHF and MVD without CHF. The aim of this study was to evaluate the systolic function and diastolic function in small breed dogs with MVD by using conventional and two-dimensional speckle tracking echocardiography (2D-STE).
Longitudinal and circumferential strains and strain rates decreased and altered in dogs with MVD while no significant differed in fractional shortening and ejection fraction. Besides, attenuation of STE-derived longitudinal strain rates were prior to that of circumferential strain rates in severe mitral regurgitation. In the present study, 28% (24 out of 84) of 2D-STE variables significantly altered in dogs with MVD, compared with healthy controls. Regional decreased early diastolic strain rate of left ventricular longitudinal deformation was detected by 2D-STE in contrast with insignificantly different findings by tissue Doppler examination. Results of this study indicated that conventional echocardiography combined with 2D-STE could help to investigate the global LV systolic and diastolic function in dogs with MVD.
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