Methods are being developed and applied for more objectively determining and quantifying abnormalities of extent and timing of regional ventricular wall motion from cineventriculograms. Using one method of analysis, normal values have been established and are being used as a basis for detecting and quantifying the severity of segmental wall motion abnormalities. Studies will be done to determine the extent to which the human left ventricle can compensate for regional function abnormalities and maintain global function as determined by the ejection fraction and the early systolic rate of ejection and early partial systolic ejection fraction. It will be determined if measures of regional function can provide earlier evidence of deteriorating LV performance than measures of global function such as ejection fraction in patients with aortic and/or mitral valve insufficiency. The influence of delayed regional contraction and relaxation on the peak negative dp/dt in diastole will be studied. In other studies a new technique for quantifying coronary artery dimensions and extent of stenosis from coronary arteriograms will be further evaluated and applied to determine vasomobility of coronary arteries and stenotic coronary artery lesions to a variety of cardiac drugs and reflexes such as hand grip and immersion of a hand in ice water. The quantified coronary artery stenosis will be related to coronary insufficiency syndromes and wall motion abnormalities. Finally, studies are and will be done to further define the natural history of coronary artery lesions and the effect of therapeutic interventions (initially aspirin and dipyridamole) on the course of lesions. These latter studies may lead to more effective measures to prevent the development and progression of coronary stenoses due to atherosclerosis.
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