STRUCTURE AND FUNCTION OF INFARCTED LEFT VENTRICLE

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We hypothesize that: 1) SPATIAL MODULATION OF MAGNETIZATION (SPAMM), a new ECG gated spin echo magnetic resonance "tagging" method for tracking fixed points in the myocardium, can depict local motion and deformation of normal, ischemia and infarcted myocardium;2) Analysis of left ventricular structure and function in ischemic heart disease can be enhanced using three-dimensional reconstruction and quantitative analysis of SPAMM images. Therefore, we will complete tasks in three areas: Analytic tools will be developed for: a) automated tracking of myocardial "tags", b) quantitation of regional dimensions in surface displays and grey scale data volumes, and c) measurement of cardiac deformation. Canine experiments (n=36) will assess left ventricular structure and function before and after creation of acute ischemia or chronic infraction. Since most in vivo imaging methods cannot track fixed points, our primary validation approach will be comparison to sonomicrometry segment length, with secondary comparisons to pathologic size and shape of nonperfused regions and scars. Human studies will examine 60 patients with recent or old infraction with comparison to biplane contrast ventriculography and two-dimensional echocardiography. Results will provide powerful new tools for assessment of left ventricular structure and function and new information about local deformation of normal, ischemic and infarcted myocardium.