Ph.D Thesis

Ph.D StudentWolf Tamir
SubjectCharacterization of the Electromechanical Changes Occurring
throughout Various Myocardial Pathologies
DepartmentDepartment of Medicine
Supervisors PROF. Gideon Uretzky
MR Shlomo Ben-Haim


Coronary artery disease is considered the major contributor to morbidity and mortality in the western world today. This disease encompasses a variety of pathological entities including acute ischemia, chronic ischemia, hibernating myocardium and infarcted tissue.

            The essence of cardiac activity lies in its ability to couple electrical and mechanical function. Hence, electromechanical coupling and uncoupling may serve as a method of delineating the processes by which myocardial dysfunction occurs.

            Because the endocardium is the most vulnerable of the cardiac layers to ischemic injury, mapping of the endocardial surface of the left ventricle using a system capable of high spatial and temporal resolutions was used to accurately localize and assess the degree of cardiac tissue viability. The novelty of this mapping technique is in its ability to perform simultaneous registration of electrical and mechanical parameters derived from specific endocardial sites.

            The tools generated in this study enabled differentiation between the various pathological states. Acute ischemic tissue is initially characterized by mechanical impairment, while endocardial electrical activity is relatively spared. Hibernating tissue is characterized by preserved electrical function and significantly reduced mechanical activity at rest. Chronic ischemic tissue displays normal electromechanical coupling at rest, but stress induced via rapid atrial pacing causes uncoupling with decreased mechanical capacity. Chronic infarction is characterized by pathological coupling of mechanical and electrical indices. In addition, endocardially sampled electrophysiological data can be used to detect variations in the extent of infarct transmurality.

These findings may have important prognostic and therapeutic implications in the treatment of ischemic heart disease patients.