The objective of this program is to develop innovative solutions to the problems of human coronary artery disease. Thus, although animal investigations form a substantial segment of the overall program, they are dominantly oriented toward providing directly relevant clinical applications. Major emphasis, therefore, will be placed upon developing new technology and methods, including balloon catheter systems for arrhythmia detection and pacing and radioisotopes for "non-invasive" assessment of cardiac flow, oxygen consumption and function. Studies will be conducted in four subsections. Electrophysiologic studies will place major emphasis upon the mechanisms of arrhythmias and mapping of ischemia using endocardial and epicardial electrodes in man. Studies of coronary flow and metabolism will also concentrate in two major areas. Studies are designed to quantitate the effect of angiographically documented human stenoses upon flow and regional function, and secondly to determine the effect of pharmacologic agents upon regional flow, function and metabolism. The section on treatment of ischemic heart disease extends these studies to patients with acute coronary disease, and provides comprehensive assessment of cardiac function and metabolism in response to drugs, circulatory assistance, retrograde coronary perfusion, and cardiac surgery. Finally, the follow-up section of this proposal will provide ongoing long-term evaluation of approximately 1,000 patients treated medically or surgically, based upon documented levels of cardiac function at the time of admission to the Cedars-Sinai Medical Center. The undersigned agrees to accept responsibility for the scientific and technical conduct of the project and for provision of required progress if a grant is awarded as the result of this application. BIBLIOGRAPHIC REFERENCES: Swan HJC: Duration of hospitalization in "Uncomplicated completed acute myocardial infarction. Am J Cardiol 37: 413-426, 1976. Wyatt HL, daLuz PL, Forrester JS, Diamond GA, Chagrasulis R and Swan HJC: Functional abnormalities in nonoccluded regions of myocardium after experimental coronary occlusion. Am J Cardiol 37: 366-371, 1976.