Relationship between changes in left ventricular bipolar electrograms and regional myocardial blood flow during acute coronary artery occlusion in the dog

SUMMARY The purpose of this study was to determine whether a quantitative relationship existed between a reduction in regional myocardial blood flow, measured by radiolabeled microspheres, and the degree and type of changes in myocardial activation recorded in bipolar left ventricular subepicar-dial and subendocardial electrograms, in open-chest dogs following acute coronary artery occlusion. We found that the degree of regional myocardial ischemia was related quantitatively to the reduction in amplitude recorded with bipolar electrograms in the nibepicardium and subendocardium, and to the increase in duration of subepicardial electrograms. Other characteristics measured in electrograms did not relate to the degree of ischemia. Despite a comparable reduction in regional myocardial blood flow, subepicardial conduction delay exceeded that recorded in the subendocardium, which often exhibited accelerated conduction. Circ Res 45: 764- 770, 1979 ACUTE myocardial ischemia, produced by coro-nary artery occlusion, results in electrophysiological alterations manifested by changes in myocardial activation. Durrer et al (1961) qualitatively de-scribed the changes recorded in extracellular bipo-lar electrograms following coronary artery occlu-sion, and since then several studies have provided quantitative data relating the extent of electrogram alterations to the development of ventricular ar