Regional left ventricular function in the three main coronary artery territories at rest and during exercise

Abstract

Twenty consecutive patients (mean age 51.6 years) with persistent severe angina pectoris underwent aorto-coronary bypass surgery receiving an overall of 60 anastomosis. On an average, 9.4 +/- 1.5 months p.o. first pass radionuclide ventriculograms (18 to 24 mCi 99m Technetium-Pertechnetate i.v.) were performed at rest and after exercise. Besides measurement of global ejection fraction (GEF), regional ejection fraction (REF) was assessed employing for the first time a new technique: each RAO-view of p.o. radionuclide left ventriculogram was subdivided into three regions according to supply of the three main coronary arteries and their branches as visualized on pre-operative coronary angiogram. GEF improved after maximum exercise in 13 cases by 8.1% points (from 50.4 to 58.5%), remained unchanged three times and decreased four times by 7.1 points (from 51.6 to 44.5%; all changes p less than 0.05). In completely revascularized regions (n = 35) REF improved 24 times by 9.7 points (from 51.1 to 60.8%), did not differ from rest REF six times and decreased in three case by 7.3 points (from 48.6 to 41.3%; all changes p less than 0.05). completely revascularized regions responded to exercise like normally perfused areas (increase 7.8 points (from 50.6 to 58.4%; n = 7; p less than 0.05). REF deteriorated in incompletely revascularized regions (n = 9) six times by 12.8 points (from 58.0 to 45.2%), remained unchanged twice and improved once by 4.5 points. Total group's REF decreased by 7.3 points (from 56.8 to 49.5%; p less than 0.05). Exercise REF of incompletely revascularized regions was highly significant inferior to that of completely revascularized regions (49.5 to 58.4%; p less than 0.01). GEF is a weighted balanced of the three regional ejection fractions. The most important parameter is REF of LAD territory.