OBJECTIVE MEASUREMENT OF CHANGES IN REGIONAL WALL-MOTION CHARACTERISTICS FOLLOWING CORONARY-ARTERY BYPASS-GRAFTING USING TOMOGRAPHIC RADIONUCLIDE VENTRICULOGRAPHY

Difficulties arise when using non-invasive methods to measure changes in regional left ventricular function. With the increasing recognition of the entity of hibernating myocardium, and the known asymmetric eff ects of coronary artery disease, this is an important problem, as it p revents detailed investigation of the effects of revascularization upo n ventricular function. We investigated the use of tomographic radionu clide ventriculography in assessing such changes. Twenty consecutive p atients (18 males, 2 females, mean age 60 years), undergoing elective coronary artery bypass surgery, were identified and imaged prior to an d after surgery. The mean global left ventricular ejection fraction wa s 42 and 45% pre- and post-surgery, respectively. Following revascular ization, it was improved in 9 patients, unchanged in 3 and deteriorate d in 8. By comparison with pooled normal data from 25 subjects, 10 pat ients were noted to have overall resting phase values within normal li mits. After surgery, an improvement was seen in 5 patients, no signifi cant change in II and a deterioration in 4. With respect to regional e jection fraction, 24 of 80 segments improved, 25 remained unchanged an d 31 deteriorated. For regional phase analysis, 26 improved, 45 remain ed unchanged and 9 deteriorated. The use of tomographic radionuclide v entriculography confirmed that important regional changes in left vent ricular function occur following revascularization, even without a cha nge in global ejection fraction.