Clinical evaluation of exercise equilibrium radionuclide angiography in patients with ischemic heart disease

The present study was undertaken to evaluate the clinical usefulness of exercise equilibrium radionuclide angiography (RI angio) in patients with ischemic heart disease (IHD), especially, for assessing the severity of exercise-induced ischemia. Fifteen patients (pts) with effort angina pectoris (EAP), 20 pts with old myocardial infarction (OMI) and 8 normal subjects underwent exercise RI angio, TI-201 stress myocardial scintigraphy, hemodynamic monitoring during exercise, coronary angiography and left ventriculography. Results were as follows; (1) Pts with OMI with exercise-induced left ventricular dysfunction (PAWP during exercise >= 25 mm Hg) showed lower resting ejection fraction (EF) and higher resting standard deviaton (SD), obtained from the histogram of the phase analysis of RI angio. (2) During exercise, EF decreased in 11 pts(73 %) with EAP and in 4 pts(20 %) with OMI, while SD increased in 14 pts(93 %) with EAP and in 2 pts(10 %) with OMI. From the above findings, SD is a more sensitive and specific index for detecting exercise-induced ischemia than EF. (3) Changes in SD during exercise closely correlated with maximum work load (>= 100 W 11.4 +- 5.460 v.s. < 100 W 18.7 +- 6.25, p < 0.05), number of involved vessels (single vessel 12.7 +- 4.690 vs multi vessel 21.2 +- 6.310, p < 0.01), PAWP during exercise (>= 25 mmHg 19.7 +- 5.830 vs < 25 mmHg 8.33 +- 3.510, p < 0.05) and the difference between thallium score at maximum exercise and that in delayed image 2.5 hours later (Δ defect score; γ = 0.55, p < 0.05). In conclusion, phase analysis of exercise RI angio is a usefull noninvasive method for assessing the severity of IHD. (author)