Exercise radionuclide ventriculography after uncomplicated myocardial infarction: what could we gain from the analysis of LVEF throughout the whole test?

Abstract

To assess the usefulness of a step by step evaluation of exercise left ventricular ejection fraction (LVEF), 219 consecutive patients with recent uncomplicated myocardial infarction and 30 normal subjects underwent a symptom-limited cycloergometer test followed by exercise radionuclide ventriculography (ExRNV). LVEF was monitored throughout the whole test. 49 patients underwent coronary arteriography for clinical reasons. 5 patterns of exercise LVEF could be observed: progressive increase: 55 patients (25%) and 27 normal subjects (90%); progressive decrease: 37 patients (17%); initial increase followed by significant decrease: 54 patients (25%); lack of initial modification and terminal decrease: 35 patients (16%); no modification: 38 patients (17%) and 3 normal subjects (10%). Grouping the patients in this fashion allowed us to increase the specificity of ExRNV from 70% to 100%, without loss of sensitivity (95%). As for the patients in subgroup C, 32/54 showed unequivocal ECG ischaemic changes, occurring simultaneously with LVEF decrease; in 33/54 LVEF dropped during the last workload; in 25/54 the last stage LVEF was equal to or higher than the basal LVEF. The statistical analysis showed that ischaemic ECG changes (P less than 0.0001), exercise-induced wall-motion abnormalities (P less than 0.0001), and the presence of multivessel coronary artery disease (P less than 0.0001) were significantly more frequent in patients showing patterns (b)-(d), which should be considered as ischaemic. Our method allowed the unequivocal identification of ischaemic patterns in LVEF during exercise, which might be missed if only its basal and final values are considered.