Correlations of systolic time intervals and radionuclide angiography at rest and during exercise

Systolic time intervals (STI) were correlated with radionuclide angiography studies (RAS) in 57 patients at rest, during maximal semisitting bicycle exercise, and at 4 minutes following the cessation of exercise. Eleven were judged as being free of coronary artery disease (group 1), while 14 had coronary artery disease without (group 2A), and 27 (group 2B) with a previous transmural myocardial infarction. For RAS, resting radionuclide ejection fraction (REF), the changes in REF and end-systolic volume, and the development of a wall motion abnormality at peak exercise were each highly correlated with the presence of coronary disease (p < 0.001). The accuracy of STI parameters in predicting the presence of coronary disease was poor (<60%). Changes in end-diastolic volume (EDV) correlated significantly with PEP LVET and LVET, changes following exercise. Moreover, patients with an abnormal (>25%) increase in EDV at peak exercise had a greater increase in LVET, in the postexercise period (p < 0.01). We conclude that STI is not accurate enough a predictor of coronary disease or left ventricular function to serve as a useful screening test. Changes in STI parameters appear to be more related to changes in ventricular volume than to ventricular function.