Background: We investigated whether poststress left ventricular dysfunction in patients with coronary artery disease may be confirmed at 30 minutes after exercise using newly modified quantitative gated single photon emission computed tomography (QGS) software that can evaluate systolic and diastolic function.
Methods and results: In this study 28 control subjects, 26 patients with angina pectoris (AP), and 27 patients with old myocardial infarction (MI) who had undergone revascularization were included. Same-day exercise/rest gated technetium 99m tetrofosmin single photon emission computed tomography was performed. QGS was used with a temporal resolution of 32 frames per R-R interval, and a left ventricular volume curve was reconstructed. From the fitted volume curve and its first derivative curve, we derived the ejection fraction (EF), peak ejection rate (PER), peak filling rate (PFR), and time to PFR (TPFR). In patients with AP and MI, the values for EF, PER, and PFR were lower after stress than at rest. TPFR was significantly prolonged in patients with MI after stress. In control subjects, EF, PER, PFR, and TPFR were not changed.
Conclusions: Modified QGS software successfully indicated the changes in systolic and diastolic function. In patients with AP and MI, poststress systolic and diastolic dysfunction was identified 30 minutes after exercise.