Adenosine-Induced Long-standing Postischemic Left Ventricular Dysfunction Evaluated With Gated SPECT

Abstract

This study was performed to determine the after-effects of pharmacologic stress (adenosine) on left ventricular (LV) function-end-diastolic volume (EDV), end-systolic volume (ESV), and ejection fraction (LVEF)-with Tl-201 and Tc-99m MIBI SPECT. A total of 263 patients were grouped according to the time interval between isotope injection and imaging. Group A: within 1 hour (n = 99; men, n = 48; women, n = 51; mean age: 63.2 years), subgrouped as patients with no perfusion defect (NPD; n = 61), reversible defect (RD; n = 33), and fixed defect (FD; n = 5). Group B: 1 to 2 hours (n = 110; men, n = 66; woman, n = 44; mean age, 63 years), NPD (n = 64), RD (n = 26), and FD (n = 20). 3) Group C: 2 to 3 hours (n = 54; men, n = 30; women, n = 24; mean age, 62 years); NPD (n = 22), RD (n = 17), and FD (n = 15). All patients were in sinus rhythm during the study and had no prior history of myocardial infarction. In group A, in the patients with RD, poststress LVEF was significantly depressed after adenosine infusion (53.1 +/- 9.5% vs 58.3 +/- 10.2%, P < 0.001) and showed a wall motion abnormality, which was worse after stress than during rest. The mean difference in LVEF (DeltaLVEF) between rest and stress was 5.2%. The DeltaLVEF in those patients with RD was significantly higher than that in the NPD (0.9%, P < 0.01) or FD (2.1%, P < 0.05) subgroups. Twenty of the 33 patients (60.6%) with RD showed an increase in LVEF > or = 5% from poststress to rest, and the poststress ESV (43.3 +/- 19.0 mL) was significantly higher than the ESV (38.5 +/- 18.4 mL, P < 0.01) at rest, but there was no significant difference in the EDV (90.5 +/- 26.4 vs 89.7 +/- 26.2 mL). In group B, DeltaLVEF was 1.5%, 4.4%, and 1.2% in patients with NPD, RD, and FD respectively. In group C, DeltaLVEF was 2.5%, 3.2%, and 0.9% in patients with NPD, RD, and FD respectively, and there was no significant difference in DeltaLVEF among patients. In group C, 4 of 17 patients (23.5%) with RD showed an increase in LVEF > or = 5% from poststress to rest. These results showed that adenosine stress-induced postischemic LV dysfunction is well noted on early quantitative gated SPECT in patients with RD and can also be observed on delayed gated SPECT, even though the incidence of LV dysfunction is less than that in early gated SPECT.