Ischaemic related transitory left ventricular dysfunction in 201Tl gated SPECT.

AIM

To report our data concerning the changes in post-stress and at-rest left ventricular ejection fraction and ventricular volumes in patients with thallium gated SPECT.

METHODS

Post-stress and at-rest thallium gated SPECT was performed in 629 consecutive patients; left ventricular ejection fraction (LVEF), left ventricular volumes and quantitative perfusion data were obtained. Transitory left ventricular dysfunction was diagnosed when post-stress LVEF did not increase at least 5% from LVEF at-rest.

RESULTS

In all patients post-stress LVEF was 64%+/-17 while at-rest LVEF was 66%+/-15 (P=0.6). Post-stress end diastolic volume (EDV) was 142 ml+/-7, at-rest EDV was 141 ml+/-92 (P=0.57), post-stress end systolic volume (ESV) was 54 ml+/-51 and at-rest ESV was 56 ml+/-59 (P=0.38). Data from the perfusion study were used to divide patients into three groups: normal patients (group I), patients with total or partially reversible defects (group II) and patients with fixed defects (group III). In group I and group III patients LVEF at-rest was lower than post-exercise (LVEF 75%+/-11 vs 81%+/-10 (P<0.001) and 57%+/-16 vs 60%+/-18 (P=0.025)), respectively. Patients in group II had a higher at-rest LVEF than post-exercise (LVEF 66%+/-14 vs 64%+/-16 (P=0.003)). While the left ventriuclar volumes in group I and III patients decreased with exercise, group II patients had increased post-stress ESV.

CONCLUSIONS

Post-stress and at-rest LVEF are similar when all patients are considered but significant differences appear when patients are divided according to the results of the perfusion study. Normal and fixed defect patients have increased post-exercise LVEF. Patients with reversible defects have decreased LVEF, which is largely due to an increased ESV. Transitory left ventricular dysfunction is related to the presence of reversibility and may benefit from revascularization.