Effect of reversible hypoperfusion on left ventricular volumes measured with gated SPECT at rest and after adenosine infusion

Abstract

Background. The aims of this study were to assess the degree of postischemic left ventricular (LV) dilatation after adenosine stress and to determine the extent to which LV volumes measured with gated single photon emission computed tomography (SPECT) correspond to those obtained by echocardiography. Methods. Eight-frame gated SPECT with a 2-day technetium-99m tetrofosmin acquisition protocol was used. End-diastolic (EDV) and end-systolic (ESV) volumes were measured automatically with the quantitative gated SPECT algorithm. Reversible myocardial hypoperfusion was evaluated with a 16-segment, 4-point perfusion score model. LV volumes at rest were also measured with echocardiography by use of the biplane Simpson rule. Results. Twenty-two patients (group 1) showed normal perfusion and normal LV systolic function, whereas 33 patients (group 2) had evident coronary heart disease with reversible hypoperfusion. Patients in group 2 had greater EDV and ESV than those in group 1 both at rest and poststress. A greater reduction in ESV from poststress to rest was seen in group 2, which resulted in a slight increase in ejection fraction for patients in this group. The change in ESV from poststress to rest was significantly influenced by the degree of reversible hypoperfusion and by the change in heart rate from poststress to rest. We found a good correlation between LV volumes measured with gated SPECT and echocardiography. Conclusion. LV volume measurements with quantitative gated SPECT are comparable to those obtained with echocardiography. Patients with ischemic heart disease have greater LV volumes than patients with normal perfusion. Exercise-augmented adenosine infusion in patients with ischemic heart disease affects ESV more than EDV. This response is partly modulated by the degree of reversible hypoperfusion and possibly represents a minor degree of poststress stunning. (J Nucl Cardiol 2000;7:655-60.)