Non-invasive detection of ischemic left ventricular dysfunction using rest gated SPECT: expectation of simultaneous evaluation of both myocardial perfusion and wall motion abnormality

Abstract

Although the accurate detection of ischemic etiology is important in the management of patients with severe left ventricular (LV) dysfunction, it is difficult to determine using a non-invasive strategy. The present study investigates whether perfusion and regional functional abnormalities identified by quantitative electrocardiographic gated single-photon emission computed tomography (QGS) at rest can detect ischemic LV dysfunction in patients with severe LV dysfunction. Rest QGS with (99m)Tc-tetrofosmin was performed on 54 consecutive patients with LV ejection fraction of </=40%. Ischemic LV dysfunction (n = 32) was defined according to the established standard. Regional perfusion and wall motion were calculated using a 14-segment model (six mid-ventricular and eight apical segments) and compared with a normal control group. The numbers of reduced [mean -1 standard deviation (SD) of normal individuals] and severely reduced (mean -2 SD) wall motion segments were similar between patients with ischemic and non-ischemic LV dysfunction (13.5 +/- 1.1 vs. 13.6 +/- 0.9 and 10.6 +/- 2.0 vs. 9.9 +/- 3.0 segments, respectively). The number of hypoperfused (mean -1 SD) segments was significantly greater in patients with ischemic LV dysfunction than in those with non-ischemic LV dysfunction (9.3 +/- 3.8 vs. 2.0 +/- 2.8 segments, P < 0.0001). The analysis of the receiver operating characteristics showed that a cut-off value of 4 hypoperfused segments among 14 segments provided the best separation between ischemic and non-ischemic LV dysfunction (sensitivity = 88% and specificity = 91%). Furthermore, patients with non-ischemic LV dysfunction had no severely hypoperfused (mean -2 SD) segments in any of the segments, whereas patients with ischemic LV dysfunction had 4.4 +/- 0.2 segments. The QGS strategy at rest can accurately differentiate patients with ischemic LV dysfunction from those with severe LV dysfunction by simultaneous regional evaluation of wall motion and myocardial perfusion.