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

Objective: 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.

Methods: Rest QGS with (99m)Tc-tetrofosmin was performed on 54 consecutive patients with LV ejection fraction of
Results: 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.

Conclusions: 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.