Circulation Journal Official Journal of the Japanese Circulation Society http://www. j-circ.or.jp he development of electrocardiogram-gated single-photon emission computed tomography (SPECT) has enabled the assessment of left ventricular (LV) function after stress and at rest, which has in turn enabled better detection of coronary artery disease (CAD), particularly that of multivessel pathology. 1-4 Recently, a novel technique was developed to evaluate not only myocardial function, but also LV mechanical dyssynchrony using phase analysis on gated SPECT. 5,6 Using this method, several studies have reported the diagnostic and prognostic value of LV mechanical dyssynchrony in patients with heart failure. 7-9 Although LV regional disparities in contractility are known to occur during periods of demand ischemia such as in exercise or dobutamine infusion, 10,11 few studies have analyzed LV mechanical dyssynchrony after stress and at rest to detect high-risk CAD by applying count-based temporal and spatial phase analysis. 12, 13 Considering the diagnostic challenge of multivessel CAD due to balanced ischemia on myocardial SPECT, we retrospectively evaluated whether exercise-induced LV mechanical dyssynchrony as assessed on phase analysis may have enhanced diagnostic value over conventional perfusion analysis in the detection of multivessel CAD. Editorial p 1832Methods Subjects Subjects consisted of 278 consecutive patients (241 men and 37 women; mean age 62±10 years) with suspected or known Background: Although stress-induced left ventricular (LV) wall motion abnormality is a well-known marker for extensive coronary artery disease (CAD), no study has yet analyzed whether phase analysis of exercise-induced LV mechanical dyssynchrony may have enhanced diagnostic value over conventional perfusion analysis in the detection of multivessel CAD.

Background: Although the Synergy between Percutaneous Coronary Intervention with Taxus and Cardiac Surgery (SYNTAX) score is used to characterize coronary anatomy based on 9 anatomic criteria such as lesion location and complexity, the relationship between SYNTAX score and myocardial ischemia has yet to be elucidated. Methods and Results:A total of 158 consecutive patients with suspected or known coronary artery disease (CAD), who underwent both 99 m Tc-sestamibi single-photon emission computed tomography (SPECT) and coronary angiography, were evaluated. Stress SPECT was assessed using a 17-segment model, and the percentage of the myocardial defect scores (DS) was calculated. In 37 patients with intermediate-high SYNTAX scores (>22), the number of men and the prevalence of multi-vessel CAD were significantly higher, and the % stress and ischemic DS were significantly greater than in 121 patients with low SYNTAX scores (≤22). Coronary risk factors, however, were similar between the 2 groups. The % stress and ischemic DS significantly correlated with SYNTAX score. In patients with a low SYNTAX score, % stress and ischemic DS also significantly correlated with the SYNTAX score, whereas no such correlation was observed in the intermediate-high SYNTAX score group.Conclusions: SYNTAX score correlated well with myocardial ischemia as assessed on stress SPECT in general. The higher the SYNTAX score, however, the less clear was the correlation with the extent of myocardial ischemia. (Circ J 2013; 77: 2772 -2777

In the identification of LMT disease, lung uptake of radiotracers was a single best parameter, which was independent of the presence or absence of previous MI.

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