Dyssynchrony contributes to false-positive myocardial perfusion SPECT results in patients with stable angina

We designed this study to evaluate the possibility that dyssynchrony might lead to false-positive myocardial perfusion single photon emission computed tomography myocardial perfusion image (MPS) results in stable angina patients.

This study included 61 patients with both clinically diagnosed stable angina and quantitative MPS results who underwent coronary angiography. The patients were divided into two groups: those who had positive MPS results and normal coronary angiography (Group I, n = 28, 64.05 ± 10.14 years, 11 males and 17 females) and those who had positive MPS results and significant coronary lesions as determined by coronary angiography (Group II, n = 33, 69.2 ± 10.4 years, 14 males and 19 females). The maximal difference in time-to-peak myocardial sustained systolic velocity among all 12 left ventricular (LV) segments (maximal difference in TS) was significantly delayed in Group I as compared with Group II (125.00 ± 46.10 vs. 87.33 ± 40.53 ms, P=0.001). The standard deviation of the time-to-peak myocardial sustained systolic velocity of all 12 LV segments (TS-SD) was also significantly different in the two groups (45.12 ± 19.25 vs. 30.10 ± 15.80 , P=0.002).

Dyssynchrony may be a cause of false-positive quantitative MPS results, even if patients have narrow QRS complexes on ECG. Dyssynchrony index can increase the specificity of quantitative MPS in stable angina patients.