Left ventricular mechanical dyssynchrony analzyed by Tc-99m sestamibi SPECT and F-18 FDG PET in patients with ischemic cardiomyopathy and the prognostic value.

To compare the left ventricular (LV) phase dyssynchrony parameters obtained from Tc-99m Sestamibi SPECT (GSPECT) and F-18 FDG PET(GPET), as well as the prognostic values in patients with ischemic cardiomyopathy (ICM). Consecutive ICM patients referred for myocardial viability assessment were retrospectively evaluated and were followed-up for 21 ± 5 months. Phase parameter from both GSPECT and GPET were analyzed by QGS software, including histogram bandwidth (BW), standard deviation (SD) and entropy. Independent predictor for cardiac death was analyzed by Cox regression analysis. The estimated cardiac survival curve was analyzed by and was compared with the log-rank test. Eight-eight (mean age 56 ± 10, male 94%, LVEF _SPECT 23 ± 10%) ICM patients were included for analysis. Moderate correlations were observed for BW (r = 0.65; p < 0.001), SD (r = 0.63; p < 0.001) and entropy (r = 0.73; p < 0.001) between GSPECT and GPET. Among all covariates, the extent of myocardial scar was significantly associated with the differences of SD (r = 0.22; p < 0.05) and entropy (r = - 0.7; p < 0.05), whereas the extent of myocardial viability was not (all p > 0.05). Entropy measured by GSPECT was the predictor for cardiac death (p = 0.037) while QRS duration was not. The cardiac survival of patients with a high entropy (≥ 59%) was significantly lower than that of patients with low entropy (< 59%) (p < 0.05). GSPECT and GPET-derived phase parameters were not interchangeable in ICM patients. Patients with LV dyssynchrony measured by gated SPECT were associated with a worse outcome.