[Left ventricular systolic synchrony assessed by phase analysis of gated myocardial perfusion imaging in patients with old myocardial infarction].

OBJECTIVE

To assess the left ventricular (LV) systolic synchrony by phase analysis of gated myocardial perfusion imaging (GMPI) with SPECT/CT in patients with old myocardial infarction (OMI) and further to identify independent predictors for LV dyssynchrony.

METHODS

Seventy-six OMI patients and seventy-four healthy volunteers (control group) underwent resting GMPI from October 2010 to September 2013 in our hospital were included in this study. The left ventricular systolic synchrony parameters including phase histogram bandwidth (BW) and phase standard deviation (SD) were obtained by Cedars-Sinai quantitative gated SPECT (QGS) phase analysis technique, and LV cardiac function was also measured. The extent of myocardial perfusion defect was analyzed by the Quantitative Perfusion SPECT (QPS) software. The value of BW and SD were compared between OMI and the control groups, between LVEF ≤ 35% and LVEF > 35% groups in OMI patients. Dyssynchrony was defined when the BW exceeded the abnormality threshold derived from a normal control group (threshold = x ± 2s for normal BW).

RESULTS

(1) The BW ((91.3 ± 58.6)° vs. (37.2 ± 11.7)°) and SD ((27.3 ± 20.8)° vs. (11.8 ± 5.4)°) were significantly higher and the LVEF was significantly lower in OMI group than in the normal control group (all P < 0.01). In addition, BW ((136.0 ± 52.9)° vs. (51.0 ± 24.0)°) and SD ((38.7 ± 21.3)° vs. (17.1 ± 14.0)°) were significantly higher in patients with LVEF ≤ 35% than in patients with LVEF > 35% (all P < 0.001). (2) Dyssynchrony (BW > 60.6°) prevalence was 57.9% (44/76) in OMI patients. Compared with the synchrony group, LVEF was significantly lower, while the left ventricular end-diastolic volume, end-systolic volume, summed motion score, summed thickening score and extent were significantly higher in dyssynchrony group (all P < 0.001). (3) Additionally, dyssynchrony prevalence was significantly higher in patients with LVEF ≤ 35% compared with patients with LVEF > 35% (91.7% (33/36) vs. 27.5% (11/40), P < 0.001). (4) Pearson correlation analysis showed that LVEF was negatively correlated with BW (r = -0.807, P < 0.001). (5) Multivariate logistic regression analysis revealed that the extent of myocardial perfusion defect was an independent predictor for dyssynchrony in OMI patients (OR = 1.076, 95% CI: 1.015-1.141, P = 0.015).

CONCLUSIONS

GMPI phase analysis can reliably reflect left ventricular systolic synchrony. The left ventricular systolic dyssynchrony in OMI patients is significantly increased. Left ventricular dyssynchrony is closely related to LVEF. The extent of myocardial perfusion defect (Extent) is an independent predictor for left ventricular systolic dyssynchrony in OMI patients.