Use of phase analysis of gated SPECT perfusion imaging to quantify dyssynchrony in patients with potential left ventricle dysfunction

Objectives Recently phase analysis using gated SPECT perfusion imaging has been evaluated in quantifying mechanical dyssynchrony for prediction of cardiac resynchronization therapy (CRT). Previous reports have shown that phase analysis can predict responders to CRT therapy. No other risk factors for developing heart failure (HF) have been correlated with mechanical dyssynchrony using phase analysis. The purpose of this study is to evaluate predictors of HF such as LV mass, EDV, ESV and LVEF with myocardial dyssynchrony using phase analysis, which could predict patients who are at risk of developing HF and subsequently undergoing CFT.

Methods The phase analysis measures of mechanical dyssynchrony from gated SPECT were retrospectively analyzed in 136 patients and compared with LV mass index, ESV, EDV, and LVEF(reduced LVEF<45%, n=30; normal LVEF>45%, n=106). We also correlated patient age (mean 64yrs, range 38-86), gender (102 male, 34 female), diabetes and hypertension history, and previous history of cardiac intervention with mechanical dyssynchrony using phase analysis.

Results Patients with reduced LVEF have more dyssynchrony than normal controls (phase SD 58.1o vs 31.3o, P<0.003; bandwidth 174.6 vs 66.35, P<0.41). Patients with depressed ESV and EDV also had reduced mechanical dyssynchrony (ESV: phase SD R2= 0.2, p<0.001, bandwidth R2 = 0.5, p<0.001; EDV: phase SD R2=0.2, p<0.001, bandwidth R2= 0.4, p<0.001). Left ventricle mass index also showed significant correlation with mechanical dyssynchrony (phase SD, bandwidth p<0.001). Patient age, stroke volume, body mass index, DM or HTN history, or patient history of cardiac intervention showed no correlation with mechanical dyssynchrony.

Conclusions This is the first study evaluating mechanical dyssynchrony in patients with various heart failure risk factors. In this study, ESV, EDV, EVEF, LVMI showed statistically significant mechanical dyssynchrony. Further studies are needed in evaluating the possible role of phase analysis using gated SPECT in predicting myocardial dysfunction