Abstract 13785: Left Ventricular Contractile Entropy in 99mTc-Sestamibi SPECT is a Novel Prognostic Predictor in Patients with Non-ischemic Dilated Cardiomyopathy

Abstract

Background: It has been reported that mechanical dispersion of myocardial contraction is increased in failing myocardium. However little is known about the association between contractile entropy evaluated by myocardial scintigraphy and prognosis in patients with non-ischemic dilated cardiomyopathy (NIDCM). Purpose: We aimed to investigate the prognostic value of contractile entropy in patients with NIDCM. Methods: Forty-seven patients (38 male, 55.1 years) with NIDCM were performed gated 99mTc-sestamibi myocardial perfusion SPECT (GMPS) and endomyocardial biopsy. Entropy was automatically calculated as a result of contractile phase analysis for each myocardial sampling point from GMPS, and it reflects a dispersion of global mechanical contraction. All patients were allocated into two groups based on the median of entropy; HE-group: entropy≥0.61 and LE-group: entropy<0.61. All patients were followed up at the mean of 2.8 years. Results: The mean QRS duration, left ventricular ejection fraction (LVEF) and plasma brain natriuretic peptide (BNP) levels were 114 msec, 35% and 225 pg/mL, respectively. Although there were no significant differences in QRS duration and plasma BNP levels between the two groups, LVEF was lower in the HE-group than in the LE-group (31.1% vs 39.8%, p=0.002). In Kaplan-Meier survival analysis, cardiac event rate was significantly higher in the HE-group (Figure). Cox proportional hazard analysis revealed that the HE-group was a significant determinant of cardiac events (Hazard Ratio: 7.66; 95%CI: 0.070-2.532; p=0.033). The mRNA expression level of sarcoplasmic endoplasmic reticulum Ca2+ ATPase (SERCA2a) in biopsy specimens was significantly lower in the LE-group (p=0.015). Conclusion: Contractile entropy, reflecting an impairment of global left ventricular contraction, might be useful to predict a poor prognosis in patients with NIDCM.