Abstract 12818: Clinical Significance of Myocardial Perfusion in Dilated Cardiomyopathy and Hypokinetic Non-Dilated Cardiomyopathy

Abstract

Introduction: Dilated cardiomyopathy (DCM) is characterized by left ventricular (LV) systolic dysfunction with LV dilatation. Hypokinetic non-dilated cardiomyopathy (HNDC) characterized by LV dysfunction without LV dilatation is proposed as a new category of DCM. Microvascular dysfunction in DCM is associated with the degree of LV dysfunction. However, the association between myocardial perfusion and clinical spectrum of DCM has not been elucidated. Hypothesis: We assessed the hypothesis that myocardial perfusion is correlated with the clinical spectrum of DCM. Methods: Thirty-six subjects (20 non-ischemic cardiomyopathy (NICM) patients and 16 control subjects, mean age: 59 ± 2 years) underwent CMR at 3T. Cine imaging, adenosine stress perfusion, T1 mapping, and late gadolinium enhancement were performed. NICM group was divided into DCM (n=10) and HNDC (n=10). Native T1 and extracellular volume fraction (ECV) were measured as an averaged values in the septum of 3 short-axis slices of base-to-apex LV myocardium. Myocardial perfusion reserve (MPR) was calculated as the ratio of stress/rest myocardial blood flow. Results: LV ejection fraction was significantly lower in NICM compared to control (29.2±1.6% vs. 56.6±1.5%, p<0.001). Native T1 and ECV were significantly higher in NICM compared to control (native T1: 1296±12ms vs. 1228±8ms, p<0.001, ECV: 32.9±1.7% vs. 27.3±0.62%, p<0.001), but they showed no significant differences between DCM and HNDC. MPR in HNDC was significantly higher than that in DCM (2.0±0.51 vs. 1.5±0.27, p=0.026), and comparable to that in control (1.9±0.11, p=0.717, Fig 1). MPR was negatively correlated with LV end diastolic volume index (r=-0.333, p=0.047, Fig 2), but MPR showed no significant correlations with native T1 and ECV. Conclusions: HNDC showed preserved MPR in contrast to impaired MPR in DCM. Myocardial perfusion may be a promising factor for the clinical spectrum of DCM.