Extent of Late Gadolinium Enhancement on Cardiac Magnetic Resonance Imaging in Japanese Hypertrophic Cardiomyopathy Patients

Background: In addition to the presence of late gadolinium enhancement (LGE) on cardiovascular magnetic resonance (CMR), the extent of LGE is considered clinically important in hypertrophic cardiomyopathy (HCM). We evaluated the extent of LGE on CMR in a large series of Japanese HCM patients. Methods and Results: CMR was performed in 317 HCM patients (147 male). The extent of LGE was scored as the sum of LGE-positive segments in a left ventricle (LV) 17-segment model. LGE was present in 246 patients (77.6%). LGE was detected in 3.5+/-3.1 segments on average. When the patients were divided according to maximum wall thickness (mild, <20 mm; moderate, 20-29 mm; severe, >= 30 mm), median LGE score increased as wall thickness increased (mild, 2 vs. moderate, 4 vs. severe, 5; P=0.000). When the patients were divided according to ejection fraction (EF) (reduced, <50%; low-normal, 50-65%; normal, >65%), median LGE score increased as EF decreased (reduced, 7 vs. low-normal, 4 vs. normal, 2; P=0.000). On multivariate analysis, reduced EF (OR, 0.947, P=0.015), pressure gradient <30 mmHg (OR, 0.359, P=0.000) and increased maximum wall thickness (OR, 1.236, P=0.000) were independent factors associated with extensive LGE. Conclusions: Progression of LGE was related to increased wall thickness, decreased contractility, and reduced intraventricular pressure gradient.