Usefulness of Delayed Enhancement Magnetic Resonance Imaging to Differentiate Dilated Phase of Hypertrophic Cardiomyopathy and Dilated Cardiomyopathy

Abstract Background The dilated phase of hypertrophic cardiomyopathy (HCM) has a poor prognosis. For correct recognition of such patients, we compared the findings in cardiac delayed enhancement (DE)-magnetic resonance imaging (MRI) between HCM and dilated cardiomyopathy (DCM) patients. Methods and Results Sixty-five patients (HCM 39, DCM 26) underwent gadolinium-DTPA–enhanced MRI. The HCM patients were divided into those with preserved (HCM-P, n = 30) and those with impaired systolic function (HCM-I, n = 9). DE-MRI demonstrated focal or diffuse DE at the left ventricular (LV) wall in 60% of HCM-P and 100% of HCM-I, but in only 12% of DCM. The DE distributed mainly septal to the anterior wall of LV, but the DE volume against whole LV muscle volume was much larger in HCM-I than in HCM-P and DCM (4.1 ± 6.1% in HCM-P, 14.6 ± 11.9% in HCM-I, and 0.8 ± 2.4% in DCM, means ± SD, P Conclusions The HCM patients had more DE than the DCM patients, and DE volume correlated to lower global and local LV function. DE-MRI may be useful to evaluate myocardial damage in HCM patients, and to differentiate the dilated phase of HCM from DCM.