Schmacht Luisa, Traber Julius, Grieben Ulrike, Utz Wolfgang, Dieringer Matthias A, Kellman Peter, Blaszczyk Edyta, von Knobelsdorff-Brenkenhoff Florian, Spuler Simone, Schulz-Menger Jeanette
From the Working Group on Cardiovascular Magnetic Resonance, Experimental, and Clinical Research Center, a joint cooperation between the Charité University Medicine Berlin and the Max-Delbrueck Center for Molecular Medicine, and HELIOS Klinikum Berlin Buch, Department of Cardiology and Nephrology, Germany (L.S., J.T., W.U., M.A.D., E.B., F.v.K.-B., J.S.-M.); DZHK (German Center for Cardiovascular Research), partner site Berlin, Germany (L.S., F.v.K.-B, J.S.-M.); Muscle Research Unit, Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty and the Max-Delbrueck Center for Molecular Medicine, Berlin, Germany (U.G., S.S.); and Laboratory of Cardiac Energetics, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD (P.K.).
Circ Cardiovasc Imaging. 2016 Jul;9(7). doi: 10.1161/CIRCIMAGING.115.004615.
Myotonic dystrophy type 2 (DM2) is a genetic disorder characterized by skeletal muscle symptoms, metabolic changes, and cardiac involvement. Histopathologic alterations of the skeletal muscle include fibrosis and fatty infiltration. The aim of this study was to investigate whether subclinical cardiac involvement in DM2 is already detectable in preserved left ventricular function by cardiovascular magnetic resonance.
Twenty-seven patients (mean age, 54±10 years; 20 females) with a genetically confirmed diagnosis of DM2 were compared with 17 healthy age- and sex-matched controls using a 1.5 T magnetic resonance imaging. For myocardial tissue differentiation, T1 and T2 mapping, fat/water-separated imaging, focal fibrosis imaging (late gadolinium enhancement [LGE]), and (1)H magnetic resonance spectroscopy were performed. Extracellular volume fraction was calculated. Conduction abnormalities were diagnosed based on Groh criteria. LGE located subepicardial basal inferolateral was detectable in 22% of the patients. Extracellular volume was increased in this region and in the adjacent medial inferolateral segment (P=0.03 compared with healthy controls). In 21% of patients with DM2, fat deposits were detectable (all women). The control group showed no abnormalities. Myocardial triglycerides were not different in LGE-positive and LGE-negative subjects (P=0.47). Six patients had indicators for conduction disease (60% of LGE-positive patients and 12.5% of LGE-negative patients).
In DM2, subclinical myocardial injury was already detectable in preserved left ventricular ejection fraction. Extracellular volume was also increased in regions with no focal fibrosis. Myocardial fibrosis was related to conduction abnormalities.
2型强直性肌营养不良症（DM2）是一种遗传性疾病，其特征为骨骼肌症状、代谢变化和心脏受累。骨骼肌的组织病理学改变包括纤维化和脂肪浸润。本研究的目的是通过心血管磁共振成像来调查在左心室功能保留的情况下，DM2患者的亚临床心脏受累是否已经可以检测到。
使用1.5T磁共振成像，将27例经基因确诊为DM2的患者（平均年龄54±10岁；20名女性）与17名年龄和性别匹配的健康对照者进行比较。进行心肌组织鉴别、T1和T2映射、脂肪/水分离成像、局灶性纤维化成像（延迟钆增强[LGE]）以及氢磁共振波谱分析。计算细胞外容积分数。根据格罗标准诊断传导异常。22%的患者可检测到位于心外膜下基底下外侧的LGE。该区域及相邻的内侧下外侧节段的细胞外容积增加（与健康对照相比，P=0.03）。在21%的DM2患者中可检测到脂肪沉积（均为女性）。对照组未显示异常。LGE阳性和LGE阴性受试者的心肌甘油三酯无差异（P=0.47）。6例患者有传导疾病指标（LGE阳性患者的60%和LGE阴性患者的12.5%）。
在DM2患者中，即使左心室射血分数保留，也已可检测到亚临床心肌损伤。在无局灶性纤维化的区域，细胞外容积也增加。心肌纤维化与传导异常有关。
