Cardiac involvement of myotonic dystrophy type II in patients with preserved ejection fraction - Detection by CMR
Journal of Cardiovascular Magnetic Resonance volume 17, Article number: P315 (2015)
Myotonic dystrophy type II (MD2) is a genetic multisystemic disorder characterized by skeletal muscle (SM) symptoms, metabolic changes as well as arrhythmias1. Histopathologic changes of the SM may include fibrosis and fatty degeneration2. The aim of this study is to evaluate myocardial structure in preserved ejection fraction (EF).
We prospectively enrolled 32 subjects with a genetically confirmed diagnosis of MD2. Exclusion criteria were known cardiac diseases and contraindication for CMR. We assessed left-ventricular (LV) volumes, mass and function applying state of the art cine imaging using a 1.5 T Scanner. Late enhancement imaging (LGE; slice thickness (sth) 7 mm) was performed to detect myocardial fibrosis 10 minutes after injection of gadoteridol (0.2 mmol/kgbw). We applied T1 Mapping based on MOLLI (TI native 211 ms, TI post-contrast 281 ms, TE 1.08 ms, sth 6 mm) before and 15 minutes after contrast application and assessed resultant extracellular volume fraction (ECV). Fat-water-separated imaging3 (GRE, TR 944.80 ms, TE 1.53-8.22 ms, sth 6 mm) was performed to identify myocardial fat deposits. Furthermore, we used 1H magnetic resonance spectroscopy (MRS) (TR 1600 ms, TE 35 ms, septal voxel 20 x 15 x 6 mm³) to quantify myocardial Triglycerides (MTG). Data were analyzed using cvi42 and standard line-fitting procedure.
26 data sets were totally completed (age 53.8 ± 11 y, LVEF 65 ± 0.6 %, 19 women). None of the patients had wall motion abnormalities. LGE was detectable in 6 of 28 subjects (LGE+; 3 women); the location was mostly subepicardial inferolateral basal (Figure 1). In case of LGE+, the T1-values of the enhanced regions were significantly different to remote myocardium in both the native (p = 0.03) and the post-contrast maps (p = 0.03). ECV and T1 values of the remote myocardium were not different between LGE+ and LGE negative (LGE-) groups besides to the inferolateral located ECV (25.6 % vs. 34.3 %, p = 0.03) (Figure 2). Fat deposits were noticeable in 6 of 30 subjects (all women, one with LGE+) in the apical portion of the interventricular septum. The content of MTG in LGE+ and LGE- subjects was not significant different (0.34 % vs. 0.74 %, p = 0.47).
Despite preserved LVEF we could detect myocardial injury in patients with myotonic dystrophy type II. Already native T1-values were increased in case of subepicardial fibrosis compared to remote myocardium. To conclude, this is the first study constituted that CMR is feasible to detect subclinical myocardial manifestations in MD2.
Day JW: Myotonic dystrophy type 2 molecular, diagnostic and clinical spectrum. Neurology. 2003, 60: 657-664. 10.1212/01.WNL.0000054481.84978.F9.
Schoser B: Muscle pathology in 57 patients with myotonic dystrophy type 2. Muscle Nerve. 2004, 29: 275-281. 10.1002/mus.10545.
Kellman P: Multiecho dixon fat and water separation method for detecting fibrofatty infiltration in the myocardium. Magn Reson Med. 2009, 61 (1): 215-21. 10.1002/mrm.21657.
About this article
Cite this article
Schmacht, L.M., Traber, J., Grieben, U.I. et al. Cardiac involvement of myotonic dystrophy type II in patients with preserved ejection fraction - Detection by CMR. J Cardiovasc Magn Reson 17 (Suppl 1), P315 (2015). https://doi.org/10.1186/1532-429X-17-S1-P315