Abstract:

Objective: To evaluate myocardial fibrosis by cardiac magnetic resonance (CMR) in the patients with myo-tonic dystrophy type 1 (DM1), and compare the value of CMR and ECG. Methods: A total of 14 patients with genetically conformed DM1 were included, and were performed CMR, electrocardiogram and dynamic electrocardiogram. Myocardial fibrosis was defined as presence of late gadolinium enhancement (LGE) in CMR. According to the results of ECG and/or dynamic ECG, the patients with DM1 were divided into normal ECG and abnormal ECG groups, and the CMR results were compared between two groups. Results: CMR examination showed that the detection rate of myocardial fibrosis in DM1 patients was 35.7% (5 out of 14). Compared with those without myocardial fibrosis, the patients with myocardial fibrosis had higher left ventricular mass index [(47.1±5.4) g/m² vs. (40.2±3.4) g/m², P=0.012)], left ventricular end-systolic volume index [(31.5±5.5) mL/m² vs. (25.8±2.8) mL/m², P=0.024)], and left atrial volume index [(43.8±7.1) mL/m² vs. (34.3±7.4) mL/m², P=0.037), while had lower left ventricular ejection fraction [(52.2±11.1)% vs. (63.9±5.3)%, P=0.019]. There was no correlation between the existence of myocardial fibrosis and the abnormal finding of ECG (44.4% vs. 20.0%, P=0.36) in the patients with DM1, while the other abnormal incidence detected by CMR was higher in abnormal ECG group than in normal ECG group (77.8% vs. 20.0%, P=0.036). Conclusions: Myocardial fibrosis occurs in some patients with DM1. For the patients with DM1, ECG screening fails to predict myocardial fibrosis, while CMR is valuable. Routine cardiac assessments for DM1 patients should include both CMR and ECG.

Key words: Myotonic dystrophy, Myocardial fibrosis, Cardiovascular magnetic resonance