Prevalence and Prognostic Impact of Cardiac Resonance Abnormalities in Myotonic Dystrophy Patients

Background myotonic dystrophy (DM) is an autosomal dominant inherited neuromuscular disorder characterized by progressive muscular weakness and multisystem involvement. Cardiovascular magnetic resonance (CMR) provides useful information about the potential risk of myocardial involvement in the early stage of several cardiomyopathies. We performed a systematic review aiming to describe the prevalence of disease–related CMR abnormalities in patients with DM; moreover, we investigated the association between CMR abnormalities and arrhythmias to detect predisposing and/or influencing prognostic factors. Matherials and methods we performed a systematic review in accordance with 2009 guidelines from the PRISMA. Results a total of 16 reports were included in our systematic review. The main findings of our systematic review are the following: the prevalence of CMR–detected LV dysfunction, defined as LVEF≤ 50%, ranged from 2% to 29% in DM1 population, and was higher than in healthy controls; conversely, it has not been described among DM2 populations. The overall LGE positivity ranged from 13% to 42% among DM1 patients and did not correlate to the LVEF as detected by echocardiography. LGE positivity was an independent predictor of AF among DM1 patients. Focal myocardial fibrosis and fat infiltration have been reported respectively in 27% and 32% of DM2 patients and seem to be associated with a high prevalence of conduction system defects. DM patients showed a non–ischemic LGE pattern characterized by mid–myocardial and subepicardial enhancement, in the septum and within the basal inferolateral segments of the LV wall. Conclusion The prevalence of CMR–detected LV dysfunction ranges up to one–third of DM1 patients; in contrast, it was not described among DM2 patients. LGE myocardial areas can be detected up to 42% of DM1 patients and 32% of those with DM2. A non–ischemic LGE pattern, characterized by mid–myocardial and subepicardial wall distribution in the septum and within the basal inferolateral segments of the LV wall, is the most prevalent among overall DM population. Myocardial LGE is an independent predictor of AF in DM1 patients; and it was associated with an increased prevalence of cardiac disorders among DM2 patients. DM1 patients showed an increased global ECV compared with healthy subjects and DM2 patients.