Patients with type 1 muscular dystrophy (MD1) exhibit a poor prognosis related to cardiac involvement. Left Ventricular (LV) dysfunction with LVEF<50% is strongly associated with mortality but appears in the late stages of the disease. LV global longitudinal strain (GLS) may predict cardiovascular events in asymptomatic patients. The aim of this study was to evaluate the prognostic value of GLS in a multicentric cohort. Between 2008 and 2017, consecutive patients with DM1 and at least 1 echocardiography with GLS were retrospectively included in 4 French referral centers. The primary endpoint (PE) was a composite of: cardiovascular death, sustained ventricular tachycardia or atrial fibrillation, high degree of conduction disorder, LVEF<50%, hospitalization for heart failure or implantation of pacemaker or defibrillator. Two hundred and twenty four patients (123 women, mean age 43.7 years) were included with an average follow-up of 751 days. The PE was reached in 34 patients (15.2%). GLS was significantly impaired in patients who achieved the PE as compared with patients free of events (16.8±3.6% vs. 18.7±2.7% respectively, P=0.006). After analysis of the ROC curve, the probability to reach the PE was significantly increased in patients with GLS<18%. Using this threshold of 18% in the multivariate analysis, we found that GLS was the only factor associated with the composite outcome (P=0.006), while LVEF was not. Moreover, survival with a follow-up until 5 years, was significantly increased in patients with GLS≥18% as compared with patients with GLS<18% (78.9% vs. 46.8% respectively, P=0.006) (Fig. 1).

LV GLS is associated with cardiovascular events in asymptomatic MD1 patients with a threshold of −18%.