Background: Type 1 myotonic dystrophy (DM1) patients' prognosis is very poor and is marked by respiratory and cardiac complications. Up until now, only a few prognostic factors for cardiovascular events have been identified, and they are predictive of end-stage disease.
Objectives: To assess the prognostic value of global longitudinal strain (GLS) for cardiovascular events in asymptomatic DM1 patients.
Methods: DM1 patients were included between 2011 and 2015 and followed up until January 2016. Patients underwent a transthoracic echocardiography at inclusion. The primary endpoint was a composite of all-cause mortality, type 2 Mobitz 2 and type 3 atrioventricular block, symptomatic sino-atrial block, HV interval ≥70 ms at invasive electrophysiology exploration, LVEF ≤45% and newly developed atrial fibrillation.
Results: Forty-six patients (25 males, mean age 40 years old) were included. The primary outcome was reached in 14 patients with a mean follow-up of 38 months. GLS of patients who reached the primary endpoint was significantly impaired as compared to those who did not (-15.1 [-16.7; -12.7] vs. -18.2 [-19.2; -16.7] respectively; P=0.001). According to ROC curve analysis, probability of primary outcome occurrence was significantly greater in patients with GLS values ≥ -17.2% (P=0.001). On multivariate analysis, PR electrocardiogram interval and GLS remained significantly and independently associated with the primary endpoint [hazard ratio (HR) 1.03, 95% confidence interval (CI) 1.01–1.04, P=0.006] for PR interval; HR 1.4, 95% CI 1.1–1.7, P=0.002 for GLS] while LVEF alone was not.
Conclusion: Left ventricular GLS is a powerful marker to predict cardiovascular events in asymptomatic DM1 patients, independently of LVEF.