Left ventricular longitudinal strain impairment predicts cardiovascular events in asymptomatic type 1 myotonic dystrophy

BackgroundType 1 myotonic dystrophy (DM1) patients' prognosis is very poor. Up until now, only a few prognostic factors for cardiovascular events have been identified, and they are predictive of end-stage disease. The aim was to assess the prognostic value of global longitudinal strain (GLS) for cardiovascular events in asymptomatic DM1 patients.MethodsDM1 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, left ventricular ejection fraction (LVEF) ≤ 45% and newly developed atrial fibrillation.ResultsForty-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.ConclusionLeft ventricular GLS is a powerful marker to predict cardiovascular events in asymptomatic DM1 patients, independently of LVEF.