LAUSR

With interest I read the article “Evaluation of Early Left Ventricular Dysfunction in Patients with Duchenne Muscular Dystrophy Using Two-Dimensional Speckle Tracking Echocardiography and Tissue Doppler Imaging,” by Cho et al. [1]. In the manuscript, the authors describe their use of speckle tracking echocardiography (STE) and tissue Doppler imaging (TDI) to detect early cardiac dysfunction in a young cohort of patients with Duchenne muscular dystrophy (DMD). In all, 13 patients with an average age of 9.69 ± 2.2 years were studied, with data demonstrating that, despite normal ejection fraction, several diastolic and systolic parameters were abnormal. Specifically, for systolic function, global longitudinal strain was significantly depressed, with the basal inferior and inferolateral segments being most affected. The data reported by Cho et al. support those we reported in a younger, larger cohort [2]. In that study, 63 patients with DMD and an average age of 5.6 ± 0.2 years were compared to a similarly aged and sized control group, both of which demonstrated normal shortening fraction. The group with DMD had significantly depressed global circumferential strain by STE, with the mid-papillary inferior, inferolateral, and anteroseptal segments each significantly depressed compared to control. Furthermore, the data by Cho et al. are a nice complement to our study for several reasons. First, in our retrospective cohort complete apical views were not captured reliably and, thus, we were unable to report longitudinal strain. This is a limitation given that other studies have demonstrated abnormal longitudinal strain in older DMD cohorts [3]. Second, the addition of TDI diastolic measurements gives more credence to the idea that simply following patients with standard echocardiographic measures of systolic function does not present a complete picture of their disease. Finally, both studies reported high intraand inter-observer reliability, attesting to the utility of these techniques. The most recent guidelines regarding management of patients with DMD recommend the use of cardiac imaging at diagnosis [4]. With proper awareness, knowledge of family history, and availability of genetic testing, patients are often diagnosed in the first half-decade of life. Due to the need for sedation to perform cardiac magnetic resonance imaging in most patients < 6–8 years of age, updated guidelines that include advanced echocardiographic techniques that can serve as early markers of cardiac dysfunction are needed [5]. Both STE and TDI meet those roles; however, larger studies are needed before appropriate inclusion into official guidelines.