Usefulness of myocardial strain imaging in Duchenne muscular dystrophy A. Fayssoil Cardiologie, Hôpital Européen Georges Pompidou, AP-HP, Paris, France Received 3 May 2008; accepted 1 November 2008 Available online 26 November 2008 Abstract Duchenne muscular dystrophy is an X-linked recessive disorder caused by the absence of dystrophin. Heart involvement is a classical complication in this disease and leads progressively to heart failure. Detecting latent myocardial involvement is essential in this disease because early use of drugs like angiotensin - converting enzyme inhibitors may delay the progression of heart disease. Myocardial strain imaging is an application of the tissue Doppler imaging. By assessing regional myocardial function, this tool might help clinicians to detect latent myocardial involvement in DMD patients. © 2008 Elsevier Ireland Ltd. All rights reserved. Keywords: Duchenne muscular dystrophy; Dystrophin; Cardiomyopathy; Strain and strain rate imaging E-mail address: fayssoil2000@yahoo.fr . Duchenne muscular dystrophy (DMD) is an X-linked recessive disorder caused by the absence of dystrophin [1]. This disease affects 1 of 3500 male births and is characterized on pathologic evaluation by skeletal and cardiac muscle degeneration with fibrous tissue replacement and fatty infiltration [1]. Dystrophin is located on the inner sides of the skeletal and cardiac muscle cells. It links the cytoskeleton to the extracellular matrix by interacting with a large number of membrane proteins and it might also play a role in the regulation or localization of signal transduction molecules [2]. The lack of dystrophin in cardiac muscle leads to progressive cardiomyocyte degeneration and fibrosis [1].The posterior basal segment of the left ventricle is the first site affected on echocardiography [3].The incidence of cardio- myopathy in DMD increases with age, affecting 30% of patients by the age of 14 years, 50% by the age of 18 years, and all older patients [3]. The onset of this disease occurs in early childhood, and most patients die of respiratory failure, congestive heart failure or sudden death at approximately 20 years of age. Heart involvement is initially asymptomatic and most DMD patients remain asymptomatic for years in spite of the progression of cardiac dysfunction because of their limited daily activities. Overt symptoms due to heart failure appear in about 30% of cases [4]. Therefore, patients may have profound cardiac dysfunction when they initially experience slight cardiac symptoms. Hence, detection of early presymptomatic cardiac involvement in DMD patients is important. Moreover, early detection of latent myocardial involvement and early use of drugs such as angiotensin- converting enzyme inhibitors or beta-blockers would be beneficial for delaying progression of heart failure in DMD patients [5]. Traditionally, tissue Doppler imaging (TDI) is used for detecting infraclinical cardiomyopathy. However, analysis of myocardial velocity profiles using conventional TDI cannot distinguish regional velocity from translational motion of the heart and the tethering effect of adjacent myocardial segments. To overcome these problems, ultra- sound-derived strain rate and strain were developed and are interesting in DMD patients [6]. Myocardial strain imaging, a echocardiographic technique using the tissue Doppler method, is useful for quantitative assessment of regional wall motion of the left ventricle. It has been recognized as a sensitive method to detect regional abnormalities in various heart diseases [7]. Strain rate measures the rate of deforma- tion of a tissue segment and is measured in 1/s. Peak systolic strain rate represents the maximal rate of deformation in systole. According to Ogata et al. [1], the strain profile is modified at the postero-lateral wall of the left ventricle in DMD patients. Postero-lateral wall abnormalities have been reported to be a common region for cardiac involvement in DMD, before overt cardiomyopathy's development [1]. In a recent study [8], myocardial strain imaging in DMD patients was characterized by decreased peak systolic strain of the posterior wall despite normal standard echocardiographic findings. Myocardial radial strain of the left ventricle was measured in 25 DMD patients (age: 14.8 ± 3.1 years) with a normal left ventricular shortening fraction and 25 age- matched healthy controls. Echocardiography with strain tools will help clinicians for early therapeutic intervention. It has been demonstrated that early therapeutic administration would be beneficial for high-risk patients with DMD to prevent heart failure. 114 Letters to the Editor