Cardiomyopathy in Duchenne Muscular Dystrophy: Current Value of Clinical, Electrophysiological and Imaging Findings in Children and Teenagers

BACKGROUND: Progressive cardiomyopathy (CMP) is one main cause of death in DMD. This cross-sectional assessment of different cardiac diagnostic procedures focusses on preterm diagnosis of cardiac dysfunction.

PATIENTS: 39 male DMD patients aged 6-20 years were included. 6 patients were still ambulatory, 21 patients received corticosteroid therapy.

METHODS: All patients were investigated by ECG, Holter ECG and heart rate variability (HRV), B-type natriuretic peptide (BNP), echocardiography (TTE), tissue Doppler Imaging (TD) and magnetic resonance imaging (MRI) with Late Gadolinium enhancement (LE) and segmental wall motion analysis (WMA).

RESULTS: 56% of the patients showed repolarization abnormalities and 76% altered HRV. Subnormal ventricular function was found in 25% by TTE and in 34% by MRI. TD differed from normal controls only in the apical septum. In MRI 89% of the patients showed different distribution and intensity of LE and WM restriction. The extent of LE was less in patients after steroid treatment (p<0.05).

DISCUSSION: MRI with segmental LE- and WM-analysis seems to be superior to TTE and TD in exploring regional distribution and severity of damage of the myocardium. ECG and HRV abnormalities are common in DMD-patients but not tightly predictive for segmental and global left ventricular dysfunction. Targeted treatment of CMP in DMD needs prospective evaluation.

CONCLUSION: A timely cardiac MRI is the most sensitive investigation for the identification of early myocardial changes in DMD which is a prerequisite for early interventions and therapeutic strategies.