Disturbed Atrial Conduction in Patients with Duchenne Muscular Dystrophy

Duchenne muscular dystrophy (DMD)-related cardiomyopathy is associated with hemodynamic and conduction abnormalities and begins at an early age with subtle symptoms.

The study population included 55 patients with DMD and 54 healthy controls. We compared electrocardiogram (ECG), conventional echocardiography, and tissue Doppler imaging (TDI) assessments between patients with DMD and healthy controls. Also, we investigated atrial electromechanical delay, which has not been previously studied in DMD patients. Mitral, septal, and tricuspid segments were analyzed by TDI.

The mean age was 13.6 ± 2.5 years (range, 9.3-17.9 years) in the patient group and 12.8 ± 2.6 years (range, 8-17.5 years) in the control group (P = .1). Patients had higher heart rates, longer QTc intervals, and P-wave dispersion (PWD) than controls (P < .001, P = .004, P < .001, respectively). The patient group had larger left ventricular end-systolic dimension (P < .001), lower left ventricular ejection fraction (EF) (P < .001), MAPSE (P < .001), TAPSE (P < .001), and mitral-E/A (P = .029) values than control subjects. Myocardial performance index (P < .001) was higher, and the E'/A' ratio (P < .001) was lower at all 3 segments in the patient group. Also, atrial electromechanical delay was longer in the patient group at these segments (P < .001). Patients had significantly longer interatrial (P = .033) electromechanical conduction delays. EF was negatively correlated with atrial conduction time variables.

We have shown deterioration in systolic and diastolic function in both ventricles, PWD, and atrial conduction in children with DMD. Patients with DMD may be at risk of atrial arrhythmias due to disturbed atrial conduction.