Electrocardiographic abnormalities in very young Duchenne muscular dystrophy patients precede the onset of cardiac dysfunction.

Overt cardiac involvement in Duchenne muscular dystrophy (DMD) typically occurs later in the disease. The primary aim was to estimate the proportion of young (<6 years of age) DMD patients with manifestations of cardiac disease by electrocardiography (ECG). Secondary aims were to assess associations between ECG abnormalities and evidence of cardiac disease by echocardiography, as well as to estimate the relationship between dystrophin mutation site and an abnormal ECG. Seventy eight steroid-naive DMD patients <6 years of age were identified. ECG abnormalities were identified in 78%, with LV pathology being the most commonly identified pattern. Only one echocardiogram was abnormal. There was no statistically significant relationship identified between ECG abnormalities and dystrophin genotype. ECG abnormalities are common in very young DMD patients, signaling cardiac involvement well before the onset of clinical symptoms.