['Dilated cardiomyopathy (DCM) is a well-recognized sequela of muscular dystrophy (MD). Early identification of cardiac involvement with timely therapy can favorably impact outcome. We hypothesize that electrocardiography (ECG) can be a useful adjunct in the identification of DCM in MD.', 'This study sought to assess the utility of electrocardiography in patients with MD.', 'A retrospective review of patients with MD was performed. ECGs and Holter monitor results were analyzed to assess for association between abnormalities and the development of DCM.', 'This study identified 150 patients. In 43% of patients (64 of 150) DCM developed. ECG abnormalities were found in 65% of patients and correlated well with the presence of DCM, with 60 of 64 (94%) with DCM having an abnormal ECG vs. 38 of 86 (44%) without DCM (P < .001). Only 4 of 52 (8%) of patients with normal ECGs had DCM. The presence of ECG abnormalities was highly sensitive (95.8%) but not specific (40.1%) to the presence of DCM. ECG abnormalities often preceded the development of DCM by a significant period of time (3.7 ± 2.6 years). Arrhythmias were common, with 17 of 150 (11%) of the cohort being affected. Those with DCM were significantly more likely to have an arrhythmia, with 16 of 64 (25%) of that group being affected (P < .01). The presence of VT was a poor prognostic indicator, with 6 of 11 patients dying within 0.68 ± 0.41 years.'] Are electrocardiographic abnormalities and arrhythmias strongly associated with the development of cardiomyopathy in muscular dystrophy?