Adeno-associated virus serotype-9 (AAV-9) microdystrophin therapy partially improved the electrocardiography (ECG) profile. Quantitative evaluation of ECG in BL10, mdx, and AAV-treated mdx. HR, heart rate; bpm, beats/min; Q Amp, Q wave amplitude; C. Index, cardiomyopathy index. *Significantly different from the other two groups; cross, significantly different from BL10 only.