Figure
1: ECG of a patient with dystrophin-deficient cardiomyopathy. Complex
QRS morphology and fragmentation reflect abnormal depolarization of
myocardium.
The mechanism for arrhythmia in the dystrophin-deficient cardiomyopathy
involves not just fibrosis of the myocardial tissue, but derangement of
the molecular electrophysiology of conduction system cells themselves.
These specialized cells are reliant on dystrophin to support
organization of ion channels and promote coordinated electrical
activity12. In mouse models deficient in dystrophin,
misregulation of critical ion channels in specialized conduction tissue
cells disturbs electrical activity, contributing to the arrhythmogenesis
in the dystrophin-deficient heart13,14. On
electrocardiogram, both short and long PR intervals may be observed, and
complete heart block has been observed15.