Reduction of the transient outward potassium current in canine X-linked muscular dystrophy

Abstract

Background: The xmd dog develops a cardiomyopathy similar to that seen in Duchenne muscular dystrophy patients. In both the canine and human diseases, ECG abnormalities may precede the development of overt cardiac pathological lesions. The purpose of this study was to determine whether specific cellular electrical abnormalities occur in dystrophic ventricular tissue. Methods and Results: Action potentials were recorded in epicardial tissue strips obtained from normal and xmd dogs. Phase I amplitude was increased from 86.8±2.7 mV in normal dogs to 94.3±1.8 mV in xmd dogs (mean±SEM; P