Electrocardiographic, biochemical, and morphologic abnormalities in dystrophic hamsters with cardiomyopathy.

Electrocardiographic (EKG) changes were investigated in 7-month-old dystrophic hamsters (DH) with cardiomyopathy and were correlated with biochemical and histologic aberrations. Abnormally tall R-I and R-aVL amplitudes, deep S-III and S-aVR waves, and elongated PR-I, QT-I, and QRS-I intervals (all at P less than 0.0001) were noted in DH compared with normal hamsters. These EKG changes are similar to those seen in Duchenne muscular dystrophy (DMD) and support cardiac hypertrophy (P less than 0.001) in DH. Excessive intracellular calcium accumulation in the heart (P less than 0.0001), diaphragm (P less than 0.001), and rectus femoris (P less than 0.05), and elevated plasma creatine kinase concentrations (P less than 0.001) were also noted in DH. Histopathology in the cardiac and skeletal muscles of DH included fatty infiltration, centronucleation, and sporadic necrosis with calcium deposition. Observed EKG abnormalities, biochemical alterations, and histological aberrations in the cardiac and skeletal muscles of DH are strikingly similar to those reported in DMD and thus substantiate the relevance of DH as a suitable model for the study of muscular dystrophy and cardiac hypertrophy.