Our observations also show that the Ca2+ uptake activity of the sarcoplasmic reticulum was depressed slightly (about 15%), whereas the myofibrillar Ca2+-stimulated ATPase activity was depressed significantly by about 18 to 20%, which seems to indicate that the right ventricle may be at the stage of maladaptive cardiac hypertrophy at 16 weeks after inducing myocardial infarction. This evidence concerns the gene DNAH8 and cardiac hypertrophy.