Secondly, the geometry and function of the left ventricle (LV), infarct size, and interstitial fibrosis were compared in the transgenic (Tg) mice with cardiomyocyte-specific overexpression of human GCH1 gene with those in C57BL/6 mice 4 weeks after MI or sham surgery32, 33. Here, GCH1 is linked to myocardial infarction.