Is adipose tissue a normal component of the myocardium?

We performed a histological comparative study between endomyocardial biopsies taken from 138 patients with various cardiac pathologies and from 42 autoptic hearts (all negative for right ventricular dysplasia), measuring the amount of adipose tissue in isolation or associated with fibrous tissue. In the clinical cases these features were present in 24 instances on the right and in one on the left side of the ventricular septum, to an extent of more than 20% of the section in six patients, clinically positive for right ventricular dysplasia. On autoptic biopsy, fibro-adipose tissue was found in seven hearts, with different distribution on both ventricles, but to a maximum amount of 20% of the section. The right side of the ventricular septum was affected in five instances. Therefore in our material there is a quantitative difference on right ventricular biopsy with respect to fibro-adipose tissue in normal hearts and in cases with right ventricular dysplasia.