Characterisation of normal human myocardium by means of morphometric analysis

A morphometric analysis of ventricular myofibres, in specimens taken at necropsy from ten normal hearts, was performed to determine the distribution of fibre and nuclear diameters and their dependence on sampling position within the heart (group a). To assess the significance of the findings, two control groups of specimens were subjected to the same analysis: b) specimens from the hearts of four patients who had died of African cardiomyopathy; c) biopsies taken from the left ventricles of two hearts undergoing surgical repair of atrial septal defects (ASD), in which the myocardium is considered normal. Although mean values for the left ventricle were 13% greater on average than those for the right, a linear correlation, independent of sampling position, was found between nuclear and fibre diameter. Mean fibre and nuclear diameters for specimens from the normal and ASD control groups followed the same correlation as for individual normal fibres, whereas there was a significant deviation in the case of the cardiomyopathy specimens. The relationship between nuclear and fibre diameters was found to distinguish between normal and pathological specimens more clearly than the mean values of either dimension considered separately. It is suggested that this relationship is a more sensitive criterion of ventricular fibre normality or pathology than the parameters used in previous studies of this nature.