[A morphometric study of myocytes of normal and hypertrophic human atria]

Morphometric study of myocytes of normal and hypertrophic human atria was performed in semithin and paraffin sections. The hypertrophy is followed by the increase of size of both the myocytes and their nuclei: the average nuclei diameter increases from 5.9 to 7.5 microns, the average length from 13.7 to 20.2 microns. The same parameters of the cell change from 13.5 to 18.5 microns and from 121.6 to 143.9 microns. The increase of the nuclei length correlates with the increase of its ploidy. The ratio nucleus cytoplasm remains unchanged as well as the ratio between muscles and connective tissue. The number of binucleated cells in the hypertrophied atrium increases by factor of 3 or 4. The number of myocytes in the atrium was calculated and was equal to 1790.10(6) +/- 241.10(6) under normal conditions and 1890.10(6) +/- 336.10(6) in case of hypertrophy. The mechanisms of the heart weight increase is discussed.