慢性肺性心に関する形態学的研究

特に左右心室系の心筋線維 Morphometry を中心として

抄録

The purpose of the present study is to investigate the characteristics of alterations occurring in the right ventricle of the heart and their influence on the left ventricle by morphologic and morphometric studies on 7 human autopsy cases with chronic cor pulmonale, and on 60 rats with experimentally induced cor pulmonale, in comparison with 6 human control hearts and 20 control rats
The results are as follows.
I. Human autopsy study.
1. The free walls of the right ventricles showed a significant increase in myocardial thickness, weight and diameter of the myocardial fibers, and prominent hypertrophy.
2. The ventricular septa were increased in weight and hypertrophied. Morphometric studies showed that the myocardial fibers in the right side of the septum (RS) were hypertrophied, while those on the left side (LS) were unchanged.
3. Concerning the free walls of the left ventricles, the average weight was not significantly different from that of control hearts. However, there were varying results in the morphometry of myocardial thickness and the diameter of myocardial fibers in each cases and no definite tendencies could be shown.
4. The ventircular septum tended to bulge toward the left ventricular chamber in some cases, resulting in so-called “reverse Bernheim phenomenon”, which might greatly influence hemodynamics in the left ventricle.
II. Experimental study. Four week-old male Sprague-Dowley rats were given a single injection (30mg/kg) of monocrotaline, a pyrrolizidine alkaloid, which has been known to produce a pulmonary hypertension associated with cor pulmonale in experimental animals.
1. 14 days after a monocrotaline injection, development of cor pulmonale was evident by the results of dilatation, the increase of relative weight and myocardial fiber diameters of the right ventricle.
2. Although there was a significant correlation (r=+0.89, p<0.001) between the diameters of the right ventricular myocardial fibers and relative weight of right ventricle, the correlation between fiber counts in a given area and relative weight of the right ventricle showed a reversely significant result (r=-0.87, p<0.001).
3. The increase of relative weight and myocardial fiber diameter in the ventricular septum as well as in the right ventricle in the 14 and 21 day groups were observed, while those in the free walls of the left ventricle were not significantly different in the experimental and control groups.
4. The cross section of the heart taken from the experimental group sacrificed 29 days after a monocrotaline injection showed displacement of the ventricular septum toward the left ventricular chamber with flattening or invagination into the left ventricle and reduced volume of cavity of the lfet ventricle. Morphometrically, myocardial fibers in the right side of the ventricular septum showed marked hypertrophy, but no noticeable changes on the left side of the septum were observed.
III. Based on these results, it was concluded that the alterations observed in the ventricular septum of the heart in chronic cor pulmonale may play an important role in the function of right ventricle, but on the other hand these may have some influence on the malfunction of the left ventricle.