Experimental Chronic Pericarditis. Further Contribution to the Study of Cardiac Hypertrophy.

Abstract

Within the past year and a half we have performed periocardotomies on 60 dogs through the more or less avascular midsternal route and have introduced into the pericardium various substances, as bacterial antigen, organic and inorganic compounds. Morphine and ether anesthesia by the intratracheal method with artificial respiration were employed. Electrocardiograms and roentgenograms were made before and at intervals after operation and just before death when it was possible to do so. At autopsy the sternum, with the anterior mediastinum, the pericardium, heart and lungs intact, was carefully removed together and subsequently dissected and weighed.

Six dogs died at the end of the first week with serous, fibrinous, and purulent pericardial effusion and with conspicuous anterior mediastinitis from the sternal wound to the heart. The heart weight-body weight ratios of these dogs ranged from 0.00988 to 0.00812, and were, thus, below the maximum normal of 0.01000, but above the average of 0.00798 established in a series of 200 normal dogs of all mongrel breeds, of various ages, sexes, and sizes. 1

One dog survived for 200 days with thick, anterior mediastinal bands of adhesions, but without any visceral adhesions. In this instance the heart weight-body weight ratio was found to be 0.00916. Another dog with a pure anterior mediastinitis for 10 days had a H. W./B. W. ratio of 0.00914. Five dogs had partial visceral synechia as well as heavy anterior mediastinal bands of adhesions for 212, 108, 83, 81 and 43 days, and these presented, respectively, H. W./B. W. ratios of 0.0133, 0.0100, 0.0131, 0.0079, 0.0082; thus presenting evidences of some cardiac hypertrophy, especially in dogs with the more extensive lesions for longer periods of time.