VENTRICULAR ENDOMYOCARDIAL CHANGES AFTER IMPAIRMENT OF CARDIAC LYMPH FLOW IN DOGS

Abstract

Chronic impairment of cardiac lymph flow was successfully produced in dogs by a wholely extra-pericardial surgical technique. Gross and histological studies were made in 73 operated aniamls, as well as in appropriate controls. The endomyocardial pathological changes that resulted consisted primarily of early ventricular subendocardial haemorrhages, and of thickening of the ventricular endocardium due to increased fibrous and elastic connective tissue. Gross greyish-white ventricular endocardial opacity occurred in a large percentage of the dogs judged to have decreased cardiac lymph flow before sacrifice. It was a rare finding in other dogs. It is concluded that chronic impairment of cardiac lymph flow in the dog produces significant endomyocardial disease. These observations in the dog are considered to be important in evaluating the pathogenesis of certain human endocardial diseases of unknown etiology. In particular, attention is focused on endomyocardial fibrosis and endocardial fibro-elastosis. The cardiac lymphatics are undoubtedly important in myocardial physiology and pathology and deserve continued investigation. It is well known that impaired lymph drainage from a part is associated with fibrosis and predisposition to infection and inflammation in that part. Interference with cardiac lymph flow may play an important role in the pathogenesis of endocardial disease, and may also be important in the pathogenesis of various forms of myo-card itis.