The Rates of Formation of Carctiac Lymph and Pericardia! Fluid After the Production of Myocardial Venous Congestion in Dogs*

Studies in dogs show that severe myocardial venous obstruction is associated with substantial increases in the rates of cardiac lymph flow and in the fonnation of pericardial fluid. The pericardial effusion occurs primarily from the epicardial surface (visceral pericardium) of the heart. The hearts in these dogs show an increased water content and histological studies reveal dilated lymphatics, perivascular and interstitial edema, small hemorrhages and patchy necrosis. In dogs with less severe myocardial venous obstruction the rates of formation of cardiac lymph and pericardial effusion are proportionately less, and the histologic alterations are less pronounced. These findings resulting from myocardial venous congestion in the dog may be relevant to understanding certain aspects of congestive heart failure and pericardia! effusion in man.