Identification of blood in the pericardial cavity in dogs by two-dimensional echocardiography

Abstract

The echocardiographic characteristics of hemopericardium with and without thrombus formation were investigated in 10 dogs and compared with that of saline solution injected into the pericardial cavity. Injection of 80 to 120 ml of saline solution produced an echolucent space between both pericardial layers and was considered as the control image in each dog for comparison with hemopericardium. Injection of heparinized blood filled the pericardial cavity with irregular echoes of variable acoustical impedence. High-density echoes of irregular distribution were observed in 3 dogs, in 5 dogs the echoes were of low acoustical density and in 2 dogs blood echoes were present but scarcely visible. Injection of clotted blood in 9 dogs (adding 20 mg of protamin sulphate and 8 mg of aminocaproic acid) produced echoes of high acoustical density easily identified in the 2-dimensional echocardiographic images. In 4 dogs attenuation and damping controls were increased to the point where myocardial echoes disappeared, while intrapericardial echoes were still visible. Thus, hemopericardium with or without thrombus formation may be identified by 2-dimensional echocardiography and differentiated from other types of pericardial effusion of lower acoustical density. Echogenicity of fluid blood in the pericardial cavity may be related to blood stasis.