Terminal echocardiographic findings during death process in man and dogs

Serial echocardiographic imaging was performed to assess terminal mechanical changes of cardiac chambers and valves, as well as sequential echocardiographic features of blood stasis, inside the heart after mechanical asystole in 7 hospitalized adults who died without apparent cardiac disease and in 7 experimental dogs sacrificed by a means of asphyxia. Marked reduction of wall motion became manifest shortly after the electrocardiograms had generated into a slow junctional rhythm with intraventricular conduction defect, an idioventricular rhythm, or an extreme sinus bradycardia. Total cessation of cardiac wall and valve motion followed; the aortic valve remained closed, with mitral and tricuspid valves semiopen after total cardiac asystole. Liquid whole blood inside the heart became echogenic shortly before mechanical asystole had approached, and homogenous echogenicity usually first appeared on the right side of the heart. As the death process progressed and total asystole persisted, the acoustic intensity of the intracavitary echoes increased, tending to form amorphous masses, with some showing rather well-defined borders. Such echocardiographic features were noted to indicate red thrombi in experimental dogs. The cardiac dimensions (left ventricle and aorta) decreased after total cardiac asystole.