Effects of Rapid Injection of Heparinized Blood into Right and Left Ventricles in Dogs

The primary purpose of selective angiocardiography is the demonstration of anatomic details of the heart and the central circulation. Secondarily, selective angiocardiography can yield important information on certain functional parameters, such as absolute volumes and volume changes for the left atrium and the left ventricle. In either instance, the changes in the circulation induced by the injection of contrast medium are important. Radiologists and cardiologists who employ angiocardiography have been interested mainly in the effects of the contrast agent itself. In particular, consideration is given to the cytotoxic effect on nervous and parenchymatous tissue (5, 9, 12), the more obvious circulatory effects such as change in heart rate, the fall in peripheral blood pressure, cardiac irregularities, subjective symptoms (1, 13, 19), and physical factors such as viscosity, osmolality, and radiodensity (3, 10). Reports in the literature concerning hemodynamic changes in the central circulation due to rapid injection of amounts of fluid comparable to the volumes used in angiocardiography are rare and usually confined to observations of pressure changes on either the right (14, 16) or the left side (6, 11) of the central circulation. Elevations in intraventricular pressures during intraventricular injection were considered to be caused chiefly by cardiac irregularities (15, 18) or associated with valvular incompetence (16). In these respects, the effect of the large quantity of fluid injected on the peripheral and central circulation has not been distinguished from the pharmacologic effect of the contrast substance itself. Nordenstrom (17) stated, “Normally, when contrast fluid is injected through catheters or cannulas into the cavities of the heart, it is not possible to alter the circulation to any appreciable extent.” Superficially, it would seem surprising that the rapid injection of a large volume of fluid of a high osmolarity such as radiographic contrast medium was without effect on the circulation. Furthermore, in a previous study (8), we observed a small increase in left ventricular volumes during selective left ventricular angiocardiography. The present work was undertaken to reevaluate the effects of intraventricular injections of large volumes of a biologically inert fluid on the heart and central circulation. Method and Material Healthy mongrel dogs, weighing between 16 and 27 kg., were anesthetized with a combination of morphine sulfate (2.5 mg.∕kg.) and chloralose (10 mg.∕kg.) or 6 per cent Pentobrocanal (0.5 ml.∕kg.). The animals were intubated, and 100 per cent oxygen was administered by means of a respirator.