Double-contrast angiocardiography. An experimental method for demonstrating surgically created interatrial septal defects in dogs.

Abstract

Venous angiocardiography with liquid opaque medium has been generally unsuccessful in demonstrating atrial septal defects in infants, children, and adults (3). Sporadic reports of success with this method have appeared, but the experience has been so inconstant that the procedure has not been recommended for the diagnosis of this abnormality. Kjellberg et al. (4), in discussing angiocardiography in the diagnosis of atrial septal defect, state that, in their opinion, “the results of examination with intravenous injection of the contrast medium do not warrant further attempts with the technique.” The present report is concerned with our experience in demonstrating such defects in dogs by the simultaneous intravenous injection of an opaque medium and 100 per cent carbon dioxide. The method of study employed was devised after the observation of results obtained by the intracardiac injection of pure carbon dioxide, as described by Stauffer et al. (5–7, 9). These investigators obtained satisfactory visualization of the anatomy of the chambers of the heart and great vessels with this medium and cineradiography. Their experience showed this to be a relatively safe procedure in dogs, even when the carbon dioxide was injected via catheter into the chambers of the left side of the heart. Carbon dioxide in amounts as great as 7.5 c.c./kg. appeared to be well tolerated by dogs and to be absorbed rapidly in the blood stream. Limited human application was also observed without incident (2). Recently, these workers have described the visualization of an atrial septal defect in dogs by this method (5, 6) but they failed to demonstrate the defect in two patients (10). As much as 11 liters of pure carbon dioxide have been injected intravenously within a five-minute period in a dog without sequelae (8). A double-contrast technic employing carbon dioxide and Diodrast has been described by Durant et al. (2). It has provided better visualization but results in a marked depressing effect on the heart which is not noted when carbon dioxide is used alone. Recent experimental work with this method has been reported by Blickman (1). Method Thirty studies were performed on 9 normal dogs and 5 with surgically created atrial septal defects. The margins of the defect were marked with metal clips in one dog. The radiographs were made with the Schönander biplane rapid film-changing device at a speed of four per second and cineradiography (not demonstrated here) using 32 frames per second. Comparison studies were done in the prone and supine positions during the intravenous injection of a liquid opaque medium, carbon dioxide, and a combination of the two injected simultaneously. Observations Position of the Left Atrium: The left atrium was outlined in one normal dog by surgical insertion of a catheter via thoracotomy and the injection of 50 c.c. of carbon dioxide. Simultaneously, opaque medium was injected into a jugular vein.