Congenital cardiac disease in dogs

Nonselective angiocardiography is used to delineate certain congenital cardiac defects. It is useful in demonstrating lesions causing a right-to-left shunt, as in tetralogy of Fallot and a reverse right-to-left patent ductus arteriosus, but not for lesions causing a left-to-right shunt, as in ventricular septal defect. Positive-contrast medium, injected IV as a bolus at 0.5 ml/lb, opacifies the heart chambers and great vessels. Using a rapid film-changing device, 3 films are made in 6 seconds. A rapid film changer can be constructed from plywood, wooden slats and plexiglass. Three cassettes are loaded into the device, the first beneath the x-ray beam and overlying plexiglass window and patient. The first film is exposed just after injection of the contrast medium, and the second and third 2 and 4 seconds later, respectively.