Indicator dilution curves in atrial septal defect.

The indicator dilution technique has evolved into an invaluable method for the detection and localization of congenital and acquired cardiac shunts. The groundwork for much of the work in this field has been laid by Wood, Swan, and Helmholz (1957); Swan (1959); Hetzel, Swan, and Wood (1959); Braunwald, Tanenbaum, and Morrow (1958) and Braunwald and Morrow (1960). Indocyanine green is the most commonly used indicator (Fox and Wood, 1957, 1960). The purpose of this report is to describe the use of indocyanine green in the diagnosis of the various types of atrial septal defects and associated congenital lesions. Dye dilution curves were recorded continuously from systemic arteries and the right heart by withdrawal of blood through a Gilford cuvette densitometer (Gilford et al., 1953) by means of a Harvard constant rate withdrawal-infusion apparatus. The indicator dilution curves were recorded at a paper speed of 5 mm./sec., with 1second time lines, using a photographic cathode-ray recording instrument. Forty-three patients with atrial septal defect, either simple or complicated by other lesions, were studied. Standard techniques of right heart catheterization and systemic arterial cannulation with a thin-walled 18 G Cournand needle were employed. Two Lehman catheters (6 or 7F) were used for right heart catheterization. Systemic arterial and right heart dye dilution curves were usually recorded simultaneously (Swan et al., 1958; Wood, Swan, and Marshall, 1958).