PHYSIOLOGIC CONSEQUENCES OF CONGENITAL HEART DISEASE 



435 



STANDING AT REST 



CUVETTE OXIMETER 

 DENSITOMETER 



2.35 mg. Indocyonine Green 

 into Pulmonary Arlery 



SIGNAL . 



Densitometer 



Cuvette Oximeter 



BASE Line 



EXERCISE 



CUVETTE OXIMETER^ 

 DENSITOMETER- 



2.45 mg. Indocyonine Green 

 into Pulmonary Arlery 1 



SIGNAL: 



Densilometer~ 

 Cuvette Onimeter 

 BASE LINE 



(ivg./L.) 



FIG. 8. Indicator-dilution curves recorded 

 simultaneously by phototube densitometer 

 and cuvette oximeter connected in parallel 

 to a common catheter sampling from root of 

 aorta. Calibration scales are on right. Inter- 

 ruptions in signal lines indicate passage of each 

 milliliter of blood through instruments. Above: 

 for a normal dog standing at rest. Below: 

 for same dog during exercise at lo km/hour on 

 horizontal treadmill. Note in curve recorded by 

 densitometer using a galvanometer with a nat- 

 ural frequency of 30 cycles/sec tliat variations 

 in concentration ot dye-blood mixture with 

 each heartbeat are clearly shown, whereas 

 variations are not visible in curve from cuvette 

 oximeter recorded with galvanometer with 

 natural period of 4 sec. [From Marshall, R. J. ; 

 Factors modifying the contours of indicator- 

 dilution curves. Circulation Res. (In press).] 



portion of the curve caused by early-appearing dye 

 recorded at the pulmonary artery to the initial portion 

 of the curve recorded .simultaneously at the systemic 

 artery, the magnitude of the left-to-right shunt can 

 be calculated as the fraction of the pulmonary flow 

 composed of shunted blood (Fl.r). Then by multi- 

 plying the pulmonary blood flow (Q„) by the fraction 

 of unshunted blood (i-Fl.^), the systemic blood flow 

 (Qs) may be determined. Measurements from the 

 curves and equations required for these calculations 

 are illustrated in figure 10. This metliod has been 

 validated by comparison of the values for systemic, 

 pulmonary, and left-to-right shunt flow by the dve 

 technique with values determined in close temporal 

 relationship by conventional application of the direct 

 Fick method (265). 



LOCALIZATION AND QUANTITATION OF V.^LVUL.AR 



REGURGITATION. The characteristic distortion of an 

 arterial dilution curve produced by valvular regurgita- 

 tion has been described. Localization of an incom- 

 petent valve by dilution curves recorded at a single 

 arterial sampling site may be accomplished by the 

 use of multiple selected injection sites or multiple 



selected sampling sites, or by combinations of these 

 techniques (284). 



Localization of an incompetent valve by dilution 

 curves recorded at a single arterial sampling site 

 after injections at multiple selected sites requires a 

 normal curve at the periphery after injection just 

 Ijeyond the first competent valve that lies downstream 

 to the incompetent valve, and an abnormal curve 

 after injection between this competent valve and the 

 incompetent one. 



Use of a single injection and multiple sampling 

 sites to localize an incompetent valve is illustrated in 

 figure II in a case of aortic regurgitation. After 

 injection into the pulmonary artery, dilution curves 

 were recorded simultaneously at the left atrium and 

 radial artery during combined right-heart and left- 

 heart catheterization (272). The normal contour of 

 the left atrial curse indicates the competence of both 

 the pulmonary and mitral vahcs, and absence of a 

 left-to-right shunt. The abnormal curve recorded at 

 the radial artery demonstrates and localizes the site of 

 valvular regurgitation to the aortic valve. 



Although in cases of severe valvular regurgitation 

 the characteristic changes in the systemic-artery 



