434 



HANDBOOK OF PHYSIOLOGY 



CIRCULATION I 



(9-33 years -53 kg - MYXOMA LEFT ATRIUM) 



(NORMAL DOG - 24 kg ) 



RADIAL 

 ARTERY 



RIGHT 



VENTRICLE 



(Outflow) 



CORONARY 

 SINUS 



SUPERIOR 

 VENA CAVA 



INFERIOR 

 VENA CAVA 



(mg /L ) 



FEMORAL 

 ARTERY 



RIGHT 



VENTRICLE 



(Outflow) 



CORONARY 

 SINUS 



SUPERIOR 

 VENA CAVA 



INFERIOR 

 VENA CAVA 



0.10 mg./kg. Cardio- green 

 into Pulmonary Artery 



0.10 mg /kg Cardio -green 

 mto Pulmonary Artery 



C.O^ (L /mm ) 



4.0 



FIG. 7. Comparison of systemic arterial and venous dilution curves recorded from various sites 

 on right side of heart in patient without arteriovenous shunt (left) and in normal anesthetized dog 

 (right). Instant of dye injection into pulmonary artery is indicated by vertical arrows. Note that 

 curves recorded from coronary sinus are similar to curves recorded from systemic artery. In con- 

 trast, curves recorded from other venous sites resemble badly damped versions of parent arterial 

 curve. Probably this modification is due to diflerences in volumes and rates of flow through various 

 vascular beds involved, which cause differences in degree of longitudinal dispersion of indicator 

 particles. Note also that curve from right ventricular mi.xed venous blood resembles a composite 

 of superior and inferior caval curves and that, because coronary flow is much smaller than systemic, 

 effect of coronaiy-sinus curve on right ventricular mixed venous curve is not apparent. Dilution 

 curves shown here were cut from photostats of original photographic record and realigned, correct- 

 ing for effect of dead space of sampling systems, so that true time relationships of dilution curves 

 recorded at vcirious sampling sites are illustrated. 



technique seems equal or superior to mctliods using 

 gaseous indicators, for example, N2O {174), Kr^' 

 (53, 207), or radioactive serum albumin (73). 



Following successive sudden single injections of 

 indocyanine green into a lobar pulmonary artery, 

 the concentration of the dye is recorded continuously 

 from the main pulmonary artery and then at sites 

 progressively more upstream — right ventricle, right 

 atrium, and venae cavae. If there is a left-to-right 

 shunt across any of the possible defects, the shunted 

 dye-blood mixture will be detected in the pulmonary 

 artery in an abnormally short interval. When during 

 these repeated injections into the lobar artery a 

 sampling site in the right side of the heart is found at 

 which the abnormal, early-appearing portion of the 

 dilution curve is absent, then the left-to-right shunt 

 has been localized to the cardiac chamber imme- 

 diately downstream to this site (274). A dilution 



curve simultaneously recorded from a systemic artery 

 aids in demonstrating that the appearance of dye in 

 the pulmonary artery is indeed abnormally early. 

 Localization of a left-to-right shunt via a ventricular 

 septal defect by this technique is illustrated in figure 9. 



The pulmonary and systemic flows as well as the 

 magnitude of the shunt can be calculated from such 

 curves without the necessity of measuring either the 

 gaseous content of blood or the respiratory gas 

 exchange (274). 



Pulmonary blood flow (Qp) is calculated from the 

 systemic arterial curve by the technique of Ramirez 

 and co-workers (195), which relates the initial 

 (forward-triangle) portion of the curve to the total 

 area that the curve would have subtended had its 

 disappearance slope not been distorted by early 

 recirculation of dye-blood mixture via the shunt 

 (fig. 10). From the ratio of the forward-triangle 



