PHYSIOLOGIC CONSEQUENCES OF CONGENITAL HEART DISEASE 



437 



Injection into pulmonary artery 



Sampling from : 

 Systemic artery 



10 sec 



Left atrium 



^^' 



FIG. 1 1. Localization of regurgitation at aortic valve by dilu- 

 tion cur\es recorded simultaneously at sites proximal (left 

 atrium) and distal (radicd artery) to competent mitral valve 

 during combined catheterization of right and left sides of heart. 

 At right: after injection of dye into pulmonary artery a normal 

 curve recorded from left atrium (below) indicates normality of 

 both pulmonary and mitral valves and absence of left -to-right 

 shunt. Abnormal curve iabore) recorded from systemic artery 

 indicates incompetence of aortic valve. 



Injection into right ventricle 

 Sampling from ^i 



Systemic artery -'""" 



Rigfit otrium 



10 sec 



FIG. 12. Diagram of method of localizing and estimating 

 regurgitant flow through tricuspid valve. Diagram of central 

 circulation in tiicuspid regurgitation is shown on right, and 

 dilution curves recorded from a systemic artery and right 

 atrium are shown on left. Vertical arrows indicate instant of dye 

 injection. \Vhen dye is injected just downstream to incompetent 

 tricuspid vaKe, a portion of dye is regurgitated through valve 

 and is detected almost instantaneously at right atrium, produc 

 ing abnormal initial concentration peak illustrated in lower 

 curve. 



that unless there is severe regurgitation, uniform 

 mixing of regurgitated dye-l^lood mixture may not 

 occur (281). Recent studies of this method in closed- 

 chest dogs with chronic experimental aortic or mitral 

 regurgitation indicate that under proper circum- 

 stances this upstream sampling technique provides a 

 surprisingly accurate indication of the presence and 

 degree of aortic or mitral regurgitation (12, 223). 

 The accuracy obtained by these methods when 

 applied to man is difficult to evaluate (65) (see 

 Chapter 20). 



Indicator-dilution curves have been of great value 

 during cardiac catheterization, but probably even 

 more basically important has been the role they play 

 in increasing the understanding of the hemodynamics 

 involved. 



Angiocardiography 



Angiocardiography, including biplane angiocardi- 

 ography and cinefluorography, plays a big role in 

 congenital cardiovascular diagnosis, especially in 

 obtaining a picture of the gross anatomic aberrations 

 present in a given patient (153). It also, however, 

 may play a role in physiologic studies of congenital 

 cardiovascular disease. Rushmer & Crystal (204) 

 ha\'e studied the changes in the configuration of the 

 ventricular chambers during the cardiac cycle by 

 cinefluorographic techniques. These methods have 

 also been applied to a study of the mechanics of 



ventricular contraction (205). Studies of incompetent 

 values and of the diastolic volume of the ventricles 

 are other areas in which cinefluorography and 

 angiocardiography can increase the knowledge of 

 cardiovascular hemodynamics (55). 



It seems reasonable that the recent developments of 

 image intensifiers and safer contrast media will 

 enhance the use of this method for studies in cardio- 

 vascular physiology. 



NORMAL CIRCULATION 



A knowledge of the averages and ranges of normal 

 values for pressures and blood oxygen saturations in 

 man is mandatory as a basis for judging the signifi- 

 cance of values obtained by similar techniques in 

 patients with cardiovascular disease. It also seems of 

 value to review the fetal circulation and to point out 

 the normal changes that occur in the circulation 

 following birth. Accordingly, this section will consist 

 of a discussion of the fetal circulation and the hemo- 

 dynamic changes occurring after birth, as well as 

 values for cardiac output, intracardiac pressures, and 

 blood oxygen .saturations that are found in normal 

 man during resting, supine conditions. 



Fetal Circulation 



By the eleventh week the heart of a human embryo 

 has developed into a four-chambered organ with its 



