PHYSIOLOGIC CONSEQUENCES OF CONGENITAL HEART DISEASE 



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PRESSURE 

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100- 



50 



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Pulmonary Artery - 

 100-1 



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PRESSURE 

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Pressure Via Catheter': 



COMBINED VALVULAR + INFUNDIBULAR STENOSIS 



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FIG. 2 1 . Pressure recordings during withdrawal of catheter tip from pulmonary artery to low right 

 ventricle in a patient with valvular and a patient with both valvular and infundibular pulmonic 

 stenosis. Note small pulsations recorded from pulmonary artery. When catheter tip was withdrawn 

 through pulmonic valve to infundibular chamber of right ventricle (lower panel), diastolic pressure 

 decreased to levels obtained from low right ventricle. Systolic pressure, however, was still \ery low, 

 increasing abruptly when catheter tip entered low right ventricle. 



reduction in coronary blood flow to the right side of 

 the heart caused by the fall in systemic pressure and 

 the concomitant increase in resistance to coronary 

 venous drainage from the right side of the heart due 

 to the increa.sed right atrial and \entricular pressure 

 under these circumstances, as postulated by Visscher 

 (251) and by Katz and co-workers (144). 



These studies demonstrate the poor ability of the 

 right ventricle to compensate for acute increases in 

 pulmonary resistance, which is in contrast with its 

 behavior when it has been subjected to a chronic 

 gradual increase in pulmonary resistance. 



Patients with i.solated pulinonary stenosis are 

 usually asymptomatic for a long time (21). Sooner or 

 later dyspnea on exertion and fatigability may occur. 

 Occasionally there is chest pain or syncope on effort, 

 presumably due to inability of the right ventricle to 

 increase its output during exertion. Sudden decom- 

 pensation with right-sided heart failure develops 

 commonly in such cases. 



Pulmonary stenosis may be either valvular or 

 infundibular in type, or both may be present. Hyper- 

 trophy of the right ventricle, especially the crista 

 supraventricularis, as a result of valvular pulmonary 

 stenosis may so narrow the outflow tract of the right 

 ventricle that further obstruction to the flow of blood 

 at this site is produced. Frequently, continuous 

 recording of pressures while withdrawing an intra- 

 cardiac catheter from the pulmonary artery to the 

 right ventricle will help in determining whether the 



stenosis is valvular, infundibular, or both. Figure 21 

 shows pressure recordings from patients with valvular 

 and with both valvular and infundibular pulmonary 

 stenosis during withdrawal of the catheter from the 

 pulmonary artery to the right ventricle. 



PULMON.'>iRY REGURGITATION. Congenital pulmonary 

 regurgitation is extremely rare, so that this lesion is 

 nearly always an acquired defect secondary to 

 bacterial endocarditis or functional regurgitation as a 

 result of pulmonary hypertension. Two of the features 

 common to all the varieties of pulmonic regurgitation 

 are /) hypertrophy of the right ventricle, and 2) 

 regurgitation of blood from the pulmonary artery into 

 the right ventricle, with the consequent production 

 of a diastolic murmur. In many cases there is also 

 considerable dilatation of the pulmonary artery. 

 Dilatation and hypertrophy of the right ventricle may 

 develop a compensatory mechanism .similar to that 

 of the enlarged left ventricle in aortic regurgitation. 

 Right ventricular hypertrophy with relatively little 

 dilatation may, however, have preceded the onset of 

 pulmonary regurgitation, owing to the pulmonary 

 hypertension associated with increased pulmonary 

 vascular resistance that may occur in chronic pul- 

 monary disease. 



TRICUSPID STENOSIS. Either stenosis or insufficiency 

 may result from Ebstein's malformation of the tri- 

 cuspid valve, which is a rare congenital disorder. The 



