STENOSIS AND INSUFFICIENCY 



655 



gery. The diastolic pressure of tlie left ventricle 

 ranged from 3 to 12 mm Hg (mean diastolic 

 pressures). These figures were obtained with open 

 chest and under anesthesia. The cardiac output was 

 not determined but was presumably low. 



Right Atrium 



The right atrial pressure pulse has the same general 

 characteristics as the left, with a generally lower 

 mean pressure and perhaps less amplitude in the 

 different waves. The right atrial pressure pulse 

 changes in the same fashion as described for the left 

 when stenosis or insufificiency of the atrioventricular 

 valve occurs. It may be of importance to stress the 

 occurrence of a giant a wave in cases with marked 

 right ventricular hypertrophy. 



McCord et al. (147) studied 23 patients with right 

 \entricular hypertrophy due to pulmonary stenosis 

 or pulmonary hypertension. They found an a wave 

 of increased amplitude in 20 cases and propose that 

 this giant a wave represents the characteristic re- 

 sponse of the right atrium in the presence of se\cre 

 right ventricular hypertrophy. Grishman et al. (93) 

 likewise found a presystolic pulsation of the liver in 

 the absence of tricuspid disease in cases with right 

 ventricular hypertrophy. 



A giant a wave (up to 20 mm Hg) in tlie absence of 

 elevated mean pressure cannot thus be taken as an 

 indication of tricuspid stenosis. For this diagnosis 

 simultaneously obtained pressure curves from the 

 right ventricle and atrium are necessary and should 

 demonstrate a diastolic pressure gradient. 



TRICUSPID STENOSIS. Ferrer et al. (71) describe the 

 findings in two patients with tricuspid stenosis, one of 

 them was also studied at autopsy. One of the cases 

 had a low cardiac output and in the other the output 

 was in the lower range of normal. The right atrial 

 pres.surc curve showed: a) Very high peaks of atrial 

 systole, ranging from 9 to 12 mm Hg. /;) A marked 

 fall in pressure during the ventricular contraction, c) 

 The opening of the tricuspid valve, which should be 

 followed by the rapid filling of the right ventricle, 

 was not attended by any marked fall in pressure. The 

 marked fall in pressure during ventricular contraction 

 indicated the absence of any regurgitation, and the 

 absence of pressure drop when the tricuspid valves 

 opened showed that the rate of flow in diastole was 

 reduced due to stenosis. 



TRICUSPID INCOMPETENCE. Bloomfield et al. (23) de- 

 scribed the right atrial pressure curves in eight cases 



of tricuspid incompetence and showed the normal 

 systolic dip (the x descent) to be replaced by a posi- 

 tive wave that had the form of a plateau or showed 

 an upward convexity; the pressure level was higher 

 than in the intervening diastolic interval and was 

 sustained until the end of isometric relaxation. 

 Similar observations were made by Lagerlof c& 

 Werko (125) and by McCord & Blount (146). The 

 latter authors also demonstrated that exercise or deep 

 inspiration increa.sed the systolic wave in the atrial 

 tracing. 



Clinical and physiological signs of tricuspid in- 

 competence may occur in the absence of anatomical 

 changes. Lottenbach & Shillingford (139) studied, 

 at necropsy, 10 patients with heart disease of various 

 etiology and accompanied by right heart failure, and 

 1 5 patients without evidence of heart disease, and 

 concluded that functional tricuspid incompetence 

 was present in all cases witli a right atrial pressure 

 during life of 8 mm of mercury or more. 



From these and other findings it is evident that 

 tricuspid incompetence of a functional nature is 

 common and develops in the majority of patients 

 as part of the progressive downhill coiu'.se of cardiac 

 disease. 



.\TRI.AL VOLUME CH.ANGES 



Attempts have been made to estimate the volume 

 changes of the left atrium in man during the cardiac 

 cycle, using two different methods: /) electrokymog- 

 raphy (2, 74, 172) and 2) serial angiocardiography 

 with frequent exposures (91, 143, 187, 193, 216). 



Electrokymograph}' 



This method gives only an estimate of the move- 

 ments of the borders of the cardiac silhouette or 

 records the intensity of the shadow caused by the 

 moving heart (densitography). Most of the works 

 published on the pulsations of the left atriuin in 

 mitral valvular disease have been inexact and im- 

 possible to reproduce. Only infrequently has it thus 

 been possible to use the electrokymographic technique 

 to study dynamic changes during the cardiac cycle. 

 It is also important to stress that only qualitative 

 changes can be recorded by this method. Thus, 

 Andersson (2), after careful study of 122 cases of 

 mitral stenosis, states that in mitral stenosis the electro- 

 kymographic tracing of the left appendage shows a) 

 increased relative amplitude of the left auricular con- 



