FIG. 3. Left atrial pressure pulses : A : mitral stenosis with 

 normal sinus rhythm and no regurgitation detected by palpa- 

 tion. B: mitral stenosis with atrial librillation and no palpable 

 regurgitation, and C/ mitral stenosis with atrial fibrillation 

 and a large regurgitation by palpation. [From .Ankeney et at. 

 (5).] 



pressure level in the atrium is higher in the former 

 type. It is conceivable that the larger the opening, the 

 more ventricular in character will the atrial pulse be 

 and the less will the pressure drop across the valve be. 

 The smaller the opening in the valve, the less will the 

 atrial cvclic variations deviate from the normal (5, 

 165, 167). 



Davila (43), in a series of cases studied during 

 operation, did not see any examples of the ventricular 

 type described above. In most of his cases of mitral 

 incompetence, the change in left atrial pressure 

 curve that was most conspicuous was a sharp rise in 

 the peaks of the a and v waves, particularly the latter; 

 in which case the peak was reached late in systole or 

 even in protodiastole. There was also an increase of 

 mean pressure, particularly the systolic mean pres- 

 sure. The mean diastolic and end-diastolic pressure 

 levels were usually close to the respective left ventricu- 

 lar pressures. 



In most cases of mitral incompetence these waves 

 in the left atrial pressure pulse are transmitted back- 

 ward through the pulmonary vascular bed and 

 may be identified in the pulmonary arterial wedge 



STENOSIS AND INSUFFICIENCY 653 



SSPno. 34 A.L.?43y. 



.lOOTOTn^Hg 



-*« 



.0. sec. 

 0.2. 



**■■■■ ii^>i>i 



1 «' I f . <ii » ii 



l\ iS) A A 





'^^t 



50 



/ 



/ ■ I ' / 



I \ 



FIG. 4. .Suprasternal pressure curves from the aortic arch, 

 pulmonary artery, and left atrium in a case of predominant 

 mitral regurgitation. Note the small head of the aortic curve, 

 the "mitral insufficiency shoulder" {MIS) on the pulmonary 

 artery cur\e and the peaked second sound wave in the left 

 atrial curs'e. [From Radner (167).] 



pressure tracing, slightly delayed. In marked re- 

 gurgitation the V wave may reach pressures higher 

 than or equally as high as the systolic pressure in the 

 pulmonary artery. This high regurgitant wave may 

 be identified in the pulmonary artery tracing (fig. 4), 

 as pointed out by Radner (167) and later by Levinson 

 et al. (135). These latter authors point out that a pre- 

 requisite for the retrograde transmission of the v 

 wave is a low or normal pulmonary vascular resist- 

 ance. 



MacCallum & McClure (144), who in 1906 pro- 

 duced mitral insufficiency in dogs, also showed that 

 the regurgitant wave of mitral insufficiency was retro- 

 gradely transmitted from the left atrium through the 

 pulmonary capillary bed, finally arriving in the 



