Pressure Changes in Right Ventricle. ii 



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The pressure changes in the right ventricle studied by optically 

 recording manometers. 



By Carl J. Wiggers. 



[From the Physiological Laboratory, Cornell University Medical 

 College, New York City.] 



Before it is possible to interpret the inspiratory and expiratory 

 changes in the shape and amplitude of right ventricular pressures 

 in the unopened chest, it is necessary to know the correct contour 

 of the pressure curve during normal cardiac cycles uninfluenced 

 by respiration. Inasmuch, however, as the recent studies of 

 Straub, 1 Piper 2 and C. Tigerstedt (left ventricle only 3 ) by optically 

 recording manometers reopened the old question as to the existence 

 of a plateau or rounded top in the ventricular pressure curve, an 

 attempt was made not only to reinvestigate the contour of the 

 curve but to explain the causes of the different records obtained. 



The changes of right ventricular pressure were, therefore, 

 studied in open chest experiments (in which a right auricular pres- 

 sure equal to intrathoracic was maintained) by inserting a sharp 

 cannula of an optical manometer with high vibration rate through 

 the musculature near the base of the right ventricle. The instru- 

 ment and method were demonstrated. 



The results show that the curve obtained depends, in a large 

 measure, on the sensitiveness and periodicity of the manometer 

 used. (1) With a manometer, periodic for the pressure change 

 involved, all the details described by C. Tigerstedt for the left 

 ventricular curve appear, viz. : an auricular wave, vibrations due 

 to closure of tricuspids, superimposed waves on ascending level, 

 broad, declining top, semilunar vibrations, rapid fall. (2) When 

 the manometer becomes damped so as to become approximately 

 aperiodic, the smaller vibrations on the ascending and descending 

 limb are entirely lost or only faintly indicated. (3) Although 



'Straub, Arch. f. d. ges. Physiol., 1911, CXLIII, p. 69. 



2 Piper, Zentralbl. f. Physiol., 1912, XXVI, No. 10, p. 429; Arch. f. Physiol., 

 1912, p. 343- 



3 C. Tigerstedt, Skan. Arch. f. Physiol., 1913, XXVIII, p. 37. 



