EFFECTS OF NERVE STIMULATION AND HORMONES ON THE HEART 



535 



CONTROL 



DIRECT RECORDINGS 

 PRESSURE 



L-EPl. 

 20y RAPIDLY 



/u/. 



FLOW 



B 



CJ^^_JV^ 



B. ULTRASONIC 

 FLOWMETER 



I 



GAUGE 



EFFECTIVE VENTRICULAR PRESSURE 



' ^ r> r. n '^ 



u L_j U'.UUUUU 



RATE OF CHANGE OF VENTRICULAR PRESSURE 



DiFF. 



^^^,— ^^\VyWV 



RATE OF AORTIC FLOW 



LUJOJ 



AORTIC FLOW PER STROKE 



RATE OF CHAMGE OF DIAMETER (dO/dt) 



DIFF. 



"T" 



RATE OF MYOCARDIAL WORK (POWER ) 



PRESS. '"^''"'^'' 



MULT. 



VORK ("POWER") 



MYOCARDIAL WORK/STFtOKE ACCUMULATED 



INTEG. 



HEART RATE 



RATE 



SONOCARDIO- METER 



METER 

 CRYSTALS 



:i.uiJ 



ACCUMULATED FLOW PER UNIT TIME ( 3 SECj 



-1 SEC— < 



— I SEC- 



FiG. 1. A: effective ventricular pressure registered through an indwelling catheter by means of a 

 miniature pressure gauge. B: instantaneous flow through the aorta recorded by a pulsed ultrasonic 

 flowmeter. C: left ventricular diameter recorded in terms of the transit time of ultrasonic waves 

 (3 megacycles) between two barium titanate crystals mounted on opposite sides of the chamber. 

 These signals are stored on multichannel tape and subsequently analyzed in terms of additional 

 functions derived by electronic analogue computers (see text). The changes in these variables pro- 

 duced by administration of /-epinephrine are shown in the right-hand column. 



CHARACTERISTICS OF VENTRICUL.^R CONTRACTILITY 



Methods of Analysis 



The performance of any pump must be evaluated 



in terms of at least three basic parameters: pressure. 



flow, and dimensions. Techniques hase been de- 

 veloped specifically to record these variables con- 

 tinuously and simultaneously in intact animals while 

 they moved about. 



Effective left ventricular pressure is measured 



