PULSATILE BLOOD FLOW 855 



LEFT VENTRICULAR PRESSURE 



200 



mm 

 Hg 



- 



LEFT ANTERIOR DESCENDING 



133 - 



b 



^ 



i 



fe 



^ 



1 



T Stt 



^ 



g 



E 



1 



fig. 21. Coronary blood flow in the left anterior descending 

 branch. The upper tracing represents the electrocardiogram 

 taken simultaneously with the left ventricular pressure, aortic 

 arch pressure, and coronary flow. [From Schenk (43).] 



cuspid ring, b) engulfing of the atrial blood by the 

 right ventricle, and c) a final quota of blood delivered 

 by atrial contraction. The question of whether or not 

 the ventricle produces a sucking force during diastole 

 is unresolved. The answer will await definitive 

 differential pressure measurements made across the 

 ventricular wall. 



Effect of Normal Respiratio 



Carol Flow 



This is illustrated in figure 25 (28). Inspiration 

 greatly increases the venous return as shown in the 

 thoracic vena cava and abdominal vena cava caudal 

 to the renal veins. 



V. PULMONARY FLOW 



Right Ventricular Ejection Pulse 



The form of the right ventricular ejection pulse 

 (fig 26) differs from that of the left ventricle in 



200 



ASCENDING 'AORTA PRESSURE 



200 — 

 mm 



Hg I 



est 



fcs: 



ci rcumfl ex to ro nAry "artery 



*l 



&si: 



FLOW 



f^ 



232 



I SEC 



fig. 22. Coronary blood flow in the circumflex branch. 

 Tracings taken from the same animal as in fig. 2 1 . [From 

 Schenk (43).] 



general by an over-all lack of the higher frequency 

 components. The initial acceleration is slower, peak 

 more rounded, at a somewhat lower velocity; and the 

 reverse flow due to pulmonary valve closure forms a 

 more rounded notch followed by a lower frequency 

 aftervibration. There are also fewer random frequency 

 vibrations throughout diastole. Presumably these 

 differences arise from a slower rate of contraction of 

 the right ventricle versus that of the left, and a 

 greater compliance per unit of arterial wall in the 

 pulmonary artery than that of the aorta, the latter 

 arising perhaps from the lower distending pressure. 

 When flow recordings are taken off the pulmonary 

 trunk near the bifurcation, one frequently notices a 

 low-frequency vibration during the diastolic period 

 which may be due to some reflections from the pulmo- 

 nary periphery. 



Measurements of differential pressure across the 

 pulmonary valve between the right ventricle and 

 pulmonary artery display less of a tendency for the 



