640 
PHYSIOLOGY 
STROKE WORK / END-DIASTOLIC VOI 
100 XDOG * 132 
75 
GM-M 
50. 
25. _ 
ATRIAL PACING + CONTROL ( 1 1 P O DAY ) 
Y = - 9.65 + 1.128 X (1) 
(1) /x <^ 
25 
50 
M L 
75 
100 
Figure 7. — A copy of the computer plot of the stroke work/end-diastolic volume relationship obtained with atrial 
pacing. Y = stroke work and X = end-diastolic volume. The regression line was plotted from the equation 
(1). The data upon which this plot is based is given in Table II. 
ocardial stimulation produced by ventricular 
pacing causes some alteration in the pattern of 
ventricular contraction. However, v^^e found 
that the "pacing" left ventricular function 
curves produced by ventricular pacing were re- 
producible from day to day in the same animal. 
REFERENCES 
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3. Sarnoff, S. J., and Berglund, E. Ventricular 
function: 1. Starling's law of the heart studied by 
means of simultaneous right and left ventricular 
function curves in the dog. Circulation 9:706, 
1954. 
4. Sarnoff, S. J., and Mitchell, J. H. The control 
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Hamilton and Philip Dow. Washington, D. C. 
Amer. Physiol. Soc, vol. 1, chap. 15, p. 489, 1962. 
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1962. 
7. Sonnenblick, E. H. Implications of muscle me- 
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1962. 
8. Sonnenblick, E. H. Instantaneous force-velocity- 
