1268 
MONITORING 
INFLATION msec 
100 200 300 
400 
10 
20 
— 30 
40^ 
-L 
J- 
O 80-90 be«:a/min 
A 90-100 
a lOO-MO 
• 110 - l}0 
18 c m 
12 cm 
° 8 cm 
Figure 7. — Mean impedance to ejection versus balloon 
inflation duration for various heart rate ranges. In 
addition, the influence of balloon position (distance 
from aortic valve to balloon tip) is given. 
cuff occluder lest anybody be frightened away 
from it by the arrhythmia problem. I know that 
both you and Jack Norman in Boston have had 
problems, and I think it stems from the fact 
that you use complete occlusion rather than in- 
complete occlusion. In a number of studies that 
I've done inducing similar failure, often with a 
greater or higher left ventricular end-diastolic 
pressure, I've used incomplete occlusion of the 
main left coronary artery, still allowing a small 
trickle through. This means that when I release 
the cuff, there are no arrhythmias, and I have 
yet to see any ventricular fibrillation. 
D. B. Jackson, Abbott Laboratories, North 
Chicago: Could we go back and look at your 
last slide? I am curious about one thing and 
that is the two curves plotting mean impedence 
to injection versus the balloon inflation, where 
the heart rate (the top heart rate and the one 
next to it) curves seem to me to be very far 
apart. Could you interpret that for me? 
Dr. Weber: I think that the plot (Figure 7) 
considers not only heart-rate range but also po- 
sition. One has to realize that in plotting de- 
creased mean impedence the reflection between 
the two curves would be augmented by the posi- 
tional effect, if I understand your question cor- 
rectly. 
