F. KRAFT-HUNTER AND E. W. HAWTHORNE 
645 
sample periods; so what we did, Dr. Hamlin, 
was to change the pacing rate and wait until 
those variables had stabilized as you could see 
on those plots. That interval that I showed is 
approximately a minute and a half. So we did it 
very slowly. Now immediately upon changing 
the rate, of course, you do see an increase in 
peak systolic ventricular pressure and a lot of 
other things which are maybe the real effect, I 
don't know. We did not look at it at that time. 
