F. KRAFT-HUNTER AND E. W. HAWTHORNE 
637 
SEQUENTIAL PACING 
' jjlM II III IIIII IIIM II-i n il llM II II I IIIIII II IIIIIIIII I I I III IMI I II ll l l lll lll l illll lll lll ll l l l lllll ll llll l l^ 
HR /min 
AAA/ 
dlnP/dt sec'l 
diydtmmH 
APmmHg 
LVP mmHg 
lAPmm 
LVID cm 
60-" 
Figure 5. — Effects of sequential pacing using and atrial stimulus to ventricular stimulus interval of 100 milli- 
seconds. Labels are the same as used in Figure 2. 
(2). In addition, the data points obtained dur- 
ing ventricular pacing while norepinephrine 
was being infused at a rate of 0.4 mg/Kg/mm. 
Comparison between lines (2) and (3) shows 
that there is shift of the curve upward and to 
the left which is reminiscent of the classical 
ventricular function curve. Under the influence 
of norepinephrine there is a greater stroke 
work for any given end-diastolic volume. 
Figure 10 shows the regression lines (1), 
(2), and (3), as described along with data ob- 
tained with ventricular pacing and propranolol 
(0.5 mg/Kg). Comparison of line (2) and line 
(4) shows that for any given end-diastolic vol- 
