Abstract
We have studied the influence of left ventricular diastolic pressure (LVDP) on diastolic coronary pressure-flow relationships independently of effects of capacitive flow in an open-chest heart-blocked canine preparation in which the left circumflex (LC) bed was vasodilated with adenosine and perfused with a programmable servo valve pressure source. At the onset of long diastoles produced by cessation of ventricular pacing, LVDP was adjusted to, and maintained at, a preselected level using a blood-filled reservoir. Right atrial pressure was kept constant at approximately 8 mmHg. LC pressure (PLC) was then made to decline and rise sequentially at a constant rate (2-40 mmHg/s), with LC inflow reaching zero at the nadir of the declining pressure ramp. The capacitance-free diastolic pressure-flow relationship was considered to lie midway between the instantaneous relationships derived from each down and up ramp pair. All capacitance-free relationships were curvilinear, and the degree of curvilinearity was accentuated with increasing preload. Pressure-axis intercepts (Pf = 0) increased from 14 +/- 1.1 (SE) to 23 +/- 1.4 mmHg as preload was raised from 6-10 to 31-35 mmHg. Coronary conductance, taken as the slope of the pressure-flow relationship at any given PLC, fell progressively as preload rose, with the fall being more marked at higher levels of preload and lower values of PLC. Diastolic coronary flow also decreased as a function of preload, reflecting the increases in Pf = 0 and decreases in conductance.(ABSTRACT TRUNCATED AT 250 WORDS)
| Original language | English (US) |
|---|---|
| Journal | The American journal of physiology |
| Volume | 246 |
| Issue number | 3 Pt 2 |
| State | Published - Mar 1984 |
| Externally published | Yes |
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ASJC Scopus subject areas
- Medicine(all)
Cite this
Preload-induced alterations in capacitance-free diastolic pressure-flow relationship. / Aversano, Thomas R; Klocke, F. J.; Mates, R. E.; Canty, J. M.
In: The American journal of physiology, Vol. 246, No. 3 Pt 2, 03.1984.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Preload-induced alterations in capacitance-free diastolic pressure-flow relationship.
AU - Aversano, Thomas R
AU - Klocke, F. J.
AU - Mates, R. E.
AU - Canty, J. M.
PY - 1984/3
Y1 - 1984/3
N2 - We have studied the influence of left ventricular diastolic pressure (LVDP) on diastolic coronary pressure-flow relationships independently of effects of capacitive flow in an open-chest heart-blocked canine preparation in which the left circumflex (LC) bed was vasodilated with adenosine and perfused with a programmable servo valve pressure source. At the onset of long diastoles produced by cessation of ventricular pacing, LVDP was adjusted to, and maintained at, a preselected level using a blood-filled reservoir. Right atrial pressure was kept constant at approximately 8 mmHg. LC pressure (PLC) was then made to decline and rise sequentially at a constant rate (2-40 mmHg/s), with LC inflow reaching zero at the nadir of the declining pressure ramp. The capacitance-free diastolic pressure-flow relationship was considered to lie midway between the instantaneous relationships derived from each down and up ramp pair. All capacitance-free relationships were curvilinear, and the degree of curvilinearity was accentuated with increasing preload. Pressure-axis intercepts (Pf = 0) increased from 14 +/- 1.1 (SE) to 23 +/- 1.4 mmHg as preload was raised from 6-10 to 31-35 mmHg. Coronary conductance, taken as the slope of the pressure-flow relationship at any given PLC, fell progressively as preload rose, with the fall being more marked at higher levels of preload and lower values of PLC. Diastolic coronary flow also decreased as a function of preload, reflecting the increases in Pf = 0 and decreases in conductance.(ABSTRACT TRUNCATED AT 250 WORDS)
AB - We have studied the influence of left ventricular diastolic pressure (LVDP) on diastolic coronary pressure-flow relationships independently of effects of capacitive flow in an open-chest heart-blocked canine preparation in which the left circumflex (LC) bed was vasodilated with adenosine and perfused with a programmable servo valve pressure source. At the onset of long diastoles produced by cessation of ventricular pacing, LVDP was adjusted to, and maintained at, a preselected level using a blood-filled reservoir. Right atrial pressure was kept constant at approximately 8 mmHg. LC pressure (PLC) was then made to decline and rise sequentially at a constant rate (2-40 mmHg/s), with LC inflow reaching zero at the nadir of the declining pressure ramp. The capacitance-free diastolic pressure-flow relationship was considered to lie midway between the instantaneous relationships derived from each down and up ramp pair. All capacitance-free relationships were curvilinear, and the degree of curvilinearity was accentuated with increasing preload. Pressure-axis intercepts (Pf = 0) increased from 14 +/- 1.1 (SE) to 23 +/- 1.4 mmHg as preload was raised from 6-10 to 31-35 mmHg. Coronary conductance, taken as the slope of the pressure-flow relationship at any given PLC, fell progressively as preload rose, with the fall being more marked at higher levels of preload and lower values of PLC. Diastolic coronary flow also decreased as a function of preload, reflecting the increases in Pf = 0 and decreases in conductance.(ABSTRACT TRUNCATED AT 250 WORDS)
UR - http://www.scopus.com/inward/record.url?scp=0021399317&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0021399317&partnerID=8YFLogxK
M3 - Article
C2 - 6703076
AN - SCOPUS:0021399317
VL - 246
JO - American Journal of Physiology
JF - American Journal of Physiology
SN - 0363-6135
IS - 3 Pt 2
ER -