Coronary pressure-flow autoregulation protects myocardium from pressure-induced changes in oxygen consumption.

@article{Bai1994CoronaryPA,
  title={Coronary pressure-flow autoregulation protects myocardium from pressure-induced changes in oxygen consumption.},
  author={Xiao-Jie Bai and T Iwamoto and A. G. Williams and W L Fan and H. Fred Downey},
  journal={The American journal of physiology},
  year={1994},
  volume={266 6 Pt 2},
  pages={
          H2359-68
        }
}
Pressure-flow autoregulation minimizes changes in coronary blood flow (CBF) when coronary perfusion pressure (CPP) is altered. This investigation determined if autoregulation also minimizes CPP-induced changes in coronary vascular volume (CVV) and CVV-dependent changes in myocardial oxygen consumption (MVO2). In 11 anesthetized dogs, the left anterior descending coronary artery was cannulated, and responses to 20-mmHg changes in CPP were examined over a range of CPP from 60 to 180 mmHg. Changes… Expand
Response of the intact canine left ventricle to increased afterload and increased coronary perfusion pressure in the presence of coronary flow autoregulation.
TLDR
The concomitant increase in CAP with increased afterload in the intact canine LV does not contribute to the afterload-induced increase in contractile force, andCoronary perfusion pressure per se does not influence LV contractile function. Expand
Coronary perfusion related changes in myocardial contractile force and systolic ventricular stiffness.
TLDR
Increased coronary blood flow enhances myocardial contractile force, systolic ventricular stiffness, and MVO2 in the intact, ejecting heart. Expand
Right coronary pressure modulates right ventricular systolic stiffness and oxygen consumption.
TLDR
Reductions in RV systolic stiffness preserve delta SL as coronary pressure is reduced over a wide range, and the resulting increase in RV efficiency reduces oxygen demand as oxygen supply is reduced, so ischemia is avoided. Expand
Coronary—Ventricular Interaction: The Gregg Phenomenon
TLDR
Although changes in coronary vascular volume alter ventricular end-diastolic wall thickness, myocardial fiber length is unchanged, the Gregg phenomenon does not result from Starling’s law; inotropic factors released from endothelium appear not to be responsible. Expand
Contribution of voltage-dependent K+ and Ca2+ channels to coronary pressure-flow autoregulation
TLDR
It is demonstrated that KV channels tonically contribute to the control of microvascular resistance over a wide range of CPPs, but do not contribute to coronary responses to changes in pressure; and progressive activation of CaV1.2 channels with increases in CPP represents a critical mechanism of coronary pressure-flow autoregulation. Expand
Downregulation of ventricular contractile function during early ischemia is flow but not pressure dependent.
TLDR
Testing the role of vascular collapse in downregulating myocardial contractile force at the onset of ischemia found identical contractile function at widely differing coronary perfusion pressures is incompatible with the vascular collapse theory. Expand
Downregulation of ventricular contractile function during early ischemia is flow but not pressure dependent.
  • M. He, H. F. Downey
  • Medicine
  • American journal of physiology. Heart and circulatory physiology
  • 1998
TLDR
Testing the role of vascular collapse in downregulating myocardial contractile force at the onset of ischemia found identical contractile function at widely differing coronary perfusion pressures is incompatible with the vascular collapse theory. Expand
Decrease in coronary vascular volume in systole augments cardiac contraction.
TLDR
It is concluded that emptying of the coronary vasculature serves a physiological purpose by facilitating cardiomyocyte thickening thereby augmenting force development and interventions to prevent myocytes thickening reduce developed tension. Expand
Local metabolic hypothesis is not sufficient to explain coronary autoregulatory behavior
The local metabolic hypothesis proposes that myocardial oxygen tension determines the degree of autoregulation by increasing the production of vasodilator metabolites as perfusion pressure isExpand
Perfusion-induced changes in cardiac contractility depend on capillary perfusion.
TLDR
The Gregg phenomenon is related to capillary perfusion in the isolated perfused papillary muscle of the rat and is found in heart preparations that lack adequate coronary autoregulation and thus protection of changes in capillary pressure. Expand
...
1
2
3
4
...