Afterload
The stress or tension that develops in the ventricular wall during
diastole.
Collateral Circulation
A vascular system of small anastomosing vessels enhanced when a main
(coronary) artery is obstructed or compromised; a “natual bypass”.
Counterpulsation
Exertion of a pulsatile pressure in direct opposition to the cardiac
cycle (i.e., pressure during diastole, relaxation during systole)
producing augmentation of diastolic pressure and systolic unloading.
Diastolic
Augmentation
ncreasing diastolic pressure to increase coronary perfusion
pressure and myocardial oxygen supply when resistance in the
coronary vascular bed is minimal.
Dicrotic
Notch
A deflection in the arterial pressure curve marking closure of the
aortic valve (i.e., end of systole), the signal event for diastolic
augmentation in counter pulsation.
Enhance
External Counterpulsation
Non-invasive counterpusation utilizing three (3) sets of compressive
air cuffs applied to calves, lower thighs and upper thighs including
the lower buttocks; sequential (distal to proximal) inflation and
simultaneous deflation of timed to the patient's ECG..
Finger
Plethysmography
An electro-optical device measuring relative blood volume in the
finger related to arterial pressure; the waveform used in EECP as a
guide in timing cuff inflation/deflation signals and calculating
diastolic: systolic peak-to-peak pressure and area ratios.
Intra-aortic
Balloon
Pump
A large volume (30-50cc) balloon catheter inserted via the femoral
artery and advanced to the descending aorta; synchronous inflation
and deflation of the balloon provide internal counterpulsation
(i.e., diastolic augmentation) in acute cardiac events, decreasing
myocardial oxygen consumption and increasing coronary perfusion
pressure.
Preload
The end-diastolic stretch of the heart muscle fiber; in the normal
ventricle this is approximately equal to end-diastolic volume or
pressure.
Shear
Force
In EECP, enhanced perfusion pressures causing increased circulatory
volume that stimulates the vascular endothelium to release vasodilation factors.
Systolic
Unloading
Decreasing afterload and thereby myocardial oxygen consumption by
decreasing vascular resistance.
Vascular
Resistance
The impedance of the arterial vascular system, especially the
arterioles and capillaries, to the flow of blood.
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