3.11

__ arises if mismatch of demand and supply of O2 with inadequate autoregulation

Ischemia

Cardiac metabolic demand for O2 increased by:

1. Increased ventricular volume (aortic regurgitation; heart failure)

2. High systolic pressure (aortic stenosis; coarctation, or narrowing, of the aorta)

3. Increased wall thickness (hypertrophy)

4. Increased HR or SV

Cardiac supply of O2 limited by:

1. increased coronary resistance (atherosclerotic plaques; thrombi; excess thromboxane A2 from platelets)

2. reduced flow (increased HR; reduced CO from dilated myopathy, hemorrhage, or valve incompetence)

3. reduced O2 availability (shock; anemia or erythrocyte disorders; respiratory disease)

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