Which statement best describes how LV end-diastolic pressure affects coronary perfusion?

Which statement best describes how LV end-diastolic pressure affects coronary perfusion?

• A. Increased LVEDP reduces coronary perfusion.
• B. Increased LVEDP improves perfusion.
• C. Perfusion is independent of LVEDP.
• D. Perfusion occurs mainly during systole.

Answer: (A)

Coronary perfusion depends on a pressure gradient that is strongest during diastole. The driving pressure is the difference between aortic diastolic pressure and the left ventricular end-diastolic pressure (CPP ≈ Pao diastolic − LVEDP). If LVEDP rises, the gradient shrinks, so less blood flows into the coronary arteries. This is especially true for the subendocardial region, where high LV pressures can compress vessels and further limit flow. So increasing LVEDP reduces coronary perfusion. The idea that perfusion is independent of LVEDP is incorrect, and coronary flow is not primarily during systole because systolic contraction compresses the coronary vessels, reducing perfusion then rather than during diastole.

Coronary perfusion depends on a pressure gradient that is strongest during diastole. The driving pressure is the difference between aortic diastolic pressure and the left ventricular end-diastolic pressure (CPP ≈ Pao diastolic − LVEDP). If LVEDP rises, the gradient shrinks, so less blood flows into the coronary arteries. This is especially true for the subendocardial region, where high LV pressures can compress vessels and further limit flow. So increasing LVEDP reduces coronary perfusion. The idea that perfusion is independent of LVEDP is incorrect, and coronary flow is not primarily during systole because systolic contraction compresses the coronary vessels, reducing perfusion then rather than during diastole.