Peak-to-peak gradient is defined as the difference between which pressures?

Peak-to-peak gradient is defined as the difference between which pressures?

• A. Peak Systolic Pressures in Proximal and Distal Chambers
• B. End-Diastolic Pressures
• C. Mean Pressures
• D. Aortic and Venous Pressures

Answer: (A)

The key idea is that the peak-to-peak gradient measures the instantaneous pressure drop across a narrowed pathway during systole. It is the difference between the peak systolic pressure on the side before the obstruction (proximal) and the peak systolic pressure on the side after the obstruction (distal), recorded in the same cardiac cycle. This reflects how much the obstruction reduces the systolic pressure as blood is ejected. End-diastolic pressures are the pressures at the end of filling, not the systolic peaks, so they don’t define this gradient. Mean pressures refer to average pressures over the cardiac cycle, not the instantaneous systolic difference. Aortic and venous pressures describe pressures in two vessels rather than the pressures on each side of a localized obstruction during systole, so they don’t specifically define the gradient across the narrowed region.

The key idea is that the peak-to-peak gradient measures the instantaneous pressure drop across a narrowed pathway during systole. It is the difference between the peak systolic pressure on the side before the obstruction (proximal) and the peak systolic pressure on the side after the obstruction (distal), recorded in the same cardiac cycle. This reflects how much the obstruction reduces the systolic pressure as blood is ejected.

End-diastolic pressures are the pressures at the end of filling, not the systolic peaks, so they don’t define this gradient. Mean pressures refer to average pressures over the cardiac cycle, not the instantaneous systolic difference. Aortic and venous pressures describe pressures in two vessels rather than the pressures on each side of a localized obstruction during systole, so they don’t specifically define the gradient across the narrowed region.