Which waveform feature represents closure of the aortic valve and onset of diastole?

Which waveform feature represents closure of the aortic valve and onset of diastole?

• A. Systolic peak
• B. Dicrotic notch
• C. Anacrotic limb
• D. End-diastolic

Answer: (B)

The main idea is to recognize the arterial pressure waveform feature that signals the moment the aortic valve closes and diastole begins. The dicrotic notch appears as a small secondary deflection on the downstroke after the systolic peak. It occurs when the aortic valve snaps shut, causing a brief change in the flow and pressure that creates the notch right as systole ends. This marks the onset of diastole, after which the waveform gradually falls as the ventricle is in diastole. The other features aren’t correct for this moment: the systolic peak shows the highest pressure during ejection, not valve closure; the anacrotic limb is the rising phase of systole; end-diastolic is a time point indicating the end of diastole, not a specific waveform deflection.

The main idea is to recognize the arterial pressure waveform feature that signals the moment the aortic valve closes and diastole begins. The dicrotic notch appears as a small secondary deflection on the downstroke after the systolic peak. It occurs when the aortic valve snaps shut, causing a brief change in the flow and pressure that creates the notch right as systole ends. This marks the onset of diastole, after which the waveform gradually falls as the ventricle is in diastole.

The other features aren’t correct for this moment: the systolic peak shows the highest pressure during ejection, not valve closure; the anacrotic limb is the rising phase of systole; end-diastolic is a time point indicating the end of diastole, not a specific waveform deflection.