Changes in the level of the top line on the pressure waveform during LV pullback could indicate which conditions?

• A. Aortic valve stenosis
• B. Mitral valve stenosis
• C. Pulmonary hypertension
• D. Tricuspid regurgitation

Answer: (A)

This concept hinges on the pressure gradient across the aortic valve during LV outflow. When the catheter is in the left ventricle, you see the LV systolic pressure as it ejects against the aortic valve. If the aortic valve is stenotic, there is a significant gradient: LV systolic pressure remains high while the aortic (systemic) systolic pressure is comparatively lower. As you pull the catheter back across the valve into the aorta, the top of the pressure waveform drops abruptly from the high LV level to the lower aortic pressure. That sudden change in the top-line level indicates a obstructed aortic valve, i.e., aortic valve stenosis.

If the aortic valve were not stenotic, the LV and aortic systolic pressures would be similar during ejection, and the transition during pullback would not show a marked drop in the top-line level. The other options affect different parts of the heart or pressures (mitral valve, pulmonary circulation, right-sided valves) and do not produce the characteristic LV-to-aorta gradient seen with aortic valve stenosis.