What kind of tracings are done in the cath lab to assess transvalvular gradients?

• A. Peak pressures from each chamber (peak-to-peak) and mean/average transvalvular gradient
• B. ECG and pulse oximetry
• C. Pulmonary artery wedge pressure alone
• D. Left atrial appendage pressure

Answer: (A)

Transvalvular gradients are determined from the pressure difference across a valve during systole, so you need pressure tracings from both sides of the valve. In the cath lab, you place catheters so you have one pressure recording upstream (before the valve) and another downstream (after the valve). By comparing these tracings, you obtain two key measurements: the peak-to-peak gradient, which is the difference between the peak systolic pressures on either side, and the mean gradient, which is the average pressure difference over the entire ejection period. These tracings directly quantify how much resistance the valve offers to flow.

This approach focuses on pressure changes across the valve; ECG and pulse oximetry monitor electrical activity and oxygenation, not the pressure difference across a valve. Wedge pressure estimates left atrial pressure but does not provide the transvalvular gradient, and left atrial appendage pressure is not used for this purpose.