During which event is the wedge pressure expected to be low amplitude and high pressure?

During balloon inflation for wedge pressure measurement, the pressure recorded in the pulmonary artery occludes the blood flow, leading to low amplitude but high pressure readings. This technique involves inflating a balloon at the tip of a catheter that has been introduced into the pulmonary artery. Once inflated, the balloon blocks the distal end of the catheter, allowing indirect measurement of the left atrial pressure.

In this occlusive state, the measured pressure reflects the pressure in the left atrium because the blood flow is halted, which can present as high pressure due to the backing up of pressure from the left ventricle. The low amplitude arises because the measurement is no longer directly responding to the pulsatile flow of blood but rather to the static pressure within the occluded system.

This specific scenario is crucial as it provides valuable information regarding left atrial pressure and can help diagnose issues such as pulmonary congestion or various cardiac conditions. In contrast, the other events listed do not produce the same distinctive low amplitude and high-pressure characteristics.