The pulmonary artery occlusive (wedge) pressure (PAOP) reflects pressure in which part of the heart?

The pulmonary artery occlusive pressure (PAOP), often referred to as the wedge pressure, is a critical measurement used in cardiology to assess the hemodynamic status of a patient. Specifically, PAOP reflects the pressure in the left atrium of the heart.

When a catheter is advanced into the pulmonary artery and then wedged into one of the pulmonary capillaries, it allows for the measurement of the pressure that is transmitted back from the pulmonary circulation. Since the left atrium receives blood from the lungs via the pulmonary veins, the pressure measured represents the pressure in the left atrium more accurately than any other cardiac chamber.

This measurement is essential for determining left ventricular function and volume status, and it is particularly useful in diagnosing conditions such as congestive heart failure. Understanding PAOP is crucial for managing patients with various cardiac and respiratory conditions, and it provides valuable information on pulmonary capillary pressures, which relate directly to left heart filling pressures. Thus, the PAOP is not indicative of pressures in the right side of the heart (right atrium or right ventricle) or the left ventricle itself but rather serves as a proxy for the left atrial pressure.