What is the normal pressure in the left atrium / pulmonary capillary wedge?

• A. 2-12 mmHg
• B. 5-15 mmHg
• C. 0-5 mmHg
• D. 12-20 mmHg

Answer: (A)

Left atrial pressure, which is approximated by the pulmonary capillary wedge pressure when the catheter is wedged, reflects the left-sided filling pressure of the heart. In a healthy resting adult, this pressure is low. The normal range commonly cited for the left atrial pressure (and hence PCWP) is about 2–12 mmHg, with the upper end around 12 mmHg. Values above this suggest elevated left‑sided filling pressures (as seen in left heart failure or significant valvular disease), while values well below this are not typical for resting conditions. Among the given options, 2–12 mmHg best fits the normal range.