What are the normal pressures for each cardiac chamber?

Normal Cardiac Chamber Pressures

Normal intracardiac pressures in adults are: right atrium 3 mm Hg (0-5 mm Hg), right ventricle 15-30/0-8 mm Hg, pulmonary artery 15-30/4-12 mm Hg, left atrium 4-12 mm Hg, left ventricle 90-140/4-12 mm Hg, and aorta 90-140/60-90 mm Hg. 1, 2

Right-Sided Cardiac Pressures

Right Atrial Pressure (RAP)

• Normal RAP is 3 mm Hg (range 0-5 mm Hg) when the inferior vena cava (IVC) diameter is < 2.1 cm and collapses > 50% with a sniff maneuver 1, 2
• Intermediate RAP is 8 mm Hg (range 5-10 mm Hg) when IVC parameters don't fit normal or elevated criteria 1, 2
• Elevated RAP is 15 mm Hg (range 10-20 mm Hg) when IVC diameter is > 2.1 cm with < 50% collapse during sniff 1, 2

Right Ventricular Pressure (RVP)

• Normal RV systolic pressure is 15-30 mm Hg 1
• Normal RV end-diastolic pressure is 0-8 mm Hg 1
• RV systolic pressure < 35 mm Hg is considered the upper limit of normal 1
• In cardiac tamponade, RV mid-diastolic pressure becomes elevated and equal to RA and pericardial pressures 1

Pulmonary Artery Pressure

• Normal pulmonary artery systolic pressure is 15-30 mm Hg 1
• Normal pulmonary artery diastolic pressure is 4-12 mm Hg 1
• A systolic pulmonary valve gradient < 10 mm Hg is considered the upper limit of normal 1

Left-Sided Cardiac Pressures

Left Atrial Pressure (LAP)

• Normal left atrial pressure ranges from 4-12 mm Hg 1
• In cardiac tamponade, pulmonary capillary wedge pressure (reflecting LAP) becomes elevated and nearly equal to intrapericardial and right atrial pressure 1

Left Ventricular Pressure (LVP)

• Normal LV systolic pressure is 90-140 mm Hg (equivalent to systolic blood pressure in absence of aortic stenosis) 1
• Normal LV end-diastolic pressure is 4-12 mm Hg 1
• LV minimum diastolic pressure when properly referenced is approximately -0.6 ± 0.6 mm Hg (range -1.6 to 0.4 mm Hg), demonstrating subatmospheric pressure during diastole 3

Aortic Pressure

• Normal aortic systolic pressure is 90-140 mm Hg 1
• Normal aortic diastolic pressure is 60-90 mm Hg 1

Critical Technical Considerations

Measurement Reference Level

• The zero reference level critically affects pressure measurements - using midchest level systematically overestimates LV diastolic pressure by approximately 5.1 mm Hg compared to the anatomically correct reference level 3
• The proper reference level is the uppermost blood level in the chamber being measured, not an arbitrary midchest position 3
• A significant linear relationship exists between patient anterior-posterior chest diameter and the magnitude of hydrostatic pressure error (r = 0.88) 3

Echocardiographic Assessment

• IVC should be measured from the subcostal view at 0.5-3.0 cm from the junction with the right atrium 1, 4
• Normal IVC diameter is < 2.1 cm with > 50% collapse during sniff maneuver 1, 4
• Tricuspid regurgitation velocity (TRV) is the primary variable for estimating pulmonary artery systolic pressure, not the derived PASP calculation 1

Important Clinical Pitfalls

Conditions Affecting Accuracy

• Normal young athletes may have dilated IVC despite normal pressures, leading to overestimation of RAP 4, 2
• Severe tricuspid regurgitation may significantly underestimate TRV and cannot exclude pulmonary hypertension 1
• High intra-abdominal pressure can falsely suggest IVC distension despite normal RAP 4
• IVC assessment has limited reliability in mechanically ventilated patients due to altered intrathoracic pressure dynamics 4

Pathological States

• In cardiac tamponade, all chamber pressures equalize, with RA pressure elevated and virtually identical to intrapericardial pressure 1
• The systolic x descent is preserved but the diastolic y descent is absent or diminished in tamponade 1
• Effusive-constrictive disease should be considered if intrapericardial pressure does not fall below atrial pressure after pericardial drainage 1