# Left Atrial Pressure Calculator

Estimates left atrial pressure based on systolic blood pressure and maximum mitral regurgitation velocity measured by spectral Doppler.

Refer to the text below the tool for more information about the formula used and its interpretation.

Left atrial pressure (LAP) can be estimated via systolic blood pressure (SBP) and maximum mitral regurgitation velocity measured by spectral Doppler, provided that there is no significant gradient across the aortic valve.

Its monitoring can provide hemodynamic insight into left-sided cardiac structures.

`Left Atrial Pressure = SBP – 4 x (MR VMAX)2`

Where:

• MR VMAX = maximum mitral regurgitation velocity
• SBP = systolic blood pressure

Left atrial pressure normal range: 6 – 12 mmHg

Maximum mitral regurgitation velocity (MR VMAX)
Systolic Blood Pressure (SBP)
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Steps on how to print your input & results:

2. Then you can click on the Print button to open a PDF in a separate window with the inputs and results. You can further save the PDF or print it.

Please note that once you have closed the PDF you need to click on the Calculate button before you try opening it again, otherwise the input and/or results may not appear in the pdf.

## Left Atrial Pressure Explained

Left atrial pressure (LAP) can be estimated via systolic blood pressure (SBP) and maximum mitral regurgitation velocity measured by spectral Doppler, provided that there is no significant gradient across the aortic valve.

The formula employed is:

`Left atrial pressure = SBP – 4 x (MR VMAX)2`

Where:

• MR VMAX = maximum mitral regurgitation velocity
• SBP = systolic blood pressure

Left atrial pressure defines the left ventricular filling pressure in patients who have systolic or diastolic left ventricular dysfunction or valvular heart disease. Its normal range varies between 6 and 12 mmHg, whilst its monitoring can provide hemodynamic insight into left-sided cardiac structures, for example when there is a concern about either:

• LV function (systolic and diastolic);
• Left atrial hypertension;
• LV preload (acute right heart failure, pulmonary hypertension).

Left atrial pressure increases to augment left ventricular filling, resulting in pulmonary and systemic venous congestion.

## References

Gorcscan J et al. Noninvasive estimation of left atrial pressure in patients with congestive heart failure and mitral regurgitation by Doppler echocardiography. Am. Heart J 1991; 121:858.

Oh J, Seward JB, Tajik AJ. The Echo Manual 3rd edition. Lippincott, Williams, Wilkins. 2007.

Ge Z, Zhang Y, Fan D, Zhang M, Duran CM. Simultaneous measurement of left atrial pressure by Doppler echocardiography and catheterization. Int J Cardiol. 1992; 37(2):243-251.

Specialty: Cardiology

System: Cardiovascular

Abbreviation: LAP

Article By: Denise Nedea

Published On: July 15, 2020

Last Checked: July 15, 2020

Next Review: July 15, 2025