Left atrial pressure calculator: mitral regurgitation velocity
Explore the MR-velocity pressure estimate, its two inputs and the acquisition requirements shown with the calculation.
Method
LAP = SBP − 4(MR Vmax)²
Use the measurement units shown below. Some fields apply only to a selected method or condition; follow the interactive tool’s method choices. The interactive tool keeps missing measurements incomplete and provides its method-specific results and reference context.
Measurements and acquisition
Systolic blood pressure mmHg
Contemporaneous cuff or invasive value
- Use a pressure obtained in the same hemodynamic state as the echo.
- Confirm the value is entered in mmHg.
- Do not mix values acquired under different loading conditions.
MR Vmax m/s
Continuous-wave Doppler
- Align the CW cursor as parallel as possible to the jet.
- Acquire a dense, complete envelope without truncation.
- Measure the highest absolute velocity on the selected envelope.
Sources and method context
Gorcsan, Snow, Paulsen & Nixon · American Heart Journal · 1991 · Noninvasive estimation of left atrial pressure in patients with congestive heart failure and mitral regurgitation by Doppler echocardiography · Am Heart J 121:858–863 · PMID 2000753
- Equation and selected-patient validation · Gorcsan et al. 1991 · abstract and pp. 858–863
Peak brachial SBP minus 4 × peak MR velocity squared; distinct envelopes in 35 of 46 patients, compared with simultaneous mean wedge pressure. This is an estimate, not a grading threshold.
- Gradient foundation · Nishimura & Tajik · JACC 1988;11:317–321 · PMID 3339169
Simultaneous dual-catheter and Doppler validation of left-sided regurgitant pressure gradients.
- MR signal interpretation · ASE 2017 native regurgitation · journal p. 330 · Continuous Wave Doppler
MR velocity reflects the LV–LA pressure difference; peak velocity alone does not quantify regurgitant severity.
Catalogue review status: Exact guideline locator mapped · clinical sign-off pending
These pages describe the educational tool. Interpret measurements with the complete clinical context and the method’s acquisition limitations.
Keep exploring
- Apical four chamber acquisition guide · Open in Probe Lab
- Apical two chamber acquisition guide · Open in Probe Lab
- Apical three chamber (apical long axis) acquisition guide · Open in Probe Lab
- Left atrial pressure calculator: E/e′ method
- Left atrial volume index calculator: LAVI
- Left ventricular pressure calculator
- Diastolic function assessment: sinus rhythm