Mitral Valve Area Calculator — PHT Method
Estimate the mitral valve orifice area from the Doppler-derived Pressure Half-Time (PHT), using the Hatle formula MVA = 220 / PHT. Results are graded as normal, mild, moderate or severe stenosis per ACC/AHA 2014 guidelines. For clinical use only — diagnosis requires a qualified cardiologist.
ms
Mild stenosis — ACC/AHA 2014 classification
- 1
Pressure Half-Time
80 ms - 2
Mitral Valve Area (Hatle formula)
220 ÷ 80 = 2.75Empirical constant 220 ms·cm² derived from catheterization data (Hatle).
How does this calculator work?
Mitral valve area = 220 / PHT (ms) by the Hatle formula. A normal valve is 4–6 cm²; < 1.5 cm² is mild stenosis; < 1.0 cm² is severe. PHT is measured from the Doppler E-wave slope on echocardiography. The result guides decision-making for balloon valvuloplasty or surgical repair.
Formula
How this is calculated
The Pressure Half-Time (PHT) is the time it takes the peak transmitral pressure gradient to fall to half its initial value. It is measured from the Doppler echocardiography E-wave deceleration slope of mitral inflow. Liselotte Hatle showed empirically that PHT correlates inversely with the mitral valve orifice area — a larger, unobstructed valve allows pressure to equalize quickly (short PHT), while a stenotic valve delays equalization (long PHT). The constant 220 ms · cm² was derived from simultaneous catheterization and Doppler data.
The formula works best for native mitral stenosis in sinus rhythm. It is less reliable after balloon valvuloplasty (the constant changes post-procedure), in the presence of significant aortic regurgitation (which alters LV filling pressure), severe mitral regurgitation, or tachycardia. The Gorlin formula using invasive hemodynamic data and the continuity equation using LVOT flow are alternative methods used when PHT is unreliable.
ACC/AHA 2014 guidelines classify mitral stenosis severity as: mild (MVA > 1.5 cm²), moderate (1.0–1.5 cm²) or severe (< 1.0 cm²). A normal mitral valve has an area of 4–6 cm². These thresholds guide the decision to intervene with balloon mitral valvuloplasty or surgical repair.
Frequently asked questions
PHT is the interval (in milliseconds) from the peak E-wave velocity of mitral inflow to the point where the velocity has fallen to its peak divided by √2 (corresponding to half the peak pressure gradient). It is derived from the Doppler deceleration slope: PHT = 0.29 × deceleration time (DT).
The PHT method gives inaccurate results after mitral balloon valvuloplasty (the empirical constant changes), in significant aortic regurgitation (elevated LV diastolic pressure shortens PHT), severe mitral regurgitation, and at very fast or slow heart rates. In these settings the continuity equation or invasive Gorlin formula is preferred.
By ACC/AHA 2014 guidelines, severe mitral stenosis is defined as MVA < 1.0 cm². Moderate stenosis is 1.0–1.5 cm² and mild is > 1.5 cm². The normal adult mitral valve area is 4–6 cm². Values below 1.5 cm² generally produce symptoms on exertion; below 1.0 cm² symptoms occur at rest.
Also known as
TG we-Calculate Editorial Team. (2026). Mitral Valve Area Calculator — PHT Method [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/mitral-valve-area-calculator
TG we-Calculate Editorial Team. "Mitral Valve Area Calculator — PHT Method." TG we-Calculate. 2026. https://we-calculate.com/calculator/mitral-valve-area-calculator.
TG we-Calculate Editorial Team, "Mitral Valve Area Calculator — PHT Method," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/mitral-valve-area-calculator
@misc{wecalculate_mitral_valve_area_calculator, title = {Mitral Valve Area Calculator — PHT Method}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/mitral-valve-area-calculator}}, year = {2026}, note = {TG we-Calculate} }
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