π« Mitral Valve Area Calculator
MVA from pressure half-time: 220 over PHT.
For informational purposes only, not medical advice. Consult a healthcare professional.
Mitral valve area by pressure half-time is the quickest severity check in mitral stenosis: divide 220 by the half-time in milliseconds. A normal valve measures 4 to 6 square centimeters; above 1.5 is mild stenosis, 1.0 to 1.5 moderate, and under 1.0 severe. The longer the half-time, the tighter the valve.
Enter the pressure half-time from the Doppler echocardiogram report. The calculator returns MVA and the ASE severity grade. It is a screening formula: planimetry and the continuity equation confirm when decisions get serious.
How to Use This Calculator
Find pressure half-time (PHT) in milliseconds on the echo Doppler report. Enter it. Read MVA in cm2 and the severity band. Severe stenosis, symptoms, or pulmonary hypertension need cardiology follow-up; the PHT method alone never schedules a valvuloplasty.
Enter pressure half-time in ms from the echo report.
Read mitral valve area in cm2.
Check the severity band against ASE cutoffs.
Confirm significant stenosis with planimetry or continuity equation.
Why 220 Over PHT
Pressure half-time is how long the transmitral pressure gradient takes to fall to half its peak. A tight valve keeps the gradient high longer, so half-time lengthens as area shrinks; the relationship is inverse and roughly hyperbolic. Hatle's empirical constant of 220 (originally 220, sometimes 229 in older texts) was fitted from catheterization data correlating half-time with Gorlin-formula valve areas. It assumes normal left atrial and ventricular compliance: stiff chambers or significant aortic regurgitation distort the decay curve and break the formula, which is why guidelines demand a second method before intervening.
Worked Example
A pressure half-time of 160 ms gives an MVA of 1.38 cm2, in the Moderate (1.0-1.5) range. Stretch PHT to 220 ms and MVA falls to exactly 1.0 cm2, the severe threshold. Normal valves sit at 4 to 6 cm2, so symptoms typically start as the area drops under 1.5.
Severity and Symptoms
Mild stenosis is usually asymptomatic and watched. Moderate stenosis with symptoms or pulmonary hypertension gets closer follow-up. Severe stenosis (under 1.0 cm2) with symptoms, atrial fibrillation, or pulmonary hypertension meets criteria for intervention: balloon valvuloplasty for suitable rheumatic valves, surgery otherwise. Exercise tolerance, not resting numbers alone, often drives timing.
Echo Findings Need Cardiology
Valve decisions integrate area by multiple methods, gradients, pulmonary pressures, rhythm, symptoms, and surgical risk. Do not act on a single PHT-derived number. New atrial fibrillation, worsening breathlessness, or chest symptoms with known mitral stenosis deserve prompt cardiology review. For informational purposes only, not medical advice. Consult a healthcare professional.
Related tools: LV mass index, mean arterial pressure and BMI calculator.
For informational purposes only, not medical advice. Consult a healthcare professional.
Frequently Asked Questions
What is normal mitral valve area?
Four to 6 cm2. Symptoms of mitral stenosis typically begin as area falls below about 1.5 cm2.
What MVA is severe mitral stenosis?
Under 1.0 cm2 by ASE criteria. Between 1.0 and 1.5 is moderate.
What is pressure half-time?
The milliseconds for the transmitral pressure gradient to decay to half its peak on Doppler. Longer half-time means a tighter valve.
When does the PHT method fail?
With significant aortic regurgitation, abnormal chamber compliance, immediately after balloon valvuloplasty, or with tachycardia distorting the curve.
What is the Gorlin formula?
The catheterization method computing valve area from cardiac output and pressure gradients. It is the invasive reference standard.
What causes mitral stenosis?
Mostly rheumatic heart disease worldwide. Degenerative calcific stenosis occurs in older adults.
What are symptoms of mitral stenosis?
Breathlessness on exertion, fatigue, palpitations from atrial fibrillation, and in advanced cases orthopnea and hemoptysis.
How is severe mitral stenosis treated?
Balloon mitral valvuloplasty for suitable pliable rheumatic valves; surgical repair or replacement otherwise, plus rate control and anticoagulation when AF develops.
What symptoms appear as the valve area shrinks?
Breathlessness on exertion comes first, as blood backs up into the lungs, then breathlessness lying flat and waking up gasping. Fatigue follows because forward flow drops. Atrial fibrillation is common once the left atrium enlarges, and it brings stroke risk. Many patients feel fine until the area drops under 1.5 cm2, which is why murmurs get followed before symptoms start.
When does mitral stenosis need intervention?
Guidelines point to symptoms plus severe stenosis (area at or under 1.5 cm2), or severe stenosis with signs like pulmonary hypertension even without symptoms. Options are balloon valvuloplasty for suitable valve shapes, or surgical repair or replacement. Timing matters: intervening before the heart weakens gives better results.
Why is pressure half-time less reliable after valvuloplasty?
The half-time method assumes the left atrium and ventricle are stiff in a predictable way. Balloon treatment changes atrial compliance immediately, so the pressure falls faster and the formula overestimates the new valve area. After the procedure, planimetry (tracing the opening directly) or the continuity equation give truer numbers.