How is pressure half-time measured?

PHT is measured by tracing the mitral valve inflow E-wave deceleration slope on continuous wave Doppler. PHT = 0.29 × deceleration time (DT). MVA = 220/PHT. A longer PHT indicates more severe obstruction.

When is the PHT method unreliable?

PHT is unreliable in: aortic regurgitation (increases LA pressure artificially shortening PHT); atrial fibrillation (variable RR intervals); immediately post-valvuloplasty; and abnormal LV compliance. Planimetry or PISA method should be used in these cases.

What defines severe mitral stenosis?

Severe MS: MVA 10 mmHg; pulmonary artery systolic pressure >50 mmHg at rest. Symptoms or pulmonary hypertension are class I indications for balloon valvuloplasty or surgery.

Mitral Valve Area by Pressure Half-Time Calculator

Calculates mitral valve area (MVA) by echocardiographic pressure half-time method: MVA = 220 / PHT (ms), where PHT is the time for the peak diastolic pressure gradient to decrease by half. Normal MVA 4–6 cm²; severe mitral stenosis <1.0 cm².

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Frequently Asked Questions

How is pressure half-time measured?

When is the PHT method unreliable?

What defines severe mitral stenosis?