What is the PHT range for severe mitral stenosis?

• A. ≥ 220 ms
• B. 90-150 ms
• C. 150-219 ms
• D. 60-120 ms

Answer: (A)

Pressure half-time from Doppler reflects how quickly the transmitral gradient falls after systole; in mitral stenosis, a smaller valve opening slows the decline of that gradient, so the PHT lengthens as the stenosis becomes more severe. The relationship is often summarized as MVA ≈ 220 divided by the PHT in milliseconds. When the PHT is 220 ms or longer, the estimated mitral valve area is about 1.0 cm² or less, which defines severe mitral stenosis. Thus the severe range corresponds to a PHT of ≥ 220 ms. Keep in mind that PHT can be influenced by heart rate, rhythm (atrial fibrillation makes it unreliable), and loading conditions, so additional methods may be used to confirm severity when needed.