Pressure tracings in mitral stenosis

Intracardiac pressures, measured simultaneously from the LA via a transseptal catheter and LV in a patient with mitral stenosis, demonstrate a persistent diastolic pressure gradient (shaded area) between the LA and LV. The time for diastole (seconds per beat), known as the DFP, and the mean gradient are used to compute the valve area from the Gorlin formula (mitral valve area = cardiac output / [37.7 × DFP × heart rate × sq rt mean gradient]).