Mitral pressure half-time technique for assessing severity of mitral stenosis: essential parameters

The flow through a stenotic mitral valve, which is mainly determined by the cross-sectional area of the valve and the pressure difference across it, is discussed. The gradient half-time is an attempt to describe the area from the decline in transmitral pressure difference alone. The gradient half-time increases with increasing severity of the stenosis. Besides the area of the mitral valve, there are other factors influencing the gradient half-time. Such factors are the transported volume and the initial pressure gradient. The compliance of the cardiac chambers and the pulmonary venous flow also influence the gradient half-time, but through changes in the pressure difference across the valve. The problem can therefore be analyzed either with or without inclusion of compliance in the calculations