Although the net atrioventricular compliance can be obtained by invasive catheterization (Ccath) in mitral stenosis (MS), feasibility of noninvasive echocardiographic calculation of the compliance (Cecho) and its hemodynamic significance were not tested.

Using valve area by 2D planimetry (A2D) and deceleration slope (dv/dt) of transmitral velocity decay in continuous wave Doppler echocardiographic tracing, Cecho was defined as -A2D/(gamma dv/dt), which was compared with Ccath obtained directly during the catheterization in 30 MS patients with sinus rhythm. Exercise Doppler echocardiography with symptom-limited treadmill was performed in 66 patients with moderate to tight MS: mean mitral gradient (MG) and peak pressure gradient of tricuspid regurgitation (PGTR) at baseline and immediately after exercise were obtained using continuous wave Doppler echocardiographic tracing. Hemodynamic variables including Cecho, MG, PGTR and mitral valve area were analyzed to determine the association with patients' exercise tolerance.

Cecho in 30 patients with tight MS (valve area 0.9±0.2 cm 2) was 4±1 ml/mmHg (2-7 mmHg), which showed a significant correlation with Ccath (r=0.48, p=0.01). Exercise time in 66 patients with moderate to tight MS showed significant negative correlation with resting MG, resting and postexercise PGTR, and positive correlation with Cecho: exercise time in those patients did not show any significant correlation with resting valve area. In multivariate analysis, Cecho and postexercise PGTR were independent factors determining exercise time in MS.

The net atrioventricular compliance in MS can be calculated by noninvasive echocardiography, and it is an important hemodynamic factor determining exercise tolerance in MS.