Inaccurate noninvasive mitral valve area calculation during pregnancy.

Objective: To compare two different Doppler echocardiographic techniques for the assessment of the transmitral area in pregnant patients with native mitral valve stenosis or prosthetic mitral valves. Methods: Eight consecutive gravid women with prosthetic mitral valves or obstructive native mitral valve disease were evaluated using both the pressure half-time and the continuity equation Doppler echocardiographic methods. Heart rate, cardiac output, and transmitral valve gradient and area were calculated. These studies were repeated postpartum in five women. Differences between the two methods were assessed by characterizing the absolute differences between the mean and standard deviation and by paired t tests. Linear regression analysis was also applied