An accurate method for sonographic estimation of the weight of very preterm fetuses.

This study was undertaken to test the accuracy of formulas we recently developed for the sonographic estimation of the weight of very preterm fetuses. The formulas were used to determine estimated weights from prenatal sonographic data for 62 premature infants born at 23-29 weeks of gestation, weight < or = 1,400 g. The mean absolute deviation of the actual birth weight from the estimated weight was 75.

Effect of exercise on valvular resistance in patients with mitral stenosis.

Objectives: This exercise study assessed the relation between valvular resistance and flow in patients with mitral stenosis.

Background: Valvular resistance has been proposed as an alternative measure of stenotic valvular lesions, which is speculated to remain stable under changing hemodynamic conditions.

Methods: In 35 of 40 patients with pure or predominant mitral stenosis, continuous wave Doppler measurements of the mitral stenotic jet were possible at rest and during supine bicycle ergometry.

Effect of heart rate on transmitral flow velocity profile and Doppler measurements of mitral valve area in patients with mitral stenosis.

To study the effect of heart rate changes on Doppler measurements of mitral valve area atrial pacing was performed in 14 patients with mitral stenosis and sinus rhythm. Continuous wave Doppler and haemodynamic measurements were performed simultaneously at rest and during pacing-induced tachycardia. (1) Mitral valve area was determined using the conventional pressure half time method.

Value of a modified continuity equation method to quantify mitral valve area in patients with mitral stenosis and sinus rhythm.

To quantify valve area in mitral stenosis, a modified continuity equation method using continuous wave Doppler and thermodilution measurements was applied. In 14 patients with mitral stenosis and sinus rhythm (age: 49 +/- 11 years), transmitral flow velocity was recorded by continuous wave Doppler during right and left heart catheterization. Mitral valve area was calculated by three different methods: 1.