[The influence of cardiac frequency on the hemodynamic consequences of mitral stenosis (author's transl)].

In eleven patients with isolated mitral stenosis and regular sinus rhythm a right cardiac catheterization was performed and the wedged pulmonary capillary pressure recorded at rest and during electrical pacing of the right atrium at successive frequencies of 100, 120, 140, and, occasionally, 160 and 180 beats/min, while cardiac output was estimated by the Fick's principle. In all cases a significant elevation of pulmonary capillary pressure with a simultaneous reduction in cardiac output was obtained. The rise of wedged pulmonary pressure was proportional to the increment in cardiac frequency and related also to the calculated area of the mitral valve.

[Calculation of the mean pressure of the pulmonary artery and of the valve surface by ECG in mitral stenosis].

From a group of 50 patients affected by pure mitral stenosis with sinus rhythm, we have tried to obtain multiple correlation equations which enable in to calculate, in each particular case, the mean pressure of the pulmonary artery and mitral valvular area from purely electrocardiographic facts. In an additional group of 16 patients we have been able to verify the mentioned equations, placing all the calculated points within the presumed limits of tolerance. So it appears that the electrocardiographic calculation of these hemodynamic parameters is possible, with sufficient approximation for clinical requirements.

[QRS in mitral stenosis: Electrohemodynamic correlation].

The electrocardiograms of 50 patients with mitral stenosis in sinus rhythm were reviewed (axis of QRS and T in the frontal and horizontal planes, with each one of their modules, Lewis index and right Sokolow-Lyon, quotient R/R + S in V1, time of beginning of the intrinsecoide deflection of QRS), they were related with the hemodynamic data; and the existence of clear relations between both methods of exploration were confirmed. 1. The QRS axis in the frontal plane kept a good relation with the hemodynamic data (mainly thzontal axis there proved to be a closer relation than in this one.