RÉSUMÉ
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. 2. The quotient R/R + S in V1 was the parameter that best correlated with the mean pressure of the pulmonary artery and with the pulmonar capillary pressure. 3. Although the right Sokolow-Lyon index is not a definite criterion for recognizing a right ventricular hypertrophy; it is very useful in correlating the total pulmonary resistances with the mean pulmonary arterial pressure, even if it did not reach pathologic values. The same can be said the Lewis index, although the dependence is less important. 4. The horizontalization of the frontal axis of T becomes more important with the increase in the hemodynamic repercution. 5. As an expression of the systemic hemodynamic alteration, the decrease in time of inscription of the intrinsecoid deflection, of the left ventricle in V6 became evident when the mitral area diminished or by increase of mean pressure of the pulmonary artery. 6. The electrocardiographic characteristics that allow to recognize the existence of a mitral area smaller than 0.8 cm2, with a possibility of error of less than 5% (false positives), are: -- a horizontal axis of QRS less or equal to + 9 degrees -- a right Sokolow-Lyon index of more than 21.56. 7. The existence of a mean pressure of more than 25 mm. Hg in the pulmonary artery can be acknowledged, with a possibility of false positives of less than 5%, by the apparition of one or more of the following data: -- a frontal axis of QRS more or equal to + 87 degrees -- a Lewis index of less than -7.44. 8. The diagnosis of mean pressures of the pulmonary artery of more than 35 mm. Hg can be established, with the same degree of possibility, by: -- a T frontal axis of less or equal to + 10 degrees -- a horizontal axis of QRS of less or equal to + 13 degrees -- a right Sokolow-Lyon index of more than 19.71 -- a quotient R/R + S in V1 more or equal to 0.88. 9. The only finding that permits to establish of a pulmonary capillary pressure higher of 25 mm. Hg, with false positives possibility of less of 5% is: -- quotient R/R + S in higher or equal to 0.07 in V1.