Prediction of right ventricular systolic pressure in pulmonary stenosis from combined vectorcardiographic data

In 38 patients with isolated unoperated pulmonary stenosis a systematic search was made for optimal VCG criteria for the prediction of peak systolic right ventricular pressure. Fifty VCG measurements, seven ECG measurements, and age of each patient were entered into a stepwise multiple regression computer program.The best individual predictors were found to be the QRS loop rotation in the horizontal plane and the closely related QRS dislocation along the 135 to 315 degree horizontal plane axis (r = 0.78). Five VCG criteria were better than the best ECG criterion (R V₁, r = 0.72). Thirty-three of the 58 variables showed significant correlations with the pressure (p < 0.01). Since the confidence intervals are large with this sample size and degree of correlation, conclusions regarding the superiority of one predictor vs. another should be drawn with great care.The multivariate equation selected by the computer involved four VCG variables and age; this improved the correlation coefficient to 0.93. This improvement from data combination is larger than in previous studies, probably because all variables were given equal opportunity to enter the equation.The results were tested on a secondary sample of 19 patients with pulmonary stenosis as their main cardiac lesion. Although this sample was less homogeneous, the formula-derived pressure estimates remained reasonably good (r = 0.88). The study suggests that the diagnostic power of ECG and VCG could be increased through the proper combination of easily obtainable measurements.