A simple method for ECG and VCG assessment of the severity of pulmonary valve stenosis

In patients with isolated pulmonary valve stenosis, the right ventricular (RV) hypertrophy is related to the hemodynamic severity of their lesions. We estimated the peak RV pressure noninvasively in 112 patients with isolated pulmonary valve stenosis by a Frank lead vectorcardiogram (VCG), an orthogonal electrocardiogram (ECG), and a standard scalar ECG. In 78 randomly assigned patients, 10 ECG measurements and 13 VCG measurements were correlated with the peak RV pressure at cardiac catheterization; the best multiple linear regression equation used the R wave in standard lead 1 (ECG), maximal rightward voltage in the terminal part of the frontal vector loop (VCG), and the Q wave in the orthogonal Z lead, giving R = 0.66 (SEM 25). The equation was validated in the other 34 patients; correlation of estimated with actual peak RV pressure was r = 0.64. A nomogram for clinical use was devised from this regression equation.