Electrocardiographic and hemodynamic correlations in primary pulmonary hypertension

In order to evaluate the pulmonary hemodynamics in primary pulmonary hypertension, the relation between the standard 12-lead electrocardiogram (ECG) and pulmonary hemodynamics as determined by right-heart catheterization was analyzed. Significant positive correlations were noted between amplitude of the R in V1, the R/S ratio in V1, and the pulmonary artery systolic pressure (r = 0.46 and 0.50, respectively, p less than 0.01). An amplitude of the R in V1 of more than 1.2 mV indicated a pulmonary artery systolic pressure of more than 90 mmHg with a sensitivity of 94% and a specificity of 47%. The cardiac index showed a significant positive relationship with amplitude of the R in V5 and V6 and the R/S ratio in V5 and V6 (r = 0.46, 0.46, 0.39, and 0.48, respectively; each with a p less than 0.01). Moreover, an AQRS greater than or equal to 100 degrees, and either an SV6 greater than or equal to 0.7 mV, or R/SV6 less than or equal to 2 indicated a cardiac index of less than 2.8L/min/m2 with a sensitivity of 82% and 84% and a specificity of 86% and 100% respectively. This study suggests, therefore, that the 12-lead ECG is useful for the evaluation of the severity of pulmonary hypertension by its ability to predict pulmonary artery systolic pressure and cardiac index with clinically useful accuracy.