Assessment of the Severity of Valvular Pulmonary Stenosis from ECG at Ages Greater and Less than One Year

The correlation between 22 ECG parameters and the systolic gradient in valvular pulmonary stenosis (PS) was studied in 126 patients at age > 1 (7.0±4.2) and in 31 infants ?1 year (0.43±0.27). The degree of sensitivity and specificity of the ECG criteria were calculated in regard to age and grade of severity of PS where the latter was mostly determined by echocardiography. The correlations of the ECG variables were much lower in patients ? 1 year and they were insignificant in most variables except R wave amplitude and R/S ratio in V1. On the other hand, in the group > 1 year of age all were significant except R amplitude and R/S ratio in V5. The amplitude of R wave in V1 correlated highest with the systolic gradient and it could be estimated with a standard error of ±29 mmHg. Although most ECG variables were correlated significantly with the degree of the systolic gradient, except S wave in V1, they did not contribute to the information brought forward by the R amplitude in V1. The bifactorial regression for the estimation of pulmonary systolic gradient from RV1 and SV1 showed a standard error of 27 mmHg. The estimates belonging to the 3 severity grades of PS showed concordance in 66 %, underestimation in 11 % and overestimation in 23 %. In the age group ?1 year, however, the discordance was 55 %. It is therefore concluded that the severity grade of the valvular PS cannot be estimated from the ECG at age ? 1 year in whom severe cases are underestimated and mild cases overestimated due to the physiologic right ventricular hypertrophy.