Prognostic significance of quantitative electrocardiographic parameters in patients with non-high-risk pulmonary embolism

Background Electrocardiogram (ECG) abnormalities indicating right ventricular strain have been reported to have prognostic value in severe cases of acute pulmonary embolism (PE). We aimed to analyze the prognostic significance of other quantitative ECG parameters in non-high-risk acute PE. Methods Consecutive patients with non-high-risk acute PE were prospectively enrolled. The following baseline ECG parameters were collected: rhythm, heart rate, QRS axis, right bundle branch block (RBBB) pattern, S1Q3T3 pattern, T-wave inversion, ST-segment elevation, Qr in lead V1, PR Interval, QRS complex duration, QT interval, P-wave amplitude and duration, R- and S-wave amplitudes. The primary endpoint was early discharge within three days. Associations between ECG parameters and early discharge were analyzed. Results Overall, 383 patients were enrolled (median age: 67 years, 57% female): 277 (72.3%) with low-risk and 106 (27.7%) with intermediate-risk. The two groups of patients differed in several ECG signs of right ventricular strain and many other quantitative parameters like R- and S-wave amplitudes. In the multivariate logistic regression analysis, the S-wave depth in lead V5 (S-V5) was the only independent prognostic factor for early discharge (odds ratio = 0.137, 95% confidence interval = 0.031-0.613, p = 0.009). The optimum cutoff value of S-V5 for predicting early discharge derived from the receiver operative characteristic curve was 0.15 mv (c-statistic = 0.66, p =0.003). Conclusions Several ECG signs of right ventricular strain and many other quantitative parameters were associated with disease severity in non-high-risk acute PE. An S-V5 lesser than 0.15 mv was predictive for early discharge in these patients.