Electrocardiographic signs to differentiate between chronic thromboembolic pulmonary hypertension and acute pulmonary embolism

Background: Acute pulmonary embolism (APE) and chronic thromboembolic pulmonary hypertension (CTEPH) both cause dyspnoea and right ventricular (RV) overload, but require different management. Electrocardiography (ECG) is widely available, yet its role in distinguishing APE from CTEPH remains underexplored.. Aim: To identify ECG parameters differentiating APE from CTEPH and develop a predictive mode. Methods: We included 184 patients: those hospitalized with intermediate-high-risk APE and patients with confirmed CTEPH. ECG parameters were analyzed using logistic regression. A predictive equation and simplified scoring model (CTEPH ECG SCORE) were developed and validated. Results: CTEPH patients showed higher rates of right axis deviation (RAD), qR pattern in V1, increased precordial ECG voltage, and prolonged P-wave duration. APE patients had higher heart rates, more frequent right bundle branch blocks, and greater T-wave inversions (TWI). The CTEPH ECG SCORE distinguished CTEPH from APE with high accuracy (AUC = 0.95). CTEPH ECG SCORE = 0.5 + (4 × RAD) + (0.5 × Sokolow-Lyon index) – (3 × HR >100) – (0.5 × TWI range). Conclusions: ECG can serve as a valuable tool for distinguishing CTEPH from APE.