Electrocardiographic signs to differentiate between chronic thromboembolic pulmonary hypertension and intermediate-high risk acute pulmonary embolism

Acute pulmonary embolism (APE) and chronic thromboembolic pulmonary hypertension (CTEPH) both causedyspnoea and right ventricular (RV) overload, but require diff erent management. Electrocardiography (ECG) is widelyavailable, yet its role in distinguishing APE from CTEPH remains underexplored. We aimed to identify ECG parametersdiff erentiating APE from CTEPH and develop a predictive model.We included 184 patients: those hospitalized with intermediate-high-risk APE and patients with confi rmed CTEPH.ECG parameters were analyzed using logistic regression, and a predictive equation and simplifi ed scoring model(CTEPH ECG SCORE) were developed and validated.CTEPH patients showed higher rates of right axis deviation (RAD), qR pattern in V1, increased precordial ECGvoltage, and prolonged P-wave duration, whereas APE patients had higher heart rates, more frequent right bundlebranch blocks, and greater T-wave inversions (TWI). The CTEPH ECG SCORE distinguished CTEPH from APE with highaccuracy (AUC = 0.95) and was calculated as follows: CTEPH ECG SCORE = 0.5 + (4 × RAD) + (2 × Sokolow-Lyonindex) – (3.5 × HR 100) – (0.5 × TWI range).ECG can serve as a valuable tool for distinguishing CTEPH from APE.