Prognostic Significance of Electrocardiographic Findings in Hemodynamically Stable Patients With Acute Pulmonary Embolism: Insights From the RIETE Registry

BACKGROUND: The simplified Pulmonary Embolism Severity Index (sPESI) is widely used for risk stratification in patients with acute symptomatic pulmonary embolism (PE). Electrocardiography (ECG) provides information on cardiac stress, including right ventricular (RV) stress, but is not included in current guidelines for PE risk stratification. METHODS: We analyzed 32,113 hemodynamically stable patients with acute symptomatic PE enrolled in the RIETE registry. ECGs obtained within 24h of diagnosis were classified as normal or abnormal according to predefined criteria. The primary outcome was 30-day all-cause mortality. Secondary outcomes included 30-day PE-related mortality and a composite endpoint of 30-day all-cause mortality, early hemodynamic deterioration, or need for escalated therapy. The prognostic performance of sPESI was compared with an ECG-augmented strategy (sPESI-ECG) using diagnostic accuracy metrics and multivariable logistic regression. A prespecified subgroup analysis was performed in patients with CT-assessed RV/LV ratio. RESULTS: An abnormal ECG was present in 63.1% of patients and was associated with more severe presentation and markers of RV dysfunction. Thirty-day mortality was higher in patients with abnormal vs normal ECG findings (5.4% vs 2.9%). For the primary outcome, sPESI-ECG showed higher sensitivity than sPESI alone (97.7% vs 94.5%) with lower specificity. Patients classified as low risk by sPESI-ECG represented a smaller subgroup with numerically lower 30-day all-cause mortality than those classified as low risk by sPESI (0.62% vs 0.82%). Findings were consistent in multivariable analysis and in the CT subgroup. CONCLUSIONS: Incorporating ECG findings into sPESI may help identify a smaller subgroup of patients at very low short-term risk.