Artificial intelligence-driven ECG biomarkers for screening of large pericardial effusion

Pericardial effusion can progress to life-threatening cardiac tamponade when large or rapidly accumulating, yet early diagnosis is frequently delayed without sufficient clinical vigilance. Echocardiography is the gold standard but is not always accessible in emergency or resource-limited settings. Electrocardiographic (ECG) findings, including low QRS voltage and electrical alternans, may prompt clinical suspicion; however, their diagnostic value remains constrained by poor quantitative standardization and limited objectivity. This study aimed to evaluate the diagnostic performance of ECG Buddy™, a smartphone-based artificial intelligence (AI) ECG analysis application, in detecting large pericardial effusion (LPE) and cardiac tamponade. We retrospectively reviewed adult patients (≥19 years) who underwent echocardiography between January 2013 and December 2023. LPE was defined as an effusion ≥2.0 cm in maximal diameter, and tamponade was defined as LPE with constrictive physiology or right atrium/right ventricle (RA/RV) diastolic collapse. An equal number of control patients without LPE were randomly sampled. Printed ECGs were analyzed using ECG Buddy™, which generated a quantitative digital biomarker (QCG-LPE). Diagnostic performance was evaluated with receiver operating characteristic-area under the curve (ROC-AUC), sensitivity, specificity, and comparison with conventional biomarkers (Troponin I, NT-proBNP). Biomarker changes before and after pericardiocentesis (PCC) were also assessed. A total of 770 patients (LPE=385, controls=385) were included, of whom 112 had tamponade and 158 underwent PCC. QCG-LPE levels differed markedly across groups: Normal 1.0 (IQR 0.3–3.5), LPE 37.8 (21.2–62.1), and Tamponade 61.8 (38.3–80.0) (p<0.001). QCG-LPE achieved an AUC of 0.980(95% CI, 0.972–0.988) for detecting LPE, with sensitivity 96.6% (95% CI, 94.3–98.7) and specificity 88.4% (95% CI, 84.9–91.6). For tamponade, the AUC was 0.880 (95% CI, 0.851–0.909), sensitivity 94.0% (95% CI, 88.1–98.8) and specificity 73.4% (95% CI, 69.7–77.0). QCG-LPE outperformed both Troponin I (AUC 0.731) and NT-proBNP (AUC 0.920) with a statistically significant difference (p<0.001). In patients undergoing PCC, biomarker values decreased significantly after the procedure (48.95 → 22.95, p<0.001), demonstrating responsiveness to therapeutic intervention. Digital ECG biomarker demonstrated excellent diagnostic accuracy for LPE and tamponade, validated against echocardiography as the gold standard. Its quantitative biomarker not only enables rapid screening but also reflects therapeutic response, suggesting potential for use as an accessible adjunct tool in emergency and resource-limited settings.