Electrocardiographic changes in patients with acute pulmonary embolism

Abstract

Introduction. Pulmonary embolism is a life-threatening condition requiring prompt diagnosis. While contrast-enhanced computed tomography is the gold standard, its limited availability and associated risks necessitate complementary diagnostic tools. Recent studies suggest that combining multiple electrocardiographic abnormalities into a composite score may enhance diagnostic performance. Material and methods. We conducted a prospective, cross-sectional study involving 200 patients with suspected pulmonary embolism admitted to two hospitals in the Republic of Moldova between 2022 and 2025. Among them, 168 had confirmed pulmonary embolism based on computed tomography pulmonary angiography, while 32 patients with similar symptoms but negative imaging served as the control group. All participants underwent a standard 12-lead electrocardiogram upon admission. A composite electrocardiographic score was applied, incorporating 10 criteria (e.g., sinus tachycardia, S1Q3T3 pattern, negative T waves in V1-V4, right bundle branch block, and right axis deviation), with a total score ranging from 0 to 12. Diagnostic thresholds were defined as follows: 0-3 low risk, 4-6 intermediate risk, and ≥7 high risk. Results. Electrocardiographic abnormalities such as negative T waves in V1–V4 (42.9% vs. 6.2%), atrial fibrillation (28.0% vs. 6.2%), and S1Q3T3 pattern (21.4% vs. 3.1%) were significantly more frequent in pulmonary embolism patients. A composite electrocardiographic score of ≥5 demonstrated excellent diagnostic performance: sensitivity 89.9%, specificity 93.8%, positive predictive value 98.7%, and overall accuracy 90.5%. The area under the ROC curve was 0.92, indicating strong discriminative ability. Among combinations of electrocardiographic findings, the pairing of S1Q3T3 with negative T waves in V1-V4 showed a statistically significant association with confirmed pulmonary embolism. Conclusions. Our study confirms that a composite electrocardiographic score ≥5 is a highly effective, rapid, and noninvasive tool for identifying pulmonary embolism, improving early triage, particularly in emergency settings where imaging may be delayed. The model significantly outperforms isolated electrocardiographic findings and should be interpreted within a broader clinical context, including symptomatology and imaging when available.