ECG score predicts those with the greatest percentage of perfusion defects due to acute pulmonary thromboembolic disease

Background: More aggressive management may be warranted for patients with acute pulmonary embolism (PE) and the greatest pulmonary vascular obstruction. We hypothesized that a scoring system based on the ECG might identify such patients. Methods: Consecutive patients investigated for PE at Christchurch Hospital between 1997 and 2002 with high-probability ventilation/perfusion (V/Q) scan findings were studied. The ECG obtained closest to and within 48 h of the scan was scored by two independent observers, and the mean ECG score was calculated. V/Q scan findings were categorized into those with < 30%, 30 to 50%, and > 50% perfusion defect by two independent observers experienced in V/Q interpretation. A consensus score was taken when disagreement occurred. Results: Two hundred twenty-nine patients were included in the study. The interobserver agreement for ECG score was 0.96 (Cronbach alpha) and V/Q score was 0.55 (kappa). The ECG predicted those with the greatest amount of perfusion defects. Mean ECG score was 2.6 (SD 2.8) in patients with < 30% perfusion defect, 3.2 (SD 2.9) in patients with 30 to 50% perfusion defect, and 5.3 (SD 3.7) in patients with > 50% perfusion defect. The area under the receiver operating characteristic curve for ECG score and those with > 50% perfusion defect was 0.71 (SE 0.04). An ECG score of 2: 3 predicted those with > 50% perfusion defect with a sensitivity of 70% (95% confidence interval [CI], 59 to 81%), and a specificity of 59% (95% CI, 51 to 67%). Conclusion: An ECG score, simple to derive, predicts those with the greatest percentage of perfusion defect. Using the ECG for management warrants prospective evaluation.