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Usefulness of the 12-Lead Electrocardiography in the Diagnosis and Evaluation of Severity of Pulmonary Thromboembolism

Background and Objectives:Aggressive medical management, such as thrombolytic therapy, is necessary to save the lives of patients with acute severe pulmonary thromboembolism (PTE). The ECG changes associated with PTE are usually nonspecific, but severe PTE can produce some specific ECG findings. The purpose of this study was to determine the role of 12-lead ECG in the diagnosis of PTE, as well as the evaluation of its severity in therapeutic decision making. Subjects and Methosds:We analyzed 42 patients (60.5±14.9 years, 17 men), in whom PTE had been confirmed by chest CT angiography or radionuclide ventilation-perfusion scan, and 63 control patients (60.3±16.5 years, 21 men), who had various cardiovascular diseases, with the exception of PTE. The systolic pulmonary artery pressure (sPAP) was estimated by Doppler echocardiography. Results:Among the finding derived from the 12-lead ECG, the sinus tachycardia (35.7 vs. 12.7%, p=0.005), a QRS axis over 90 degree (28.5 vs. 7.9%, p=0.005), the S1Q3T3 sign (45.2 vs. 23.8%, p=0.021) and T-wave inversion at V2-4 (31.0 vs. 14.3%, p=0.040) were more common in the PTE than the control group. There were no significant ECG changes in 3 patients (7.1%) in the PTE group. In the PTE group, the T-wave amplitudes at leads II and aVF showed correlation with the sPAP (r=-0.400, p=0.009; r=-0.321, p=0.038, respectively). A T-wave amplitude greater than 0.5 mm at lead II was predictive of severe pulmonary hypertension (50 mmHg) in patients with PTE, with a sensitivity , specificity, positive predictive value and negative predictive value of 59.3, 86.7, 88.9 and 54.2%, respectively (OR=6.532, 95% CI, 1.592 to 26.785). Conclusion:The use of common ECG abnormalities as diagnostic tools of PTE was limited, due to their low sensitivity, despite the high specificity. However, the T-wave amplitude (cut-off value=0.5 mm) at lead II was very simple and useful in distinguishing patients with severe pulmonary thromboembolism from those without. (Korean Circulation J 2005;35:389-395)