Abstract 3488: Electrocardiographic Differentiation of Negative T Waves of Acute Pulmonary Embolism from that of Acute Coronary Syndromes
Objectives We studied whether ECG criteria could be used to discriminate between acute pulmonary embolism (APE) and acute coronary syndromes (ACS) in patients with negative T waves (Neg T) in precordial leads.
Background Neg T in precordial leads are often seen in ACS, but also occur in APE. Because elevated cardiac troponin levels are found in severe APE as well as in ACS, this variable is of limited value for differential diagnosis.
Methods and Results We studied 40 patients with APE and 87 with ACS who had Neg T of at least 1 mm in ≥ 2 contiguous precordial leads (V1 to V4) at admission. The diagnosis of APE was confirmed by pulmonary angiography, lung perfusion scintigraphy, or spiral computed tomographic scanning. In patients with ACS, coronary angiography was performed a median of 3 days after admission, and 79 patients had well-defined culprit lesions. In 74 (94%) of these patients, the culprit lesion was located in the left anterior descending coronary artery. There were no significant differences in sex, time to ECG recording and the incidence of positive-troponin T at admission (56 vs 46%) between APE and ACS. As compared with patients with ACS, those with APE were younger (63 vs 69 yrs, p<0.01) and more rapid heart rate at admission (102 vs 73 bpm, p<0.01). On admission ECG, ST deviation was similar in APE and ACS. As compared with ACS, APE was more frequently associated with pulmonary P waves (23 vs 8%), S1Q3T3 pattern (20 vs 0%), low voltage (30 vs 6%), clockwise rotation (28 vs 0%), and Neg T in leads II (30 vs 14%), III (89 vs 5%), aVF (43 vs 10%), V1 (100 vs 51%), and V2 (100 vs 81%) (p<0.05, respectively). In contrast, Neg T in leads I (0 vs 48%), aVL (0 vs 76%), V3 (63 vs 100%), V4 (43 vs 95%), V5 (10 vs 76%), and V6 (3 vs 44%) were less frequent in APE than in ACS (p<0.01, respectively). Neg T in both leads III and V1 were observed in only 1% of patients with ACS, as compared with 88% of patients with APE (p<0.001). The sensitivity, specificity, and predictive accuracy of this finding for the diagnosis of APE were 88%, 99%, and 95%, respectively, which were higher than those based on other ECG variables.
Conclusions In patients with Neg T in precordial leads, the presence of Neg T in both leads III and V1 strongly suggests APE. This ECG finding allows APE to be simply but accurately differentiated from ACS.