Signal‐Averaged ECG in Noninvasive Assessment of Reperfusion in the Acute Phase of Myocardial Infarction

Abstract

Background:Coronary artery patency after thrombolytic therapy has important prognostic implications for survival after acute myocardial infarction (Ml). Several noninvasive methods have been tested to assess the effectiveness of thrombolytic therapy. However, the value late potential (LP) analysis from the signal‐averaged ECG for assessment of reperfusion has not been established. Methods:In 50 patients (34 males, 16 females, mean age 59 ± 12 years, range, 35 years to 84 years) with acute Ml, signal‐averaged ECG recordings were performed using the FD‐3 solid‐state Holter recorder and analyzed prior to and 1, 2, and 3 hours from the initiation of thrombolytic treatment. Reduction in ST elevation of > 50% compared with baseline values was taken as a marker of successful reperfusion. Results:At 2 hours, 28 (56 %) patients were considered to have successful reperfusion: LPS were not present in any patient with successful reperfusion compared with 8 (36%) patients without reperfusion (P = 0.002). At 3 hours 31 (62 %) patients were considered to have successful reperfusion: 1 (3%) had abnormal signal‐averaged ECG versus 6 (35%) patients without reperfusion (P = 0.01). An abnormal signal‐averaged ECG identified patients with failed reperfusion with very high specificity and positive predictive value (100% and 100% at 2 hours; 97% and 86% at 3 hours, respectively). Conclusions:Patients with failed reperfusion have abnormal signal‐averaged ECGs more frequently than patients with successful reperfusion. Thus, signal‐averaged ECG may be helpful for identification of patients without reperfusion who may urgently need invasive treatment or rethrombolysis to restore blood flow in the infarct‐related artery. A.N.E. 1999;4(3):301–308