Initial Electrocardiographic Findings Associated with Failed Resolution of ST-segment Elevation after Thrombolytic Therapy in Acute ST-segment Elevation Myocardial Infarction (STEMI)

Na, Ji Ung; Choi, Pil Cho; Lee, Jeong Hun

Abstract

PURPOSE
Electrocardiography is a non-invasive tool for use in prediction of reperfusion and outcome of acute myocardial infarction. We attempted to determine initial electrocardiographic findings associated with failed resolution of ST-segment elevation (STE) among patients with ST-segment Elevation Myocardial Infarction (STEMI) treated with a thrombolytic agent.
METHODS
This retrospective study included patients with STEMI who were treated with a thrombolytic agent at the emergency department between October 2008 and March 2011. During the study period, among 331 patients with STEMI, 43 patients were enrolled. Resolution of STE was evaluated by comparison of initial electrocardiography (ECG) with follow-up ECG, taken 90 minutes after thrombolytic therapy. Determination of success or failure of resolution of STE was based on the electrocardiographic criteria of the American College of Cardiology and the American Heart Association (ACC/AHA). Patients were divided into two groups according to these criteria, and initial electrocardiographic findings were compared for the two groups.
RESULTS
Of a total of 43 patients, 22(55.16%) demonstrated failed resolution of STE after thrombolytic therapy. The risk of failed resolution of STE was approximately nine times higher in the anterior location of STE, compared to the inferior location of STE (OR 9.09, 95% CI, 1.46-94.69, p<0.01). In addition, the absence of reciprocal ST depression was associated with a six times higher risk of failed resolution of STE, compared with the presence of reciprocal ST depression (OR 6, 95% CI, 1.17-39.23, p=0.01). However, other electrocardiographic findings, including abnormal Q-wave, wide QRS complex, and QTc prolongation did not differ statistically between the two groups.
CONCLUSION
Failed STE resolution after thrombolytic therapy was more frequent in STEMI patients with ST elevation in an anterior location or without reciprocal ST depression.