Difficulty to Recognizing Acute Total Occlusion of Coronary Artery in Non-ST Elevation Myocardial Infarction: A pitfall of ST-segment Elevation in Electrocardiogram

Author : Y.S. Pratama, R. Puspitoadhi A. Yudanto, I. Uddin
Upload Date : 19-04-2018

Background: Electrocardiogram is an integral part to diagnose myocardial infarction (MI). In minority, patients with acute total occlusion (TO), no ST-segment elevation is present. It may affect the clinical decision and reperfusion strategy in MI.

Case Presentation: A 47 years old man came to the hospital with typical angina 3 hours before admission. He is a smoker, vital signs normal and ECG confirmed QS in lead III and AvF with upright T-wave. Serial ECG showed T wave changes without ST elevation. Serial troponin increase and diagnosed as NSTEMI. On his second day hospitalization, RV infarct and total AV block was developed along with pathological Q wave with no ST elevation. PCI and temporary pacemaker was performed. Angiography showed culprit lesion in RCA and chronic subtotal occlusion in LCx. Third day after PCI, his heart rate was back to sinus rhythm and temporary pacemaker was removed. Patient was discharged in the ninth day of hospitalization.

Discussion: The presence of ST elevation indicated TO of coronary artery but TO in RCA and LCx sometimes not showing ST elevation. Second day in charged, pathological Q wave, cardiogenic shock due to RV infarction and total AV block was developed that strongly indicated TO of RCA. No ST elevation in TO possibilities were such as: 1) Decreased ECG sensitivity to detect TO in inferolateral, 2) Transient ST elevation may be missed due to spontaneous reperfusion, 3) “Pseudonormalization” of ST-segment in inferior MI 4) Slow progression of TO with adequate collateral flow. Although no ST elevation was visible, acute or evolving changes of Q waves potentially allowed clinician to identify the occlusion of infarct-related artery.

Conclusion: In minority patient with acute total occlusion, no ST-segment elevation is present. Clinical findings and ECG monitoring are important. Even with no ST-segment elevation noted, it doesn’t mean no total occlusion of coronary artery. Early detection is difficult in this condition.

KEYWORDS : ST-segment elevation, acute total occlusion, electrocardiogram

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