A “Carousel” ECG Confusion

Abstract

A man in his 60s with history of hypertension, type II diabetes, hyperlipidemia, established coronary artery disease, and recent coronary intervention presented to the hospital with recurrent chest pain with some atypical features. He underwent placement of a drug-eluting stent to the right coronary artery 6 weeks before, at which time, he had a 90% mid-right coronary artery stenosis in addition to a 90% distal apical left anterior descending artery stenosis. The right coronary artery intervention was uneventful with no residual stenosis; but an apical left anterior descending artery lesion failed coronary intervention. The patient claimed strict compliance with dual antiplatelet therapy. His physical examination and initial troponin were normal. A 12-lead ECG on admission showed slight ST elevation and new Q waves in the inferior leads (Figure 1A). Compared with baseline tracing (Figure 1B), the prominent changes were concerning for a recent inferior wall myocardial infarction because of acute right coronary artery stent occlusion.Does the ECG show a recent Q-wave myocardial infarction? What is the explanation for the new ECG changes?Please turn the page to read the diagnosis.