Precordial ST-segments elevation. Which vessel is occluded and where?

ST-segment elevation in the precordial leads is almost always interpreted as anterior wall myocardial infarction due to occlusion of the left anterior descending artery (LAD). However, isolated right ventricular infarction can present with precordial ST-segment elevation (Fig. 1 , patient A) mimicking anterior wall myocardial infarction [1]. Isolated right ventricular infarction is a rare event; it occurs in cases of occlusion of a non-dominant right coronary artery (RCA), isolated right ventricular branch occlusion or in cases of RCA occlusion where the left ventricle inferior wall is protected by left to right collaterals or a bypass graft [1]. The inferior ST segments are usually elevated due to right ventricular inferior wall involvement. In anterior wall myocardial infarction, the inferior ST segments are usually isoelectric or depressed. On the other hand, occlusion of a distal LAD, especially when wrapping around the apex (Fig. 1, patient B), can also present with concomitant anterior as well as inferior ST-segment elevation, giving an electrocardiographic pattern almost similar to isolated right ventricular infarction [1].

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