ST-segment elevation in lead aVR and acute coronary syndrome

Physicians often ignore lead aVR during ST segment analysis of ECG recordings as it supposedly carries no useful information. Occlusion of the left main coronary artery (LMCA) or the proximal part of left anterior descending artery (LAD) causes ischemia of a large part of the left ventricle, which often manifests as cardiogenic shock. Proximal occlusion of the left coronary artery often induces ST-segment elevation in lead aVR, together with ST-depression in most other leads; changes that can easily be interpreted as acute myocardial infarction without ST segment elevation (NSTEMI). Since only early reperfusion lowers high mortality associated with proximal left coronary artery occlusion, early contact with the invasive coronarography unit is appropriate upon encountering ST-segment elevation in lead aVR in patients with suspected acute coronary syndrome (ACS). In the article we describe two patients with ACS and illustrate the importance of ST-segment analysis in lead aVR.