Author Affiliation: Department of Cardiology, Academic Cardiology, University of Tennessee College of Medicine, Chattanooga.
Much attention has recently been given to the use of ST-segment elevation (STE) in electrocardiographic lead aVR in the setting of acute coronary syndromes as indicative of left main and/or proximal left anterior descending coronary artery disease.1 It must be remembered, however, that STE in lead aVR is not specific for these coronary findings. While Nakamura et al1 discuss a differential diagnosis in their “Comment” section, they fail to mention one of the most common causes of STE in lead aVR, which is left ventricular (LV) hypertrophy. Left ventricular hypertrophy, usually but not always, shifts the QRS axis leftward in the frontal plane, with secondary ST-T abnormalities directed rightward. While the classic “LV strain pattern” is most often noted in limb leads 1 and aVL, because of an ST-segment vector directed between +60° and +240°, there are cases of LV hypertrophy with an ST-segment vector of approximately +270° (as in this case) wherein the ST-segment vector continues to lie on the positive side of the perpendicular to the aVR lead axis and, therefore, generates STE in that lead. The absence of LV hypertrophy by QRS voltage criteria, moreover, does not exclude this diagnosis, since patients with increased LV mass may exhibit repolarization abnormalities alone.
Zema MJ. ST-Segment Elevation in Lead aVR on the Presenting Electrocardiogram. Arch Intern Med. 2012;172(15):1190-1191. doi:10.1001/archinternmed.2012.2079