Electrocardiographic applications of lead aVR

Lead aVR, 1 of 12 electrocardiographic leads, is frequently ignored in clinical medicine. In fact, many clinicians refer to the 12-lead electrocardiogram (ECG) as the 11-lead ECG, noting the commonly held belief that lead aVR rarely offers clinically useful information. In this report, we discuss the findings in lead aVR, which are potentially of value, including ST-segment elevation in the patient with acute coronary syndrome suggestive of left main coronary artery occlusion, PR-segment elevation in the patient with acute pericarditis, prominent R wave in the patient with significant tricyclic antidepressant poisoning, and ST-segment elevation in narrow complex tachycardia suggestive of Wolff-Parkinson-White syndrome.