Extreme axis deviation
Also callednorthwest axis · extreme axis · extreme right axis deviation · right superior axis · no man's land axis
Definition
A mean frontal-plane QRS axis between -90 and ±180 degrees, in the upper-right ('northwest') quadrant of the hexaxial circle, beyond the adult ranges for marked left axis deviation (-45 to -90 degrees) and marked right axis deviation (+120 to +180 degrees); it is also called extreme right axis deviation. Ventricular activation then travels up and to the right, toward aVR and away from lead I, giving a dominant R wave in aVR and a deep, wide S wave in lead I. It is seen with ventricular rhythms (including ventricular tachycardia and ventricular escape rhythms), severe hyperkalemia, toxicity from sodium channel blockers or tricyclic antidepressants, dextrocardia, and reversal of the limb-lead cables.
Sources
- Surawicz B, Childers R, Deal BJ, Gettes LS. AHA/ACCF/HRS recommendations for the standardization and interpretation of the electrocardiogram: part III: intraventricular conduction disturbances. Circulation. 2009;119(10):e235-e240. doi.org/10.1161/CIRCULATIONAHA.108.191095
- Pérez-Riera AR, Yanowitz F, Barbosa-Barros R, et al. Electrocardiographic "northwest QRS axis" in the Brugada syndrome: a potential marker to predict poor outcome. JACC Case Rep. 2020;2(14):2230-2234. doi.org/10.1016/j.jaccas.2020.07.037
- González-Najera MF, Figueroa-Galván FS, Sáenz-Ordóñez EA, et al. Northwest axis on electrocardiogram: decoding an unusual cardiac axis in a young patient. JACC Case Rep. 2026;31(30):108329. doi.org/10.1016/j.jaccas.2026.108329
Last reviewed 2 October 2026. Every definition in the EKG Dictionary cites the guideline, consensus statement or original paper it comes from.