Indeterminate axis

An indeterminate axis means that the overall direction of ventricular depolarisation cannot be determined from the 6 standard limb leads. This can happen when depolarisation mainly moves anterior-posterior (i.e. front-to-back) and there is little overall movement in the frontal plane that the limb leads record in. If the axis is indeterminate, all of the limb leads (I, II, III, aVL, aVR, aVF) may look similar, e.g isoelectric.

Featured Example