Retrograde Activation of Atria in Auriculoventricular Block

Abstract

THE retrograde conduction of automatic ventricular beats in a complete auriculoventricular (A-V) block was considered for a long time to be impossible.¹ New data accumulated in the recent years concerning this phenomenon have changed this view, and today retrograde conduction is considered not at all uncommon. The form of the abnormal P waves (P') is identical. They are peaked, of short duration, inverted in leads II, III and aVF and positive in lead aVR. They indicate an activation of the atria in a reversed direction, i.e., from the area of the A-V node towards the sinus node. Certain features are common to all tracings displaying these retrograde P waves: (1) Retrograde P waves appear only after automatic ventricular beats and not after conducted beats from atria to ventricles, or as isolated blocked P waves. (2) The abnormal P waves are seen very late in the atrial diastole, only shortly