How is the P wave described in an Accelerated Idioventricular Rhythm?

In an Accelerated Idioventricular Rhythm (AIVR), the hallmark feature is that the ventricular rate is typically between 40 to 100 beats per minute, which is considered an accelerated form of the idioventricular rhythm, usually seen in situations like myocardial infarction or during the recovery phase of acute coronary syndromes.

In terms of the P wave, it is described as present and upright because, in AIVR, the rhythm often emerges from an irritable focus within the ventricles but may still have the potential for atrial activity to occur. This allows the P waves to be conducted forward, which you can observe as upright in lead II on the ECG. This finding indicates that the atria are still depolarizing, resulting in a visible P wave, and it typically aligns with the QRS complexes that appear wide due to the slower conduction through the ventricles in this rhythm.

The absence of P waves, inverted P waves, or inconsistent P waves are not characteristic of AIVR, as these would indicate a different pathological scenario, such as complete dissociation between atria and ventricle or ectopic atrial activity that doesn't consistently relate to the ventricular depolarization.