What rhythm abnormality is characterized by a lack of relationship between P waves and QRS complexes?

The rhythm abnormality characterized by a lack of relationship between P waves and QRS complexes is known as third-degree AV block, also referred to as complete heart block. This condition results from a complete interruption of the electrical conduction from the atria to the ventricles. In this scenario, the atrial activity (P waves) and the ventricular activity (QRS complexes) are independent of each other.

In third-degree AV block, the atria contract independently of the ventricles, leading to a situation where P waves appear at a regular rate that is not conducted to the ventricles, resulting in QRS complexes being generated at their own intrinsic rate. This disassociation causes the hallmark feature of the rhythm: the lack of correlation between the P waves and the QRS complexes.

This contrasts with other arrhythmias, where there may be some form of relationship or pattern between the atrial and ventricular activity. For instance, in atrial fibrillation, while the P waves are disorganized and absent, QRS complexes are still irregularly timed but not completely dissociated. In ventricular tachycardia, QRS complexes are typically wide and fast, and P waves may be present but are usually not identifiable. Sinus arrhythmia demonstrates a relationship