How is "idioventricular rhythm" characterized?

Idioventricular rhythm is characterized as a slow ventricular rhythm, typically occurring at a rate of 20 to 40 beats per minute, and arises from an ectopic ventricular pacemaker. This rhythm is often seen when the normal pacemakers of the heart (the SA node and sometimes the AV node) fail to function appropriately, leading to the ventricles taking over the pacing responsibility.

This condition reflects a situation where the typical conduction pathways are interrupted or compromised, preventing normal electrical signals from propagating effectively through the heart. As a result, the ventricles generate their own intrinsic rhythm due to the activation of non-conducting myocardial tissue within the ventricles.

In contrast, a rapid ventricular rhythm (which is over 100 bpm) would not define idioventricular rhythm, as it is characterized by a significantly slower rate. A normal heart rate at rest would also not apply, as idioventricular rhythms are inherently abnormal and are not associated with typical resting rates. Additionally, rhythms that arise from the atria would refer to atrial arrhythmias, which are distinct from idioventricular rhythms that originate in the ventricles.