Idioventricular Rhythm

A ventricular escape rhythm occurring when supraventricular pacemakers (SA node and AV junction) fail. The ventricle's intrinsic rate is 20–40 bpm — the slowest of the three intrinsic pacemakers. This is a protective mechanism to prevent asystole.

• Regular wide-complex rhythm (QRS >120 ms) at 20–40 bpm.
• No P waves or AV dissociation may be present.
• QRS morphology depends on ventricular focus.
• Very slow rate distinguishes it from AIVR (50–110 bpm) and VTach (>100 bpm).

Indicates severe conduction system disease or complete SA/AV node failure. High risk of hemodynamic compromise due to slow rate. Requires immediate intervention: atropine, transcutaneous pacing, or temporary transvenous pacing. Never suppress with antiarrhythmics — it's a protective escape rhythm.