Accelerated idioventricular rhythm

ventricular rhythm up to 120bpm (from Chou's & Hurst's)

Accelerated idioventricular rhythm (AIVR) is a relatively benign reperfusion arrhythmia
Suggests successful reperfusion (partial or complete) of an occluded coronary vessel in AMI (spontaneous or s/p thrombolytics)
Other presentations: digoxin toxicity, severe electrolyte abnormalities, cardiac ischemia
May be seen during cardiac arrest resuscitation
Unlikely to cause hemodynamic instability
Suppression can cause instability
- → avoid antiarrhythmic medications (lidocaine, amiodarone, procainamide, etc.) which can cause asystole
Tends to be transient. Treatment is to simply observe!
When occurring spontaneously, strongly consider cath!

Ventricular rhythms

Wide QRS complex rhythm with no P-waves or no P-QRS association (look closely at lead V1)
Ventricular rate 20-40: ventricular escape rhythm (idioventricular rhythm)
Ventricular rate 40-120s: Accelerated ventricular escape rhythm (accelerated idioventricular rhythm, AIVR)
Ventricular rate > 120s-130s: Ventricular tachycardia
- Caveat: VT can have slower rates if patient is on an antiarrhythmic (e.g., oral flecainide or amiodarone)
- Other mimics of VT (rate often <120)
  - Hyperkalemia
  - Sodium channel blocker toxicity