Rates of 75-100 beats per minute are usual. Accelerated idioventricular rhythm probably represents enhanced automaticity in the ventricles and manifests itself when sinus rates slow.
In a recent study, Accelerated idioventricular rhythm was observed in 15.2% of local patients after reperfusion was established through direct percutaneous coronary intervention for acute MI. Accelerated idioventricular rhythms (AIVR) are ectopic ventricular rhythms with rates intermediate between idioventricular escape rhythms (30 to 40/min) and ventricular tachycardia (120 to 180/min). When the ventricle paces the heart at a rate greater than 40 but less than 100 bpm, the term accelerated idioventricular rhythm is used.
Accelerated Idioventricular Rhythm is an electrocardiographic diagnosis and does not generally produce any particular symptoms. Making a correct diagnosis remains one of the most important concerns because the usual treatments for patients with the more common form of ventricular arrhythmia, such as VT, may not apply.
Causes of Accelerated Idioventricular Rhythm
Accelerated Idioventricular Rhythm arises from subordinate or second-order pacemakers and manifests itself when the patient's prevailing sinus rate becomes lower than the accelerated rate (AIVR) of the otherwise suppressed focus. This arrhythmia occurs as a rule in patients who have heart disease, e.g., those with acute myocardial infarction or with digitalis toxicity. Presence of acute myocardial infarction: Patients with AIVR most commonly have a history of recent or concomitant chest pain or other features of evolving acute myocardial infarction.
- Heart disease (eg, acute myocardial infarction, digitalis toxicity, at reperfusion of a previously occluded coronary artery)
- Possibly during resuscitation
- Drugs (eg, digoxin)
- Dilated cardiomyopathy
- Outpatient procedures (due to spinal anesthesia)
Treatment of Accelerated Idioventricular Rhythm
Accelerated idioventricular rhythm itself is most likely self-limiting. However, because it has not been determined whether this arrhythmia would be benign in infants with severe congenital heart disease, a cautious approach and careful observation are recommended.