From the Research
Accelerated Idioventricular Rhythm (AIVR) is a cardiac arrhythmia that is usually benign and self-limiting, requiring no specific treatment in hemodynamically stable patients, as evidenced by the most recent study 1. The diagnosis of AIVR is based on the presence of an ectopic ventricular rhythm with a rate of 50-110 beats per minute, which is faster than normal ventricular escape rhythm but slower than ventricular tachycardia. AIVR typically occurs when the sinus node slows down or fails, allowing a ventricular focus to take over as the dominant pacemaker. This rhythm is commonly seen during reperfusion after myocardial infarction, in digitalis toxicity, cardiomyopathies, or electrolyte disturbances.
Causes and Risk Factors
The causes of AIVR include:
- Myocardial ischemia in coronary artery disease
- Digitalis toxicity
- Cardiomyopathies
- Electrolyte disturbances
- Hypothermia, as seen in a case report where a patient developed AIVR after cardiac surgery due to hypothermia 1
Treatment
In hemodynamically stable patients, no specific treatment is required, and the focus should be on addressing the underlying causes, such as correcting electrolyte abnormalities, stopping offending medications, or treating myocardial ischemia 2. If a patient becomes symptomatic with hypotension or chest pain, atropine 0.5-1 mg IV can be administered to increase the sinus rate and suppress the ventricular focus. For recurrent symptomatic episodes, isoproterenol infusion at 2-10 mcg/min may be used temporarily.
Prognosis
AIVR is generally considered a "benign" arrhythmia because it often serves as a transitional rhythm during reperfusion and typically resolves spontaneously as the sinus node regains control of cardiac rhythm. However, in some cases, AIVR can be associated with extensive myocardial damage and delayed microvascular reperfusion, as seen in a study of patients with ST-elevation myocardial infarction treated with primary percutaneous coronary intervention 3.
Clinical Considerations
In clinical practice, it is essential to prioritize the patient's hemodynamic stability and address any underlying causes of AIVR. The use of catheter ablation may be considered in patients with frequent AIVR and impaired left ventricular ejection fraction, as seen in a study of patients with frequent AIVR 2.