From the FDA Drug Label
Atropine also may lessen the degree of partial heart block when vagal activity is an etiologic factor In some patients with complete heart block, the idioventricular rate may be accelerated by atropine; in others, the rate is stabilized.
The prehospital treatment of accelerated idioventricular rhythm with atropine may accelerate the idioventricular rate in some patients with complete heart block, while in others it may stabilize the rate. However, the effect of atropine on accelerated idioventricular rhythm is not explicitly stated in the label, and therefore, no conclusion can be drawn about its use in this specific context 1.
From the Research
Prehospital treatment of accelerated idioventricular rhythm (AIVR) generally requires no specific intervention if the patient is hemodynamically stable. AIVR is typically a benign, transient rhythm with a rate of 50-110 beats per minute that often serves as an escape rhythm during reperfusion after myocardial infarction or in the setting of digoxin toxicity 2. For stable patients, monitor vital signs, provide supplemental oxygen if needed, establish IV access, and perform continuous cardiac monitoring while transporting to the hospital. Avoid antiarrhythmic medications as they may suppress this protective rhythm and potentially lead to asystole. If the patient becomes hemodynamically unstable (rare with AIVR), treat the underlying cause rather than the rhythm itself. For bradycardic patients with signs of poor perfusion, atropine 0.5mg IV may be considered, though it's often ineffective for ventricular rhythms. In cases of severe hemodynamic compromise, transcutaneous pacing might be necessary. The key principle is recognizing that AIVR itself rarely requires treatment and often resolves spontaneously as the underlying condition improves. Focus instead on identifying and addressing potential causes such as acute coronary syndrome, electrolyte abnormalities, or medication effects.
Some key points to consider in the management of AIVR include:
- AIVR is often associated with successful reperfusion in patients with ST-elevation myocardial infarction treated with primary percutaneous coronary intervention, but it is not a marker of successful reperfusion 3.
- AIVR can occur in patients with and without structural heart disease, and its occurrence after thrombolysis during acute myocardial infarction is a marker of successful reperfusion 4.
- Frequent AIVR has unique clinical manifestations, and patients with a burden of over 70%, impaired left ventricular ejection fraction, and/or symptoms of syncope or presyncope due to over-response to sympathetic tone should be considered for catheter ablation 2.
- AIVR is a rare but benign form of ventricular tachycardia that might be challenging to differentiate from other more worrisome forms, and it can occur in healthy newborns without the need for medical therapy 5.
Overall, the management of AIVR should focus on identifying and addressing the underlying cause of the rhythm, rather than treating the rhythm itself, and monitoring for any signs of hemodynamic instability.