What is the treatment for accelerated ventricular rhythm (aVRT)?

Treatment of Accelerated Ventricular Rhythm (aVRT)

The treatment of accelerated ventricular rhythm (aVRT) should be guided by the patient's hemodynamic stability, with immediate synchronized cardioversion for unstable patients and a more conservative approach for stable patients, as most cases of aVRT are benign and self-limiting. 1

Understanding aVRT

Accelerated ventricular rhythm is characterized by:

• Ventricular rate typically between 50-110 bpm
• Usually slightly faster than the sinus rate (within 12% above sinus rate)
• Left bundle branch block morphology
• Atrioventricular dissociation with fusion beats
• QRS duration approximately twice that of normal sinus rhythm 2, 3

Treatment Algorithm Based on Clinical Presentation

For Hemodynamically Unstable Patients

1. Immediate synchronized cardioversion if the patient shows signs of:
   • Hypotension
   • Altered mental status
   • Signs of shock
   • Chest pain
   • Heart failure 1

For Hemodynamically Stable Patients

1. Observation without treatment is appropriate for most cases of aVRT, as it is often transient and benign 2, 4

2. Beta blockers (first-line pharmacological therapy)

   • Metoprolol has been shown to be the most effective drug to decelerate the arrhythmia rate and relieve symptoms 3
   • Consider for symptomatic patients with palpitations or chest discomfort

3. Catheter ablation should be considered in patients with:

   • AIVR burden >70% per day
   • Impaired left ventricular ejection fraction (LVEF)
   • Syncope or presyncope due to over-response to sympathetic tone
   • Symptoms refractory to medical therapy 4

Special Considerations

Monitoring for Complications

• Regular assessment of LVEF is important as high AIVR burden (>73.8% per day) is associated with impaired cardiac function 4
• LVEF typically returns to normal within 6 months after successful treatment in most patients 4

Pediatric Considerations

• In infants with aVRT and structurally normal hearts, the condition is typically benign
• Withholding antiarrhythmic therapy is reasonable as spontaneous resolution often occurs 2

Potential Pitfalls

1. Misdiagnosis of aVRT as ventricular tachycardia may lead to unnecessary aggressive treatment
2. Failure to recognize tachycardia-induced cardiomyopathy in cases of persistent aVRT with high burden
3. Overlooking underlying structural heart disease that may be causing or exacerbating aVRT
4. Inappropriate use of calcium channel blockers which may worsen hemodynamic status in patients with impaired ventricular function

Follow-up Recommendations

• Regular ECG monitoring to assess arrhythmia burden
• Echocardiography to evaluate LVEF, particularly in patients with high arrhythmia burden
• Adjustment of beta blocker dosage based on symptom control and heart rate response

The management of aVRT requires careful assessment of symptoms, hemodynamic status, and ventricular function, with treatment ranging from conservative observation to catheter ablation in more severe cases.