Catheter Ablation for Atrioventricular Nodal Reentrant Tachycardia (AVNRT)

Introduction to Catheter Ablation

The American College of Cardiology, American Heart Association, and Heart Rhythm Society (ACC/AHA/HRS) guidelines recommend catheter ablation of the slow pathway as first-line therapy for all patients with symptomatic AVNRT due to its high success rate (>95%) and low complication rate (<1% risk of AV block) 1
Patient preference is a consideration for catheter ablation, even in patients who could be managed with medications but prefer a definitive treatment 2
The ACC/AHA/HRS guidelines give a Class I recommendation (Level of Evidence: B-NR) for catheter ablation in patients with AVNRT, particularly those with recurrent symptoms, hemodynamically significant episodes, or patient preference for a definitive treatment 1

The ACC/AHA/HRS guidelines recommend oral verapamil or diltiazem (Class I, Level B-R) for patients who are not candidates for or prefer not to undergo catheter ablation 1
Oral beta blockers (Class I, Level B-R) are recommended for patients who are not candidates for or prefer not to undergo catheter ablation 1
Flecainide or propafenone (Class IIa, Level B-R) may be considered in patients without structural heart disease who are not candidates for or prefer not to undergo catheter ablation 1
Clinical follow-up without therapy (Class IIa, Level B-NR) is recommended for minimally symptomatic patients who are not candidates for or prefer not to undergo catheter ablation 2

RF ablation has a success rate of >95% for acute success and a recurrence rate of 3.4-5%, with a risk of AV block of <1% 2
Cryoablation has a higher recurrence rate, with some studies showing a 9.4-15% recurrence rate compared to 3.4-5% with RF ablation 2
The ACC/AHA/HRS guidelines recommend RF ablation as the first-line ablation technique for AVNRT due to its high success rate (>95%) and low recurrence rate (3.4%) 2
The decision between RF and cryoablation should consider patient age, anatomy, and risk tolerance, with the ACC/AHA/HRS guidelines providing guidance on this decision 2

Patients who undergo successful ablation typically require only yearly follow-up 3
Patients who choose medical management should be monitored more frequently to assess symptom control and medication side effects 1
Success rates and complication rates are dependent on operator experience with each technique, and longer follow-up periods may reveal more recurrences, particularly with cryoablation 2