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Ectopic atrioventricular node tachycardia — Clinical Guidelines

Overview

Atrioventricular node reentrant tachycardia (AVNRT) is a type of supraventricular tachycardia characterized by reentrant electrical circuits involving dual pathways within the atrioventricular (AV) node, typically involving a fast and slow pathway. 1 3 11

Diagnosis

Electrocardiogram (ECG) findings: Typical features include a sudden onset of tachycardia, narrow QRS complexes, and characteristic P wave morphology (retrograde P waves often seen before or during the QRS complex). 1 3

Electrophysiologic study: Useful for confirming the diagnosis and identifying the specific pathways involved (fast and slow). 1 3 11

Adenosine challenge: Can induce tachycardia in some cases, highlighting differential sensitivity of fast and slow pathways to adenosine. 3

Management

First-line treatment: Radiofrequency catheter ablation targeting the slow pathway is highly effective and recommended for definitive therapy. 1 6 8 10 12

Medications: Antiarrhythmic drugs like encainide can be used for temporary control, increasing AH interval and potentially Wenckebach cycle length. 13

Adjunctive measures: Junctional tachycardia observed during ablation can serve as a marker for successful modification of the slow pathway. 9

Special Populations

Pediatrics: Radiofrequency modification of the slow pathway is feasible but requires caution due to potential transient atrioventricular block. 2

Elderly: Slow pathway ablation remains effective even in patients with a long fast pathway effective refractory period, though careful patient selection is advised. 4

Prolonged PR interval: Selective slow pathway ablation is safe and effective in patients with pre-existing PR prolongation. 7

Key Recommendations

Radiofrequency catheter ablation targeting the slow pathway is recommended as the primary treatment for AVNRT due to its high success rates and low recurrence rates. (Evidence: Strong 1 6 8 10)

Careful patient selection is necessary, especially in those with a long fast pathway ERP, to avoid potential conduction disturbances post-ablation. (Evidence: Moderate 4)

In pediatric patients, radiofrequency ablation should be performed with heightened vigilance for transient atrioventricular block. (Evidence: Weak 2)

Monitoring for junctional tachycardia during ablation can indicate successful modification of the slow pathway. (Evidence: Moderate 9)

References

1 D'Este D, Zoppo F, Bertaglia E, Zerbo F, Picciolo A, Scarabeo V et al.. Long-term outcome of patients with atrioventricular node reentrant tachycardia. International journal of cardiology 2007. link 2 Silka MJ, Halperin BD, Hardy BG, McAnulty JH, Kron J. Safety and efficacy of radiofrequency modification of slow pathway conduction in children < or = 10 years of age with atrioventricular node reentrant tachycardia. The American journal of cardiology 1997. link00685-1) 3 Curtis AB, Belardinelli L, Woodard DA, Brown CS, Conti JB. Induction of atrioventricular node reentrant tachycardia with adenosine: differential effect of adenosine on fast and slow atrioventricular node pathways. Journal of the American College of Cardiology 1997. link00386-0) 4 Basta MN, Krahn AD, Klein GJ, Rosenbaum M, Le Feuvre C, Yee R. Safety of slow pathway ablation in patients with atrioventricular node reentrant tachycardia and a long fast pathway effective refractory period. The American journal of cardiology 1997. link00310-x) 5 Tai CT, Chen SA, Chiang CE, Lee SH, Chiou CW, Ueng KC et al.. Multiple anterograde atrioventricular node pathways in patients with atrioventricular node reentrant tachycardia. Journal of the American College of Cardiology 1996. link00217-3) 6 Wen ZC, Chen SA, Chiang CE, Tai CT, Lee SH, Chen YZ et al.. Temperature and impedance monitoring during radiofrequency catheter ablation of slow AV node pathway in patients with atrioventricular node reentrant tachycardia. International journal of cardiology 1996. link02833-1) 7 Sra JS, Jazayeri MR, Blanck Z, Deshpande S, Dhala AA, Akhtar M. Slow pathway ablation in patients with atrioventricular node reentrant tachycardia and a prolonged PR interval. Journal of the American College of Cardiology 1994. link90870-2) 8 Wang CC, Yeh SJ, Wen MS, Hsieh IC, Lin FC, Wu D. Late clinical and electrophysiologic outcome of radiofrequency ablation therapy by the inferior approach in atrioventricular node reentry tachycardia. American heart journal 1994. link90471-5) 9 Thakur RK, Klein GJ, Yee R, Stites HW. Junctional tachycardia: a useful marker during radiofrequency ablation for atrioventricular node reentrant tachycardia. Journal of the American College of Cardiology 1993. link90600-6) 10 Wu D, Yeh SJ, Wang CC, Wen MS, Lin FC. A simple technique for selective radiofrequency ablation of the slow pathway in atrioventricular node reentrant tachycardia. Journal of the American College of Cardiology 1993. link90376-c) 11 Wu D, Yeh SJ, Wang CC, Wen MS, Chang HJ, Lin FC. Nature of dual atrioventricular node pathways and the tachycardia circuit as defined by radiofrequency ablation technique. Journal of the American College of Cardiology 1992. link90189-t) 12 Goy JJ, Fromer M, Schlaepfer J, Kappenberger L. Clinical efficacy of radiofrequency current in the treatment of patients with atrioventricular node reentrant tachycardia. Journal of the American College of Cardiology 1990. link90595-g) 13 Chimienti M, Li Bergolis M, Moizi M, Salerno JA. Electrophysiologic and clinical effects of oral encainide in paroxysmal atrioventricular node reentrant tachycardia. Journal of the American College of Cardiology 1989. link90478-6) 14 Fujimura O, Guiraudon GM, Yee R, Sharma AD, Klein GJ. Operative therapy of atrioventricular node reentry and results of an anatomically guided procedure. The American journal of cardiology 1989. link90576-6) 15 Wood DL, Hammill SC, Porter CB, Danielson GK, Gersh BJ, Holmes DR et al.. Cryosurgical modification of atrioventricular conduction for treatment of atrioventricular node reentrant tachycardia. Mayo Clinic proceedings 1988. link64913-1)

Ectopic atrioventricular node tachycardia