EFFECT OF CONTINUOUS ENHANCED VAGAL TONE ON DUAL ATRIOVENTRICULAR NODE AND ACCESSORY PATHWAYS

Authors

  • Hameed Ullah Khyber Girl Medical College https://orcid.org/0009-0006-1362-3129
  • Muhammad Idrees Khan Health department, KPK https://orcid.org/0000-0001-8856-8247
  • Asif Mehmood Category D Hospital Havalian Abbottabad
  • Yasir Hayat Khyber Girls Medical University Peshawar
  • Talia Mansoor Post Graduate Medical Institute Peshawar
  • Romana Post Graduate Medical Institute Peshawar

Keywords:

Vagal tone, dual AV node, accessory pathways, arrhythmia, catheter ablation

Abstract

Background: Continuous increased vagotonus effect on dual atrioventricular (AV) node and accessory pathway requires a flexible concept in the field of cardiac electrophysiology. The AV node has a critical function in regulation of the heart´s electrical conduction and accessory pathways are abnormal alternate routes to which an impulse can be transmitted across, circumventing these checkpoints–causing arrhythmias such as atrioventricular re-entrant tachycardia (AVRT) or Wolff-Parkinson-White Syndrome (WPW). Objective was to evaluate the effect of continuous enhanced vagal tone on dual AV node physiology and accessory pathways, focusing on conduction properties, arrhythmia induction, and the success of catheter ablation. Methods: A prospective observational study was conducted in the Department of Cardiology, Hayatabad Medical Complex, Peshawar, between April 2023 and April 2024. The study included 250 patients with dual AV node physiology or accessory pathways, undergoing electrophysiological studies and catheter ablation. Continuous vagal stimulation was applied during these procedures to assess its impact on conduction delays, refractory periods, and arrhythmia induction. Statistical analysis was performed using Chi-square and logistic regression, with a significance level of p<0.05. Results: The mean PR interval delay during vagal stimulation was 202 ms, and the mean refractory period was 250 ms. Arrhythmias were induced in 35% of the patients. Catheter ablation was successful in 85% of cases, though 30% experienced recurrence of arrhythmia within one year. The results showed a significant association between continuous vagal tone and arrhythmia induction, as well as a protective effect of longer refractory periods against recurrence. Conclusion: Continuous enhanced vagal tone significantly influences the conduction properties of dual AV nodes and accessory pathways, increasing the likelihood of arrhythmias. While catheter ablation remains effective, these findings suggest that vagal modulation could be explored as a potential adjunct to improve long-term outcomes in patients with complex arrhythmias.

References

1. Ho SY. Anatomy of the atrioventricular junction, atrioventricular grooves, and accessory pathways. Card Electrophysiol Clin 2020;12(4):437–45.

2. Marazzato J, Marazzi R, Doni LA, Angeli F, Bagliani G, Leonelli FM, et al. Arrhythmias involving variants of accessory pathways. Card Electrophysiol Clin 2020;12(4):505–18.

3. Cardona-Guarache R, Han FT, Nguyen DT, Chicos AB, Badhwar N, Knight BP, et al. Ablation of supraventricular tachycardias from concealed left-sided nodoventricular and nodofascicular accessory pathways. Circ Arrhythm Electrophysiol 2020;13(5):e007853.

4. Iso K, Okumura Y, Watanabe I, Nagashima K, Takahashi K, Arai M, et al. Is vagal response during left atrial ganglionated plexi stimulation a normal phenomenon? Circ Arrhythm Electrophysiol 2019;12(10):e007281.

5. Takahashi K, Watanabe I, Okumura Y, Nagashima K, Wakamatsu Y, Arai M, et al. Impact of atrial fibrillation on the vagal response to ganglionated plexi stimulation: comparison between patients with and without atrial fibrillation. J Nihon Univ Med Assoc 2019;78(1):15–19.

6. Escudero CA, Ceresnak SR, Collins KK, Pass RH, Aziz PF, Blaufox AD, et al. Loss of ventricular preexcitation during noninvasive testing does not exclude high-risk accessory pathways: a multicenter study of WPW in children. Heart Rhythm 2020;17(10):1729–37.

7. Liu W, Li J, Xiong N. Fasciculoventricular accessory pathway unmasked by a pseudo gap phenomenon. J Electrocardiol 2019;55:41–4.

8. Hoffmayer KS, Han FT, Singh D, Scheinman MM. Variants of accessory pathways. Pacing Clin Electrophysiol 2020;43(1):21–9.

9. Rana IA, Afzal W. Accessory cardiac conduction pathway with an unusual presentation. J Coll Physicians Surg Pak 2019;29(Suppl 2):S77–9.

10. Kinjo T, Kimura M, Kaname N, Horiuchi D, Itoh T, Ishida Y, et al. Landiolol, an intravenous β1‐selective blocker, is useful for dissociating a fusion of atrial activation via accessory pathway and atrioventricular node. J Arrhythm 2023;39(6):937–46.

11. Matta M, Marazzato J, De Ponti R, Gaita F, Anselmino M. Ablation of accessory pathways with uncommon electrophysiologic properties. Card Electrophysiol Clin 2020;12(4):567–81.

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Published

2026-01-14

How to Cite

1.
Hameed Ullah, Muhammad Idrees Khan, Asif Mehmood, Yasir Hayat, Talia Mansoor, Romana. EFFECT OF CONTINUOUS ENHANCED VAGAL TONE ON DUAL ATRIOVENTRICULAR NODE AND ACCESSORY PATHWAYS. J Ayub Med Coll Abbottabad [Internet]. 2026 Jan. 14 [cited 2026 Jan. 19];37(3):301-5. Available from: https://jamc.ayubmed.edu.pk/index.php/jamc/article/view/13843

Issue

Vol. 37 No. 3 (2026): JOURNAL OF AYUB MEDICAL COLLEGE ABBOTTABAD

Section

ORIGINAL ARTICLE

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Copyright (c) 2026 Hameed Ullah, Muhammad Idrees Khan, Asif Mehmood, Yasir Hayat , Talia Mansoor, Romana

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