Elimination of slow pathway conduction: an accurate indicator of clinical success after radiofrequency atrioventricular node modification

Department of Medicine, University of Western Ontario, London, Canada.

OBJECTIVES. The purpose of this study was to determine the optimal end point of radiofrequency atrioventricular (AV) node modification using anatomically guided slow pathway approaches in patients with AV node reentrant tachycardia. BACKGROUND. The optimal end point for AV node modification using radiofrequency energy is uncertain, although elimination of inducible AV node reentrant tachycardia has been used. METHODS. We followed up 51 consecutive patients (40 women, 11 men, mean age +/- SD 41 +/- 16 years) with symptomatic AV node reentrant tachycardia for 12 +/- 6 months (range 4 to 24) after radiofrequency AV node modification using an anatomically guided slow pathway approach. Inducible AV node reentrant tachycardia was eliminated in all patients, whereas residual slow pathway conduction persisted in 12 patients (24%) after ablation. One study was complicated by complete AV block and two patients were lost to follow-up (one with and one without residual slow pathway conduction). RESULTS. Clinical recurrence of AV node reentrant tachycardia was documented in seven patients (14%) 3 days to 3 months (median 1 month) after ablation. The recurrence rate was significantly higher in patients with than in those without residual slow pathway conduction (6 [55%] of 11 vs. 1 [3%] of 37, p < 0.01). The recurrence rate was not different between patients with only residual slow pathway conduction and those with residual slow pathway conduction and inducible single echo cycles (three [60%] of five in both groups, p = NS). The number of radiofrequency energy applications was not significantly different between those without and those with recurrence (20 +/- 17 vs. 16 +/- 9, p = NS). Junctional tachycardia during application of radiofrequency energy tended to be more frequently observed in those with a successful outcome (77% vs. 57%, p > 0.05). Of the 22 patients who underwent modification before 1992, residual slow pathway conduction was present in 9 (41%) of 22 patients. Atrioventricular node reentrant tachycardia recurred in five (56%) of these nine patients. A greater effort made in 1992 to eliminate slow pathway conduction in 29 patients resulted in residual slow pathway conduction in only 3 (11%) with recurrence in 2 (4%). CONCLUSIONS. Complete elimination of slow pathway conduction is feasible in the majority of patients. Elimination of slow pathway conduction is highly predictive of long-term success after AV node modification using an anatomically guided approach.

This article has been cited by other articles:

				Z. Iakobishvili, J. Kusniec, R. Shohat-Zabarsky, A. Mazur, A. Battler, and B. Strasberg Junctional rhythm quantity and duration during slow pathway radiofrequency ablation in patients with atrioventricular nodal re-entry supraventricular tachycardia Europace, August 1, 2006; 8(8): 588 - 591. [Abstract] [Full Text] [PDF]

				J.R. Clague, N. Dagres, H. Kottkamp, G. Breithardt, and M. Borggrefe Targeting the slow pathway for atrioventricular nodal reentrant tachycardia: initial results and long-term follow-up in 379 consecutive patients Eur. Heart J., January 1, 2001; 22(1): 82 - 88. [Abstract] [PDF]

				C.-T. Kuo, K.-H. Lin, N.-J. Cheng, P.-H. Chu, T.-S. Hsu, C.-W. Chiang, and Y.-S. Lee Characterization of Atrioventricular Nodal Reentry With Continuous Atrioventricular Node Conduction Curve by Double Atrial Extrastimulation Circulation, February 9, 1999; 99(5): 659 - 665. [Abstract] [Full Text] [PDF]

				W. G. Fisher, M. A. Pelini, and M. E. Bacon Adjunctive Intracardiac Echocardiography to Guide Slow Pathway Ablation in Human Atrioventricular Nodal Reentrant Tachycardia : Anatomic Insights Circulation, November 4, 1997; 96(9): 3021 - 3029. [Abstract] [Full Text]

				A. E. Epstein, W. M. Miles, D. G. Benditt, A. J. Camm, E. J. Darling, P. L. Friedman, A. Garson, J. C. Harvey, G. A. Kidwell, G. J. Klein, et al. Personal and Public Safety Issues Related to Arrhythmias That May Affect Consciousness: Implications for Regulation and Physician Recommendations: A Medical/Scientific Statement From the American Heart Association and the North American Society of Pacing and Electrophysiology Circulation, September 1, 1996; 94(5): 1147 - 1166. [Full Text]

				R. G. Sheahan, G. J. Klein, R. Yee, C. A. Le Feuvre, and A. D. Krahn Atrioventricular Node Reentry With `Smooth' AV Node Function Curves : A Different Arrhythmia Substrate? Circulation, March 1, 1996; 93(5): 969 - 972. [Abstract] [Full Text]

				J. C. Doig, J. Saito, L. Harris, and E. Downar Coronary Sinus Morphology in Patients With Atrioventricular Junctional Reentry Tachycardia and Other Supraventricular Tachyarrhythmias Circulation, August 1, 1995; 92(3): 436 - 441. [Abstract] [Full Text]