Percutaneous catheter modification of the atrioventricular node. A potential cure for atrioventricular nodal reentrant tachycardia.

Abstract

Our purpose was to describe a technique of atrioventricular (AV) node modification for patients with drug refractory AV nodal reentrant tachycardia (AVNRT). Nine patients (mean age, 45±20; range, 14-82) with recurrent drug refractory AVNRT (n=8) or sudden cardiac death thought to be precipitated by AVNRT (n = 1) underwent a percutaneous catheter procedure to modify AV nodal function. The area between the electrode recording the maximal His-bundle electrogram and the ostium of the coronary sinus was divided into three zones. Perinodal direct current shocks of 100-300 J were delivered to one (n=2), two (n=3), or three (n=4) zones without complications. The procedure endpoints were modification of AV conduction (either first degree AV block or complete retrograde ventriculo-atrial [VA] block) and failure to induce AVNRT before or after isoproterenol and/or atropine administration. Six of nine patients (67%) have had no inducible or spontaneous AVNRT over a mean follow-up of 12.3 ±4.1 months (range, 4.5-17). One of the six underwent repeat, successful modification, because AVNRT was inducible at restudy 2 days after the initial procedure. AVNRT recurred in three patients (33%), one early (3 days) and two late (3-4 months). Two of these patients underwent complete ablation of the AV junction and permanent pacemaker placement, whereas one is controlled with drug therapy. Therefore, AV nodal modification resulted in tachycardia control without antiarrhythmic drugs in six of nine (67%) and obviated the need for complete AV junctional ablation in seven of nine patients (78%

Anatomic and Functional Characteristics of a Slow Posterior AV Nodal Pathway

“…This would also explain why the slow potential guidance and pure anatomic approach are similarly effective 63 ; they are both primarily targeted toward the same posterior area that corresponds to PNE location. The upward shift of the baseline of the recovery curve caused by fast-pathway (septal) ablation [15][16][17] can also be explained in the context of the proposed hypothesis; the impulse entering the node from the septum input 41 has to go around the ablation obstacle to reach the crista input and activate the node. This prolongs the nodal delay measured from the "a" complex of the His bundle derivation and makes retrograde septal invasion from PNE activation less likely.…”

“…10,11 Results of ablation therapy provide further convincing evidence of dual-pathway physiology; ablation carried out posteriorly to the compact node eliminates the slow pathway, [12][13][14] whereas ablation carried out anterosuperiorly to the compact node eliminates the fast pathway. [15][16][17] The anatomic and functional substratum underlying the different manifestations of AV nodal dual-pathway physiology and reentry remains unclear. 3,4,6 Early studies indicated that the crista terminalis and interatrial septum inputs together with the proximal portion of the compact node provide a substratum for asymmetrical pathways and reentry.…”

High resolution mapping of Koch's triangle using sixty electrodes in humans with atrioventricular junctional (AV nodal) reentrant tachycardia.

“…As far as we are aware, however, the presence of a zone of slow conduction within Koch's triangle has not been reported previously. An 13. The shaded area is the first 3 milliseconds of atrial excitation; the dashed line marks the 6-millisecond isochron.…”

Selective Radiofrequency Catheter Ablation of the Slow Pathway for Common and Uncommon Atrioventricular Nodal Reentrant Tachycardia.

“…Permanent cure of AVNRT with the preservation of AVN conduction was initially achieved by surgical ablation of perinodal tissue.1,2 The catheter ablation technique which selectively ablates the fast or slow pathway was then developed, and selective slow pathway ablation is now the dominant non-pharmacologic curative therapy for AVNRT. [3][4][5][6][7][8][9][10][11][12][13][14] It has been well accepted that there are two types of AVNRT, common and uncommon. Slow-fast form common AVNRT with the slow pathway as an antegrade limb of reentry circuit and the fast pathway as a retrograde limb is characterized on ECG by a long PR interval, 15,16) while the fast-slow form or slow-slow form of uncommon AVNRT with the fast or slow pathway as an antegrade limb and the slow pathway as a retrograde limb is characterized on ECG in general by a long RP interval.…”

“…[17][18][19] Uncommon AVNRT occurs much less frequently than common AVNRT, and it also has more variations in ECG manifestations and mechanisms. 19 23) Radiofrequency catheter ablation targeting the slow pathway has been shown to be highly effective and safe as a curative therapeutic modality in the slow-fast form of common AVNRT, [3][4][5][6][7][8][9][10][11][12][13][14] however, its utility in uncommon AVNRT has not been fully investigated. In this study, the efficacy and safety of radiofrequency catheter ablation for uncommon AVNRT was compared with common AVNRT.…”