Radiofrequency ablation therapy in concealed left free wall accessory pathway with decremental conduction

Decremental accessory pathway conduction after ablation and antidromic atrioventricular reciprocating tachycardia 8 years after successful radiofrequency ablation

INTRODUCTION

This is a rare case of antidromic reciprocating tachycardia developing 8 years after successful catheter ablation.

RESULT

A 15-year-old girl had recurrence of palpitations 8 years after the ablation of manifest right posteroseptal accessory pathway. Atrial burst pacing revealed Wenckebach atrioventricular conduction with preexcitation. Wide QRS tachycardia with identical morphology to sinus rhythm associated with retrograde His potential recorded immediately after the V-wave was induced by isoproterenol infusion. Atrial premature stimulus applied at the identical timing of His potential advanced the subsequent ventricular beat and His potential.

CONCLUSION

Catheter ablation may produce decremental accessory pathway conduction and rarely cause antidromic atrioventricular reciprocating tachycardia. This may be explained by a presence of "de novo" accessory pathway with decremental conduction properties that became manifest after the first ablation.

A permanent junctional reciprocating tachycardia with an atypically located accessory pathway successfully ablated from within the middle cardiac vein

Permanent form of junctional reciprocating tachycardia (PJRT) is an uncommon form of atrioventricular re-entrant tachycardia due to an accessory pathway characterized by slow and decremental retrograde conduction. The majority of accessory pathways in PJRT are localized in the posteroseptal zone. Despite the high success rate, failure may occur during endocardial radiofrequency catheter ablation due to epicardial insertion of the accessory pathway. We report a case of PJRT in a 25-year-old man in whom the accessory pathway was located epicardially in the posteroinferior region and ablated from within the middle cardiac vein by radiofrequency catheter ablation.

Electrophysiological characteristics and radiofrequency ablation of accessory pathways with slow conductive properties

BACKGROUND

Atrioventricular accessory pathways (AP) with unusually long ventriculo-atrial (VA) conduction times are present in a significant subset of patients with the Wolff-Parkinson-White (WPW) syndrome, not including patients with the permanent form of atrioventricular junctional reciprocating tachycardia.

METHODS AND RESULTS

We compared the electrophysiological characteristics and outcomes after radiofrequency (RF) ablation in 34 patients with the WPW syndrome, a VA interval >80 ms, and paroxysmal tachycardia with an RP/PR ratio <1 (the slow group), vs 80 patients with WPW syndrome and a VA interval <80 ms (the fast group). AP were found in the posteroseptal region significantly more often in the slow than in the fast group. In addition, the decremental conductive properties of the AP were more common in the slow than in the fast group. Catheter ablation of AP was highly successful in both groups, although ablation required a greater number of RF applications and longer procedure times in the slow group, especially for AP with decremental conductive properties.

CONCLUSIONS

A posteroseptal AP location was more common in AP associated with long conduction times than in AP with typical conductive properties. Both types of AP were successfully ablated, although the slow group required longer procedures and more RF energy deliveries.

Unusual locations for adenosine-sensitive accessory atrioventricular pathways with decremental conduction

INTRODUCTION

Accessory AV pathways with decremental conduction are uncommon and, in particular, are thought not to occur at the anterior portion of the mitral annulus.

METHODS AND RESULTS

This report describes successful catheter ablation in three patients with accessory AV pathways that were adenosine sensitive and showed decremental conduction properties. The pathways were located at the anteroseptal, anteroparaseptal, and anterolateral aspects of the mitral annulus.

CONCLUSION

Accessory pathways with decremental conduction do occur anywhere around the mitral annulus, even in the area of fibrous continuity between the aortic leaflet of the mitral valve and the aortic valve itself.