An Unusual Accessory Pathway: Anteroseptal to Ventricular Outflow Region Connection

Abstract

Accessory pathways are typically located along the left or right atrioventricular junction. Distinct ventricular pre-excitation patterns determined by surface electrocardiography can provide reasonable pathway localization prior to invasive mapping and catheter ablation. We report an accessory pathway producing an unusual electrocardiographic appearance suggestive of ventricular outflow region pre-excitation. Pacing maneuvers and standard intracardiac recordings confirmed an atrial insertion immediately adjacent to the atrioventricular (AV) node and supported a ventricular insertion at the outflow tract region well away from the AV junction. The elimination of pathway conduction was achieved with radiofrequency (RF) energy at the atrial insertion after successful ice mapping excluded AV block at the target site. This is the second such pathway observed at our institution over a 20-year period.

Correlative Anatomy for the Invasive Electrophysiologist: Outflow Tract and Supravalvar Arrhythmia

“…As a result of the fascicle‐like remnants in the adult outflow tract, confusion with activation mapping and pace mapping sometimes results 31 . These fascicle like developmental remnants may or may not connect with the adult conduction system (dead‐end fascicle) 32 . Even if these fibers are not the origin of the arrhythmia, proximity to the focus can result in relatively fast conduction to nonneighboring myocardial tissue, and pace mapping may produce variable results depending on the output for pacing.…”

Successful Targeted Ablation of the Pathway Potential in the Noncoronary Cusp of the Aortic Valve in an Infant with Incessant Orthodromic Atrioventricular Reentrant Tachycardia

“…It is possible that such pathways may be the reason why some “right anteroseptal pathways” require prolonged ablation with high energy delivery and why some recur despite initial conduction block. Another reported unusual pathway in the anteroseptal region connected the right ventricular outflow tract (RVOT) myocardium to the anteroseptal atrium 16 . Since the immediate anterior neighbor of the right coronary cusp is the infundibular portion of the RVOT, although not attempted, ablation in the RCC may have been successful in this reported case as well (Fig.…”

A Rare Case of Permanent Junctional Reciprocating Tachycardia Ablated on the Roof of the Left Atrium

“…Because of the relationship of the noncoronary cusp to the atrial septum, many of these epicardial pathways could be safely ablated by energy delivery in the noncoronary cusp at a location where an accessory pathway potential was recorded. Other reports specifically addressing left‐sided anteroseptal pathways have described ablation of these pathways at the region of the aortomitral continuity, both the left and noncoronary cusps of the aortic valve and distally in the LV outflow tract away from the His–Purkinje system 3–9 …”

“…Other reports specifically addressing left-sided anteroseptal pathways have described ablation of these pathways at the region of the aortomitral continuity, both the left and noncoronary cusps of the aortic valve and distally in the LV outflow tract away from the His-Purkinje system. [3][4][5][6][7][8][9] Our patient had a concealed decremental AP, and mapping was performed during tachycardia looking for a possible accessory pathway potential or a site of early atrial activation at the mitral annulus and left or noncoronary aortic cusp regions. At none of these sites was a possible AP potential found.…”

“…Case reports have described successful ablation of theses pathways in the left ventricular outflow tract, along the anteroseptal region of the mitral annulus at the aortomitral continuity, and in the left and noncoronary cusps of the aortic valve. [3][4][5][6][7] In this report, we describe a case where these previously reported mapping approaches did not yield what were felt to be appropriate ablation sites and the ablation was performed successfully on the roof of the left atrium close to the right superior pulmonary vein.…”