PMC524521_01
Orthodromic AV re-entrant tachycardia. Orthodromic AV re-entrant tachycardia induction with programmed atrial stimulation. Notice VA fusion on CS2 (lateral portion of the mitral ring; see arrow).
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F1
A well-localized accessory pathway insertion was detected in the lateral left free wall with atrial-ventricular (AV) and ventricular-atrial (VA) intervals of fusion noticeable only in CS2 (Fig 1).
Brockenbrough needle and the fossa ovalis. Brockenbrough needle in right atrium approaching the fossa ovalis (right panel); typical "tenting" of the fossa (see arrow) just before septal puncture (left panel). Note the left atrial free wall close to the interatrial septum. (FO = fossa ovalis; LA = left atrium; RA = right atrium).
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F2
Careful up and down movements of ICE catheter allowed a clear visualization of the needle as well as its contact with the septal wall causing the typical "tenting" effect (Fig 2), which allowed precise location of the puncture of the needle.
Ablation of the accessory pathway. Radiofrequency erogation during atrial pacing with maximal pre-excitation. Notice AV fusion (major arrow) followed by AV split (two minor arrows) on the ABLd recording, corresponding to lateral mitral annulus.
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F3
Although the AV and VA intervals that had been selected to deliver radiofrequency energy were similar to those previously recorded, the only difference was a better AV ratio (Fig 3).
PMC524521_02
Left sided accessory pathway. The shortest AV and VA are recorded in CS2 (see arrows) during programmed atrial stimulation (A) and atrio-ventricular orthodromic re-entrant tachycardia (B) respectively suggesting a left sided posterolateral accessory AV connection.
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F4
The accessory pathway insertion resulted well-localized in the left lateral mitral ring during AVRT and atrial pacing with maximal pre-excitation (Fig 4A,4B).