Successful atrial fibrillation ablation without pulmonary vein isolation utilizing focal impulse and rotor mapping in an atriopulmonary Fontan

Figures

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  Figure 1. A: Regular narrow-complex long RP tachycardia elicited during exercise study. B: Symptomatic irregularly irregular tachycardia without P waves consistent with atrial fibrillation was noted on event monitor. C: During isoproterenol infusion, triggers were noted with runs of intra-atrial reentrant tachycardia with earliest signals at the ablation catheter (yellow arrow). D: An array of catheters was utilized to appropriately investigate and ablate tachycardias. The ablation catheter is positioned at the border zone. Embolization coils are seen within the collateral vessel (red arrows). E: Voltage map of the right atrium/Fontan pathway revealed a dense strip of scar (red) within the inferolateral limb of the Fontan, continuous with the inferior vena cava, with a border zone between normal tissue and scar. ICE = intracardiac echocardiography; IVC = inferior vena cava; PA = posteroanterior; RAO = right anterior oblique; SVC = superior vena cava.

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  Figure 2. A: Fontan angiography revealed a markedly dilated IVC and RA, with unobstructed Fontan pathway to branch pulmonary arteries. A large venoatrial collateral from the SVC to left atrium was seen (green arrow) and subsequently embolized. B: A 64-pole FIRM multipolar basket (blue arrow) was introduced into the Fontan. C, D: Electroanatomic mapping was performed to define any underlying electrophysiological abnormalities contributing to atrial fibrillation maintenance. The FIRM basket catheter is visualized within 3-dimensional high-density electroanatomic maps. A rotor (yellow area) was identified within the Fontan near the border zone. E: Raw unipolar electrograms collected from the FIRM basket catheter, which are then exported to a proprietary mapping system that determines physiologically plausible activation paths. F: FIRM-derived computational phase map depicting electrical propagation during atrial fibrillation, revealing a rotor (yellow arrows) and adjacent focal impulse (asterisks). AP = anteroposterior; FIRM = focal impulse and rotor mapping; IVC = inferior vena cava; PA = posteroanterior; RA = right atrium; RAO = right anterior oblique; SVC = superior vena cava.

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  Figure 3. Representative electroanatomic map of the right atrium/Fontan pathway demonstrating the various identified pathologic triggers and mechanisms of maintenance of arrhythmia and subsequent sites of ablation. CTI = cavo-tricuspid isthmus; IART = intra-atrial reentrant tachycardia; IVC = inferior vena cava; RA = right atrium; RAO = right anterior oblique; SVC = superior vena cava.