Sustained localized reentry within the left atrial appendage as a mechanism of recurrent arrhythmia following atrial fibrillation ablation

Figures

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  Figure 1.. Scheme of entrainment. For patients undergoing ablation for symptomatic atrial fibrillation, activation and entrainment mapping were undertaken as diagnostic techniques to differentiate focal, localized and macro-reentry AT. For rapid distinction of left and right ATs, entrainment was performed at the high RA, proximal and distal CS, respectively. For LA circuits, PPI-TCL difference at the proximal and distal CS distinguished perimitral reentry from other reentries within the LA. When left ATs were indicated, entrainments were as follows: First entrainment was performed at the anterior and posterior wall of the LA, left atrial ridge, PV, roof and septal area of LA and LAAW near the mitral annulus; AT, atrial tachycardia; RA, right atrium; CS, coronary sinus; LA, left atrium; PPI-TCL, postpacing interval-tachycardia cycle length; PV, pulmonary vein; LAAW, left atrial anterior wall; LAA, left atrial appendage; LPV, left PV.

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  Figure 2.. An 80-year-old female patient admitted for repeat RFCA with persistent atrial fibrillation following a fixed ablation approach consisting of circumferential pulmonary vein anteroom isolation and three linear ablation lesion sets across the mitral isthmus, left atrial roof and cavo-tricuspid isthmus. During the ablation of mitral isthmus, the patient converted back to sinus rhythm. As a response to bidirectional mitral isthmus conduction block, an additional ablation line was created at the anterior wall. During this procedure, an organized AT was observed. (A) First endocardial post diastolic activation site was observed at the base of the LAA. (B) EKG displaying a characteristic positive P-wave in inferior lead and negative P-wave in lead I and lead avL. (C) Entrainments were performed at the base of LAA, distal and proximal coronary sinus, roof and anteroseptal parts of left atrium. Tachycardia cycle length was 229 msec and postpacing interval was 250 msec at the base of the LAA, suggesting the pacing site was anatomically adjacent to the circuit. (D) AT completely contained within the LAA as confirmed by lasso catheter. Additional ablation at the base of the LAA eliminated the…

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  Figure 3.. A 67-year-old male patient with persistent atrial fibrillation developed recurrent AT requiring a second procedure following the isolation of pulmonary veins and ablation lesion sets across the mitral isthmus, left atrial roof and cavo-tricuspid isthmus. (A) Activation map mimicking macro-reentry due to the adjacent blocked ablation lines next to the localized reentry at the base of the LAA. (B) AT had a characteristic P-wave morphology that implied an LAA origin. (C) Tachycardia cycle length of AT was 280 msec and postpacing interval was 299 msec. (D) Entrainment at the base of LAA suggested a localized reentry. Ablation at the base of LAA successfully terminated the AT. AT, atrial tachycardia; LAA, left atrial appendage.

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  Figure 4.. A 41-year-old male patient suffering from paroxysmal atrial fibrillation was readmitted for recurrent palpitations. Paroxysmal AT was induced following isolation of the pulmonary vein during the repeat ablation. (A) Activated map confirming a local reentry mechanism. (B) Entrainment was applied at the base of LAA. (C) Tachycardia cycle length of AT was 261 msec and postpacing interval was 266 msec. (D) High-frequency, low-amplitude and long fractionated electrocardiogram was recorded. Ablation applied at that point resulted in tachycardia termination. AT, atrial tachycardia; LAA, left atrial appendage.