Successful Zero-Fluoroscopy Ablation of an Atypical Clockwise Simple-Loop Biatrial Flutter Involving the Bachmann Bundle Region

Figures

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  Figure 1. ECG and Catheter Recording (A) The 12-lead electrocardiogram demonstrates 4:1 atrial tachycardia. (B) A decapolar catheter positioned in the coronary sinus (CS) reveals 4:1 atrial tachycardia with a cycle length of 212 ms, showing an eccentric atrial activation pattern.

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  Figure 2. Voltage and Local Activation Time Mapping (A) Biatrial voltage map displaying an extensive anterior scar with preserved conduction channels in the superior region. (B) The local activation time map revealing the presence of perimitral atrial flutter, highlighting the re-entrant circuit around the mitral valve.

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  Figure 3. Local Activation Time Map Showing a Clockwise Macro Reentrant Tachycardia Involving Both Atria Posterior and anterior views of a local activation time map demonstrating biatrial tachycardia following completion of the anterior mitral line. The red arrows highlight the superior conduction pathway, connecting the septal superior vena cava to the left atrial appendage, and an inferior pathway involving retrograde conduction through the coronary sinus to the septal region of the right atrium.

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  Figure 4. Bachmann Bundle and Entrainment Maneuvers (A) Biatrial anatomy highlighting the anterior mitral line ablation (red) and the role of the Bachmann bundle (yellow) in facilitating electrical communication between the superior vena cava and the left atrial appendage region. (B) Perfect entrainment achieved from the septal aspect of the superior vena cava (blue). (C) Perfect entrainment achieved from the inferior branch of the Bachmann bundle in the medial aspect of the left atrial appendage (blue). PPI = postpacing interval; TCL = tachycardia cycle length.

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  Figure 5. Ablation Outcomes (A) Radiofrequency ablation performed in the medial aspect of the inferior left atrial appendage antrum, coinciding with the inferior branch of the Bachmann bundle. The tachycardia was successfully interrupted after the second radiofrequency ablation. (B) The final ablation set shows the anterior mitral line, the medial inferior left atrial appendage antrum line, and redo isolation of the right superior pulmonary vein. Posterior wall isolation and cavotricuspid isthmus ablation are not shown. CL = cycle length; LAT = local activation time.