Revisiting right atrial isolation rationale for atrial fibrillation: functional anatomy of interatrial connections.

Introduction: Direct catheter ablation for atrial fibrillation does not yield reproducible permanent control as for other atrial arrhythmias. Therefore, there is a need for an alternative intervention, i.e., left atrial exclusion, based on elective ablation of the interatrial connecting bundles.

Methods And Results: We describe the "operative anatomy" of the three major interatrial connections: the Bachmann bundle, the coronary sinus bundle, and the left atrial-atrioventricular node connection, based on macroscopic dissections of human and porcine hearts and our previous experience. We identified the three right atrial attachments, with the coronary sinus (CS) and left atrial (LA)-atrioventricular (AV) nodal connection being most problematic for safe ablation.

Conclusions: To obtain a complete isolation of the left from the right atrium, all three connections must be ablated. The CS connection must be ablated distal to the ostium. If present, the LA-AV nodal connection can be safely ablated from the left atrium.