Anatomic proximity of the esophagus to the coronary sinus: Implication for catheter ablation within the coronary sinus

Introduction: The anatomic proximity between the esophagus and the coronary sinus (CS) might render the esophagus vulnerable to thermal injury during ablation. Therefore, we investigated the anatomic relationship between the esophagus and the CS in patients with atrial fibrillation (AF). Methods and Results: Thirty patients (25 males, mean age = 54 ± 11 years) with drug-refractory paroxysmal AF were included. Sixteen-slice multidetector computed tomography was performed to depict the course of the esophagus and relationship to the CS. The esophagus was in direct contact with the CS in 57% (17/30) of patients (group 1). The mean length of the contact was 6.1 ± 3.4 mm. In the remaining 13 patients, the esophagus did not come in direct contact with the CS (group 2). The shortest distance between the esophagus and the CS was 4.0 ± 2.6 mm. The CS diameter (9.4 ± 1.8 vs 8.5 ± 2.4 mm, P = 0.15), esophagus width (18.6 ± 1.6 vs 18.6 ± 1.7 mm, P = 0.87), anteroposterior diameter of the left atrium (35.9 ± 3.8 vs 35.0 ± 3.3 mm, P = 0.58), thickness of the anterior wall of the esophagus (2.9 ± 0.6 vs 2.9 ± 0.6 mm, P = 0.97), and shortest distance from the esophagus to the CS ostium (19.3 ± 5.4 vs 25.0 ± 6.2 mm, P = 0.02) and to the great cardiac vein (8.5 ± 5.3 vs 12.1 ± 6.9 mm, P = 0.10) were compared between the two groups. Conclusions: In 57% of our patients, the esophagus was in direct contact with the CS, and a significantly shorter distance between the esophagus and the CS ostium was noted in these patients. It is important to prevent esophageal damage when applying energy within the CS.