Feasibility and safety of using an esophageal protective system to eliminate esophageal thermal injury: implications on atrial-esophageal fistula following AF ablation.

BACKGROUND: Ablation for atrial fibrillation (AF) requires energy delivery in close proximity to the esophagus (Eso) which has accounted for the LA-Eso fistula, a rare but life-threatening complication.
PURPOSE: We evaluated an Eso cooling system to protect the Eso during RF ablation. METHODS AND
RESULTS: An "in vitro" heart-Eso preparation was initially used to test a temperature-controlled fluid-circulating system (EPSac [esophageal protective system]-RossHart Technologies Inc.) and an expandable compliant Eso sac during cardiac RF delivery (4 mm tip, perpendicular to the heart, 15 g pressure) at 25, 35, and 45 W, 100 +/- 5 Omega for 30 seconds with the EPSac at 25, 15, 10, and 5 degrees C. All cardiac lesions were transmural. Eso thermal injury could only be avoided with the EPSac at 10 and 5 degrees C. The system was then tested in 6 closed chest dogs, each receiving 12 RFs (LA aiming at the Eso) for 30 seconds: without EPSac (control) at 35 W (1 dog); at 45 W with EPSac at 25 degrees C (1 dog), 10 degrees C (2 dogs), and 5 degrees C (2 dogs). The EPSac volume was intentionally increased to displace the Eso toward the LA (2 dogs 5 and 10 degrees C). Eso injured control and EPSac at 25 degrees C; Eso spared EPSac at 5 and 10 degrees C, without Eso displacement. Shallow external Eso injury noted when intentionally displacing the Eso toward the LA.
CONCLUSIONS: The EPSac spares the Eso from collateral thermal injury. It requires circulating fluid at 5 or 10 degrees C and a compliant sac to avoid displacement of the Eso. Its safety and efficacy remain to be demonstrated in patients undergoing AF ablation.