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.