Compound motor action potential guided 240 seconds plus bonus freeze for safe and durable left atrial appendage isolation in patients with recurrent persistent atrial fibrillation: How to isolate the appendage with cryoballoon (the CMAP guided ICE-B protocol).

INTRODUCTION: Pulmonary vein isolation (PVI) is the cornerstone ablation strategy for treatment of atrial fibrillation (AF). Ablation outside the PVs is sometimes needed particularly in persistent or longstanding AF. This study reported left atrial appendage isolation (LAAI) using cryoballoon (CB) focusing on technical data and short-term clinical follow-up.

METHODS AND RESULTS: Patients with recurrent persistent AF after multiple AF procedures were enrolled. LAAI was performed using the second generation CB guided by compound motor action potential (CMAP) and 240 seconds plus bonus freeze (ICE-B) protocol. Ten patients were included, median age was 69.5 (56-73) years, CHA2 DS 2 -VASc score was 3 (1.8-4), LA diameter was 44 (38.8-46.5) mm. All patients had a mean of three AF procedures before the LAAI procedure. All patients were under successful CMAP guidance. During the CB LAAI procedure, the median time to LAA isolation was 100 (76-270) seconds, minimal freeze temperature was -50 (-57 to -47)°C. A "pull-down (or pull-away)" CB maneuver was performed in all patients. Median fluoroscopic time was 4.8 (3.4-6.8) minutes and acute LAAI success rate was 100%. No phrenic nerve injury or other major complications were observed. At 6-week follow-up, remapping of the LAA showed durable isolation of all PVs (100%), all patients were scheduled for LAA occlusion. Six-month follow-up showed that 80% of patients were free from AF/AT recurrence.

CONCLUSION: CMAP plus ICE-B guided LAAI using cryo-technology appears feasible and safe, results in durable LAAI, and shows promising clinical results in patients with recurrent persistent AF.