A Novel Prophylactic Left Atrial Ablation in Cardiac Surgery Patients to Prevent POAF; An Initial Experience

Purpose: Post-operative Afib (POAF) incidence is 20-47% after cardiac surgery and is associated with both short-term morbidity and long-term mortality. Post-op left atrial inflammation may lead to POAF. We evaluated the impact of prophylactic left atrial posterior wall isolation (LAPWI) with non-atriotomy radiofrequency ablation on POAF incidence after cardiac surgery.

Methods: All patients provided informed consent for this IRB-approved pilot study. Thirty-five cardiac surgery patients undergoing a planned midline sternotomy (n= 26 CABG, n=4 Valve, n=5 CABG+Valve) underwent non-atriotomy prophylactic LAPW with a novel all-encompassing radiofrequency clamp. While on-pump, five-paired ablations were performed to achieve transmurality and LAPWI. LAPWI was confirmed with exit block testing prior to cross-clamp and cardiac arrest. Acute in-hospital POAF was identified by review of 24-hour telemetry and ECG. Out-of-hospital POAF was identified by clinic ECG and continuous monitoring (patch) at 6-months when available. Class I or IIIa antiarrhythmic drug (AAD) use was assessed. Statistics are reported as mean +/- SD with (range).

Results: Prophylactic LAPWI was completed in all patients. Age 69 +/- 8 (53-87) years, 6 females: 29 males, BMI 29 + /- 5 (18-42), LVEF% 47 +/- 10 (25-65), LA Size 4.0 +/- 0.7 (2.7-5.8) cm, CHA2DVAS2C 3.6 +/- 1.5 (1-7), and HASBLED 2.7 +/- 1.2 (1-5). All patients underwent left atrial appendage management with epicardial occlusion devices. In-hospital [7.6 +/- 3.5, (2-14) days] freedom from POAF was 97% (34/35) and freedom from POAF without AAD was 91% (32/35). One patient developed acute POAF with rapid ventricular response on post-operative 2 and required rhythm control with amiodarone. Two patients were initiated on amiodarone for post-operative premature ventricular contractions but did not develop POAF. At post-operative clinic visits with ECG [30.3 +/- 19.7 (5-91) days], all patients exhibited freedom from out-of-hospital AF and were off AAD. Three patients underwent 14-day continuous rhythm monitoring at 6-months and were free from AF. No major ablation procedure related complications occurred. One patient death occurred on post-operative day 2 due to cardiac tamponade from coronary anastomotic bleeding.

Conclusion: POAF leads to cardiac surgery patient morbidity and mortality while also causing significant acute and long-term burdens on the healthcare system. Current efforts aimed at the prevention of acute POAF, including posterior left pericardiotomy, are promising but may not address all causes of POAF or presentations of POAF (e.g., out-of-hospital). A prophylactic LAPWI may provide a unique opportunity to electrically isolate the left atrium from the development of acute and out-of-hospital POAF. Further study, including a randomized control study, are necessary to confirm these initial findings.

Identify the source of the funding for this research project: None