Left Atrial Appendage Electrical Isolation and Occlusion to Treat Persistent Atrial Fibrillation: A Safety and Feasibility Study

Overview

Atrial fibrillation (AF) affects as many as 1 in 16 people over the age of 65 and reduces the quality of life of large numbers of people in the UK and around the world. Catheter ablation is a minimally invasive treatment that has been developed to help eliminate AF. Recent studies have identified that a particular area of the heart, namely the left atrial appendage (LAA), which is a pouch in the left atrium (small collecting chamber of the heart), may be the main source of AF in many cases. There is a clear lack of knowledge about the structure, anatomy, function and electrical properties of the LAA, which is fundamental to furthering our understanding and management of AF. In addition, it is well known that AF significantly increases the risk of stroke. The majority of strokes occur due to blood clots forming in the LAA. Traditionally, the most effective treatment to minimise the risk of stroke has been to thin the blood with agents such as warfarin. This therapy requires regular blood tests at much inconvenience to patients and increases the risk of bleeding complications. Recently, a large study demonstrated that use of an implanted device (Watchman®) to occlude the LAA is as effective as warfarin in preventing stroke and confers a lower mortality rate. We aim to investigate whether it is safe and feasible to ablate the LAA and to implant a Watchman® device during the same procedure in patients who are in atrial fibrillation all of the time.

While catheter ablation has revolutionized the treatment of atrial fibrillation (AF), the long-term outcomes in treating persistent AF are variable, often requiring more than one procedure to maintain long-term freedom from AF. Electrical isolation of the pulmonary veins (PVs) is central to catheter ablation strategies, with the majority of paroxysmal AF recurrences being associated with reconnection of previously isolated PVs. Persistent AF is different, with recurrences being attributable to foci and or substrate outside the PVs, including the left atrial appendage (LAA). Recently, a non-randomised, consecutive study of 987 patients undergoing repeat catheter ablation for persistent (82%) and paroxysmal (18%) AF has demonstrated that almost 30% of recurrences were due to an LAA focus and that the addition of LAA electrical isolation to a standard persistent AF ablation strategy improves freedom from AF. Percutaneous LAA occlusion has been demonstrated to be as effective as warfarin in reducing the risk of thromboembolic stroke in patients with AF. The combination of a standard AF ablation lesion set with LAA electrical isolation and LAA occlusion may be an elegant method of improving success rates of ablation for persistent AF whilst also mitigating stroke risk and reducing the bleeding risks from long-term anticoagulation. However, the feasibility and safety of concomitant endocardial electrical isolation and mechanical occlusion of the LAA is not known. In this study we test the hypothesis that concomitant electrical isolation of the LAA and its occlusion with a Watchman device, following a standard persistent AF lesion set is feasible and safe.