Comparison of Treatment Outcomes Between Convergent Procedure and Catheter Ablation for Persistent and Longstanding Persistent Atrial Fibrillation

In the last 20 years, atrial fibrillation has become one of the leading healthcare burden in Europe and other developed countries. With an ever-increasing prevalence and incidence, atrial fibrillation is expected to remain a significant problem in the near future. Due to numerous detrimental effects atrial fibrillation has on the patient's health, having an efficient and safe treatment is crucial for managing the problem.

The gold standard for an atrial fibrillation treatment is a catheter ablation. In typical catheter ablation procedure, triggers in pulmonary veins are addressed with a pulmonary vein isolation- offering a high long-term success rate in patients with paroxysmal atrial fibrillation. However, the same cannot be said for persistent and longstanding persistent atrial fibrillation. Studies have shown that efficiency of catheter ablation for persistent and longstanding persistent atrial fibrillation, including multiple procedures per patient, ranges around 50 %. It is postulated that extrapulmonary vein triggers, such as foci located in the posterior wall of the left atrium, play an important role in initiating and maintaining persistent and longstanding persistent atrial fibrillation. In the past, to address this issue, a convergent procedure was developed. In convergent procedure an epicardial ablation of posterior wall is performed through a subxyphoid window. Next, an endocardial ablation with an ablation catheter is performed to isolate pulmonary veins. Because the epicardial lesions are applied in the opposite direction and not towards the esophagus, ablation of posterior wall can safely be performed. The procedure offers a high long-term success rate (85%) in patients with persistent and longstanding persistent atrial fibrillation. However, due to higher associated invasiveness, the convergent procedure carries a higher risk of complications compared with catheter ablation (4 % vs 9 %).

With advancements in ablation catheter technology, such as continuous force measurement at the tip of the catheter, the depth and volume of the lesion can be estimated. This information greatly increases the reliability of lesion formation. The operator can thus effectively apply lesions to the posterior wall of the left atrium more safely in regards to the collateral damage to the esophagus.

The objectives of the study are:

• To compare procedural, safety and efficiency profile of convergent procedure with catheter ablation procedure, both targeting pulmonary veins triggers and triggers located in the posterior wall of the left atrium.
• To compare long-term success rate of convergent procedure with catheter ablation procedure, both targeting pulmonary veins triggers and triggers located in the posterior wall of the left atrium.