Treating Atrial Fibrillation: What's Next?

Luis Andrade
Luis Andrade
Atrial fibrillation (AF) afflicts approximately five million people in the world. AF is not a benign condition; in fact, it has a high association with morbid-mortality incidence.1,2 Approximately 3-5% of patients over the age of 65 have AF; it is also the cause of strokes in 30% of victims under 65 years of age.3 Furthermore, cardiac heart failure has been reported as a result of atrial fibrillation. In this article, I will review the present literature in AF. What is going to be the treatment of choice for AF in the future? In recent years, with the better understanding of arrhythmias, ablation therapy has become a new hope for thousands of patients suffering from these flagella. The current treatment of AF has four focuses: cardioversion, controlling ventricular rate, anticoagulation, and pharmacological prophylaxis. However, the primary flaw of these treatments is that they do not provide a cure for AF. However, curative therapies are currently being developed, based on either modifying the maintenance substrate of AF using linear ablation, or by eliminating the initiating trigger essential in the pulmonary vein (PV).4 The PV focus acts like a spontaneous pacemaker, and is responsible for the transformation of sinus rhythm into atrial fibrillation. For many years, a complicated open-heart surgery procedure called the Maze operation was performed in order to compartmentalize the atria.5 The Maze procedure was based on the hypothesis that intra-atrial re-entry involving multiple reentrant wavelets is responsible for sustaining AF. This procedure has been associated with a very high clinical success rate.3 This procedure has opened the door for interventional cardiologists intending to reproduce the same results by a non-invasive method in patients with paroxysmal or chronic AF. Currently, the most common techniques used to treat AF are linear ablation, radiofrequency catheter ablation of triggered foci in the PVs, and circumferential ablation and/or segmented isolation of the PVs. Linear ablation compartmentalizes the atria and prevents the reentrant of multiple wavelets required for atrial fibrillation maintenance. Focal ablation removes the arrhythmogenic foci in the pulmonary veins and prevents AF initiation. Circumferential ablation electrically isolates the PVs from the atria and prevents the arrhythmia from reaching the atria. Comparing success rates between the mentioned different approaches, it is clear that focal ablation and circumferential ablation are both more efficacious than linear ablation.3 The success rates of focal and circumferential ablation are lower than that of the surgical Maze procedure. However, because the Maze procedure is actually an open-heart surgery intervention, a focal and circumferential approach would still be preferable as the first option for treatment of AF refractory to electrical cardioversion and pharmacology treatment. The results of new trials are still pending. However, the success rates are varying between 60 and 70 percent. In addition, there are promising results with the use of Lasso catheters in the treatment of atrial fibrillation. It is uncertain and difficult to predict which technique will prevail over the other at the present time. There are three factors that would most likely shift the medical community s preference to one or the other or a hybrid approach. These factors are procedure length, safety, and complications. Pappone et al. is a proponent of a circumferential approach that limits the length of the procedure to 1-2 hours, resulting in less anticoagulation therapy and a faster recovery time. However, not everyone is a candidate for the Pappone approach. It would be safe to predict that a clear-cut technique is still in the making. In addition, the length of the procedure and an easy to handle technique will probably be what decides the future of AF.