Magnetic nanoparticles and neurotoxins for treating atrial fibrillation: a new way to get burned?

Atrial fibrillation (AF) is the most common cardiac dysrhythmia,1with over 2.6 million Americans affected. Partly due to the high risk of stroke in these patients, AF is associated with significant morbidity and mortality.2 The number of individuals affected with AF is expected to rise 6-fold over the next 40 years. Catheter-based ablation may offer a more effective means of treating AF than conventional medical therapy.3–5 Ablation techniques have been adopted after limited clinical trials with a relatively small number of patients.4–7 In an effort to guide the best treatment strategies, a registry has been established to follow the increasing numbers of AF patients who are being treated with ablation.8 Although the generally accepted initial ablation strategy is isolation of the pulmonary veins, which are often the source of ectopic beats that initiate AF, animal models have shown that the cardiac ganglionated plexi play a role in inducing and maintaining AF.9 Initial clinical studies indicate that ablation of the ganglionated plexi, in addition to pulmonary vein isolation, may improve ablation outcome.10 Indeed, fortuitous ablation of the ganglionated plexi during pulmonary vein isolation may contribute to procedure success. However, targeting the ganglionated plexi for selective ablation requires their localization, presently achieved by additional mapping to detect sites where high-frequency stimulation elicits heart rate slowing and then ablation at that site, which, for endocardial catheter techniques, includes the surrounding atrial myocardium. Better methods to identify and ablate these focal neural networks are desirable for potential use as adjunct treatments to conventional cryoablation or radiofrequency ablation.