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Percutaneous Epicardial Catheter Ablation Opens Another Chapter in the Catheter‐Based Ablation for Atrial Fibrillation

Over the past two decades, no other story in cardiology has received as much attention as the nonpharmacological treatment of cardiac arrhythmias, catheter-based ablation. The story began to unfold with the development of the catheterbased radiofrequency (RF) ablation of accessory pathways, proven to be the first nonsurgical curative treatment in cardiology.1,2 Shortly thereafter, electrophysiologists realized they could perform ablations to cure a variety of supraventricular tachycardia (SVT) easily and effectively, yielding spectacular outcomes that had rarely been witnessed with other treatment modalities. What followed is quite remarkable. Professionals from several disciplines (i.e., basic and clinical scientists, engineers, and health care providers)—from various industries to academia—formed the vanguard of interventional electrophysiology. The ensemble of new talents and intellects helped create new catheters, mapping systems, and a variety of tools and technologies that facilitated ablation procedures. These advances dramatically transformed the field of clinical electrophysiology—from the sedate specialty that merely carried out diagnostic electrophysiologic studies or antiarrhythmic drug testing—to an exciting and dynamic discipline that provided effective treatment for SVT via its interventional approach. Fortunately, the story did not end with SVT ablation, but continued for all types of cardiac arrhythmias. At present, most tachyarrhythmias can be reproducibly ablated with great success. For example, patients with typical cavotricuspid isthmus-dependent atrial flutter can now be ablated in 1 hour or less with a success rate of over 95% and a very low likelihood of complications. One by one, many arrhythmias joined the long list of tachycardias that use catheter ablation as the first-line treatment. However, finding the best way to ablate atrial fibrillation (AF), “the mother of all arrhythmias,” remains a major challenge—the Holy Grail for the electrophysiologist! Just as the Knight Templar faced daunting tasks when searching for the grail, so has the electrophysiologist dealt with many obstacles when ablating AF. First, the electrophysiologic mechanisms underlying human AF remain unclear and are likely to be somewhat different from patient to patient (i.e., paroxysmal to persistent). The seminal work by Haissaguerre et al.3 clearly establishes the important role of pulmonary veins (PVs) as triggering and perpetuating AF. As