LAUSR

While the ablation endpoint in patients with paroxysmal atrial fibrillation (AF) has been largely standardized, that is, pulmonary vein (PV) isolation, the optimal approach for patients with persistent AF remains unknown. The STAR AF II trial found no reduction in the rate of recurrent AF when either linear ablation or ablation of complex fractionated electrograms was performed in addition to PV isolation among patients with persistent AF. Moreover, the CABANA trial assessing hard end‐points such as death, disabling stroke, serious bleeding, or cardiac arrest in a randomized fashion could not definitely reveal the advantage of catheter ablation compared with medical therapy among patients with AF. Catheter ablation in this decade has seemed to become simpler and simpler, and the relative importance of complete, durable, and efficient PV isolation has increased, although new strategies such as left atrial posterior wall isolation, isolation of the left atrial appendage, and elimination of Marshall vein/bundle activities are recently being applied in selected patients to improve rhythm outcomes. Cryoballoon ablation (Arctic Front Advance; Medtronic, Inc; POLAR XTM; Boston Scientific) and hot balloon ablation (SATAKE HotBalloon; Toray Industries, Inc.) are device technologies focusing on the efficiency of PV isolation that are widely used worldwide, although one issue compared to conventional radiofrequency catheter ablation is the increased use of fluoroscopy and contrast agents. The KODEX‐EPD (EPD Solutions; A Philips Company), the fourth three‐dimensional mapping system available worldwide after the commercial release of CARTO (Biosense Webster, Inc.), Ensite NavX (Abbott), and Rhythmia (Boston Scientific), may resolve these limitations and may be compatible with balloon‐based ablation because a wide variety of diagnostic and ablation catheters can be used with no need for specific adjustments. The principle used by this novel system to obtain anatomical and electrical information is unique and has recently been applied to differentiate cancer from inflammation in vivo. It exploits the distinct dielectric properties of biological tissue by measuring voltages between body surface sensors and the catheters. The system can collect anatomic information without actual physical surface contact, that is, a 5–10‐mm distance between the surface and catheter is acceptable, and can distinguish atrial surface, PVs, and heart valves by detecting gradients and bending of the electrical field. In 2019, the accuracy of anatomical mapping by the KODEX‐EPD was first evaluated in animals and humans by using pulmonary venography and the CARTO system as comparisons. In this issue of Journal of Cardiovascular Electrophysiology, Brodie et al. evaluated anatomical mapping with an Achieve catheter (Medtronic, Inc.) in the KODEX‐EPD system, which was delivered in Israel from January 2020 to a limited market. This was a first study systematically comparing the anatomical accuracy of the left atrium and PVs created by the KODEX using an Achieve catheter during PV isolation to the gold standard of computed tomography (CT) imaging. High correlation between the two modalities in the measurement of both ostial diameters of the PVs and left atrium as well as in distance measurements along the posterior wall was reported. Similar to previous studies, measurements made with the KODEX‐EPD system were highly accurate although they were, on average, a few millimeters longer and wider than those on CT imaging, and disagreements in the accessory right‐sided vein and left common PVs were present. The excellent interobserver measurements revealed high reliability of the mapping, and potentially shorter mapping time (within a few minutes) was estimated. With the KODEX system, the operator can continuously acquire data by gently wiggling the catheter in real time without the need for direct catheter tissue contact.