Reflexion hd

A venous access site in the right internal jugular vein was used to introduce a duo‐decapolar catheter (Bee‐AT, Japan‐Lifeline Co., Ltd., Tokyo, Japan), of which the distal 10‐poles were positioned in the coronary sinus while the proximal 10‐poles were placed along the crista terminalis for internal cardioversion. After a double transseptal puncture, a 20‐pole circular mapping catheter (Optima™ or Reflexion HD™; St. Jude Medical, St. Paul, MN) and irrigated‐tip ablation catheter (Cool Flex™ or FlexAbility™; St. Jude Medical) were inserted into the LA for the mapping and ablation. A 3D geometry of the LA was created and fused with the pre‐operative 3DCT using an EnSite NavX™ system (St. Jude Medical). A temperature monitoring probe (SensiTherm™; St. Jude Medical) was inserted into the esophagus.

We have developed an online real‐time phase mapping system (ExTRa Mapping™, Nihon Kohden Co., Tokyo, Japan), as shown in Figure 1. Because this phase mapping system was based on 41 bipolar intra‐atrial electrograms (including 9 virtual electrograms) recorded by a 20‐pole spiral‐shaped catheter with a diameter of 2.5 cm (Reflexion HD™, St. Jude Medical Inc., MN, USA), the mapping system achieved a high signal density (~8 signals/cm²). Based on the 5‐second wave dynamics during AF, each phase map movie was fully automatically created with the ExTRa Mapping within a few seconds and was immediately played at a 1/10 speed for 50 seconds.
To improve the detection and spatiotemporal interpolation of the intra‐atrial signals and to achieve a rapid prediction of the atrial excitations during AF, both computer simulation (in silico) part and specialized artificial intelligence part were incorporated into the system. Combined with the timing of the action potential onset determined by the intra‐atrial signals, the in silico part calculated the virtual atrial action potentials based on the in silico model of human non‐PAF.5 Therefore, the virtual action potentials during non‐PAF could faithfully reproduce the restitution properties of human atria under structural remodeling.

The NavX system (NavX with CFE software; St. Jude Medical, Inc) was used for catheter ablation. The three‐dimensional bi‐atrial geometry was created on the NavX system, and sequential contact mapping was performed using a 7‐F decapolar circular catheter (Reflexion™ HD; St. Jude Medical, Inc). Voltage mapping was performed to investigate the relationship between structural remodeling and electrical remodeling. Mapping was performed during sinus rhythm. In patients with non‐paroxysmal AF, voltage mapping was obtained during sinus rhythm after ablation. Mapping points were acquired to fill all color gaps on the voltage map using an electroanatomical mapping system. Each acquired point was classified according to the peak‐to‐peak electrogram as follows: healthy, >0.5 mV; diseased, 0.2‐0.5 mV; and scarred, <0.1 mV. The low‐voltage area was defined as sites of ≥3 adjacent to low‐voltage points of <0.5 mV, as described previously.¹⁷