B-PO01-072 DIELECTRIC-BASED TISSUE THICKNESS MEASURED WITH A RADIOFREQUENCY ABLATION CATHETER: INITIAL CLINICAL RESULTS

Abstract

Current algorithms that indicate adequacy of radiofrequency (RF) lesion formation incorporate parameters such as contact force, power, and duration, but omit tissue thickness. A new dielectric-based method for measuring tissue thickness (DTT, Wall Viewer™) at the catheter-tissue interface has recently been developed (pre-market). DTT performance in clinically relevant atrial anatomy, such as the cavotricuspid isthmus (CTI), is unknown. To evaluate the correlation between DTT and tissue thickness measured with intracardiac echocardiography (ICE) in subjects undergoing CTI ablation. Eight subjects at two centers underwent a CTI ablation (NCT03858361 and NCT04438395). Right atrial maps were created with an electroanatomic mapping system (KODEX-EPD). The DTT algorithm is based on a pre-trained algorithm model that incorporates real-time catheter position and local dielectric tissue interrogation by catheter electrodes. Prior to ablation, DTT measurements were taken with an ablation catheter (ThermoCool® SF) along the CTI by blinded operators and compared with tissue thickness determined on stored CTI ICE images after the procedure. Bi-directional CTI block was confirmed with differential pacing. Average RA mapping time was 23 ± 5 min. Acute bi-directional block was confirmed in all subjects. CTI thickness measured with ICE (range 1.3 - 5.0 mm) was compared to DTT tissue thickness at 43 points. There was a significant linear correlation between DTT and ICE tissue thicknesses (p < 0.001, slope: 0.73 and r: 0.57). In total, 86.0% (37/43) of DTT values fell within 1.5 mm of ICE measurements with the largest deviation of 2.1 mm. Clinically relevant atrial tissue thickness was accurately measured by a dielectric-based method with a commercially available RF ablation catheter. Real-time tissue thickness measurement may better inform RF dosing to ensure lesion transmurality while limiting collateral structure damage.