B-PO03-034 INTRACARDIAC ECHOCARDIOGRAPHY VALIDATION OF SALINE-ENHANCED RADIOFREQUENCY NEEDLE-TIP ABLATION FOR THE CONTROLLABLE CREATION OF TRANSMURAL LESIONS

Abstract

In saline-enhanced radiofrequency needle-tip (SERF) ablation, heated saline is injected into the myocardium via a needle, while the needle is used as a monopolar ablation electrode. In comparison to lesions created by conventional radiofrequency ablation, lesions created by SERF ablation are larger and more often transmural. With the implementation of SERF ablation, real-time validation of lesion formation is needed for the controllable creation of transmural lesions. The aim of the study was to analyze the ability of 2D-intracardiac echocardiography (ICE) and impedance measurements to detect transmural lesions. Fifty-six SERF energy deliveries at left ventricular sites of 11 dogs guided by 2D-ICE were analyzed (power: 15-50 W; time: 25-120 sec; irrigation saline: 60 °C with 10 mL/min flow rate). Impedance measurements were taken before, during, and after the energy delivery. One week after the ablation procedure, hearts were explanted en bloc for ex-vivo lesion validation. Continuous lesions from the endocardium to the epicardium were defined as transmural lesions. On 2D-ICE, 31 (63.3%) lesions were considered to be transmural. For 23 of these lesions, transmurality was confirmed in gross pathology, resulting in a sensitivity of 70%, a specificity of 47%, a positive predictive value of 74% and a negative predictive value of 59% for detecting transmural lesions. In confirmed transmural lesions, impedance measurements did not differ compared to non-transmural lesions on gross pathology (baseline impedance 85.5 Ω [IQR 79.5 - 95.8] vs. 84.0 Ω [IQR 82.0 - 85.0], p=0.497; impedance after SERF ablation 75.0 Ω [IQR 68.2 - 85.8] vs. 69.0 Ω [IQR 68.0 - 77.0], p=0.297; impedance drop 11.0 Ω [IQR 4.8 - 16.8] vs. 14.0 Ω [IQR 11.0 - 17.0], p=0.289 and impedance drop rate 13.5 % [IQR 5.9 - 16.6] vs. 17.1 % [IQR 13.8 - 19.4], p=0.183). 2D-ICE can potentially be used to guide and validate SERF ablation lesion formation in real-time for the controllable creation of transmural lesions.