Abstract 15220: The Thermal Characteristics to Phrenic and Esophageal Injuries During Ablation of QDOTMICRO (50w-Qmode and 90w/4sec-Qmode+) vs 50w-TactiCath SE vs 50w-Thermocool Smart Touch: Findings From an In-Vivo Por

Introduction: Recently, there have been numerous strategies for treating atrial fibrillation, including the choice of catheters However, the thermal characteristics of each catheter, particularly in terms of safety, have not been fully understood.

Hypothesis: Our aim was to characterize the thermal damage to collateral tissues during 50W-HPSD ablation and 90W/4sec-vHPSD ablation using three different ablation catheters.

Methods: In 28 pigs, we implanted thermocouples on the superior vena cava, close to the phrenic nerve, and on the esophageal, close to the inferior vena cava. We performed endocardial ablation near the fiducial markers of the thermocouples using three different RF catheters: ablation index (AI)-guided HPSD (Qmode) and vHPSD ablation (Qmode+) with QDOTMICRO, lesion size index-guided HPSD ablation (targeting 5.0) with TactiCath Sensor Enabled (Tacti), and AI-guided HPSD ablation (targeting 400) with Thermocool Smart Touch (STSF). We measured tissue temperatures during ablation, including maximum tissue temperature (Tmax), time to maximum tissue temperature (t-Tmax), time to achieve a lethal temperature of 50°C (t-50°C), and time to return to baseline from Tmax (t-Tbase).

Results: In terms of the frequency of esophageal injury, there were no significant differences among the different catheters. However, the depth of esophageal injury from the adventitia showed a significant difference. In terms of phrenic nerve injury, Tacti had the highest frequency compared to the other catheters (100%, p=0.0012). Tmax, t-Tmax, t-50°C, and t-Tbase showed significant differences, as shown in figure.

Conclusions: The thermal effects on collateral tissues differ among the three different catheters and settings. STSF and Qmode result in a gradual increase in tissue temperature, while Tacti and Qmode+ lead to a rapid temperature increase. These distinct thermal distributions may contribute to the risk of phrenic nerve and esophageal injuries.