Comparison of three different approaches to very high‐power short‐duration ablation using the QDOT‐MICRO catheter.

Background/Objectives: The QDOT‐MICRO™ catheter allows very high‐power and short‐duration (vHPSD) ablation. This study aimed to investigate lesion characteristics using different ablation settings. Methods: Radiofrequency applications (90 W/4 s, temperature‐control mode with 55°C or 60°C target) were performed in excised porcine myocardium using three different approaches: single (SA), double nonrepetitive (DNRA), and double repetitive applications (DRA). Applications were performed with an interval of 1 min for DNRA, and without interval for DRA. Results: A total of 480 lesions were analyzed. Lesion depth and volume were largest for DRA followed by DNRA and SA regardless of catheter direction (depth: 3.8 vs. 3.3 vs. 2.6 mm, p <.001 for all comparisons; volume: 176.6 vs. 145.1 vs. 97.0 mm3, p <.001 for all comparisons). Surface area was significantly larger for DRA than for SA (45.1 vs. 38.3 mm2, p <.001) and larger for DNRA than for SA (44.5 vs. 38.3 mm2, p <.001), but was similar between DRA and DNRA (45.1 vs. 44.5 mm2, p =.54). Steam‐pops more frequently occurred for DRA than for SA (15.6% vs. 4.4%, p =.004) and DNRA (15.6% vs. 6.9%, p =.061), but the incidence was similar between SA and DNRA (4.4% vs. 6.9%, p = 1). Although surface area and lesion volume were larger in lesions with steam‐pops than without steam‐pops (46.5 vs. 38.1 mm2, p =.018 and 128.3 vs. 96.8 mm3, p =.068, respectively), lesions were not deeper (pop(+): 2.5 mm vs. pop(−): 2.6 mm, p =.75). Conclusions: DNRA produces larger lesions than SA without increasing the risk of steam‐pops. DRA produces the largest lesions among the three groups, but with an increased risk of steam‐pops. Even with steam‐pops, lesions do not become deeper in vHPSD ablation. [ABSTRACT FROM AUTHOR]