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 mm , p < .001 for all comparisons). Surface area was significantly larger for DRA than for SA (45.1 vs. 38.3 mm , p < .001) and larger for DNRA than for SA (44.5 vs. 38.3 mm , p < .001), but was similar between DRA and DNRA (45.1 vs. 44.5 mm , 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 mm , p = .018 and 128.3 vs. 96.8 mm , 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.