Optimization of High-Power Short-Duration Pulmonary Vein Isolation Using QDOT Catheter - the A-Q-RATE POWER Trial

Abstract Background/Introduction The safety and efficacy of novel ablation catheter QDOT Micro, capable of delivering high-power short-duration (HPSD) radio-frequency (RF) applications, has already been demonstrated in clinical trials. It has been shown that lesions performed with 90 Watts/4 sec (vHPSD) are shallower but wider compared to HPSD (50 Watts/4 sec) or conventional ablation settings. Thus, it may be speculated that vHPSD applications may not achieve transmurality at thick (up to 4 mm) parts of anterior aspects of pulmonary vein (PV) - left atrial (LA) wall junction. Purpose To compare acute completeness of PV isolation (PVI) focused on anterior wall achieved using vHSPD versus HPSD in patients undergoing ablation for atrial fibrillation (AF). Methods Prospective, dual-center, randomized study was conducted over a 8-month period. Patients were randomized 1:1 to vHPSD versus HPSD delivered at anterior aspects of PV. Posterior parts of PV were ablated with vHPSD in both arms. The carina region between ipsilateral PVs was ablated using 35 W and ablation index of 380. Need for additional RF applications to achieve complete PVI was the primary outcome. Results 70 patients (mean age 63.5±11.2; 57.1% male) with paroxysmal (61.4%) or persistent AF (38.6%) were randomized to vHPSD (n=35) or HPSD (n=35). Additional RF touch-up applications at the anterior aspects of PV were significantly more frequently needed in the vHPSD group compared with the HPSD group (46% vs 19%, p<0.001) and in the right PVs (57% vs 20%, p=0.001) versus left PVs (34% vs 17%, p=0.1). Median procedure duration, LA dwell time and fluoroscopy time were similar in both groups [112 (IQR 90, 130) min vs 107 (IQR 90,125) min, p= 0.58; 95 (IQR 70,106) min vs 90 (IQR 71,100) min, p=0.55; and 28 (IQR 14,69) sec vs 46 (IQR 0,89) sec, p=0.97, respectively). In one patient in vHPSD we were not able to isolate right superior pulmonary vein (RSPV) despite additional RF touch-up applications. Conclusions vHPSD RF applications using the QDOT Micro catheter may not achieve transmurality in a significant proportion of anterior parts of PV. The proposed hybrid strategy consisting of HPSD delivery at anterior aspects of PV with vHPSD delivered at other parts of PV ostia is associated with significantly higher rate of first-pass PVI without extending procedural and fluoroscopy duration.