High-resolution parahisian mapping and ablation using microelectrode embedded ablation catheters.

BACKGROUND: Accurate mapping of the compact atrioventricular (AV) node is critical during ablation of a range of arrhythmias. OBJECTIVE: The purpose of this multicenter prospective study was to test the hypothesis that microelectrode (ME)-embedded catheters more accurately define the near-field compact AV node compared to conventional catheters. METHODS: For the mapping phase, detailed AV junction maps were created in 47 patients using an ME-embedded catheter. His electrograms (EGMs) detected by conventional electrodes (Hisc) and by ME (Hisµ) were annotated. For the ablation phase, AV nodal ablation (Qmode 50 W) was performed in 10 patients after pacemaker implantation, with initial Hisc-only ablation in group 1 (n = 6) and initial Hisµ ablation in group 2 (n = 4). For the clinical phase, a prospective registry of parahisian tachycardia using QDOT was obtained. RESULTS: In the mapping phase, 7.0 ± 5.4 Hisc and 8.0 ± 5.6 Hisµ points were acquired per map (n = 47). Hisµ cloud was smaller and more proximally located than Hisc cloud: (99.4 ± 74.7 mm2 vs 197.6 ± 110.6 mm2; P = .0008). Hisµ EGMs had larger amplitudes than Hisc EGMs (0.40 ± 0.38 mV vs 0.16 ± 0.1 mV; P = .0002). In the ablation phase, for group 1: Hisc-only ablation never resulted in AV block, whereas Hisµ ablation resulted in AV block after limited ablation in all patients (after 13.3 ± 9.2 s); and for group 2: Hisµ ablation always resulted in AV block after 1 application (after 14.3 ± 10.3 s). In the clinical phase, a Hisµ-avoidance strategy could avoid AV block in a prospective registry of 11 patients. CONCLUSION: ME more accurately defines the region of the compact node, and ablation in this region is associated with a high risk for AV block. ME-based mapping has the potential to significantly enhance ablation safety and efficacy.

Image-guided ablation of scar-related ventricular tachycardia: towards a shorter and more predictable procedure.

PURPOSE: The aim of this study was to analyze the feasibility and reproducibility of using image integration software at a remote setting over the MUSIC network to perform image-guided VT ablation. Furthermore, we analyzed the efficacy of a focused workflow with electroanatomical mapping (EAM) limited to imaging-defined scar. METHODS: In a prospective two-centre study, consecutive patients undergoing image integration-guided VT ablation (magnetic resonance [DE-MRI] and/or multidetector computed tomography [MDCT]) were included. Patients were divided into two groups (Group 1, complete EAM; Group 2, EAM limited to imaging-defined substrate). RESULTS: Forty-nine patients (62 ± 15 years; 90% male; LVEF 41 ± 14%; ischemic 69%) who underwent image integration-guided VT ablation were included (MDCT 98%; DE-MRI in 35%). Total procedure time was 172 ± 48 min (ablation 31 ± 17 min; fluoroscopy 23 ± 13 min). Procedure time was shorter in Group 2 as compared to Group 1 (Group 2 [n = 26] vs. Group 1 [n = 23]; procedure time: 151 ± 33 vs. 180 ± 53 min, P = 0.01). Non-inducibility of all VT was achieved in 37 (76%), with no difference between Group 1 and 2 (Group 2 vs. Group 1; VT non-inducibility 71 vs. 74%, P = 0.8). During a follow-up period of 19 ± 8 months, 13 patients (27%) had a VT recurrence. Two patients (4%) died during follow-up. There were no differences in VT-free survival between Group 1 and Group 2 (p = 0.77). CONCLUSION: Image-integrated VT ablation is feasible through a network between highly experienced centers and remotely located centers. Focused image integration-guided VT ablation is associated with short and predictable procedure duration, achieving high-long term success rates.

Pulmonary vein isolation using a higher power shorter duration CLOSE protocol with a surround flow ablation catheter.

INTRODUCTION: The CLOSE protocol combines ablation index (AI) and ≤6 mm interlesion distance using standard power settings for the treatment of atrial fibrillation (AF). The purpose was to compare the safety and efficacy of a conventional CLOSE and a higher power shorter duration (HPSD)-CLOSE pulmonary vein isolation (PVI) strategy. METHODS AND RESULTS: All consecutive patients referred for PVI were included after informed consent was obtained from them. Group 1 was treated with a standard CLOSE protocol and group 2 with a HPSD-CLOSE protocol (45 W anterior and 35 W posterior). Procedural parameters and 6-month follow-up were analyzed. In total, 174 patients (group 1: n = 94 [paroxysmal: n = 74]; group 2: n = 80 [paroxysmal: n = 65], similar baseline characteristics) were included. PVI was reached in all, but procedure duration (82 ± 18 minutes vs 100 ± 22 minutes; P < .0001) and radiofrequency (RF) time (23 ± 5 minutes vs 36 ± 11 minutes; P < .0001) was shorter in group 2. First pass isolation was similar in groups 2 and 1 (left veins: 94% vs 90%; P = .42 and right veins: 83% vs 84%; P = .79, respectively). Six-month off- antiarrhythmic drugs freedom of AF/AT was similar in groups 2 and 1 (82% [paroxysmal: 86%] vs 83% [paroxysmal: 88%]; P = .93, respectively). Major complications were similar (group 2: 1% vs group 1: 3%; P = .39). CONCLUSION: A higher-power short duration approach can shorten a CLOSE procedure and reduce ablation time without having a negative impact on safety or efficiency.