Insights into electrophysiological mechanisms of atrial fibrillation propagation using simultaneous bi-atrial mapping

Funding Acknowledgements Type of funding sources: Public hospital(s). Main funding source(s): Oxford Biomedical Research Centre Introduction Early evidence of pulmonary vein triggers initiating AF has led to focus on the left atrium (LA). Little work has been done to characterise the role of the right atrium (RA) in AF maintenance. Purpose To characterise the relative roles of the LA and RA in maintenance of atrial fibrillation and explore mechanisms of AF propagation. Methods Simultaneous bi-atrial mapping was carried out in patients undergoing first time catheter ablation using 2 linked non-contact charge density mapping systems to obtain 30-second recordings during AF. The predominant channel of communication between chambers was identified and the time difference across this channel measured (see figure). The proportion of signals earlier in each chamber was calculated and a dominant chamber identified if preceding the opposite chamber for ≥60% of the recording. AF was characterised in each chamber according to frequency of specific propagation patterns (localised rotational activation (LRA) and focal firing (FF)). The difference in AF characteristics in the LA and RA according to acute procedural outcome (termination with ablation vs. DCCV) was measured using 2-way ANOVA and predictors of AF termination identified using binomial logistic regression. Results Twenty-one patients were included (16 persistent AF, 5 paroxysmal AF, 11 in sinus rhythm at baseline) with 41 maps obtained prior to ablation. A dominant chamber was identified in 11 maps (in 9 patients). Of these, 5 maps (in 4 patients) were LA dominant, and 6 maps (in 5 patients) were RA dominant. The remainder showed balanced interatrial propagation. For patients with persistent AF, in the RA, those needing DCCV had more LRA than those with termination with ablation (79 activations, (95% CI 65-93) vs. 51 (30-71); p = 0.025). There was no difference in the LA in the two groups (77 vs 59, p = 0.541). There were fewer FFs in the RA vs LA in patients needing DCCV (123 (106-140) vs. 155 (137-172), p = 0.012)(see panel F). No differences in distribution of LIA were observed. The frequency of LRA (p = 0.003) and FF (p = 0.004) in the RA, and RA AFCL (p = 0.041), were predictors of acute procedural outcome. Conclusions Our novel approach of simultaneous bi-atrial mapping revealed that mechanisms responsible for AF maintenance were evenly distributed between atria whilst acute AF termination with left atrial ablation was dependent on the contribution of right atrial substrate. Strategies incorporating right atrial mechanisms may result in improved outcomes from AF ablation. Abstract Figure.

Catheter Robots in the Cardiovascular System

Robotic-assisted endovascular therapy is a novel approach to augment precise skill requirements while simultaneously reducing radiation exposure. The CorPath system enhances the scope of minimally invasive procedures and facilitates the interventionalists to perform procedures in the field of vascular surgery, neurosurgery and interventional cardiology. The reason for increasing interest in the CorPath system is the ability to control these robots through wireless connection, raising the possibility for remote interventions. CorPath is currently the only commercially available endovascular robotic system. Robotic-assisted approach has a high technical success rate in the field of peripheral vascular and coronary interventions and has encouraging results regarding neurointerventions. Remote endovascular procedures may transform the future of stroke treatment in areas where distance-related time loss can affect procedural outcome.

Impact of electroanatomical mapping-guided lead implantation on procedural outcome of His bundle pacing

Aims Conventional His bundle pacing (HBP) can be technically challenging and fluoroscopy-intense, particularly in patients with His-Purkinje conduction disease (HPCD). Three-dimensional electroanatomical mapping (EAM) facilitates non-fluoroscopic lead navigation and HB electrogram mapping. We sought to assess the procedural outcome of routine EAM-guided HBP compared with conventional HBP in a real-world population and evaluate the feasibility and safety of EAM-guided HBP in patients with HPCD. Methods and results We included 58 consecutive patients (72 ± 13 years; 71% male) who underwent an attempt to conventional (EAM− group; n = 29) or EAM-guided (EAM+ group; n = 29) HBP between June 2019 and April 2020. The centre’s learning curve was initially determined (n = 40 cases) to define the conventional control group and minimize outcome bias favouring EAM-guided HBP. His bundle pacing was successful in 26 patients (90%) in the EAM+ and 27 patients (93%) in the EAM− group (P = 0.64). The procedure time was 90 (73–135) and 110 (70–130) min, respectively (P = 0.89). The total fluoroscopy time [0.7 (0.5–1.4) vs. 3.3 (1.4–6.5) min; P < 0.001] and fluoroscopy dose [21.9 (9.1–47.7) vs. 78.6 (27.2–144.9) cGycm2; P = 0.001] were significantly lower in the EAM+ than EAM− group. There were no significant differences between groups in His capture threshold (1.2 ± 0.6 vs. 1.4 ± 1.0 V/1.0 ms; P = 0.33) and paced QRS duration (113 ± 15 vs. 113 ± 17 ms; P = 0.89). In patients with HPCD, paced QRS duration was similar in both groups (121 ± 15 vs. 123 ± 12 ms; P = 0.77). The bundle branch-block recruitment threshold tended to be lower in the EAM+ than EAM− group (1.3 ± 0.7 vs. 1.8 ± 1.2 V/1.0 ms; P = 0.31). No immediate procedure-related complications occurred. One patient (2%) experienced lead dislodgement during 4-week follow-up. Conclusion Implementation of routine EAM-guided HBP lead implantation is feasible and safe in a real-world cohort of patients with and without HPCD and results in a tremendous reduction in radiation exposure without prolonging procedure time or increasing procedure-related complications.

Novel electroanatomical map for permanent his bundle pacing: the Mont Blanc approach - influence of the learning curve and procedural outcome

Aims Pacing the specific conduction system like the Bundle of His (HB) can lead to more physiologic activation patterns compared to traditional right ventricular apical pacing. The aim of this study was to estimate the feasibility and value of electroanatomical mapping (EAM) for HB pacing during the learning curve and its impact on procedural outcome. Methods and results Fifteen consecutive patients were treated using EAM of the His bundle region before implantation. Voltage and activation maps of HB potentials were performed. The activation time from His potential to R wave (ECG-reference) was measured and correlated to the HV interval. The atrial and ventricular potentials were blended so the active window could only see the His potential. After completing the activation map, it was transformed into a peak-to-peak voltage map of the HB. With reversed black and white colour scale, the exact point of the maximal His signal amplitude was visualized. Procedural data for the implantation were analysed using this innovative approach. The average total procedural time and fluoroscopy time was 88.2 ± 19.1 min and 10.9 ± 4.5 min, respectively. The 3D mapping time was 18.4 ± 5.1 min. The 13.9 ± 5.1 His potential points were needed in average to complete the map. No periprocedural complications were seen in this cohort. In 86.7% of cases, His bundle pacing was successful. The average threshold for the His bundle stimulation and the R-wave amplitude was 1.62 ± 1 V (@1.0 ms) and 4.8 ± 3.2 mV, respectively. The pacing impedance was 513.5 ± 102.8 Ω. Average paced QRS complex width was 116.9 ± 20.3ms. On average 2.6 ± 1.6 lead positions were targeted to find the optimal pacing site. Conclusion Electroanatomical mapping-guided implantation of His-bundle leads can facilitate the identification of optimal pacing sites and allow to minimize procedure and fluoroscopy times even during the phase of the learning curve.