Association of left atrium voltage amplitude and distribution with the risk of atrial fibrillation recurrence and evolution after pulmonary vein isolation: An ultrahigh-density mapping study.

INTRODUCTION: Ultrahigh-density-voltage mapping (uHDV M) is a new tool that can add new insights into the pathophysiology of atrial fibrillation (AF). The aim of this study was to evaluate the performance of uHDV M in predicting postablation AF recurrence (AFR). METHODS AND RESULTS: We included 98 consecutive patients undergoing pulmonary vein isolation for AF (40.8% persistent) using an uHDV M system and followed for 1 year. The left atrium (LA) mean voltage (Vm ) and the Vslope (slope of the voltage histogram calculated by linear interpolation, with the relative frequency on the vertical axis and the bipolar potential on the horizontal axis) were calculated from 12 567 ± 5486 points per map. Patients with AFR (N = 29) had lower Vm and higher Vslope as compared with patients without AFR (N = 69). Receiver operating characteristic curves identified Vm as the strongest predictor of AFR, with a higher incidence of AFR in patients with Vm 0.758 mV (57.6%) or lower than patients with Vm higher than 0.758 mV (15.4%; P < .0001). Among patients with Vm  higher than 0.758 mV, patients with Vslope 0.637 or higher exhibited higher (P = .043) AFR incidence (31.3%) than patients with Vslope lower than 0.637 (10.2%). This classification showed incremental predictive value over relevant covariables. Vm values were lower and Vslope values were higher in patients that progressed from paroxysmal to persistent AF. Patients with Vslope 0.637 or higher had a 14.2% incidence of postablation atypical atrial flutter, whereas patients with Vslope lower than 0.637 did not present this outcome. CONCLUSIONS: The risk of AFR, atrial flutter, and progression from paroxysmal to persistent AF can be detected by quantitative analysis of LA uHDV M identifying diverse patterns of atrial substrate alterations.

Do 'difficult to identify' pulmonary vein connections explain continuing high recurrence rates after atrial fibrillation ablation?

Despite the emerging technical evolution of the last two decades, the primary success rate of single-procedure pulmonary vein isolation (PVI), the cornerstone for any atrial fibrillation ablation procedure, is highly variable ranging from 53% to 92%. The recent development of ultra-high-density electroanatomic mapping systems, capable of acquiring and annotating multiple electrograms, with high spatiotemporal precision, which are processed by automated algorithms to generate activation and substrate maps to support and guide ablation procedures, has opened a new stage in cardiac electrophysiology. In this article, we review the existing evidence on the utility of high-density mapping on catheter-based PVI, the possibility to detect pulmonary vein potentials that remain undetected when using a standard approach and its potential relevance to the clinical outcome, and how this new technology is providing novel pathophysiological insights on complete PVI and atrial fibrillation ablation outcomes.

Identification of pulmonary vein reconnection gaps with high-density mapping in redo atrial fibrillation ablation procedures.

Aims: Maps obtained by means of electroanatomic high-density mapping (HDM) systems have shown their use in the identification of conduction gaps in experimental atrial linear lesion models. The objective of this study was to assess the use of HDM in the recognition of reconnection gaps in pulmonary veins (PV) in redo atrial fibrillation (AF) ablation procedures. Methods and results: One hundred and eight patients were included in a non-randomized study that assessed the recognition of reconnection gaps in PV by means of HDM compared to a control group that received conventional non-fluoroscopic guidance with a circular multipolar catheter (CMC). Among the HDM group, adequate recognition of reconnection gaps was obtained in 60.99% of the reconnected PVs (86 of 141), a figure significantly higher than that achieved with analysis of CMC recorded signals (39.66%, 48 of 121; P = 0.001). The number of applications and total radiofrequency time were also significantly lower in the HDM group (12.46 ± 6.1 vs. 15.63 ± 7.7 and 7.61 ± 3 vs. 9.29 ± 5; P = 0.02, and P = 0.03, respectively). At the 6-month follow-up, no statistically significant differences were found in recurrence of AF or any other atrial tachycardia between the HDM group (8 patients, 14.8%) and the control group in (16 patients, 29.6%; P = 0.104). Conclusion: An analysis of the high-density activation maps allows greater precision in the identification of reconnection gaps in PV, which results in lower radiofrequency time for the new isolation.

Mediguide-Assisted Transseptal Puncture without Echocardiographic Guidance.

BACKGROUND: First description of a technique for left atrium transseptal puncture (TSP) with minimal radiation exposure by using the nonfluoroscopic MediGuide™ tracking system (MG; St. Jude Medical, St. Paul, MN, USA) without the assistance of intracardiac echocardiography. METHODS: This study included 31 consecutive patients with atrial fibrillation undergoing an MG-assisted percutaneous catheter ablation procedure. A Brockenbrough transseptal needle (BRK) is connected to a standard pressure transducer through a two-input valve. Then, an MG-enabled guidewire is inserted so that its tip exactly matches the BRK's distal tip. After the acquisition of two short radioscopic cine-loops we are able to trace the needle tip on the MG screen, performing the usual TSP maneuver but without fluoroscopy. Successful left atrium access is confirmed by noticing the change in the pressure curve and by advancing the guidewire into the left pulmonary veins. As a control group, 31 matched patients who underwent atrial fibrillation ablation with fluoroscopically guided, pressure-monitored TSP were included. RESULTS: Sixty-two MG-assisted TSP attempts were performed; all but two were successfully accomplished without changing to the conventional technique (96.7%). The mean total fluoroscopy time, until the double transseptal access was performed, was 26.65 ± 37.97 seconds in the MG group and 129.13 ± 37.77 seconds in the conventional-TSP group (P < 0.001). No major complications occurred during any of the procedures. CONCLUSION: This new technique for TSP using MG is feasible and can be performed with minimal radiation exposure without the need for additional imaging techniques, achieving a significant reduction of fluoroscopy time.

Atrial Fibrillation Ablation Guided by a Novel Nonfluoroscopic Navigation System.

INTRODUCTION AND OBJECTIVES: Rhythmia is a new nonfluoroscopic navigation system that is able to create high-density electroanatomic maps. The aim of this study was to describe the acute outcomes of atrial fibrillation (AF) ablation guided by this system, to analyze the volume provided by its electroanatomic map, and to describe its ability to locate pulmonary vein (PV) reconnection gaps in redo procedures. METHODS: This observational study included 62 patients who underwent AF ablation with Rhythmia compared with a retrospective cohort who underwent AF ablation with a conventional nonfluoroscopic navigation system (Ensite Velocity). RESULTS: The number of surface electrograms per map was significantly higher in Rhythmia procedures (12 125 ± 2826 vs 133 ± 21 with Velocity; P < .001), with no significant differences in the total procedure time. The Orion catheter was placed for mapping in 99.5% of PV (95.61% in the control group with a conventional circular mapping catheter; P = .04). There were no significant differences in the percentage of PV isolation between the 2 groups. In redo procedures, an ablation gap could be identified on the activation map in 67% of the reconnected PV (40% in the control group; P = .042). The measured left atrial volume was lower than that calculated by computed tomography (109.3 v 15.2 and 129.9 ± 13.2 mL, respectively; P < .001). There were no significant differences in the number of complications. CONCLUSIONS: The Rhythmia system is effective for AF ablation procedures, with procedure times and safety profiles similar to conventional nonfluoroscopic navigation systems. In redo procedures, it appears to be more effective in identifying reconnected PV conduction gaps.

Ablation of Atrial Fibrillation in Combination with Left Atrial Appendage Occlusion in A Single Procedure. Rationale and Technique.

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia, and is associated with a fivefold increase in the risk of ischemic stroke and systemic embolism. Left atrial appendage (LAA) is the source of thrombi in up to 90% of patients with nonvalvular atrial fibrillation (AF). Although thromboembolic prophylaxis by means of oral anticoagulants (OAC) has been shown to be very effective (OAC), they also confer an inevitably risk of serious bleeding. Catheter ablation (CA) is an effective treatment for symptomatic AF but its role in stroke prevention remains unproved. Recently, LAA percutaneous occlusion has been demonstrated to be equivalent to OACs in reducing thromboembolic events. The aim of this review is to describe the rationale, feasibility, outcomes and technique of a combined procedure of AFCA and percutaneous LAAO, two percutaneous interventions that share some procedural issues and technical requirements, in patients with symptomatic drug-refractory AF, high risk of stroke, and contraindications to OACs.