Zero fluoroscopy catheter ablation for atrial fibrillation: a systematic review and meta-analysis

Catheter Ablation in Atrial Fibrillation: Recent Advances

Atrial fibrillation (AF) is the leading cause of arrhythmia-related morbidity and mortality. Recurrent symptoms, hospitalizations, and cost burden to patients have necessitated treatments beyond antiarrhythmic drugs (AADs) for patients with AF. Catheter ablation has proven to be effective over medical therapy alone; however the recurrence rates for atrial tachyarrhythmias post-ablation remain significant, particularly in patients with persistent and long-standing persistent AF. Hence, new techniques for catheter ablation have arisen, such as non-thermal energy sources, novel catheters, electroanatomical mapping, and ablation of additional targets. In this review, we discuss the recent advances in the field of catheter ablation, including newer modalities for the prevention of adverse events and future perspectives.

Safety and efficacy of intracardiac echocardiography-guided zero-fluoroscopy ablation in atrial fibrillation patients: a comparative study of high-power short-duration and low-power long-duration strategies

Introduction

In atrial fibrillation (AF) ablation, fluoroscopy has been a standard tool for catheter guidance. However, the combination of electroanatomic mapping systems (EAMs) and intracardiac echocardiography (ICE) now allows for minimal or zero-fluoroscopy procedures. Concurrently, high-power short-duration (HPSD) ablation has emerged as a promising technique, offering enhanced resistive heating while reducing conductive heating. This approach potentially improves both safety and efficacy. Despite these advancements, there is a lack of comprehensive clinical data on the safety and effectiveness of HPSD ablation when used in conjunction with ICE-guided zero-fluoroscopy procedures.

Objective

To compare two different ablation strategies-high-power short-duration (HPSD) and low-power long-duration (LPLD)-both utilizing intracardiac echocardiography (ICE)-guided zero-fluoroscopy in the context of atrial fibrillation (AF) ablation.

Methods

This retrospective study included 173 consecutive patients with AF who underwent ICE-guided zero-fluoroscopy ablation. Patients were divided into two groups: HPSD and LPLD. All procedures were conducted using an EAM system with ICE guidance. Both groups underwent routine pulmonary vein isolation (PVI), with additional linear ablations performed for persistent AF when necessary. We compared treatment outcomes and the incidence of complications between the two groups.

Results

All procedures were successfully completed under ICE-guided zero-fluoroscopy, establishing a feasible and reliable workflow. The procedure and ablation times were significantly shorter in the HPSD group compared to the LPLD group. At one-year follow-up, sinus rhythm was maintained in 77 patients in the HPSD group and 74 patients in the LPLD group, with no significant difference between the two group. Postoperative complications occurred in 5 patients in the HPSD group and 3 patients in the LPLD group. Importantly, there were no major adverse cardiac and cerebrovascular events (MACCE) in either group.

Conclusion

A zero-fluoroscopy workflow utilizing an EAM system combined with ICE appears to be both feasible and safe for ablation in AF patients. In patients undergoing ICE-guided zero-fluoroscopy ablation, the HPSD strategy is comparable to LPLD ablation in effectiveness while offering the benefit of shorter procedure and ablation times.

Initial experience with zero-fluoroscopy pulmonary vein isolation in patients with atrial fibrillation: single-center observational trial

Pulmonary vein isolation (PVI) stands as a widely practiced cardiac ablation procedure on a global scale, conventionally guided by fluoroscopy. The concurrent application of electroanatomical mapping systems (EAMS) and intracardiac echocardiography offers a means to curtail radiation exposure. This study aimed to compare procedural outcomes between conventional and our initial zero-fluoroscopy cases in patients with paroxysmal or persistent atrial fibrillation (AF), undergoing point-by-point PVI. Our prospective observational study included 100 consecutive patients with AF who underwent point-by-point radiofrequency PVI. The standard technique was used in the first 50 cases (Standard group), while the fluoroless technique was used in the subsequent 50 patients (Zero group). The zero-fluoroscopy approach exhibited significantly shorter procedural time (59.6 ± 10.7 min vs. 74.6 ± 13.2 min, p < 0.0001), attributed to a reduced access time (17 [16; 20] min vs. 31 [23; 34.5] min, p < 0.001). Comparable results were found for the number of RF applications, total ablation energy, and left atrial dwelling time. In the Zero group, all procedures were achieved without fluoroscopy, resulting in significantly lower fluoroscopy time (0 [0; 0] sec vs. 132 [100; 160] sec, p < 0.0001) and dose (0 [0; 0] mGy vs. 4.8 [4.1; 8.2] mGy, p < 0.0001). The acute success rate was 100%, with no major complications. Zero-fluoroscopy PVI is feasible, safe, and associated with shorter procedure times compared to the standard approach, even in cases without prior experience in zero-fluoroscopy PVI.

Intracardiac Echocardiography: An Invaluable Tool in Electrophysiological Interventions for Atrial Fibrillation and Supraventricular Tachycardia

Researchers have investigated ways to develop optimal imaging techniques to increase the safety and effectiveness of electrophysiological (EP) procedures. Intracardiac echocardiography (ICE) is an advanced imaging tool that can directly visualize cardiac anatomical structures in high resolution, assess tissue heterogeneity and arrhythmogenic substrates, locate intracardiac catheters, monitor catheter-tissue contact and ablation injury in real-time, excluding intracardiac thrombi, and quickly detect procedural complications. Additionally, real-time imaging via ICE can be integrated with a three-dimensional (3D) electroanatomical mapping (EAM) system to reconstruct cardiac anatomy. This technique also promotes the development of zero-radiation EP procedures. Many EP studies and procedures have implemented ICE because it has several advantages over fluoroscopy and transesophageal echocardiography (TEE). ICE-guided EP procedures can be performed under conscious sedation; esophageal intubation and additional anesthesiologists are not required. Atrial fibrillation (AF) and supraventricular tachycardias (SVT) are the most common tachyarrhythmias in clinical settings. A comprehensive understanding of critical anatomical structures, such as the atrial septum, fossa ovalis (FO), and great heart vessels, is needed for the successful catheter ablation of these arrhythmias.

Ablation of Paroxysmal Atrial Fibrillation: between Present and Future

Pulmonary vein isolation (PVI) is the established cornerstone for atrial fibrillation (AF) ablation, indeed current guidelines recognize PVI as the gold standard for first-time AF ablation, regardless of if it is paroxysmal or persistent. Since 1998 when Haïssaguerre pioneered AF ablation demonstrating a burden reduction after segmental pulmonary vein (PV) ablation, our approach to PVI was superior in terms of methodology and technology. This review aims to describe how paroxysmal atrial fibrillation ablation has evolved over the last twenty years. We will focus on available techniques, a mechanistic understanding of paroxysmal AF genesis and the possibility of a tailored approach for the treatment of AF, before concluding with a future perspective.

The Influence of Different Multipolar Mapping Catheter Types on Procedural Outcomes in Patients Undergoing Pulmonary Vein Isolation for Atrial Fibrillation

(1) Background: During pulmonary vein isolation (PVI) for atrial fibrillation (AF), multipolar mapping catheters (MMC) are often used. We aimed to compare the procedural outcomes of two MMCs, specifically a circular-shaped and a five-spline-shaped MMC. (2) Methods: We enrolled 70 consecutive patients in our prospective, observational trial undergoing PVI procedures for paroxysmal AF. The initial 35 patients underwent PVI procedures with circular-shaped MMC guidance (Lasso Group), and the procedures for the latter 35 cases were performed using five-spline-shaped MMC (PentaRay Group). (3) Results: No significant differences were identified between the two groups in total procedure time (80.2 ± 17.7 min vs. 75.7 ± 14.8 min, p = 0.13), time from femoral vein puncture to the initiation of the mapping (31.2 ± 7 min vs. 28.9 ± 6.8, p = 0.80), mapping time (8 (6; 13) min vs. 9 (6.5; 10.5) min, p = 0.73), duration between the first and last ablation (32 (30; 36) min vs. 33 (26; 40) min, p = 0.52), validation time (3 (2; 4) min vs. 3 (1; 5) min, p = 0.46), first pass success rates (89% vs. 91%, p = 0.71), left atrial dwelling time (46 (37; 53) min vs. 45 (36.5; 53) min, p = 0.56), fluoroscopy data (time: 150 ± 71 s vs. 143 ± 56 s, p = 0.14; dose: 6.7 ± 4 mGy vs. 7.4 ± 4.4 mGy, p = 0.90), total ablation time (1187 (1063; 1534) s vs. 1150.5 (1053; 1393.5) s, p = 0.49), the number of ablations (78 (73; 93) vs. 83 (71.3; 92.8), p = 0.60), and total ablation energy (52,300 (47,265; 66,804) J vs. 49,666 (46,395; 56,502) J, p = 0.35). (4) Conclusions: This study finds comparable procedural outcomes bet-ween circular-shaped and five-spline-shaped MMCs for PVI in paroxysmal AF, supporting their interchangeability in clinical practice for anatomical mapping.

The Fluoroless Future in Electrophysiology: A State-of-the-Art Review

Fluoroscopy has always been the cornerstone imaging method of interventional cardiology procedures. However, radiation exposure is linked to an increased risk of malignancies and multiorgan diseases. The medical team is even more exposed to X-rays, and a higher incidence of malignancies was reported in this professional group. In the last years, X-ray exposure has increased rapidly, involving, above all, the medical team and young patients and forcing alternative fluoroless imaging methods. In cardiac electrophysiology (EP) and pacing, the advent of 3D electroanatomic mapping systems with dedicated catheters has allowed real-time, high-density reconstruction of both heart anatomy and electrical activity, significantly reducing the use of fluoroscopy. In addition, the diffusion of intracardiac echocardiography has provided high anatomical resolution of moving cardiac structures, providing intraprocedural guidance for more complex catheter ablation procedures. These methods have largely demonstrated safety and effectiveness, allowing for a dramatic reduction in X-ray delivery in most arrhythmias' ablations. However, some technical concerns, as well as higher costs, currently do not allow their spread out in EP labs and limit their use to only procedures that are considered highly complex and time-consuming and in young patients. In this review, we aim to update the current employment of fluoroless imaging in different EP procedures, focusing on its strengths and weaknesses.

Comparison of intracardiac vs. transesophageal echocardiography for "one-stop" procedures of combined radiofrequency catheter ablation and left atrial appendage closure with the Watchman device in the treatment of atrial fibrillation

Background and objective

This study aimed to assess the efficacy and safety of "one-stop" procedures that combined radiofrequency catheter ablation and left atrial appendage closure (LAAC) with the Watchman device under the guidance of intracardiac echocardiography (ICE) vs. transesophageal echocardiography (TEE) in patients with atrial fibrillation.

Methods and results

In this study, we prospectively enrolled patients who underwent "one-stop" procedures under the guidance of ICE (n = 193, 109 men, 65.02 ± 8.47 years) or TEE (n = 109, 69 men, 64.23 ± 7.75 years) between January 2021 and October 2022. Intraprocedural thrombus formation in the left atrial appendage (LAA) was observed in 3 (1.46%) patients in the ICE group and 15 (11.63%) patients in the TEE group (P < 0.05) before LAAC. Total fluoroscopy time and dose in the ICE group were less than those in the TEE group. The total "one-stop" turnaround time and LAAC procedure time in the ICE group were significantly shorter than those in the TEE group (P < 0.05). Postoperative esophagus discomfort, nausea and vomiting, and hypotension were more often seen in the TEE group (P < 0.001). There was no significant difference in matched cases between ICE and fluoroscopy measurements (P = 0.082). The TEE results related to LAAC and clinical events were similar between the two groups during the follow-up (P > 0.05).

Conclusion

The ICE-guided "one-stop" procedure was safe and feasible with less radiation exposure, shorter turnaround time, and fewer complications and intraoperative thrombus formations than the TEE group. ICE offered accurate measurements in the LAA dimension during LAAC. Echocardiography during the "one-stop" procedures was necessary to rule out the intraoperative thrombus.

Feasibility and safety of cavotricuspid isthmus ablation using exclusive intracardiac echocardiography guidance: a proof-of-concept, observational trial

Introduction

Catheter ablation is the preferred treatment for typical atrial flutter (AFl), but it can be challenging due to anatomical abnormalities. The use of 3D electroanatomical mapping systems (EAMS) has reduced fluoroscopy exposure during AFl ablation. Intracardiac echocardiography (ICE) has also shown benefits in reducing radiation exposure during AFl ablation. However, there is a lack of evidence on the feasibility of ICE-guided, zero-fluoroscopy AFl ablation without the use of EAMS.

Methods

In this prospective study, we enrolled 80 patients with CTI-dependent AFl. The first 40 patients underwent standard fluoroscopy + ICE-guided ablation (Standard ICE group), while the other 40 patients underwent zero-fluoroscopy ablation using only ICE (Zero ICE group). Procedure outcomes, including acute success, procedure time, fluoroscopy time, radiation dose, and complications, were compared between the groups.

Results

The acute success rate was 100% in both groups. Out of the 40 cases, the zero-fluoroscopy strategy was successfully implemented in 39 cases (97.5%) in the Zero ICE group. There were no significant differences in procedure time [55.5 (46.5; 66.8) min vs. 51.5 (44.0; 65.5), p = 0.50] and puncture to first ablation time [18 (13.5; 23) min vs. 19 (15; 23.5) min, p = 0.50] between the groups. The Zero ICE group had significantly lower fluoroscopy time [57 (36.3; 90) sec vs. 0 (0; 0) sec, p < 0.001] and dose [3.17 (2.27; 5.63) mGy vs. 0 (0; 0) mGy, p < 0.001] compared to the Standard ICE group. Total ablation time was longer in the Standard ICE group [597 (447; 908) sec vs. 430 (260; 750), p = 0.02], but total ablation energy [22,458 (14,836; 31,116) Ws vs. 17,043 (10,533; 29,302) Ws, p = 0.10] did not differ significantly. First-pass bidirectional conduction block of the CTI and acute reconnection rates were similar between the groups. No complications or recurrences were observed during the follow-up period.

Conclusion

Our study suggests that zero-fluoroscopy CTI ablation guided solely by ICE for AFl is feasible and safe. Further investigation is warranted for broader validation.

Comparison of pulmonary vein isolation using cryoballoon, high-power short-duration, and conventional radiofrequency ablation for atrial fibrillation: a propensity score-weighted study

Background

The comparative efficacy, saftey, and heart rate variability (HRV) parameters after pulmonary vein isolation using cryoballoon (Cryo-PVI), high-power short-duration (HPSD-PVI), and conventional radiofrequency ablation (conventional-PVI) for atrial fibrillation (AF) is unclear.

Materials and methods

In this propensity score-weighted, retrospective analysis of a single-center cohort, we analyzed 3,395 patients (26.2% female, 74.5% paroxysmal AF) who underwent AF catheter ablation without an empirical left atrial ablation. Procedural factors, recurrence rates, complication rates, and the post-procedural HRV parameters were compared across the Cryo-PVI (n = 625), HPSD-PVI (n = 748), and conventional-PVI (n = 2,022) groups.

Results

Despite the shortest procedural time in the Cryo-PVI group (74 min for Cryo-PVI vs. 104 min for HPSD-PVI vs. 153 min for conventional-PVI, p < 0.001), the major complication (p = 0.906) and clinical recurrence rates were similar across the three ablation groups (weighted log-rank, p = 0.824). However, the Cryo-PVI group was associated with a significantly lower risk of recurrent AF in patients with paroxysmal AF [weighted hazard ratio (WHR) 0.57, 95% confidence interval (CI) 0.37-0.86], whereas it was associated with a higher risk of recurrent AF in patients with persistent AF (WHR 1.41, 95% CI 1.06-1.89, p for interaction of <0.001) compared with the conventional-PVI group. In the subgroup analysis for the HRV, the Cryo-PVI group had the highest low-frequency-to-high-frequency ratio at 1-year post-procedure, whereas the HPSD-PVI group had the lowest low-frequency-to-high-frequency ratio at 1-year post-procedure (p < 0.001).

Conclusions

The Cryo-PVI group had better rhythm outcomes in patients with paroxysmal AF but worse rhythm outcomes in patients with persistent AF and a higher long-term post-procedural sympathetic nervous activity and sympatho-vagal balance compared with the conventional-PVI group.

Intracardiac Echocardiography Guidance Improves Procedural Outcomes in Patients Undergoing Cavotricuspidal Isthmus Ablation for Typical Atrial Flutter

Atrial flutter (AFL) represents a prevalent variant of supraventricular tachycardia, distinguished by a macro-reentrant pathway encompassing the cavotricuspid isthmus (CTI). Radiofrequency (RF) catheter ablation stands as the favored therapeutic modality for managing recurring CTI-dependent AFL. Intracardiac echocardiography (ICE) has been proposed as a method to reduce radiation exposure during CTI ablation. This study aims to comprehensively compare procedural parameters between ICE-guided CTI ablation and fluoroscopy-only procedures. A total of 370 consecutive patients were enrolled in our single-center retrospective study. In 151 patients, procedures were performed using fluoroscopy guidance only, while 219 patients underwent ICE-guided CTI ablation. ICE guidance significantly reduced fluoroscopy time (73 (36; 175) s vs. 900 (566; 1179) s; p < 0.001), fluoroscopy dose (2.45 (0.6; 5.1) mGy vs. 40.5 (25.7; 62.9) mGy; p < 0.001), and total procedure time (70 (52; 90) min vs. 87.5 (60; 102.5) min; p < 0.001). Total ablation time (657 (412; 981) s vs. 910 (616; 1367) s; p < 0.001) and the time from the first to last ablation (20 (11; 36) min vs. 40 (25; 55) min; p < 0.01) were also significantly shorter in the ICE-guided group. Acute success rate was 100% in both groups, and no major complications occurred in either group. ICE-guided CTI ablation in patients with AFL resulted in shorter procedure times, reduced fluoroscopy exposure, and decreased ablation times, compared to the standard fluoroscopy-only approach.

Catheter Ablation for the Management of Atrial Fibrillation: An Update of the Literature

Catheter ablation has been shown to be more effective at maintaining sinus rhythm and improving quality of life when compared to antiarrhythmic drugs. Radiofrequency and cryoablation are two effective methods. However, catheter-only ablation strategies have not consistently produced high success rates in treating longstanding and persistent AF patients. The emerging treatment of choice for such cases is hybrid ablation, which involves a multidisciplinary and minimally invasive approach to achieve surgical ablation of the direct posterior left atrial wall in combination with endocardial catheter ablation. Studies have shown promising results for the hybrid approach when compared with catheter ablation alone, but it is not without risks. Large and randomised studies are necessary to further evaluate these strategies for managing AF.