Feasibility of implementation of a "simplified, No-X-Ray, no-lead apron, two-catheter approach" for ablation of supraventricular arrhythmias in children and adults

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 between conventional approach and three-dimensional mapping system in the catheter ablation of accessory pathway associated with coronary sinus diverticulum: A single-center experience

BACKGROUND

Posteroseptal accessory pathways (APs) associated with coronary sinus (CS) diverticulum present a rare and challenge for ablation. This study aimed to compare the safety and efficacy of conventional approach and three-dimensional (3D) mapping system in the catheter ablation.

METHODS AND RESULTS

This was a retrospective study of all patients (from January 2013 to July 2022) who underwent catheter ablation of posteroseptal AP associated with CS diverticula in our center. Patients who underwent catheter ablation using the traditional fluoroscopy method were included in the conventional method group (n = 13). Patients who underwent catheter ablation using the 3D mapping method were included in the 3D mapping group (n = 11). Clinical characteristics, ablation procedure, and outcomes were recorded and analyzed between the two groups. Out of 669 patients with posteroseptal APs, 24 of them (3.6%) were associated with CS diverticula. All patients in both groups successfully completed the electrophysiological study. In the conventional method group, two patients experienced complications (one patient with pericardial effusion and the other patient with femoral arterial hematoma), and two patients had recurrence. However, no patients suffered from complications or recurrence during follow-up. The procedure time and fluoroscopy time in the conventional method group were significantly longer than those in the 3D mapping method group.

CONCLUSIONS

The utilization of 3D mapping led to reduced fluoroscopy time, shorter procedure duration, enhanced acute success rates, and decreased incidence of complications.

Toward Fluoro-Free Interventions: Using Radial Intracardiac Ultrasound for Vascular Navigation

Transcatheter cardiovascular interventions have the advantage of patient safety, reduced surgery time and minimal trauma to the patient's body. Transcathether interventions, which are performed percutaneously, are limited by the lack of direct line of sight with the procedural tools and the patient anatomy. Therefore, such interventional procedures rely heavily on image guidance for navigating toward and delivering therapy at the target site. Vascular navigation via the inferior vena cava, from the groin to the heart, is an imperative part of most transcatheter cardiovascular interventions including heart valve repair surgeries and ablation therapy. Traditionally, the inferior vena cava is navigated using fluoroscopic techniques such as venography and computed tomography venography. These X-ray-based techniques can have detrimental effects on the patient as well as the surgical team, causing increased radiation exposure, leading to risk of cancer, fetal defects and eye cataracts. The use of a heavy lead apron has also been reported to cause back pain and spine issues, thus leading to interventionalist's disc disease. We propose the use of a catheter-based ultrasound augmented with electromagnetic tracking technology to generate a vascular roadmap in real time and perform navigation without harmful radiation. In this pilot study, we used spatially tracked intracardiac echocardiography to reconstruct a vessel from a phantom in a 3-D virtual environment. We illustrate how the proposed ultrasound-based navigation will appear in a virtual environment, by navigating a tracked guidewire within the vessels in the phantom without any radiation-based imaging. The geometric accuracy is assessed using a computed tomography scan of the phantom, with a Dice coefficient of 0.79. The average distance between the surfaces of the two models comes out to be 1.7 ± 1.12 mm.

Zero and Minimal Fluoroscopic Approaches During Ablation of Supraventricular Tachycardias: A Systematic Review and Meta-Analysis

Introduction

Catheter ablations for cardiac arrhythmias are conventionally performed under fluoroscopic guidance. To guide these procedures, zero/minimal fluoroscopy (Z/MF) approaches have become available, using three-dimensional electroanatomical mapping systems. Our aim was to conduct a meta-analysis comparing these two different methods for the treatment of paroxysmal supraventricular tachycardia (SVT).

Methods

Electronic databases were searched and systematically reviewed for studies comparing procedural parameters and outcomes of conventional, fluoroscopy-guided vs. Z/MF approaches in patients undergoing electrophysiology (EP) procedures for SVTs. The random-effects model was used to derive mean difference (MD) and risk ratios (RRs) with 95% confidence interval (CI).

Results

Twenty-four studies involving 9,074 patients met our inclusion criteria. There was no difference between the groups in terms of acute success rate (RR = 1.00, 95% CI, 0.99–1.01; p = 0.97) and long-term success rate (RR: 1.01, 95% CI, 1.00–1.03; p = 0.13). Compared to the conventional method, zero-and-minimal fluoroscopy (Z/MF) ablation significantly reduced fluoroscopic time [MD: −1.58 min (95% CI, −2.21 to −0.96 min; p < 0.01)] and ablation time [MD: −25.23 s (95% CI: −42.04 to −8.43 s; p < 0.01)]. No difference could be detected between the two groups in terms of the procedure time [MD: 3.06 min (95% CI: −0.97 to 7.08; p = 0.14)] and the number of ablation applications [MD: 0.13 (95% CI: −0.86 to 1.11; p = 0.80)]. The complication rate was 1.59% in the entire study population and did not differ among the groups (RR: 0.68, 95% CI: 0.45–1.05; p = 0.08).

Conclusions

The Z/MF approach for the catheter ablation of SVTs is a feasible method that reduces radiation exposure and ablation time without compromising the acute and long-term success or complication rates.

Efficacy and Safety of Zero-Fluoroscopy Approach during Catheter Ablation of Accessory Pathway

Background: Catheter ablation (CA) is a safe and efficient treatment in patients with an atrioventricular accessory pathway (AP). Electroanatomical mapping (EAM) systems are useful during CA of AP, especially for reducing fluoroscopy. There are limited data about the feasibility of CA procedures performed with the use of the EAM system entirely without fluoroscopy in adults with AP. The aim of the study is to assess the feasibility, efficacy and safety of CA with the use of EAM without fluoroscopy, compared to CA with EAM and fluoroscopy in patients with AP. Methods: The study included 83 consecutive patients (age 38.25 ± 15.8 years), who were subjected to CA for AP. In 40 patients CA was performed with the use of EAM without fluoroscopy (EAM group), and in 43 patients CA was performed with EAM and fluoroscopy (control group). Baseline characteristics, procedure parameters and complications were obtained from the medical records. Data on permanent success rate was obtained after the mean follow-up time of 1 year. Primary outcomes were acute procedural success rate, long term success rate at 1-year follow-up and complications. Secondary outcomes were the procedure time and number of applications. Results: There were no statistically significant differences in baseline characteristics between the groups, except for the AP locations. Right-sided AP was more common in the EAM group, while left-sided AP was more common in the control group (p = 0.007 and p = 0.004, respectively). Acute procedural success was achieved in 38 patients (95.0%) in the EAM group and in 39 patients (90.7%) in the control group (p = 0.449). Long term success rate was achieved in 36 patients (90.0%) in the EAM group and in 36 (83.7%) patients in the control group (p = 0.399). There was one minor complication in the form of RBBB in the EAM group (p = 0.138). The mean procedure time was shorter in the EAM group compared to the control group (93.0 ± 58.3 min vs. 127.6 ± 57.5 min; p = 0.009). Conclusions: CA of both right-sided and left-sided AP completely guided by EAM without the use of fluoroscopy is feasible, safe and effective.

Sensor Enabled Catheter Ablation Study (SECAS)

Background EnSite Precision technology (Abbott, Chicago, Illinois) is a novel mapping and navigation system facilitating the visualization and manipulation of intracardiac catheters during arrhythmia ablation procedures. When using Sensor Enabled (SE) catheters (Abbott, Chicago, Illinois), the mapping system uses both electrical impedance and magnetic data to facilitate more accurate mapping and navigation. Whether this translates into better clinical outcomes is unknown. Methods This retrospective study will examine whether SE catheters improve the success rate or decrease the risks compared to Biosense Thermocool catheters (Biosense Webster Inc., Irvine, California) not employing sensor-enabled technology utilizing NavX EnSite Precision algorithms. Charts of 146 patients who underwent radiofrequency ablations for supraventricular and ventricular arrhythmias between 2016 and 2019 in the Beirut Cardiac Institute were reviewed and analyzed. It was concluded that SE catheters have the same success rate as electrical impedance catheters. Results A total of 70% of the ablations carried using the impedance-based catheter were successful compared to 74% using the SE catheter. However, the difference was statistically non-significant (p-value: 0.7). As for complications, the ventricular fibrillation rate was increased in the SE catheter group. Three procedures were complicated by pericardial effusion, three patients had reversible heart block, and one death was recorded, all reported while using the standard catheter (p-value: 0.01). Conclusion SE catheters have the same success rates compared to standard catheters using the EnSite Precision mapping system.

Implementation of zero or near-zero fluoroscopy catheter ablation for idiopathic ventricular arrhythmia originating from the aortic sinus cusp

Complete elimination of fluoroscopy during radiofrequency ablation (RFA) of idiopathic ventricular arrhythmias (IVAs) originating from the aortic sinus cusp (ASC) is challenging. The aim was to assess the feasibility, safety and a learning curve for a zero-fluoroscopy (ZF) approach in centers using near-zero fluoroscopy (NOX) approach in IVA-ASC. Between 2012 and 2018, we retrospectively enrolled 104 IVA-ASC patients referred for ZF RFA or NOX using a 3-dimensional electroanatomic (3D-EAM) system (Ensite, Velocity, Abbott, USA). Acute, short and long-term outcomes and learning curve for the ZF were evaluated. ZF was completed in 62 of 75 cases (83%) and NOX in 32 of 32 cases (100%). In 13 cases ZF was changed to NOX. No significant differences were found in success rates between ZF and NOX, no major complications were noted. The median procedure and fluoroscopy times were 65.0 [45-81] and 0.0 [0-5] min respectively, being shorter for ZF than for NOX. With growing experience, the preference for ZF significantly increased-43% (23/54) in 2012-2016 vs 98% (52/53) in 2017-2018, with a simultaneous reduction in the procedure time. ZF ablation can be completed in almost all patients with IVA-ASC by operators with previous experience in the NOX approach, and after appropriate training, it was a preferred ablation technique. The ZF approach for IVA-ASC guided by 3D-EAM has a similar feasibility, safety, and effectiveness to the NOX approach.

Zero fluoroscopy approach versus fluoroscopy approach for cardiac arrhythmia ablations: A systematic review and meta-analysis

BACKGROUND

Radiofrequency catheter ablation for cardiac arrhythmias has traditionally been guided by fluoroscopy. Fluoroscopy exposes the patient, operator, and staff to ionizing radiation which has no safe dose void of stochastic and deterministic biologic risks. Zero fluoroscopy (ZF) approaches for catheter ablation have been advocated to eliminate these risks. We conducted a meta-analysis comparing acute procedure success, recurrence-free survival, complications, and procedure times between the approaches.

METHODS

We conducted a literature search from inception through December 2020 in the databases of EMBASE and MEDLINE. We included randomized controlled trials and cohorts that compared the outcomes of interest in ZF and conventional/low fluoroscopy (CF/LF) approaches. The outcomes sought were acute procedure success, recurrence-free survival, complications, and procedure times. Effect estimates were combined, using the random-effects, generic inverse variance method of DerSimonian and Laird.

RESULTS

Sixteen studies from 2013 to 2020, including 6052 patients (2219 ZF, 3833 CF/LF) were included. There were no significant differences in acute procedure success rate (odds ratio [OR]: 1.10, 95% confidence interval [CI]: 0.75-1.59), recurrence-free survival (OR: 1.08, 95% CI: 0.78-1.49), periprocedural complication rate (OR: 0.72, 95% CI: 0.45-1.16), or total procedure time (weighted mean difference 2.32 min, 95% CI: -2.85-7.50) between ZF and CF/LF approaches, respectively. Overall, only 1.26% of patients crossed over from ZF to CF/LF arm.

CONCLUSIONS

Periprocedural and postprocedural outcomes with a ZF approach compared favorably with traditional fluoroscopic guidance without increasing procedural times. As comfort with ZF grows, coupled with evolving mapping technologies, this method has potential to become the standard approach for catheter ablation.

Radiation Safety and Electrophysiologists: Radiation Protection Status - Go for Zero Fluoroscopy European Heart Rhythm Association Registry

BACKGROUND

The purpose of this study was to analyze electrophysiologists' radiation-protective devices for occupational exposure across European countries.

METHODS

Data reported herein were gathered from the international, multicenter prospective Go for Zero Fluoroscopy registry performed in years 2018-2019. The registry encompassed 25 European electrophysiological centers from 14 countries and up to 5 operators from each center.

RESULTS

The analysis included 95 operators (median age: 39 years, 85% of male, median training time: 5 years). The most frequently used X-ray protection tools (used by ≥80% of the group) were lead aprons, thyroid shields, screens below the table, glass in the laboratory, and least often (<7%) protective gloves and cabin. No statistically significant differences regarding the number of procedures performed monthly, electrophysiologists' experience and gender, and radiation exposure dose or radiation protection tools were observed, except lead thyroid shields and eyeglasses, which were more often used in case of fewer electrophysiological procedures performed (<20 procedures per month). Operators who were protected by >4 X-ray protection tools were exposed to lower radiation levels than those who were protected by ≤4 X-ray protection tools (median radiation exposure: 0.6 [0.2-1.1] vs. 0.2 [0.1-0.2] mSv per month, p < 0.0001; 1.1 [0.1-12.0] vs. 0.5 [0.1-1.1] mSv per year, p < 0.0001), respectively.

CONCLUSIONS

Electrophysiologists' radiation-protective devices for occupational exposure are similar across European centers and in accordance with the applicable X-ray protection protocols, irrespective of the level of experience, number of monthly performed EP procedures, and gender.

Intracardiac Echocardiography to Guide Non-fluoroscopic Electrophysiology Procedures

Intracardiac echocardiography (ICE) is the most practical method for online imaging during electrophysiological procedures. It allows guiding of complex catheter ablation procedures together with electroanatomical mapping systems, either with minimal or with zero fluoroscopy exposure. Besides safe and reproducible transseptal puncture, ICE helps to assess location and contact of the tip of the ablation catheter relative to specific anatomical structures. Another option is visualization of the arrhythmogenic substrate in patients with ventricular arrhythmias. This article describes the clinical utility of ICE in non-fluoroscopic electrophysiology procedures more in detail.

Into a Fluoroless Future: an Appraisal of Fluoroscopy-Free Techniques in Clinical Cardiac Electrophysiology

Purpose of Review

There are risks to both patients and electrophysiology providers from radiation exposure from fluoroscopic imaging, and there is increased interest in fluoroscopic reduction. We review the imaging tools, their applications, and current uses to eliminate fluoroscopy.

Recent Findings

Multiple recent studies provide supporting evidence for the transition to fluoroscopy-free techniques for both ablations and device implantation. The most frequently used alternative imaging approaches include intracardiac echocardiography, cardiac MRI guidance, and 3D electroanatomic mapping systems. Electroanatomic mapping and intracardiac echocardiography originally used to augment fluoroscopy imaging are now replacing the older imaging technique. The data supports that the future of electrophysiology can be fluoroscopy-free or very low fluoroscopy for the vast majority of cases.

Summary

As provider and institution experience grows with these techniques, many EP labs may choose to completely forego the use of fluoroscopy. Trainees will benefit from early experience with these techniques.

Fluoroless catheter ablation of accessory pathways in adult and pediatric patients: a single centre experience

Catheter radio-frequency ablation (RFA) and cryo-ablation (CRA) procedures are an effective and safe treatment options for adult and pediatric patients with accessory pathway (AP) mediated tachycardias. Non-fluoroscopic techniques during catheter ablation (CA) procedures reduce potentially harmful effects of radiation. Our aim was to investigate the efficacy and safety of completely fluoroless RFA and CRA procedures in pediatric and adult patients with APs. Consecutive patients with AP-related tachycardia and high risk asymptomatic ventricular pre-excitation were assessed in retrospective analysis. Three-dimensional (3D) electro-anatomical mapping (EAM) and intra-cardiac echocardiography (ICE) were used as principal imaging modalities. Fluoroscopy was not used during any stage of the procedures. Among 116 included patients (22.76 ± 16.1 years, 68 patients < 19 years), 60 had left-sided APs, 16 right-sided APs and 40 septal APs. Altogether, 96 had RFA and 20 CRA procedures. The acute success rates (ASR) of RFA and CRA were 97.9% and 95%, respectively (p = 0.43), with recurrence rates (RR) of 8.33% and 40%, respectively (p < 0.0001). The outcome difference was principally driven by lower RR with RFA in septal APs (9.1% vs. 38.9%, p = 0.025). Pediatric patients with APs (12.21 ± 3.76 years) had similar procedural parameters and outcomes compared to adult patients. There were no procedure-related complications. In adult and pediatric patients with AP-related tachycardias, both CRA and RFA can be effectively and safely performed without the use of fluoroscopy. In addition, RFA resulted in better outcomes compared to CRA.

Fluoroless radiofrequency and cryo-ablation of atrioventricular nodal reentry tachycardia in adults and children: a single-center experience

BACKGROUND

Radiofrequency ablation (RFA) and cryo-ablation (CRA) have been traditionally performed with fluoroscopy which exposes patients and medical staff to the potential harmful effects of the X-ray. Therefore, we aimed to assess the feasibility, safety, and effectiveness of RFA and CRA of atrioventricular nodal reentry tachycardia (AVNRT) guided by the three-dimensional (3D) electro-anatomical mapping (EAM) system without the use of fluoroscopy.

METHODS

We analyzed 168 consecutive patients with AVNRT, 62 of whom were under 19 years of age (128 in RFA (age 34.04 ± 21.0 years) and 40 in CRA (age 39.41 ± 22.8 years)). All procedures were performed completely without the use of the fluoroscopy and with the 3D EAM system.

RESULTS

The acute success rates (ASR) of the two ablation methods were very high and similar (for RFA 126/128 (98.4%) and for CRA 40/40 (100%); p = 0.43). Total procedural time (TPT) was similar in RFA and CRA groups (75.04 ± 42.31 min and 73.12 ± 30.54 min, respectively; p = 0.79). Recurrence rates (1 (2.5%) and 8 (6.25%); p = 0.35) were similar. There were no complications associated with procedures in either group. In pediatric group, ASR (61/62 (98.38%) and 105/106 (99.05%), respectively; p = 0.69) and TPT (75.16 ± 42.2 min and 74.23 ± 38.3 min, respectively; p = 0.88) were similar to the adult group. High ASR was observed with both ablation methods (for RFA 49/50, 98%, and for CRA 12/12, 100%; p = 0.62] with very high arrhythmia-free survival rates (for RFA 98% and for CRA 100%; p = 0.62).

CONCLUSION

Based on these results, it can be suggested that fluoroless RFA or CRA guided by the 3D EAM system can be routinely performed in all patients with AVNRT without compromising safety, efficacy, or duration of the procedure.

State of Fluoroless Procedures in Cardiac Electrophysiology Practice

In the past decade, the use of interventional electrophysiological (EP) procedures for the diagnosis and treatment of cardiac arrhythmias has exponentially increased. These procedures usually require fluoroscopy to guide the advancement and frequent repositioning of intracardiac catheters, resulting in both the patient and the operator being subjected to a considerable degree of radiation exposure. Although shielding options such as lead gowns, glasses, and pull-down shields are useful for protecting the operator, they do not lessen the patient’s level of exposure. Furthermore, the prolonged use of lead gowns can exponentiate the onset of orthopedic problems among operators. Recent advancements in three-dimensional cardiac mapping systems and the use of radiation-free imaging technologies such as magnetic resonance imaging and intracardiac ultrasound allow operators to perform EP procedures with minimal or even no fluoroscopy. In this review, we sought to describe the state of fluoroless procedures in EP practice.

Zero-fluoroscopy approach for ablation of supraventricular tachycardia using the Ensite NavX system: a multicenter experience

BACKGROUND

Three-dimensional electroanatomic mapping systems have demonstrated a significant reduction in radiation exposure during radiofrequency catheter ablation procedures. We aimed to investigate the safety, feasibility and efficacy of a completely zero-fluoroscopy approach for catheter ablation of supraventricular tachycardia using the Ensite NavX navigation system compared with a conventional fluoroscopy approach.

METHODS

A multicenter prospective non-randomized registry study was performed in seven centers from January 2013 to February 2018. Consecutive patients referred for catheter ablation of supraventricular tachycardia were assigned either to a completely zero-fluoroscopic approach (ZF) or conventional fluoroscopy approach (CF) according to the operator's preference. Patients with atrial tachycardia were excluded.

RESULTS

Totally, 1020 patients were enrolled in ZF group; 2040 patients ablated by CF approach were selected for controls. There was no significant difference between the zero-fluoroscopy group and conventional fluoroscopy group as to procedure time (60.3 ± 20.3 vs. 59.7 ± 22.6 min, P = 0.90), immediate success rate of procedure (98.8% vs. 99.2%, P = 0.22), arrhythmia recurrence (0.4% vs. 0.5%, P = 0.85), total success rate of procedure (98.4% vs. 98.8%, P = 0.39) or complications (1.1% vs. 1.5%, P = 0.41). Compared with the conventional fluoroscopy approach, the zero-fluoroscopy approach provided similar outcomes without compromising the safety or efficacy of the procedure.

CONCLUSION

The completely zero-fluoroscopy approach demonstrated safety and efficacy comparable to a conventional fluoroscopy approach for catheter ablation of supraventricular tachycardia, and mitigated radiation exposure to both patients and operators.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT03042078; first registered February 3, 2017; retrospectively registered.

Combined use of electro-anatomic mapping system and intracardiac echocardiography to achieve zero-fluoroscopy catheter ablation for treatment of paroxysmal atrial fibrillation: a single centre experience

Fluoroscopy is the principal imaging method for catheter ablation (CA) of atrial fibrillation (AF). However, radiation exposure carries potential health risk to patients and operators alike. Our aim was to study safety and efficacy of zero-fluoroscopy CA of paroxysmal AF with a combined use of electroanatomic mapping system (EAM) and intracardiac echocardiography (ICE). In addition, impact of ICE/EAM automatic integration system and contact force (CF) sensing technology on procedural times were assessed. We included 144 consecutive patients (69% males, age 60 ± 10 years, BMI 29 ± 4,6) referred for CA of symptomatic paroxysmal AF. All procedures were performed only with EAM system and ICE. No fluoroscopy was used. The acute procedural success of complete pulmonary vein isolation was achieved in all patients (100%) and adverse events were detected in eight patients (5.6%). In 53 (37%) patients the use of ICE/EAM automatic integration system shortened procedural times compared to those performed without it (148 ± 35 vs. 187 ± 44 min, p < 0.05). Similarly, 89 (60%) procedures where CF sensing catheter was used were shorter compared to those performed without it (163 ± 41 vs. 188 ± 46 min, p < 0.05). Zero-fluoroscopy approach for treatment of paroxysmal AF seems feasible, safe, and acutely effective. Additional reduction of procedural times could be achieved with the use of ICE/EAM automatic integration system and CF sensing technology.

Feasibility and performance of catheter ablation with zero-fluoroscopy approach for regular supraventricular tachycardia in patients with structural and/or congenital heart disease

Patients with structural heart disease (SHD) are more difficult to ablate than those with a structurally healthy heart. The reason may be technical problems. We compared periprocedural data in unselected patients (including SHD group) recruited for zero-fluoroscopy catheter ablation (ZF-CA) of supraventricular arrhythmias (SVTs).Consecutive adult patients with atrioventricular nodal reentry tachycardia (AVNRT), accessory pathways (AP), atrial flutter (AFL), and atrial tachycardia (AT) were recruited. A 3-dimensional electroanatomical mapping system (Ensite Velocity, NavX, St Jude Medical, Lake Bluff, Illinois) was used to create electroanatomical maps and navigate catheters. Fluoroscopy was used on the decision of the first operator after 5 minutes of unresolved problems.Of the 1280 patients ablated with the intention to be treated with ZF approach, 174 (13.6%) patients with SHD (age: 58.2 ± 13.6; AVNRT: 23.9%; AP: 8.5%; AFL: 61.4%; and AT: 6.2%) were recruited. These patients were compared with the 1106 patients with nonstructural heart disease (NSHD) (age: 51.4 ± 16.4; AVNRT: 58.0%; AP: 17.6%; AFL: 20.7%; and AT: 3.7% P ≤ .001). Procedural time (49.9 ± 24.6 vs 49.1 ± 23.9 minutes, P = .55) and number of applications were similar between groups (P = 0.08). The rate of conversion from ZF-CA to fluoroscopy was slightly higher in SHD as compared to NSHD (13.2% vs 7.8%, P = .02) while the total time of fluoroscopy and radiation doses were comparable in the group of SHD and NSHD (P = .55; P = .48).ZF-CA is feasible and safe in majority of patients with SHD and should be incorporated into a standard approach for SHD; however, the procedure requires sufficient experience.

Direct results of a prospective randomized study comparing ablation with the nMARQ catheter and the PVAC catheter used with and without a 3D system (MAPER 3D Study)

INTRODUCTION

Our aim was to compare in a prospective randomized study the safety, direct results and periprocedural data of ablation using an nMARQ catheter, a PVAC catheter used with the EnSite system, or a PVAC catheter only under fluoroscopy control.

MATERIAL AND METHODS

One hundred two patients (70 male, 57 ±11 years) with atrial fibrillation (AF) were prospectively randomized to: group 1 - ablation performed with an nMARQ catheter and the CARTO 3 system; group 2 - a PVAC catheter used with the EnSite system; group 3 - ablation with a PVAC catheter without a 3D system.

RESULTS

Complete isolation of 400/402 pulmonary veins (PV) (99.5%). Linear ablation was performed in 23 patients in group 1 (small distance between lines isolating PV), in 3 patients in group 2, in 1 patient in group 3. The superior vena cava was isolated in 1 patient, 9 patients, and 9 patients respectively. Duration of fluoroscopy and dose area product were significantly smaller in group 1 (6.5 ±2.9 min/808.8 ±393.9 cGy/cm² vs. 13.6 ±5.6 min/1662.6 ±677.8 cGy/cm² and 18.8 ±7.6 min/2327.9 ±975.5 cGy/cm²; p < 0.001). Procedure duration was shorter in group 1 (82.9 ±18.8 min vs. 101.2 ±19.6 min, p < 0.001 and 99.8 ±20.8 min, NS). Contrast injection was necessary in 2 patients in group 1, in 8 patients in group 2 and in all patients in group 3. Because nMARQ is a thermocool catheter, the volume of fluid injection was significantly greater (2348.5 ±543.5 ml vs. 1077.9 ±280.5 ml and 1076.5 ±375.6 ml, p < 0.001). There were no periprocedural deaths. We observed no cardiac tamponade, neurological complications and no atrioesophageal fistula during follow-up.

CONCLUSIONS

The lowest radiological exposure was observed during ablation performed with an nMARQ catheter. 3D systems reduced fluoroscopy duration and the necessity of contrast injection. The nMARQ catheter requires injection of a large volume of fluid.

A simplified approach for evaluating sustained slow pathway conduction for diagnosis and treatment of atrioventricular nodal reentry tachycardia in children and adults

PURPOSE

During incremental atrial pacing in patients with atrioventricular nodal reentrant tachycardia, the PR interval often exceeds the RR interval (PR > RR) during stable 1:1 AV conduction. However, the PR/RR ratio has never been evaluated in a large group of patients with pacing from the proximal coronary sinus and after isoproterenol challenge. Our study validates new site of pacing and easier method of identification of PR > RR.

MATERIAL AND METHODS

A prospective protocol of incremental atrial pacing from the proximal coronary sinus was carried out in 398 patients (AVNRT-228 and control-170). The maximum stimulus to the Q wave interval (S-Q = PR), SS interval (S-S), and Q-Q (RR) interval were measured at baseline and 10 min after successful slow pathway ablation and after isoproterenol challenge (obligatory).

RESULTS

The mean maximum PR/RR ratios at baseline were 1.17 ± 0.24 and 0.82 ± 0.13 (p < 0.00001) in the AVNRT and controls respectively. There were no PR/RR ratios ≥1 at baseline and after isoproterenol challenge in 12.3% of the AVNRT group and in 95.9% of the control group (p < 0.0001). PR/RR ratios ≥1 were absent in 98% of AVNRT cases after slow pathway ablation/modification in children and 99% of such cases in adults (P = NS). The diagnostic performance of PR/RR ratio evaluation before and after isoproterenol challenge had the highest diagnostic performance for AVNRT with PR/RR > = 1 (sensitivity: 88%, specificity: 96%, PPV-97%, NPV-85%).

CONCLUSIONS

The PR/RR ratio is a simple tool for slow pathway substrate and AVNRT evaluation. Eliminating PR/RR ratios ≥1 may serve as a surrogate endpoint for slow pathway ablation in children and adults with AVNRT.

Maximum voltage gradient technique for optimization of ablation for typical atrial flutter with zero-fluoroscopy approach

Radiofrequency catheter ablation (RFCA) is an established effective method for the treatment of typical cavo-tricuspid isthmus (CTI)-dependent atrial flutter (AFL). The introduction of 3-dimensional electro-anatomic systems enables RFCA without fluoroscopy (No-X-Ray [NXR]). The aim of this study was to evaluate the feasibility and effectiveness of CTI RFCA during implementation of the NXR approach and the maximum voltage-guided (MVG) technique for ablation of AFL.Data were obtained from prospective standardized multicenter ablation registry. Consecutive patients with the first RFCA for CTI-dependent AFL were recruited. Two navigation approaches (NXR and fluoroscopy based as low as reasonable achievable [ALARA]) and 2 mapping and ablation techniques (MVG and pull-back technique [PBT]) were assessed. NXR + MVG (n  =  164; age: 63.7 ± 9.5; 30% women), NXR + PBT (n  =  55; age: 63.9 ± 10.7; 39% women); ALARA + MVG (n  =  36; age: 64.2 ± 9.6; 39% women); and ALARA + PBT (n  =  205; age: 64.7 ± 9.1; 30% women) were compared, respectively. All groups were simplified with a 2-catheter femoral approach using 8-mm gold tip catheters (Osypka AG, Germany or Biotronik, Germany) with 15 min of observation. The MVG technique was performed using step-by-step application by mapping the largest atrial signals within the CTI.Bidirectional block in CTI was achieved in 99% of all patients (P  =  NS, between groups). In NXR + MVG and NXR + PBT groups, the procedure time decreased (45.4 ± 17.6 and 47.2 ± 15.7 min vs. 52.6 ± 23.7 and 59.8 ± 24.0 min, P < .01) as compared to ALARA + MVG and ALARA + PBT subgroups. In NXR + MVG and NXR + PBT groups, 91% and 98% of the procedures were performed with complete elimination of fluoroscopy. The NXR approach was associated with a significant reduction in fluoroscopy exposure (from 0.2 ± 1.1 [NXR + PBT] and 0.3 ± 1.6 [NXR + MVG] to 7.7 ± 6.0 min [ALARA + MVG] and 9.1 ± 7.2 min [ALARA + PBT], P < .001). The total application time significantly decreased in the MVG technique subgroup both in NXR and ALARA (P < .01). No major complications were observed in either groups.Complete elimination of fluoroscopy is feasible, safe, and effective during RFCA of CTI in almost all AFL patients without cardiac implanted electronic devices. The most optimal method for RFCA of CTI-dependent AFL seems to be MVG; however, it required validation of optimal RFCA's parameters with clinical follow-up.

Nonfluoroscopic Catheter Ablation. Results From a Prospective Multicenter Registry

INTRODUCTION AND OBJECTIVES

Nonfluoroscopic catheter ablation is feasible in most procedures. The aim of our registry was to evaluate the safety and feasibility of a zero-fluoroscopic approach to catheter ablation in several Spanish centers.

METHODS

Eleven centers prospectively included a minimum of 20 patients. Patients with an arrhythmic substrate deemed suitable by the operator for a zero-fluoroscopic approach throughout the procedure were recruited. Patients with intracardiac devices were not included. Attending electrophysiologists, fellows, and resident physicians participated in each procedure, as in usual care.

RESULTS

The study included 247 patients. Ablation was performed in 235 patients (95.2%). In 2 patients, who were not included in the analysis, fluoroscopy was performed as the first-line treatment. The arrhythmic substrate was located in the right chambers in most of the procedures (231 of 233 [99.15%]). Fluoroscopy was used in 24 procedures (10.3%). Catheter ablation was successful in 96.4% of the procedures and severe complications occurred in 2 patients (0.85%). Two variables were related to the need for fluoroscopy: the performing center (minimum 0% vs maximum 30.3%; P=.001) and procedural failure (13% vs 2.4%; P<.05).

CONCLUSIONS

The Spanish multicenter registry reveals that a zero-fluoroscopic approach is feasible in most right-sided catheter ablation procedures. Randomized trials are necessary to confirm the safety of this approach. The need for fluoroscopy was related to procedural failure, with significant differences among performing centers.

Meta-Analysis of Zero or Near-Zero Fluoroscopy Use During Ablation of Cardiac Arrhythmias

Data regarding the efficacy and safety of zero or near-zero fluoroscopic ablation of cardiac arrhythmias are limited. A literature search was conducted using PubMed and Embase for relevant studies through January 2016. Ten studies involving 2,261 patients were identified. Compared with conventional radiofrequency ablation method, zero or near-zero fluoroscopy ablation significantly showed reduced fluoroscopic time (standard mean difference [SMD] -1.62, 95% CI -2.20 to -1.05; p <0.00001), ablation time (SMD -0.16, 95% CI -0.29 to -0.04; p = 0.01), and radiation dose (SMD -1.94, 95% CI -3.37 to -0.51; p = 0.008). In contrast, procedure duration was not significantly different from that of conventional radiofrequency ablation (SMD -0.03, 95% CI -0.16 to 0.09; p = 0.58). There were no significant differences between both groups in immediate success rate (odds ratio [OR] 0.99, 95% CI 0.49 to 2.01; p = 0.99), long-term success rate (OR 1.13, 95% CI 0.42 to 3.02; p = 0.81), complication rates (OR 0.98, 95% CI 0.49 to 1.96; p = 0.95), and recurrence rates (OR 1.29, 95% CI 0.74 to 2.24; p = 0.37). In conclusion, radiation was significantly reduced in the zero or near-zero fluoroscopy ablation groups without compromising efficacy and safety.

Fluoroless catheter ablation of various right and left sided supra-ventricular tachycardias in children and adolescents

Electrophysiology study (EPS) and catheter ablation (CA) in children and adolescents carries a potentially harmful effect of radiation exposure when performed with the use of fluoroscopy. Our aim was to evaluate the feasibility, safety and effectiveness of fluoroless EPS and CA of various supra-ventricular tachycardias (SVTs) with the use of the 3D mapping system and intracardiac echocardiography (ICE). Forty-three consecutive children and adolescents (age 13 ± 3 years) underwent fluoroless EPS and CA for various supra-ventricular tachycardias. A three-dimensional (3D) mapping system NavX™ was used for guidance of diagnostic and ablation catheters in the heart. ICE was used as a fundamental imaging tool for transseptal punctures. Acute procedural success rate was 100 %. There were no procedure related complications and short-term follow up (10 ± 3 months) revealed 93 % arrhythmia free survival rate. Fluoroless CA of various SVTs in the paediatric population is feasible, safe and can be performed successfully with 3D mapping system and ICE.

Validation of Standard and New Criteria for the Differential Diagnosis of Narrow QRS Tachycardia in Children and Adolescents

To establish an appropriate treatment strategy and determine if ablation is indicated for patients with narrow QRS complex supraventricular tachycardia (SVT), analysis of a standard 12-lead electrocardiogram (ECG) is required, which can differentiate between the 2 most common mechanisms underlying SVT: atrioventricular nodal reentry tachycardia (AVNRT) and orthodromic atrioventricular reentry tachycardia (OAVRT). Recently, new, highly accurate electrocardiographic criteria for the differential diagnosis of SVT in adults were proposed; however, those criteria have not yet been validated in a pediatric population.All ECGs were recorded during invasive electrophysiology study of pediatric patients (n = 212; age: 13.2 ± 3.5, range: 1-18; girls: 48%). We assessed the diagnostic value of the 2 new and 7 standard criteria for differentiating AVNRT from OAVRT in a pediatric population.Two of the standard criteria were found significantly more often in ECGs from the OAVRT group than from the AVNRT group (retrograde P waves [63% vs 11%, P < 0.001] and ST-segment depression in the II, III, aVF, V1-V6 leads [42% vs 27%; P < 0.05]), whereas 1 standard criterion was found significantly more often in ECGs from the AVNRT group than from the OAVRT group (pseudo r' wave in V1 lead [39% vs 10%, P < 0.001]). The remaining 6 criteria did not reach statistical significance for differentiating SVT, and the accuracy of prediction did not exceed 70%. Based on these results, a multivariable decision rule to evaluate differential diagnosis of SVT was performed.These results indicate that both the standard and new electrocardiographic criteria for discriminating between AVNRT and OAVRT have lower diagnostic values in children and adolescents than in adults. A decision model based on 5 simple clinical and ECG parameters may predict a final diagnosis with better accuracy.

Optimizing outcomes of catheter ablation in infants and toddlers

Since the introduction of transcatheter ablation in the late 1980s, there has been significant technical development. With a very high success rate and low complication rate, ablation has now become the standard of care in children and adults. However, long-term data remain insufficient and the application of ablation therapy in small children is debatable. In this review, current treatment strategies and results in toddlers and infants will be discussed. There has been improvement in success rate and complication rate for ablation in small children. Technological advancements in non-fluoroscopic electroanatomical mapping systems (3D systems) have led to the reduction of radiation and have facilitated ablations in complex cases. However, long-term effects of ablation lesions in small children remain a potential concern.