Nonfluoroscopic imaging systems reduce radiation exposure in children undergoing ablation of supraventricular tachycardia

X-ray Doses in Relation to Body Mass, Indication, and Substrate During Pediatric Electrophysiological Procedures on the Heart

The main goal of this study is to determine typical values of dose area product (DAP) and difference in the effective dose (ED) for pediatric electrophysiological procedures on the heart in relation to patient body mass. This paper also shows DAP and ED in relation to the indication, the arrhythmia substrate determined during the procedure, and in relation to the reason for using radiation. Organ doses are described as well. The subjects were children who have had an electrophysiological study done with a 3D mapping system and X-rays in two healthcare institutions. Children with congenital heart defects were excluded. There were 347 children included. Significant difference was noted between mass groups, while heavier children had higher values of DAP and ED. Median DAP in different mass groups was between 4.00 (IQR 1.00-14.00) to 26.33 (IQR 8.77-140.84) cGycm2. ED median was between 23.18 (IQR 5.21-67.70) to 60.96 (IQR 20.64-394.04) µSv. The highest DAP and ED in relation to indication were noted for premature ventricular contractions and ventricular tachycardia-27.65 (IQR 12.91-75.0) cGycm2 and 100.73 (IQR 53.31-258.10) µSv, respectively. In arrhythmia substrate groups, results were similar, and the highest doses were in ventricular substrates with DAP 29.62 (IQR 13.81-76.0) cGycm2 and ED 103.15 (IQR 60.78-266.99) µSv. Pediatric electrophysiology can be done with very low doses of X-rays when using 3D mapping systems compared to X-rays-based electrophysiology, or when compared to pediatric interventional cardiology or adult electrophysiology.

A novel image integration technology mapping system significantly reduces radiation exposure during ablation for a wide spectrum of tachyarrhythmias in children

Objective

Radiofrequency catheter ablation (RFCA) has evolved into an effective and safe technique for the treatment of tachyarrhythmia in children. Concerns about children and involved medical staff being exposed to radiation during the procedure should not be ignored. "Fluoroscopy integrated 3D mapping", a new 3D non-fluoroscopic navigation system software (CARTO Univu Module) could reduce fluoroscopy during the procedure. However, there are few studies about the use of this new technology on children. In the present study, we analyzed the impact of the CARTO Univu on procedural safety and fluoroscopy in a wide spectrum of tachyarrhythmias as compared with CARTO3 alone.

Methods

The data of children with tachyarrhythmias who underwent RFCA from June 2018 to December 2021 were collected. The CARTO Univu was used for mapping and ablation in 200 cases (C3U group) [boys/girls (105/95), mean age (6.8 ± 3.7 years), mean body weight (29.4 ± 7.9 kg)], and the CARTO3 was used in 200 cases as the control group (C3 group) [male/female (103/97), mean age (7.2 ± 3.9 years), mean body weight (32.3 ± 19.0 kg)]. The arrhythmias were atrioventricular reentrant tachycardia (AVRT, n = 78), atrioventricular node reentrant tachycardia (AVNRT, n = 35), typical atrial flutter (AFL, n = 12), atrial tachycardia (AT, n = 20) and ventricular arrhythmias [VAs, premature ventricular complexes or ventricular tachycardia, n = 55].

Results

① There was no significant difference in the acute success rate, recurrence rate, and complication rate between the C3 and C3U groups [(94.5% vs. 95.0%); (6.3% vs. 5.3%); and (2.0% vs. 1.5%); P > 0.05]. ② The CARTO Univu reduced radiation exposure: fluoroscopy time: AVRT C3: 8.5 ± 7.2 min vs. C3U: 4.5 ± 2.9 min, P < 0.05; AVNRT C3: 10.7 ± 3.2 min vs. C3U: 4.3 ± 2.6 min, P < 0.05; AT C3: 15.7 ± 8.2 min vs. C3U: 4.5 ± 1.7 min, P < 0.05; AFL C3: 8.7 ± 3.2 min vs. C3U: 3.7 ± 2.7 min, P < 0.05; VAs C3: 7.7 ± 4.2 min vs. C3U: 3.9 ± 2.3 min, P < 0.05. Corresponding to the fluoroscopy time, the fluoroscopy dose was also reduced significantly. ③ In the C3U group, the fluoroscopy during VAs ablation was lower than that of other arrhythmias (P < 0.05).

Conclusion

The usage of the "novel image integration technology" CARTO Univu might be safe and effective in RFCA for a wide spectrum of tachyarrhythmias in children, which could significantly reduce fluoroscopy and has a more prominent advantage for VAs ablation.

ALARA in Pediatric Electrophysiology Laboratory

The effects of radiation on patients and the providers are dose-dependent and cumulative. Pediatric patients are not only more sensitive to radiation but also may undergo more procedures and diagnostic tests throughout their lifetime. As providers, the endeavor is to cause no harm and it behooves us to either eliminate or minimize the radiation exposure to patients without affecting the efficacy and outcomes of the diagnostic or therapeutic modalities. Pediatric electrophysiologists have taken the lead in attempting to minimize the radiation exposure to patients and staff with innovative and advanced techniques. The techniques range from minimizing the exposure to radiation with better understanding and applications of the physics associated with fluoroscopic imaging to using alternative imaging modalities that do not use radiation.

Ripple Mapping: A precise tool for atrioventricular nodal reentrant tachycardia ablation

INTRODUCTION

Ablation for atrioventricular nodal reentrant tachycardia (AVNRT) classically utilizes evaluation of signal morphology within the anatomic region of the slow pathway (SP), which involves subjectivity. Ripple Mapping (RM) (CARTO-3© Biosense Webster Inc, Irvine, CA) displays each electrogram at its 3-dimensional coordinate as a bar changing in length according to its voltage-time relationship. This allows prolonged, low-amplitude signals to be displayed in their entirety, helping identify propagation in low-voltage areas. We set out to evaluate the ability of RM to locate the anatomic site of the slow pathway and assess its use in guiding ablation for AVNRT.

METHODS

Patients ≤18 yrs with AVNRT in the EP laboratory between 2017 and 2021 were evaluated. RM was performed to define region of SP conduction in patients from 2019-2021, whereas standard electro-anatomical mapping was used from 2017-2019. All ablations were performed using cryo-therapy. Demographics, outcomes and analysis of variance in number of test lesions until success were compared between groups.

RESULTS

A total 115 patients underwent AVRNT ablation during the study; 46 patients were in the RM group and 69 were in the control group. There were no demographic differences between groups. All procedures, in both groups, were acutely successful. In RM group, 89% of first successful lesions were within 4mm of the predicted site. There was significantly reduced variability in number of test lesions until success in the RM group (p=0.01).

CONCLUSIONS

RM is a novel technique that can help identify slow pathway location, allowing for successful ablation of AVNRT with decreased variability. This article is protected by copyright. All rights reserved.

The Evolution of Pediatric and Congenital Electrophysiology as a Subspecialty

Over the past 50 years, pediatric and congenital electrophysiology has progressed from a rare subspecialty practiced at just a handful of centers to become an essential part of nearly every congenital heart program the world over. This paper traces the evolution of the subspecialty in North America by recognizing the individuals who dedicated their careers to this field and trained subsequent generations of practitioners, thereby establishing a legacy that insures continued progress in the treatment of arrhythmias for children and patients with congenital heart disease. Data were generated from a survey of the current membership of the Pediatric and Congenital Electrophysiology Society and were supplemented by review of archived Society records. Maps depicting the locations for clinicians and training centers over time provide a graphic display of progress in this field.

Acute outcomes of three-dimensional mapping for fluoroscopy reduction in paediatric catheter ablation for supraventricular tachycardia

BACKGROUND

Catheter ablation is a safe and effective therapy for the treatment of supraventricular tachycardia in children. Current improvements in technology have allowed progressive reduction in radiation exposure associated with the procedure. To assess the impact of three-dimensional mapping, we compared acute procedural results collected from the Catheter Ablation with Reduction or Elimination of Fluoroscopy registry to published results from the Prospective Assessment after Pediatric Cardiac Ablation study.

METHODS

Inclusion and exclusion criteria from the Prospective Assessment after Pediatric Cardiac Ablation study were used as guidelines to select patient data from the Catheter Ablation with Reduction or Elimination of Fluoroscopy registry to compare acute procedural outcomes between cohorts. Outcomes assessed include procedural and fluoroscopy exposure times, success rates of procedure, and complications.

RESULTS

In 786 ablation procedures, targeting 498 accessory pathways and 288 atrioventricular nodal reentrant tachycardia substrates, average procedural time (156.5 versus 206.7 minutes, p < 0.01), and fluoroscopy time (1.2 versus 38.3 minutes, p < 0.01) were significantly shorter in the study group. Success rates for the various substrates were similar except for manifest accessory pathways which had a significantly higher success rate in the study group (96.4% versus 93.0%, p < 0.01). Major complication rates were significantly lower in the study group (0.3% versus 1.6%, p < 0.01).

CONCLUSIONS

In a large, multicentre study, three-dimensional systems show favourable improvements in clinical outcomes in children undergoing catheter ablation of supraventricular tachycardia compared to the traditional fluoroscopic approach. Further improvements are anticipated as technology advances.

Clinical predictors of heart block during atrioventricular nodal reentrant tachycardia ablation: A multicenter 18-year experience

BACKGROUND

Catheter ablation is considered the first-line treatment of symptomatic atrioventricular nodal reentrant tachycardia (AVNRT). It has been associated with a risk of heart block (HB) requiring a pacemaker. This study aims to determine potential clinical predictors of complete heart block as a result AVNRT ablation.

METHODS

Consecutive patients undergoing catheter ablation for AVNRT from January 2001 to June 2019 at two tertiary hospitals were included. We defined ablation-related HB as the unscheduled implantation of pacemaker within a month of the index procedure. Use of electroanatomic mapping (EAM), operator experience, inpatient status, age, sex, fluoroscopy time, baseline PR interval, and baseline HV interval was included in univariate and multivariate models to predict HB post ablation.

RESULTS

In 1708 patients (56.4 ± 17.0 years, 61% females), acute procedural success was 97.1%. The overall incidence of HB was 1.3%. Multivariate analysis showed that age more than 70 (odds ratio [OR] 7.907, p ≤ .001, confidence interval [CI] 2.759-22.666), baseline PR ≥ 190 ms (OR 2.867, p = .026, CI 1.135-7.239) and no use of EAM (OR 0.306, p = .037, CI 0.101-0.032) were independent predictors of HB.

CONCLUSION

Although the incidence of HB post AVNRT ablation is generally low, patients can be further stratified using three simple predictors.

Novel Minimal Radiation Approach for Percutaneous Pulmonary Valve Implantation

The aim of the study is to evaluate the impact of multimodality imaging technology during percutaneous pulmonary valve implantation (PPVI). Among percutaneous procedures, PPVI traditionally has one of the highest patient radiation exposures. Different protocol modifications have been implemented to address this problem (i.e., improvements in guidance systems, delivery systems, valve design, post-implantation evaluation). Although the effectiveness of individual modifications has been proven, the effect of an approach which combines these changes has not been reported. We performed a retrospective chart review of 76 patients who underwent PPVI between January 2018 and December 2019. Patients were classified in "Traditional protocol," using routine biplane angiography and/or 3D rotational angiography (3DRA); and "Multimodality protocol" that included the use of VesselNavigator for guidance, selective 3DRA for coronary evaluation, Long DrySeal Sheath for valve delivery, and Intracardiac Echocardiography for valve evaluation after implantation. Radiation metrics, procedural time, and clinical outcomes were compared between groups. When the traditional protocol group was compared with the multimodality protocol group, a significant reduction was described for total fluoroscopy time (31.6 min vs. 26.2 min), dose of contrast per kilogram (1.8 mL/Kg vs. 0.9 mL/Kg), DAP/kg (26.6 µGy·m²/kg vs. 19.9 µGy·m²/kg), and Air Kerma (194 mGy vs. 99.9 mGy). A reduction for procedure time was noted (140 min vs. 116.5 min), but this was not statistically significant. There was no difference in clinical outcomes or the presence of complications between groups. The combination of novel technology in PPVI caused a significant reduction in radiation metrics without increasing the complication rate in our population.

Fluoroless intravascular ultrasound image-guided liver navigation in porcine models

Background

An intravascular ultrasound catheter (IVUSc) was developed for intracardiac ultrasound to assess interventions with compelling results. However, intrahepatic vascular exploration was rarely tested and was always associated with X-ray techniques. The aim of this study was to demonstrate the feasibility to navigate through the whole liver using an IVUSc, providing high-quality images and making it unnecessary to use ionizing radiation.

Methods

An ex vivo pig visceral block and an in vivo pig model were used in this study. The IVUS equipment was composed of an US system, and of an 8 French lateral firing IVUSc capable of producing 90-degree sector images in the longitudinal plane. After accessing the intravascular space with the IVUSc into the models, predetermined anatomical landmarks were visualized from the inferior vena cava and hepatic veins and corroborated.

Results

IVUS navigation was achieved in both models successfully. The entire navigation protocol took 87 and 48 min respectively, and 100% (21/21) and 96.15% (25/26) of the landmarks were correctly identified with the IVUSc alone in the ex vivo and in vivo models respectively. IVUS allowed to clearly visualize the vasculature beyond third-order branches of the hepatic and portal veins.

Conclusions

A complete IVUS liver navigation is feasible using the IVUSc alone, making it unnecessary to use ionizing radiation. This approach provides high-definition and real-time images of the complex liver structure and offers a great potential for future clinical applications during diagnostic and therapeutic interventions.

Predictors of zero X ray procedures in supraventricular arrhythmias ablation

To evaluate predictors of zero-X ray procedures for supraventricular arrhythmias (SVT) using minimally fluoroscopic approach (MFA). Patients referred for RF catheter ablation of SVT were admitted for a MFA with an electro-anatomical navigation system or a conventional fluoroscopic approach (ConvA). Exclusion criterion was the need to perform a transseptal puncture. 206 patients (98 men, age 53 ± 19 years) underwent an EP study, 93 (45%) with an MFA and 113 (55%) with a ConvA. Fifty-five had no inducible arrhythmias (EPS). Fifty-four had AV nodal reentrant tachycardia (AVNRT), 49 patients had typical atrial flutter (AFL), 37 had AV reciprocating tachycardia (AVRT/WPW), 11 had focal atrial tachycardia (AT), and underwent a RF ablation. X-ray was not used at all in 51/93 (58%) procedures (zero X ray). MFA was associated with a significant reduction in total fluoroscopy time (5.5 ± 10 vs 13 ± 18 min, P = 0.01) and operator radiation dose (0.8 ± 2.5 vs 3 ± 8.2 mSV, P < 0.05). The greatest absolute dose reduction was observed in AVNRT (0.1 ± 0.3 vs 5.1 ± 10 mSV, P = 0.01, 98% relative dose reduction) and in AFL (1.3 ± 3.6 vs 11 ± 16 mSV, P = 0.003, 88% relative dose reduction) groups. Both AVNRT or AFL resulted the only statistically significant predictors of zero x ray at multivariate analysis (OR 4.5, 95% CI 1.5-13 and OR 5, 95% CI 1.7-15, P < 0.001, respectively). Success and complication rate was comparable between groups (P = NS). Using MFA for SVT ablation, radiological exposure is significantly reduced. Type of arrhythmia is the strongest predictor of zero X ray procedure.

The use of intracardiac echocardiography catheters in endocardial ablation of cardiac arrhythmia: Meta-analysis of efficiency, effectiveness, and safety outcomes

Aims

The optimal use of intracardiac echocardiography (ICE) may reduce fluoroscopy time and procedural complications during endocardial ablation of cardiac arrhythmias. Due to limited evidence in this area, we conducted the first systematic literature review and meta‐analysis to evaluate outcomes associated with the use of ICE.

Methods and Results

Studies reporting the use of ICE during ablation procedures vs without ICE were searched using PubMed/MEDLINE. A meta‐analysis was performed on the 19 studies (2186 patients) meeting inclusion criteria, collectively representing a broad range of arrhythmia mechanisms. Use of ICE was associated with significant reductions in fluoroscopy time (Hedges' g −1.06; 95% confidence interval [CI] −1.81 to −0.32; P < .01), fluoroscopy dose (Hedges' g −1.27; 95% CI −1.91 to −0.62; P < .01), and procedure time (Hedges' g −0.35; 95% CI −0.64 to −0.05; P = .02) vs ablation without ICE. A 6.95 minute reduction in fluoroscopy time and a 15.2 minute reduction in procedure time was observed between the ICE vs non‐ICE groups. These efficiency gains were not associated with any decreased effectiveness or safety. Sensitivity analyses limiting studies to an atrial fibrillation (AF) only population yielded similar results to the main analysis.

Conclusion

The use of ICE in the ablation of cardiac arrhythmias is associated with significantly lower fluoroscopy time, fluoroscopy dose, and shorter procedure time vs ablation without ICE. These efficiency improvements did not compromise the clinical effectiveness or safety of the procedure.

Management of asymptomatic ventricular preexcitation

An incidental discovery of Wolff Parkinson White (WPW) pattern on the electrocardiogram (ECG) is not an infrequent finding facing the physician. Most patients discovered incidentally are asymptomatic and it is hard to justify further management of such patients given the time-honored adage to “first do no harm.” However, this finding does have implications. This article is an attempt to guide clinicians about this important issue that is often faced in the office.

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.

Efficacy and safety of catheter ablation of atrioventricular nodal re-entrant tachycardia by means of flexible-tip irrigated catheters

PURPOSE

Irrigated-tip ablation catheters increase safety and efficacy of ablation procedures, but their use in atrioventricular nodal re-entrant tachycardia (AVNRT) ablation has not been systematically evaluated. The aim of this study is to evaluate the safety and efficacy of radiofrequency (RF) catheter ablation of AVNRT by means of the novel flexible-tip open-irrigated catheter FlexAbility™ and a 3D electroanatomic mapping (EAM) system.

METHODS

This is a single-center and single-operator study on 80 patients referred for AVNRT catheter ablation. Outcome included acute and long-term procedural success as well as complications reported over a median follow-up of 19 months (interquartile range 6-24 months).

RESULTS

Acute success was achieved in all 80 patients. One procedure-related major complication, involving the vascular access, occurred. Mean fluoroscopy time was 106 ± 71 s. One patient (1.2%) suffered long-term AVNRT recurrence. Five patients (6.2%) underwent ablation for AVNRT combined with ablation for other clinical arrhythmias.

CONCLUSIONS

Irrigated RF ablation of AVNRT by means of the novel flexible-tip open-irrigated catheter associated to 3D EAM system is effective and safe. Success rates are comparable to those of other techniques. Complication rate is very low.

Intracardiac echocardiography versus fluoroscopy for endovascular and endocardial catheter navigation during cryo-ablation of the slow pathway in AVNRT patients

Background

A new zero-fluoroscopy technique for electrophysiology catheter navigation relying on intracardiac echocardiography (ICE) has been recently reported (Ice&ICE trial). We investigated potential differences in efficacy, safety or procedural performance between conventional fluoroscopy- and ICE-guided cryothermal ablation (CA) in symptomatic AVNRT patients.

Methods

Clinical and electrophysiological data of AVNRT patients included in the Ice&ICE trial (22 patients, 16 females; =zero-fluoroscopy group) were compared to those of consecutive AVNRT patients, who underwent fluoroscopy-guided CA (25 patients, 17 females; = fluoroscopy group) during the last 2 years in our institution.

Results

Slow pathway ablation or modulation was successful in all patients. Fluoroscopy time and radiation dose in the fluoroscopy group were 11.2 ± 9.0 min and 20.3 ± 16.2Gycm², whereas no fluoroscopy was used in the opposite group (p <  0.001, respectively). EPS duration was not different between the groups (zero-fluoroscopy:101.6 ± 40.2 min, fluoroscopy:99.4 ± 37.2 min, p = n.s.). Catheter placement time was significantly shorter in the fluoroscopy group (2.2 ± 1.6 min vs. 12.0 ± 7.5 min, p <  0.05), whereas cryo-application duration (from the first cryo-mapping to the last CA) was significantly shorter in the zero-fluoroscopy group (27.5 ± 37.0 min vs. 38.1 ± 33.9 min, p <  0.05). Mean cryo-mapping and CA applications were numerically lower in the zero-fluoroscopy group (CM:7.5 ± 5.7 vs. 8.8 ± 6.2; CA:3.1 ± 1.7 vs. 3.2 ± 2.0, p = n.s.). No major adverse events occurred in both groups. After 15.0 ± 4.2 months, arrhythmia recurrence was not different between the groups (4.5% vs. 8.0%, p = n.s.).

Conclusions

Zero-fluoroscopy ICE-guided EP catheter navigation shows comparable efficacy and safety to fluoroscopic guidance during CA in AVNRT patients. ICE visualization of catheters and endocardial structures within the triangle of Koch shortens the cryo-application duration, though time needed for catheter placement is longer, when compared with conventional fluoroscopic guidance, which results in similar mean EPS duration with both navigation techniques.

Trial registration

(German Clinical Trials Register ID: DRKS00011360; Registration Date 14.12.2016)

Electronic supplementary material

The online version of this article (10.1186/s12947-019-0162-2) contains supplementary material, which is available to authorized users.

Electroanatomic mapping-guided pediatric catheter ablation with limited/zero fluoroscopy

Objective:

The use of fluoroscopy in pediatric catheter ablation has decreased because of mapping systems. In this study, we present the efficiency and reliability of the electroanatomic mapping system in nonfluoroscopic pediatric catheter ablation.

Methods:

The medical records of patients aged <18 years who underwent ablation between November 2016 and April 2018 were evaluated. Fluoroscopy was not used in cases involving ablation of right sided-arrhythmia foci. Fluoroscopy was used only for trans-septal puncture or retroaortic approach/coronary angiography.

Results:

A total of 76 patients underwent catheter ablation for 78 supraventricular and ventricular tachyarrhythmia substrates under the guidance of EnSite Velocity system. Fluoroscopy was used in only 14 (18.4%) of these substrates. The mean fluoroscopy duration in these 14 procedures was 5.4±3.15 min. No complications were noted, except a temporary right bundle branch block in one patient and pericardial effusion in another following cryoablation. The acute success rate in achieving complete elimination of arrhythmia substrates was 97.4% (76/78). The recurrence rate was 5.1% (4/78) at follow-up.

Conclusion:

Fluoroscopy can be completely eliminated in most pediatric catheter ablation procedures with the use of mapping systems by achieving high acute success rates and acceptable low complication rates.

Incidence of Echocardiographic Abnormalities Following Pediatric SVT Ablation: Comparison of Cases Utilizing Fluoroscopy Alone to Cases with Adjunctive 3D Electroanatomic Mapping

There are few data on the incidence of echocardiographic (echo) abnormalities following catheter ablation in children in the era of 3D mapping. Wide practice variation exists regarding routine post-ablation echo. We hypothesized a low incidence of clinically significant echo abnormalities following SVT ablation in otherwise healthy children. Single center data from 2009 to 2015 were reviewed; routine post-ablation echo was standard practice. Cases were categorized as utilizing fluoroscopy alone (FLUORO) or 3D mapping with a low fluoroscopic protocol (CARTO3). Congenital heart disease was excluded. Outcomes of interest included new valvular abnormalities, pericardial effusions, and wall motion abnormalities. Findings were compared to baseline studies when available and classified as normal/unchanged, clinically insignificant, or clinically significant. Outcomes were compared between FLUORO and CARTO3 groups. Of 347 ablations, 319 (92%) underwent post-procedural echo: 57% male; 55% FLUORO; mean age 13.4 ± 3.6 years. The most common ablation target was an accessory pathway (AP) in 66% (n = 144 WPW, 66 concealed), followed by AVNRT in 32% (n = 102). Radiofrequency (RF) energy was utilized in 82% (n = 262). Post-ablation echos were normal in 81% (n = 259). Clinically insignificant findings were seen in 18% (n = 58), most commonly trivial-small pericardial effusions in 11% (n = 34). Two significant findings required additional follow-up or treatment. There were no cases of wall motion abnormalities or clinically significant effusions. There were no differences in frequency of echo abnormalities between the FLUORO and CARTO3 groups. Clinically significant echocardiographic abnormalities are rare following SVT ablation in children with structurally normal hearts, independent of the use of 3D mapping.

Current management and clinical outcomes for catheter ablation of atrioventricular nodal re-entrant tachycardia

Aims

Historical studies of ablation of atrioventricular nodal re-entrant tachycardia (AVNRT) have shown high long-term success rates and low complication rates. The potential impact of several recent practice trends has not been described. This study aims to characterize recent clinical practice trends in AVNRT ablation and their associated success rates and complications.

Methods and results

Patients undergoing initial ablation of AVNRT between 1 July 2005 and 30 June 2015 were included in this study. Patient demographics and procedural data were abstracted from procedure reports. Follow-up data, including AVNRT recurrence and complications, was evaluated through electronic medical record review. In total, 877 patients underwent catheter ablation for AVNRT. By the last recorded year, three-dimension (3D) electroanatomical mapping (EAM) was used in 36.2%, 43.2% included anaesthesia, and 23.1% utilized irrigated catheters. Long-term procedural success was 95.5%. The use of anaesthesia, 3D EAM, and irrigated ablation catheters were not associated with differences in success. The presence of an atrial 'echo' or 'AH' jump at the end of an acutely successful procedure was not associated with long-term recurrence (P = 0.18, P = 0.15, respectively). Complications, including AV block requiring a pacemaker (0.4%), were uncommon.

Conclusion

In a large, contemporary cohort, catheter ablation for AVNRT remains highly successful with low complications rates. The increased use of anaesthesia as well as modern mapping and ablation tools were not associated with changes in clinical outcomes. Further prospective evaluation of such contemporary practices is warranted given the lack of evidence to support their escalating use.

Catheter ablation for supraventricular tachycardia in children ≤ 20 kg using an electroanatomical system

PURPOSE

Catheter ablation is the only choice of treatment in some small children with medically refractory supraventricular tachycardia (SVT). Electroanatomical mapping systems (EMS) are more commonly utilized in electrophysiological procedures in recent years, which resulted in a significant decrease in fluoroscopy exposure. The potential benefit of EMS in small children has not been studied. Therefore, we investigated the outcomes of children undergoing catheter ablation weighing ≤ 20 kg using an electroanatomical mapping system.

METHODS

This study evaluated the outcomes, characteristics, and follow-ups of children ≤ 20 kg who underwent SVT ablations between April 2012 and April 2018 in a pediatric electrophysiology center where EMS were routinely used.

RESULTS

In a 6-year period, 1129 children underwent SVT catheter ablation under EMS guidance at our institution. A total of 84 of them were weighing ≤ 20 kg. The acute success rate was 97.6% in 85 tachycardia substrates. No fluoroscopy was used in 58 of the patients, while a median of 5 (4-14) min of fluoroscopy was used in the remaining 26 patients. Recurrences were seen in 4 patients (4.8%) at a mean follow-up of 3.89 ± 2.08 years. Five patients developed non-vital complications (2 right bundle block and 3 temporary complete block that spontaneously resolved during the procedure).

CONCLUSIONS

The outcome of catheter ablation with the guidance of EMS for the treatment of SVT in small children is favorable. Fluoroscopy exposure can be decreased and even eliminated in most patients.

A Cost-Effective Analysis of Systematically Using Mapping Systems During Catheter Ablation Procedures in Children and Teenagers

The aim of this study is to evaluate the cost-effectiveness of an extended use of 3D non-fluoroscopic mapping systems (NMSs) during paediatric catheter ablation (CA) in an adult EP Lab. This study includes 58 consecutive patients (aged between 8 and 18) who underwent CA from March 2005 to February 2015. We compare the fluoroscopy data of two groups: group I, patients who underwent CA from 2005 to 2008 using only fluoroscopy, and group II, patients who underwent CA from 2008 to 2015 performed also using NMSs. Two cost-effectiveness analyses were carried out: the first method was based on the alpha value (AV), and the second one was based on the value of a statistical life (VSL). For both methods, a children's correction factor was also considered. The reduction cost estimated from all these methods was compared to the real additional cost of using NMSs. The use of an NMS during a CA procedure has led to an effective dose reduction (ΔE) of 2.8 milli-Sievert. All presented methods are based on parameters with a wide range of values. The use of an NMS, applying directly AV values or VSL values, is not cost-effective for most countries. Only considering the children's correction factor, the CA procedure using an NMS seems to be cost-effective. The cost-effectiveness of a systematic use of NMSs during CA procedures in children and teenagers remains a challenging task. A positive result depends on which value of AV or VSL is considered and if the children's correction factor is applied or not.

Procedural outcomes of fluoroless catheter ablation outside the traditional catheterization lab

Aims

Non-fluoroscopic catheter ablation is becoming routine. In experienced centres, fluoroscopy is rarely required. The use of a traditional catheterization lab (cath lab) may no longer be necessary. We began performing catheter ablations at a paediatric centre outside the traditional cardiac cath lab in 2013. The purpose of this study was to compare procedural features of paediatric catheter ablation performed outside the cath lab to those performed within a cath lab.

Methods and results

We prospectively looked at patients presenting to the paediatric centre with supraventricular tachycardia (SVT) undergoing catheter ablation outside the cath lab in a standard operating room (OR group). We compared retrospectively to a control group matched for age, type, and location of arrhythmia who had ablations in a traditional cath lab (CL group). Catheter visualization was exclusively by electro-anatomic mapping. Fifty-nine patients with SVT underwent catheter ablation in the OR from October 2013 to December 2015. Thirty-three patients had accessory pathways, 29 were manifest, and 13 of those were left sided. Twenty-six had atrioventricular nodal re-entrant tachycardia. Transseptal puncture with transoesophageal echocardiography guidance was used for 10 left-sided pathways, whereas the other 3 had patent foramen ovales. Procedure time did not differ significantly between groups (OR group mean 131 min, range 57-408; CL group mean 152 min, range 68-376; P = 0.12). Acute success was similar in both groups [OR group: 58/59 (98.3%) and CL group: 57/59 (96.6%)]. There were no major complications in either group. There was no fluoroscopy used in either group.

Conclusion

Although performing paediatric catheter ablations outside the traditional cath lab is early in our experience, we produced similar outcomes and results without encountering procedural difficulties of performing ablations in a non-conventional setting. Larger multi-centred trials will be essential to determine the feasibility of this practice.

Radiation Safety in Children With Congenital and Acquired Heart Disease: A Scientific Position Statement on Multimodality Dose Optimization From the Image Gently Alliance

There is a need for consensus recommendations for ionizing radiation dose optimization during multimodality medical imaging in children with congenital and acquired heart disease (CAHD). These children often have complex diseases and may be exposed to a relatively high cumulative burden of ionizing radiation from medical imaging procedures, including cardiac computed tomography, nuclear cardiology studies, and fluoroscopically guided diagnostic and interventional catheterization and electrophysiology procedures. Although these imaging procedures are all essential to the care of children with CAHD and have contributed to meaningfully improved outcomes in these patients, exposure to ionizing radiation is associated with potential risks, including an increased lifetime attributable risk of cancer. The goal of these recommendations is to encourage informed imaging to achieve appropriate study quality at the lowest achievable dose. Other strategies to improve care include a patient-centered approach to imaging, emphasizing education and informed decision making and programmatic approaches to ensure appropriate dose monitoring. Looking ahead, there is a need for standardization of dose metrics across imaging modalities, so as to encourage comparative effectiveness studies across the spectrum of CAHD in children.

Radiofrequency catheter ablation of atrioventricular node reentrant tachycardia in children with limited fluoroscopy

BACKGROUND

Limited fluoroscopy cryo-ablation using a 3D electro-anatomical system (3DS) has been used for AVNRT in children. We aimed to facilitate a fluoroscopy limited approach of RF ablation of AVNRT in children.

METHODS

A retrospective study was performed of procedure parameters in children undergoing RF ablation of AVNRT in 75 consecutive children (June 2011 to November 2013 - Group A) using standard fluoroscopy techniques compared to those of 64 consecutive children (December 2013 to May 2015 - Group B), using a fluoroscopy limited approach with 3DS.

RESULTS

The acute success rate was 98.7% (74/75) and 98.4% (63/64) for groups A and B, respectively. The recurrence rate was 2.7% (2/74) and 0% (0/63) with a mean follow-up period of 45.5±12.1 and 14.3±6.1months for group A and group B, respectively. The mean procedure and fluoroscopy times were significantly lower for group B compared to group A (119±37 (43-203) and 0.83±1.04 (0.05-3.83) minutes versus 146±53 (72-250) and 16.1±8.9 (4.39-55) minutes, p<0.003 and p<0.0001, respectively). There were no ablation-related complications.

CONCLUSIONS

A fluoroscopy limited approach for RF ablation of AVNRT in children using a 3DS is easily acquired and adapted, and significantly reduces the fluoroscopy and procedure time with excellent efficacy, safety and low recurrence rate.

CONDENSED ABSTRACT

This study confirmed that a 3D mapping system (3DS) to guide ablations of AVNRT in children reduces radiation exposure. Combined, limited fluoroscopy and 3DS in a methodology that resembles the familiar conventional fluoroscopy approach for RF ablation of AVNRT in children is proposed. Combined limited fluoroscopy and RF-energy in children with AVNRT are associated with a shorter procedure time, minimal fluoroscopy time, a high success rate and a low recurrence rate.

Limited fluoroscopy catheter ablation of accessory pathways in children

BACKGROUND

Limited fluoroscopy ablation using 3D electro-anatomical system (3DS) has been used for arrhythmias in children, however it is not a common practice. We aimed to facilitate a fluoroscopy limited approach for ablation of accessory pathways (AP) in children.

METHODS

Following electrophysiologic (EP) catheter placement a single dual-plane fluoroscopic image (right anterior oblique-30° and left anterior oblique-60° views) was acquired and the 3DS views were rotated to be a perfect match to the fluoroscopy. Ninety-four consecutive pediatric patients [mean age 11.8±4.1 (4.2-18) years, 61.7% males] with Wolf-Parkinson-White syndrome underwent ablation of an AP. Fifty-seven had manifest AP, 54 had left-sided AP (LSAP) and 40 had right-sided AP (RSAP).

RESULTS

The acute success rate was 95.7% (90/94), with a recurrence rate of 1.1% (1/90) at a mean follow-up of 13±5.5 (4.4-22.9) months. Mean procedure and fluoroscopy times were 144±45 (55-262)min and 1.8±1.4 (0.1-5.6)min, respectively. Comparison of the first 20 procedures to the next 74 procedures demonstrated an extended procedure time (171±53min vs 135±38min, p<0.005), however the fluoroscopy time, the number of long applications, the time to effect, and the acute success rate were similar. There were no permanent ablation-related complications.

CONCLUSIONS

A limited fluoroscopy approach for ablation of AP in children using 3DS is easily acquired, adapted, reduces the fluoroscopy time, and has an excellent efficacy and safety profile.

The Current State and Future Potential of Pediatric and Congenital Electrophysiology

Pediatric electrophysiologists specialize in the diagnosis and treatment of rhythm abnormalities in pediatric, congenital heart disease, and inherited arrhythmia syndrome patients. The field originated out of the unique knowledge base that rhythm management in young patients required. In the 1970s, pediatric electrophysiology was recognized as a distinct cardiac subspecialty and it has evolved rapidly since that time. Despite the considerable growth in personnel, technology, and complexity that the field has undergone, further opportunities to progress pediatric electrophysiology exist. In this review, we highlight some of the clinical focus of pediatric and adult congenital electrophysiologists to date and identify areas within this specialty where the pediatric and congenital electrophysiology community could come together in order to drive improvements in rhythm management for patients.

Near zerO fluoroscopic exPosure during catheter ablAtion of supRavenTricular arrhYthmias: the NO-PARTY multicentre randomized trial

AIMS

Aim of this study was to compare a minimally fluoroscopic radiofrequency catheter ablation with conventional fluoroscopy-guided ablation for supraventricular tachycardias (SVTs) in terms of ionizing radiation exposure for patient and operator and to estimate patients' lifetime attributable risks associated with such exposure.

METHODS AND RESULTS

We performed a prospective, multicentre, randomized controlled trial in six electrophysiology (EP) laboratories in Italy. A total of 262 patients undergoing EP studies for SVT were randomized to perform a minimally fluoroscopic approach (MFA) procedure with the EnSiteTMNavXTM navigation system or a conventional approach (ConvA) procedure. The MFA was associated with a significant reduction in patients' radiation dose (0 mSv, iqr 0-0.08 vs. 8.87 mSv, iqr 3.67-22.01; P < 0.00001), total fluoroscopy time (0 s, iqr 0-12 vs. 859 s, iqr 545-1346; P < 0.00001), and operator radiation dose (1.55 vs. 25.33 µS per procedure; P < 0.001). In the MFA group, X-ray was not used at all in 72% (96/134) of cases. The acute success and complication rates were not different between the two groups (P = ns). The reduction in patients' exposure shows a 96% reduction in the estimated risks of cancer incidence and mortality and an important reduction in estimated years of life lost and years of life affected. Based on economic considerations, the benefits of MFA for patients and professionals are likely to justify its additional costs.

CONCLUSION

This is the first multicentre randomized trial showing that a MFA in the ablation of SVTs dramatically reduces patients' exposure, risks of cancer incidence and mortality, and years of life affected and lost, keeping safety and efficacy.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT01132274.

Use of three-dimensional mapping in young patients decreases radiation exposure even without a goal of zero fluoroscopy

At present, three-dimensional mapping is often used during cardiac ablations with an explicit goal of decreasing radiation exposure; three-dimensional mapping was introduced in our institution in 2007, but not specifically to decrease fluoroscopy time. We document fluoroscopy use and catheterisation times in this setting. Data were obtained retrospectively from patients who underwent ablation for atrioventricular nodal re-entrant tachycardia from January, 2004 to December, 2011. A total of 93 patients were included in the study. Among them, 18 patients who underwent radiofrequency ablation without three-dimensional mapping were included in Group 1, 13 patients who underwent cryoablation without three-dimensional mapping were included in Group 2, and 62 patients who underwent cryoablation with three-dimensional mapping were included in Group 3. Mean fluoroscopy times differed significantly (34.3, 23.4, and 20.3 minutes, p<0.001) when all the groups were compared. Group 3 had a shorter average fluoroscopy time that did not reach significance when compared directly with Group 2 (p=0.29). An unadjusted linear regression model showed a progressive decrease in fluoroscopy time (p=0.002). Mean total catheterisation times differed significantly (180, 211, and 210 minutes, p=0.02) and were related to increased ablation times inherent to cryoablation techniques. Acute success was achieved in 89, 100, and 97% of patients (p=0.25), and chronic success was achieved in 80, 92, and 93% of patients (p=0.38). Complication rates were similar (17, 23, and 7%, p=0.14). In conclusion, three-dimensional mapping systems decrease fluoroscopy times even without an explicit goal of zero fluoroscopy. Efficacy and safety of the procedure have not changed.

Comparison of cryoablation with 3D mapping versus conventional mapping for the treatment of atrioventricular re-entrant tachycardia and right-sided paraseptal accessory pathways

Aim Transcatheter cryoablation is a well-established technique for the treatment of atrioventricular nodal re-entry tachycardia and atrioventricular re-entry tachycardia in children. Fluoroscopy or three-dimensional mapping systems can be used to perform the ablation procedure. The aim of this study was to compare the success rate of cryoablation procedures for the treatment of right septal accessory pathways and atrioventricular nodal re-entry circuits in children using conventional or three-dimensional mapping and to evaluate whether three-dimensional mapping was associated with reduced patient radiation dose compared with traditional mapping.

METHODS

In 2013, 81 children underwent transcatheter cryoablation at our institution, using conventional mapping in 41 children - 32 atrioventricular nodal re-entry tachycardia and nine atrioventricular re-entry tachycardia - and three-dimensional mapping in 40 children - 24 atrioventricular nodal re-entry tachycardia and 16 atrioventricular re-entry tachycardia.

RESULTS

Using conventional mapping, the overall success rate was 78.1 and 66.7% in patients with atrioventricular nodal re-entry tachycardia or atrioventricular re-entry tachycardia, respectively. Using three-dimensional mapping, the overall success rate was 91.6 and 75%, respectively (p=ns). The use of three-dimensional mapping was associated with a reduction in cumulative air kerma and cumulative air kerma-area product of 76.4 and 67.3%, respectively (p<0.05).

CONCLUSIONS

The use of three-dimensional mapping compared with the conventional fluoroscopy-guided method for cryoablation of right septal accessory pathways and atrioventricular nodal re-entry circuits in children was associated with a significant reduction in patient radiation dose without an increase in success rate.

Feasibility, accuracy, and safety of 3-dimensional electroanatomic mapping without fluoroscopy in patients with congenital heart defects

BACKGROUND

Use of nonfluoroscopic 3-dimensional electroanatomic mapping (NF-3DEAM) in patients with congenital heart defects (CHDs) is not well reported.

OBJECTIVE

The purpose of this study was to evaluate the feasibility, accuracy, and safety of NF-3DEAM in patients with CHDs.

METHODS

Retrospective review of electrophysiologic study (EPS) in patients with CHD from 2009 to 2013 was conducted. Patients undergoing EPS with NF-3DEAM using the EnSite NavX system (St. Jude Medical) were included and those with fluoroscopy were excluded. Cardiac angiography performed in close proximity was matched with 3DEAM by proper aspect ratio using manual alignment by overlay images and comparing distances between cardiac landmarks using Pearson correlation coefficient and intraclass correlation. Success and complications were reviewed.

RESULTS

Three-dimensional electroanatomic mapping and angiograms were compared in 48 EPS (45 patients); 13 patients with intracardiac leads, quiescent chambers indicating significant scarring, and who required transseptal puncture were excluded. Indications for EPS included documented tachyarrhythmia and preoperative mapping. Mean age was 25.3 ± 9.8 years. Simple CHDs (isolated shunt lesions or valvular lesions) were identified in 13 studies (27%) and complex CHDs (others) were identified in 35 studies (73%). Ablations were performed in 25 studies (52%). Average time to obtain right atrial geometry was 25.3 minutes (range 14-47 minutes) and right ventricular geometry was 22.8 minutes (range 12-35 minutes). Pearson correlation coefficient and intraclass correlation of cardiac landmarks were 0.90 and 0.80, respectively. Anatomic landmarks, mapping, and ablation were accurate in all 3DEAMs. No complications were recorded.

CONCLUSION

NF-3DEAM is feasible, safe, and accurate in CHD patients without extensive scarring, intracardiac leads, and need for transseptal puncture.

The Benefit of a General, Systematic Use of Mapping Systems During Electrophysiological Procedures in Children and Teenagers: The Experience of an Adult EP Laboratory

Standard imaging during electrophysiological procedures (EPs) uses fluoroscopy. The aim of this study was to evaluate the feasibility, efficacy, safety and effect of an extended use of non-fluoroscopic mapping systems (NMSs) for imaging during paediatric EPs in an adult EP laboratory focusing on the amount of X-ray exposure. This study is a retrospective analysis that includes consecutive young patients (83 pts, aged between 8 and 18) who underwent EPs from March 2005 to February 2015. We compare the fluoroscopy data of two groups of pts: Group I, pts who underwent EPs from 2005 to 2008 using only fluoroscopy and Group II, pts who underwent EPs from 2008 to 2015 performed also using NMSs. The use of an NMS resulted in reduced fluoroscopy time in Group II {median value 0.1 min (95 % CI [0.00-1.07])} compared to Group I {median value 3.55 min (95 % CI [1.93-7.83]) (MW test, P < 0.05)}. There was a complementary reduction in the total X-ray exposure from 2.53 Gy cm(2) (95 % CI [1.51-4.66]) in Group I to 0.05 Gy cm(2) in Group II (95 % CI [0.00-1.22]) (MW test, P < 0.05). Regarding ablation procedures, the median effective dose decreased from 3.04 mSv (95 % CI [1.22-6.89]) to 0.25 mSv (95 % CI [0.00-0.60]) (MW test, P < 0.05). The use of an NMS dramatically reduces fluoroscopy time and total X-ray exposure during EPs in children and teenagers in an adult EP laboratory. In our experience, this reduction is mainly related to the systematic day-to-day use of NMSs.

Getting to zero: impact of electroanatomical mapping on fluoroscopy use in pediatric catheter ablation

PURPOSE

Over the past several years, alternative imaging techniques including electroanatomic mapping systems such as CARTO®3 (C3) have been developed to improve anatomic resolution and potentially limit radiation exposure in electrophysiology (EP) procedures. We retrospectively examined the effect of the introduction of C3 on patient radiation exposure during EP studies and ablation procedures at a children's hospital.

METHODS

All patients that underwent EP and ablation procedures between January 2012 and August 2015 were included; demographic information, fluoroscopy time (FT), total radiation dose (RAD), and dose-area product (DAP) were collected. Patients were stratified by time period (before vs. after C3 introduction) in three groups: (1) normal heart, (2) congenital heart disease (CHD), and (3) those requiring trans-septal (TS) access. The normal heart group was further separated by arrhythmia diagnosis (accessory pathway (AP), AV nodal reentry tachycardia (AVNRT), atrial, or ventricular arrhythmia). Mean values were compared using a single sample t test, as well as analysis of covariance to control for age, weight, and arrhythmia diagnosis.

RESULTS

Mean FT decreased after introduction of C3 in patients in all three patient groups (p < 0.01). When separated by arrhythmia diagnosis, FT decreased in the AP and AVNRT groups (p < 0.0001). After controlling for age, weight, and arrhythmia diagnosis, there was a statistically significant decrease in FT in all three groups and in both RAD and DAP in the normal heart group. Zero fluoroscopy was achieved in 50/159 (31 %) and ≤1 min of FT in 71/159 (45 %) of cases.

CONCLUSIONS

We have shown a significant decrease in multiple measures of radiation after introduction of C3. Continued refinements are needed to further decrease radiation utilization and achieve the goal of zero fluoroscopy.

Reduction of radiation exposure in catheter ablation of atrial fibrillation: Lesson learned

Over the last decades, the concern for the radiation injury hazard to the patients and the professional staff has increased in the medical community. Since there is no magnitude of radiation exposure that is known to be completely safe, the use of ionizing radiation during medical diagnostic or interventional procedures should be as low as reasonably achievable (ALARA principle). Nevertheless, in cardiovascular medicine, radiation exposure for coronary percutaneous interventions or catheter ablation of cardiac arrhythmias may be high: for ablation of a complex arrhythmia, such as atrial fibrillation, the mean dose can be > 15 mSv and in some cases > 50 mSv. In interventional electrophysiology, although fluoroscopy has been widely used since the beginning to navigate catheters in the heart and the vessels and to monitor their position, the procedure is not based on fluoroscopic imaging. Therefore, non-fluoroscopic three-dimensional systems can be used to navigate electrophysiology catheters in the heart with no or minimal use of fluoroscopy. Although zero-fluoroscopy procedures are feasible in limited series, there may be difficulties in using no fluoroscopy on a routine basis. Currently, a significant reduction in radiation exposure towards near zero-fluoroscopy procedures seems a simpler task to achieve, especially in ablation of complex arrhythmias, such as atrial fibrillation. The data reported in the literature suggest the following three considerations. First, the use of the non-fluoroscopic systems is associated with a consistent reduction in radiation exposure in multiple centers: the more sophisticated and reliable this technology is, the higher the reduction in radiation exposure. Second, the use of these systems does not automatically lead to reduction of radiation exposure, but an optimized workflow should be developed and adopted for a safe non-fluoroscopic navigation of catheters. Third, at any level of expertise, there is a specific learning curve for the operators in the non-fluoroscopic manipulation of catheters; however, the learning curve is shorter for more experienced operators compared to less experienced operators.

Reducing patient radiation exposure during paediatric SVT ablations: use of CARTO® 3 in concert with "ALARA" principles profoundly lowers total dose

BACKGROUND

"ALARA--As Low As Reasonably Achievable" protocols reduce patient radiation dose. Addition of electroanatomical mapping may further reduce dose.

METHODS

From 6/11 to 4/12, a novel ALARA protocol was utilised for all patients undergoing supraventricular tachycardia ablation, including low frame rates (2-3 frames/second), low fluoro dose/frame (6-18 nGy/frame), and other techniques to reduce fluoroscopy (ALARA). From 6/12 to 3/13, use of CARTO® 3 (C3) with "fast anatomical mapping" (ALARA+C3) was added to the ALARA protocol. Intravascular echo was not utilised. Demographics, procedural, and radiation data were analysed and compared between the two protocols.

RESULTS

A total of 75 patients were included: 42 ALARA patients, and 33 ALARA+C3 patients. Patient demographics were similar between the two groups. The acute success rate in ALARA was 95%, and 100% in ALARA+C3; no catheterisation-related complications were observed. Procedural time was 125.7 minutes in the ALARA group versus 131.4 in ALARA+C3 (p=0.36). Radiation doses were significantly lower in the ALARA+C3 group with a mean air Kerma in ALARA+C3 of 13.1±28.3 mGy (SD) compared with 93.8±112 mGy in ALARA (p<0.001). Mean dose area product was 92.2±179 uGym2 in ALARA+C3 compared with 584±687 uGym2 in ALARA (p<0.001). Of the 33 subjects (42%) in the ALARA+C3 group, 14 received ⩽1 mGy exposure. The ALARA+C3 dosages are the lowest reported for a combined electroanatomical-fluoroscopy technique.

CONCLUSIONS

Addition of CARTO® 3 to ALARA protocols markedly reduced radiation exposure to young people undergoing supraventricular tachycardia ablation while allowing for equivalent procedural efficacy and safety.

Optimized Fluoroscopy Setting and Appropriate Project Position Can Reduce X-ray Radiation Doses Rates during Electrophysiology Procedures

Background:

Nonfluoroscopic three-dimensional electroanatomical system is widely used nowadays, but X-ray remains indispensable for complex electrophysiology procedures. This study aimed to evaluate the value of optimized parameter setting and different projection position to reduce X-ray radiation dose rates.

Methods:

From June 2013 to October 2013, 105 consecutive patients who underwent complex ablation were enrolled in the study. After the ablation, the radiation dose rates were measured by two different settings (default setting and optimized setting) with three projection positions (posteroanterior [PA] projection; left anterior oblique [LAO] 30° projection; and LAO 45° projection). The parameter of preset voltage, pulse width, critical voltage, peak voltage, noise reduction, edge enhancement, pulse rate, and dose per frame was modified in the optimized setting.

Results:

The optimized setting reduced radiation dose rates by 87.5% (1.7 Gy/min vs. 13.6 Gy/min, P < 0.001) in PA, 87.3% (2.5 Gy/min vs. 19.7 Gy/min, P < 0.001) in LAO 30°, 85.9% (3.1 Gy/min vs. 22.1 Gy/min, P < 0.001) in LAO 45°. Increase the angle of projection position will increase the radiation dose rate.

Conclusions:

We can reduce X-ray radiation dose rates by adjusting the parameter setting of X-ray system. Avoiding oblique projection of large angle is another way to reduce X-ray radiation dose rates.

Radiation safety protocol using real-time dose reporting reduces patient exposure in pediatric electrophysiology procedures

Radiation exposure during pediatric catheterization is significant. We sought to describe radiation exposure and the effectiveness of radiation safety protocols in reducing exposure during catheter ablations with electrophysiology studies in children and patients with congenital heart disease. We additionally sought to identify at-risk patients. We retrospectively reviewed all interventional electrophysiology procedures performed from April 2009 to September 2011 (6 months preceding intervention, 12 months following implementation of initial radiation safety protocol, and 8 months following implementation of modified protocol). The protocols consisted of low pulse rate fluoroscopy settings, operator notification of skin entrance dose every 1,000 mGy, adjusting cameras by >5 at every 1,000 mGy, and appropriate collimation. The cohort consisted of 291 patients (70 pre-intervention, 137 after initial protocol implementation, 84 after modified protocol implementation) at a median age of 14.9 years with congenital heart disease present in 11 %. Diagnoses included atrioventricular nodal reentrant tachycardia (25 %), atrioventricular reentrant tachycardia (61 %), atrial tachycardias (12 %), and ventricular tachycardia (2 %). There were no differences between groups based on patient, arrhythmia, and procedural characteristics. Following implementation of the protocols, there were significant reductions in all measures of radiation exposure: fluoroscopy time (17.8 %), dose area product (80.2 %), skin entry dose (81.0 %), and effective dose (76.9 %), p = 0.0001. Independent predictors of increased radiation exposure included larger patient weight, longer fluoroscopy time, and lack of radiation safety protocol. Implementation of a radiation safety protocol for pediatric and congenital catheter ablations can drastically reduce radiation exposure to patients without affecting procedural success.

[Interventional therapy of tachyarrhythmias in the pediatric population]

Over the past decades, interventional therapy of tachyarrhythmias in children without structural heart disease has evolved as an alternative to chronic pharmacological treatment. Catheter ablation in children over 5 years with symptomatic tachycardia using radiofrequency- or cryoenergy is nowadays performed with high success and low complication rates at experienced centers. The use of modern technologies such as non-fluoroscopic 3-dimensional mapping has further increased efficacy and safety of catheter ablation, and has led to a significant reduction of fluoroscopy time and dose.Arrhythmia substrates treated most frequently by catheter ablation in children include accessory pathways (WPW syndrome) leading to atrioventricular reentrant tachycardia (AVRT) and dual AV nodal pathways causing atrioventricular nodal reentrant tachycardia (AVNRT). Success rates of catheter ablation for these substrates during long-term follow up are over 90 %. Less common forms of tachycardias in children, such as focal atrial tachycardia, ventricular outflow tachycardias or idiopathic left ventricular tachycardia, are also amenable to catheter ablation with good long-term results. In asymptomatic children with preexcitation on the surface ECG (accessory pathway with the risk of rapid antegrade conduction during atrial fibrillation) the indication for catheter ablation of the accessory pathway for the prevention of sudden cardiac death should already be evaluated during childhood.

The Growing Culture Of A Minimally Fluoroscopic Approach In Electrophysiology Lab

Most of interventional procedures in cardiology are carried out under fluoroscopic imaging guidance. Besides other peri-interventional risks, radiation exposure should be considered for its stochastic (inducing malignancy) and deterministic effects on health (tissue reactions like erythema, hair loss and cataracts). In this article we analized the radiation risk from cardiovascular imaging to both patients and medical staff and discusses how customize the X-ray system and how to implement shielding measures in the cath lab. Finally, we reviewed the most recent developments and the latest findings in catheter navigation and 3D electronatomical mapping systems that may help to reduce patient and operator exposure.