Cryoablation for accessory pathways located near normal conduction tissues or within the coronary venous system in children and young adults.

BACKGROUND: Cryoablation may offer advantages over radiofrequency (RF) ablation for certain arrhythmia substrates, such as septal accessory pathways (APs). Data for young patients, especially regarding recurrence risk, require expansion. OBJECTIVES: The purpose of this study was to study institutional outcomes for cryoablation of APs located in potentially difficult septal regions for children and young adults. METHODS: Cryoablation was attempted in 35 young patients (mean age 15.6 years) with 37 APs that were either close to normal conduction tissues or inside the coronary venous system. Outcomes were compared with previously published institutional data for RF ablation at these same locations. RESULTS: Acute cryoablation success was achieved for 29 (78%) of 37 APs. Apart from permanent PR prolongation in one case and right bundle branch block in one other, there were no detrimental effects on normal conduction. At median follow-up of 207 days (range 2-695 days), AP conduction recurred for 13 (45%) of 29 ablated APs. Younger patient age and midseptal AP location correlated with higher likelihood of recurrence. Acute success rates for cryoablation were similar to RF ablation in our laboratory, but recurrence rates were significantly higher (P <.001). CONCLUSION: Cryoablation yields acute success rates comparable with RF ablation for difficult septal APs in young patients. The risk of AP recurrence appears higher after cryoablation, although safety benefits may provide suitable compensation for this deficiency. Methods for creating more effective cryoablation lesions need to be explored.     

Time and temperature profile of catheter cryoablation of right septal and free wall accessory pathways in children

Introduction: The overall acute success with cryoablation for accessory pathways (APs) has been reported to be lower than with radiofrequency ablation. Generally, prior cryomapping (limited to −30°C) has been used to test for loss of AP conduction and absence of atrioventricular (AV) node impairment. However, the temperature at which loss of AP conduction occurs may be variable. The purpose of this study was to evaluate the time and temperature profile at which loss of AP conduction occurs.
Methods and Results: A retrospective study evaluated 25 patients (mean age 13.3 ± 3.6 years) who underwent cryoablation for right-sided APs (22 manifest/3 concealed). Direct cryoablation (–80°C) without cryomapping was performed using a "time to success" strategy. If AP conduction was successfully interrupted within 25 seconds of the onset of cryoablation, the lesion was continued for 240 seconds; otherwise it was terminated and further mapping was performed. Cryoablation was successful in 24/25 (96%) patients. Temperature at loss of AP conduction was −66.2 ±−16.7°C (range +32 to −84°C) with conduction block at temperatures lower than −30°C for all but 3 APs. Critical time to success (interval from cryoadherence to loss of AP conduction) was significantly shorter for permanently successful cryolesions, compared with transiently successful lesions (6.3 ± 4.1 vs. 11.2 ± 2.2 sec; P < 0.001). There were no major complications.
Conclusions: Cryothermal energy required for successful ablation may be variable and restricting test applications to −30°may limit its efficacy. A "time to success" strategy may improve outcome of cryoablation for right-sided APs in children without compromising safety.     

Acute Success of Cryoablation of Left-Sided Accessory Pathways: A Single Institution Study

Objective: To compare the acute success and recurrence rate of cryoablation for left-sided accessory pathways (AP) with controls who underwent radiofrequency ablation (RFA) at the same institution.
Background: Catheter cryoablation of supraventricular tachycardia (SVT) is considered to be a safer alternative a compared with RFA. At our institution, cryoablation has become the primary interventional modality for all APs. The reported success rates of cryoablation for AP-mediated tachycardia have generally been less favorable than for RFA. However, the location of AP may influence cryoablation outcome. Furthermore, there are little data available on cryoablation of left-sided pathways.
Methods: A chart review was performed for all patients undergoing cryoablation between August 2005 and August 2007. Twenty-nine patients (mean age 13 years, range 6–18 years) were identified with SVT secondary to left-sided AP. The data collected included patient age, height, weight, date of procedure, mapping, ablation and procedure time, pathway location, success, and recurrence. Cryoablation was performed via a transseptal approach. Procedural success and recurrence rate were compared with our most recent 28 patients undergoing RFA ablation.
Results: Procedural success was achieved in 97% of patients in the cryoablation group, compared with 100% in the RFA control group. Recurrence rate in the cryoablation group was 1 of 24 (4.2%) patients compared with 4 of 28 (14%) patients in the RFA group over 12 months.
Conclusion: Cryoablation can be safely and effectively used in the treatment of left-sided AP. Long-term outcomes remain to be seen.     

Cryoablation of accessory pathways in the coronary sinus in young patients: a multicenter study from the Pediatric and Congenital Electrophysiology Society's Working Group on Cryoablation

Introduction: This is a multicenter retrospective study evaluating the immediate- and mid-term outcomes of cryoablation of accessory pathways in the coronary sinus in children or in patients with congenital heart disease.
Methods and Results: Twenty-one patients (median age 13.0 years, range 2–40) from six institutions were included. The accessory pathways were concealed in 11 and manifest in 10. Of 12 patients who had coronary sinus angiography, two had large coronary sinus diverticula, one had a dilated coronary sinus due to a left superior vena cava to coronary sinus, and one had a "pouch" at the mouth of the coronary sinus. Six patients underwent ablation procedures with cryoablation alone, while in the remaining 15 patients, both cryoablation and radiofrequency ablation were utilized. The ablation procedure included left-sided endocardial mapping via a retrograde or transeptal approach in 13 (62%). Procedural success was achieved with cryoablation in the coronary sinus in 15/21 (71%). Four patients (19%) had successful radiofrequency ablation at the right or left posterior septum. Two patients (10%) had unsuccessful procedures. Of the 15 patients with initially successful cryoablation procedures, six (40%) had arrhythmia recurrences at a median of 17 days (range 1–120). Recurrences could not be explained by differences in patient or procedural variables.
Conclusion: Cryoablation in the coronary venous system in young patients is feasible but associated with a high arrhythmia recurrence rate. Cryoablation techniques and/or equipment need to be improved in order to safely create more permanent lesions in this arrhythmia substrate.     

Lengthier cryoablation and a bonus cryoapplication is associated with improved efficacy for cryothermal catheter ablation of supraventricular tachycardias in children

Introduction Cryoablation is an effective treatment for children with supraventricular tachycardias (SVT). The present study documents the effect of two different cryoablation protocols on acute and chronic success rates. Methods and results Fifty-three consecutive patients (age range, 5–20 years) were treated; patients 1 to 17 were treated by a standard ablation protocol and patients 18 to 53 were treated by a modified ablation protocol that required lengthier cryoablations plus delivery of a bonus cryoapplication to consolidate the acutely successful irreversible lesion created at intervention. Electrophysiological study (EPS) was performed with diagnostic catheters and cryoablations were performed with a 7FR 4 mm tip catheter (CryoCath Technologies). Acute endpoints for non-inducibility of atrioventricular nodal re-entrant tachycardia (AVNRT) by programmed atrial stimulation at baseline or during isoproterenol performed 30 min post procedure, as well as non-inducibility and conduction block over the accessory pathway (AP). The chronic endpoint was arrhythmia recurrence post intervention. No permanent cryo-related complications or adverse outcomes were reported. Acute success rates for patients 1 to 17 and 18 to 53 were 88 and 100%, respectively. The cumulative percentage of patients without arrhythmia recurrence at 12 month follow-up was significantly different at 73 and 90%, respectively. Conclusions Lengthier cryoablation delivery, approximating 7 min per cryoablation, increases the acute success rate at intervention. Moreover, these lengthier cryoablation deliveries plus a bonus cryoapplication to consolidate the acutely successful irreversible lesion created at intervention may also significantly improve the chronic success rate, while also maintaining an excellent safety profile for cryoablation treatment of children with SVT such as AVNRT and AP located near the AV junction.     

Safety and efficacy of cryoablation of accessory pathways adjacent to the normal conduction system

Cryoablation of Septal Accessory Pathways. INTRODUCTION: Catheter ablation has become a routine treatment for patients with Wolff-Parkinson-White syndrome because of its low risk and high efficacy; however, radiofrequency ablation in the septum close to the AV node or His bundle still carries a definite risk for AV block. Cryoenergy catheter ablation has recently become available. This technique has specific features, such as the ability to create reversible loss of function to predict the effects of ablation (ice mapping) and the adherence of the catheter tip to the endocardium with freezing, which avoids the risk for dislodgment. Both of these characteristics may minimize the risk of complications. The aim of this study was to analyze the effectiveness and safety of catheter cryoablation in 20 patients with para-Hisian or midseptal accessory pathways (AP). METHODS AND RESULTS: Eleven patients with para-Hisian and 9 patients with midseptal AP underwent catheter cryoablation. Ice mapping at -30 degrees C was performed to ascertain the disappearance of AP conduction and the absence of impairment of AV nodal conduction. If the expected result was obtained, cryoablation was performed by lowering the temperature to -75 degrees C for 4 minutes in order to create a permanent lesion. Cryoablation was successful in all patients using a mean of 1.2 +/- 0.4 applications. Recurrences occurred in 4 patients (20%) who underwent a second successful cryoablation session. No complications were observed. CONCLUSION: Cryoablation appears to be a safe and effective technique for ablation of APs close to the AV node or His bundle because of the ability to predict the acute effects of ablation with ice mapping before creation of an irreversible lesion.     

Transcatheter cryo-ablation of septal accessory pathways,multicenter observational study in Japan

BackgroundAblation using radiofrequency energy has to be carefully performed when the arrhythmia substrate is located in close proximity to the atrioventricular (AV) node due to the risk of inadvertent permanent AV block. The aim of this study was to evaluate the efficacy and safety of catheter-based cryo-therapy for septal accessory pathways (APs).MethodsA total of eleven patients (median = 56.3 years, range 13–74 years) with septal APs underwent cryoablation. Ice-mapping was performed during sinus rhythm and an AV reciprocating tachycardia utilizing the APs as a requisite limb with cooling of the catheter tip temperature to a maximum of -30℃ for less than 45 s. Cryo-ablation was performed for 4 min at a temperature of -80℃ only if ice-mapping abolished the pre-excitation or retrograde conduction over the AP without injury to the AV nodal conduction.ResultsCryo-ablation was acutely successful in all eleven patients. No permanent cryo-related complications or adverse outcomes were reported. During the follow-up (range 14–26 months), no patients experienced any arrhythmia recurrences.ConclusionIce-mapping was a feasible and reliable method to determine the exact location of the APs owing to the possibility of validating the ablation site. Cryo-ablation of APs located near the AV junction is a safe and efficacious technique with a high success rate over the long term.IRB informationEthical Committee of Japan Red Cross Yokohama City Bay Hospital #2018?19.     

Ablation of manifest septal accessory pathways: a single-center experience

Background

Ablation of septal accessory pathways (SAPs) is associated with an increased risk of heart block. Data on outcomes of SAP ablation in adults are limited.

Objectives

To describe outcomes of SAP ablation in our center.

Methods

Patients with Wolff-Parkinson-White syndrome (WPW) undergoing an EP study at our center between January 2008 and August 2019 were identified from our institutional database. Location of the pathway was noted as anteroseptal (AS), midseptal (MS), or posteroseptal (PS). Outcomes of the ablation including success, complication rates, and recurrences were also recorded.

Results

Thirty-three patients with SAP underwent 35 EP studies: AS (n?=?13), MS (n?=?5), and PS (n?=?15). Thirty pathways were targeted for ablation, two of which required a 2nd procedure resulting in 32 attempts at ablation in 30 patients. In the remaining 3 patients, SAP did not have malignant features and were not targeted for ablation. Single-procedure success rate was 28/30 (93.33%): 9/10 AS, 5/5 MS, and 14/15 PS ablations. One AS pathway was successfully ablated during a 2nd procedure. Two complications were observed: 1 pericardial effusion in a patient who underwent epicardial mapping and ablation of both PS and right free wall APs. Additionally, transient 2:1 AV block occurred during an MS pathway ablation that recovered during follow-up and did not require permanent pacing procedure.

Conclusion

In this single-center experience, ablation of manifest SAP was associated with high success rates and low complication rates. No instances of permanent heart block requiring pacing occurred.

     

Radiofrequency ablation of arrhythmias guided by non-fluoroscopic catheter location: a prospective randomized trial.

AIMS: To compare the utility of non-fluoroscopic mapping systems (Carto and Ensite NavX) with that of conventional mapping in patients referred for catheter ablation of a wide variety of arrhythmias. METHODS AND RESULTS: Patients referred for catheter ablation (excluding atrial fibrillation, atypical atrial flutter, ventricular tachycardia in structural heart disease, and complete AV nodal ablation) were randomized equally to a procedure guided by Carto, Ensite NavX, or conventional mapping. A total of 145 patients were recruited (82 men, aged 49+/-16, range 18-85). In 19 patients, no ablation was performed, and in the remaining, typical atrial flutter, atrioventricular nodal re-entrant tachycardia, and atrioventricular re-entrant tachycardias [including Wolff-Parkinson-White (WPW)] accounted for 93% of ablations. Overall procedure time, immediate and short-term success, complication rate, and freedom from symptoms at follow-up were identical for all groups. NavX led to the least X-ray exposure: Navx vs. conventional, median (range): 4 (0-50) vs. 13 (2-46) min (P<0.001); NavX vs. Carto, median (range): 4 (0-50) vs. 6 (1-55) min (P=0.008). Both Carto and NavX increased disposable costs by 50% when compared with conventional (P<0.001). For typical atrial flutter, Carto and NavX reduced screening times without increasing procedure cost. If ablation was not performed, NavX was twice as expensive as Carto or conventional. CONCLUSION: Ensite NavX and Carto procedures have similar effectiveness and safety to a conventional approach; however, they both reduce X-ray exposure, with NavX producing a significantly greater effect than Carto. Although this benefit is achieved at a greater financial cost, there may be long-term benefits to catheter laboratory staff.     

Transcatheter cryoablation of tachyarrhythmias in children: initial experience from an international registry

OBJECTIVES: We sought to describe the early pediatric experience of transcatheter cryoablation, and identify whether specific arrhythmia substrates and/or ablation locations were particularly suited to cryoablation. BACKGROUND: Radiofrequency (RF) ablation has become established therapy for pediatric tachyarrhythmias. However, challenges remain in terms of the safety and efficacy of RF ablation in specific locations; new methods may address these issues. METHODS: Prospective data were available for 64 patients age 13 +/- 4 (mean +/- SD) years undergoing cryoablation at 14 centers participating in the Cryocath International Patient Registry. Dysrhythmia duration was 5.0 +/- 4.2 years, with diagnoses of atrioventricular node re-entrant tachycardia (AVNRT) (n=30), anteroseptal (n=11), midseptal (n=5), or other (n=15) accessory pathway (AP) mediated AV re-entry, ventricular tachycardia (VT) (n = 3), and ectopic atrial tachycardia (EAT) (n=2). Two patients had more than one arrhythmia substrate. Transcatheter cryoablation was offered by cardiologist preference after written informed procedural consent of each patient and/or legal guardian. Cryomapping was performed at -30 degrees C and cryoablation was delivered with 4-min applications at -75 degrees C. RESULTS: Acute success was achieved in 45 of 65 (69%) cryoablation patients, with best success rates in AVNRT (83%) and right septal AP (75%), and lower success rates in other AP (43%), VT (66%), and EAT (0%). No device-related adverse events were reported. The success of radiofrequency (RF) ablation applied in 14 cryoablation failures was 4 of 4 for AVNRT patients, 1 of 1 for anteroseptal AP patients, 5 of 6 for other AP patients, 0 of 1 for VT patients, and 0 of 2 for EAT patients. CONCLUSIONS: Transcatheter cryoablation is a safe and well-tolerated alternative to RF ablation in pediatric patients on the basis of our initial experience. Success is highest in AVNRT and in substrates recognized as technically challenging or risky for RF ablation.     

��Near-zero�� fluoroscopic exposure in supraventricular arrhythmia ablation using the EnSite NavX? mapping system: personal experience and review of the literature

Purpose

Radiofrequency catheter ablation (RFCA) of supraventricular tachyarrhythmias carries a small but non-negligible radiation risk. Studies in children already showed the feasibility of using three-dimensional mapping systems as the primary guide for catheter visualization and positioning in these RFCAs. We aim to demonstrate the feasibility and safety of such an approach in young and middle-aged patients.

Methods

Fifty patients (age 34?±?12) with supraventricular tachyarrhythmias underwent electrophysiological study; of these, 47 patients proceeded to RFCA guided by the EnSite NavX^TM system (23 with atrioventricular nodal reentry tachycardia, 16 with an accessory pathway, six with typical atrial flutter, and two with right atrial tachycardia).

Results

In 38/50 cases (76%), electroanatomical mapping avoided fluoroscopy entirely, including four cases requiring access to the left heart chambers by a retrograde approach. In the remaining 12/50 cases (24%), fluoroscopy use was limited to 122?±?80 s, with a correspondingly low radiation exposure (dose area product 1.3?±?1.1 mGy?×?m²). All procedures were acutely successful, with a procedural time of 113?±?37 minutes, and without incurring in any major complication. Over a mean follow-up of 12?±?3 months, we observed one recurrence of pre-excitation and one relapse of atrial flutter.

Conclusions

Our study shows that non-fluoroscopic RFCA of supraventricular tachyarrhythmias using the EnSite NavX^TM system is feasible, safe, and effective in a population of relatively young adults. Our experience of a non-fluoroscopic approach in these procedures deserves consideration, particularly in the young or in other patients at higher radiation risk.     

Cryoablation versus radiofrequency ablation for treatment of pediatric atrioventricular nodal reentrant tachycardia: Initial experience with 4-mm cryocatheter

BACKGROUND: Initial reports have shown cryoablation to be safe and efficacious for treatment of atrioventricular nodal reentrant tachycardia (AVNRT). No direct comparisons of cryoablation vs radiofrequency (RF) catheter ablation in pediatric patients have been made. OBJECTIVES: The purpose of this study was to compare the outcomes of cryothermal vs RF catheter ablation for treatment of AVNRT in pediatric patients. METHODS: We retrospectively reviewed consecutive ablation procedures for treatment of AVNRT at a single arrhythmia center. The RF group consisted of patients who underwent RF ablation from 2002 until cryothermy became available. The cryoablation group consisted of patients who underwent cryothermal ablation from 2004 to 2005. The groups were compared for procedural and electrophysiologic outcomes. RESULTS: RF (n = 60, age 14 +/- 4 years) and cryoablation (n = 57, age 14 +/- 4 years) groups had similar demographic and baseline parameters. Procedural times were shorter in the RF group (RF ablation 112 +/- 31 minutes vs cryoablation 148 +/- 46 minutes, P < .001). Fluoroscopy times were comparable (RF ablation 21 +/- 15 minutes vs cryoablation 20 +/- 13 minutes, P = .77). In an intention-to-treat analysis, success of the procedure was 100% for RF ablation and 95% for cryoablation (P = .11). No permanent AV block occurred in either group. Recurrence rates were higher for the cryoablation group, but this did not reach statistical significance (RF ablation 2% vs cryoablation 8%, P = .19). CONCLUSION: Cryoablation appears to be similar to RF for ablation of AVNRT with respect to short-term efficacy and safety of the procedure in a pediatric population. Recurrence rates are higher with cryoablation.     

Paediatric catheter cryoablation: techniques, successes and failures

PURPOSE OF REVIEW: The benefit of transcatheter cryoablation over radiofrequency ablation is its ability to find the most suitable site for ablation through transitory electrical paralysis of the heart tissue in contact with the catheter tip, frozen to -30 degrees C (cryomapping). Cryoablation is thus 'made to measure' for paediatric patients. The purpose of this review is to show the results of cryoablation in the literature in order to understand when it can be used in children as an alternative to radiofrequency ablation. RECENT FINDINGS: Modified cryoablation protocols have increased acute success rates and decreased recurrences. Single institutions, comparing the results obtained with cryoablation and radiofrequency ablation for the treatment of supraventricular arrhythmias, have demonstrated the same success rate. Furthermore, some authors have attempted to identify parameters predictive of efficacy during cryoablation of atrioventricular nodal re-entry tachycardia. SUMMARY: On the basis of the more recent literature data, cryoablation should be considered the treatment of choice for atrioventricular nodal re-entry tachycardia and atrioventricular re-entry tachycardia caused by an accessory pathway very close to the atrioventricular junction in school-age children. The short and long-term efficacy of cryoablation is correlated with highly accurate cryomapping and the creation of a stable lesion through consolidation of the first effective lesion.     

Posteroseptal accessory pathway in association with coronary sinus diverticulum: electrocardiographic description and result of catheter ablation

Aims

A precise knowledge of the coronary sinus (CS) anatomy and its potential anomalies seems essential to increase the rate of success in patients with a prior history of multiple ablation failures of the posteroseptal accessory pathway or in whom this procedure cannot be performed easily. We aimed to describe the anatomic and electrocardiographic characteristics of the CS diverticulum in association with the posteroseptal accessory pathway and subsequent catheter ablation results.

Methods

We retrospectively recruited 12 patients with posteroseptal accessory pathways associated with CS diverticula from patients referred to Tehran Heart Center for electrophysiological study and ablation between January 2004 and December 2011.

Results

The study population consisted of eight males and four females at a mean age of 48.2?±?17.5 years with posteroseptal accessory pathways. The most frequent initial presentation was orthodromic atrioventricular re-entrant tachycardia and atrial fibrillation. The rate of acute success for radiofrequency ablation and the recurrence rate were 75 and 16.6 %, respectively. Larger diverticula tended to have more failure and recurrence rate, albeit not significant. None of the patient’s characteristics could significantly predict the success of the ablation.

Conclusion

Our total initial failure rate and subsequent recurrence was around 41 %. Better results might have been achieved had we applied irrigated tip catheters or NavX^TM-guided cryoablation or subxiphoid epicardial mapping and ablation.     

Cryoablation of colorectal liver metastases: minimally invasive tumour control

Background: Freezing is used for in situ destruction (ablation) of liver tumours not eligible for resection. The procedure is typically done during laparotomy. The objective of this report was to study tumour control at the site of freezing and a minimally invasive approach to cryoablation of colorectal liver metastases. Methods: A prospective study of 19 patients was conducted between 1999 and 2003. Twenty‐five tumours were ablated during 24 procedures (i.e. 5 reablations). Sixteen procedures were performed percutaneously, 5 during laparotomy and 3 laparoscopically. Magnetic resonance imaging (MRI) was used for intraprocedural monitoring during most procedures. Nine patients had concomitant liver resections performed (5 during laparoscopy, 4 during laparotomy). Results: Out of 25 ablations, 18 (72%) were assumed adequate. Total ice‐ball volume during percutaneous procedures was median 62?cm ³ (range 32–114). Excellent imaging of the extent of freezing was achieved using MRI. Hospital stay for patients treated percutaneously was median 4 days (range 3–30). No perioperative mortality occurred. Tumour recurrence at the site of ablation occurred in 8 of 18 (44%) tumours adequately ablated. Actuarial 2‐year tumour‐free survival at site of ablation was 48%. At the time of analyses 12 out of 13 (92%) patients assumed to be adequately ablated were alive. Of all patients, 14 out of 19 (74%) survived. Conclusions: Short‐term tumour control can be achieved following cryoablation of colorectal liver metastases. A minimally invasive approach is feasible but the diameter of metastases considered for percutaneous cryoablation should not exceed 3?cm.     

三维标测引导房室结折返性心动过速射频消融的疗效及其优势

目的 观察Ensite Navx三维标测引导射频消融治疗房室结折返性心动过速(AVNRT)的有效性及安全性。方法 射频消融治疗AVNRT患者213例,将其分为三维标测组（101例）和常规治疗组（112例）,三维标测组在Ensite Navx三维标测系统引导下,必要时联合短暂X线透视进行射频消融;常规治疗组在传统X线透视下行射频消融治疗。观察指标:①放置标测导管过程中X线曝光时限和射线剂量;②操作消融导管进行建模消融过程中X线曝光时限和射线剂量;③手术时间;④即刻成功率与总体成功率;⑤并发症的发生率（血气胸、心脏压塞、III度房室传导阻滞）。结果 ①放置标测导管过程中两组的X线曝光时间、曝光剂量分别为:三维标测组(2.3±1.3)min、(1.7±1.1)mGy,常规治疗组（2.4±1.1）min、（1.6±1.0）mGy,二者无统计学差异;②操作消融导管消融过程中,三维标测组X线曝光时间、曝光剂量为:（2.6±1.8）min、（3.5±1.8）mGy,显著低于常规治疗组的（8.9±2.0）min、（11.8±2.6）mGy(均P<0.01);③手术时间:三维标测组、常规治疗组分别为（48±16）min,（47±13）min,无显著差异;④术中两组患者均消融成功;术后随访6个月,三维标测组无复发病例,常规治疗组有1例复发,在Ensite Navx三维标测系统引导下再次消融成功,两组总体成功率无显著差异;⑤并发症:射频术中两组均未出现相关并发症。结论 应用Ensite Navx三维标测引导射频消融能够治疗AVNRT安全有效,且不增加手术时间和并发症,X线曝光时间、曝光剂量显著降低。     

Safety and results of cryoablation in patients <5 years old and/or <15 kilograms

Current recommendations discourage elective radiofrequency ablation in patients <5 years old and/or weighing <15 kg, primarily because of the greater complication rate. To describe the current use, complications, and immediate outcomes of cryoablation in this patient population, a multicenter retrospective review of all patients <5 years old and/or weighing <15 kg who were treated with cryoablation for arrhythmia was performed. Eleven centers contributed data for 68 procedures on 61 patients. Of those, 34% were elective and 24% (n = 16) were both cryoablation and radiofrequency ablation. The median age and weight at ablation was 3.5 years (range 8 days to 9.9 years) and 15.2 kg (range 2.3 to 23), respectively. Congenital heart disease was present in 23% of the patients. The immediate success rate of cryoablation alone was 74%. No major complications occurred with cryoablation only; however, 2 of the 16 patients who underwent cryoablation and radiofrequency ablation had major complications. Of the 50 patients receiving cryoablation, 8 (16%) had variable degrees of transient atrioventricular block. The recurrence rate was 20% after cryoablation and 30% after cryoablation plus radiofrequency ablation. In conclusion, cryoablation appears to have a high safety profile in these patients. Compared to older and larger patients, the efficacy of cryoablation in this small, young population was lower and the recurrence rates were higher. Cryoablation's effect on the coronary arteries has not been fully elucidated and requires additional research.     

The Pediatric Radiofrequency Ablation Registry's Experience with Ebstein's Anomaly

Radiofrequency Ablation in Pediatric Ebstein's Anomaly. Introduction : Abnormal anatomy and complex electrophysiology in patients with Ebstein's anomaly of the tricuspid valve may confound attempts at radiofrequency ablation (RFA).
Methods and Results : Data for 65 pediatric Ebstein's patients (9.8 ± 5.4 years, 4 months to 20 years; 39 ± 25 kg, 5.1 to 108 kg) were obtained from the Pediatric Radiofrequency Ablation Registry. The degree of tricuspid regurgitation (DOTR) and the degree of Ebstein's anomaly were assessed with echocardiography/Doppler. Leading indications were drug refractoriness (24 [37%] of 65 patients) and life-threatening arrhythmia (14 [22%] of 65 patients). For the 65 patients, 82 typical (nondecremental) accessory pathways (APs) (62% right free wall, 34% right septal, and 4% left sided), 17 other supraventricular tachycardias (1 ectopic atrial, 7 AV reentry, 5 Mahaim, and 4 intra-atrial reentry tachycardias), and 1 ventricular mechanism were mapped. Thirty-four (52%) of 65 patients had a single AP (21 right free wall, 10 septal, and 3 left); 19 (29%) of 65 patients multiple APs; 6 (9%) of 65 patients a single AP plus a non-AP mechanism; and 6 (9%) of 65 patients non-AP mechanism(s) only. REA acute success rates and recurrence rates for right free wall, right septal, and other mechanisms were 79%/32%, 89%/29%, and 75%/27%. Mild DOTR and a body surface area (BSA) ≤ 1.7 m² independently predicted a better acute success rate. BSA ≤ 1.7 m² also predicted long-term success.
Conclusion : In this patient subset, life-threatening arrhythmias and multiple electrophysiologic mechanisms are commonly encountered during REA. Mild DOTR and a BSA ≥ 1.7 m² predict a higher acute success rate. While acute success rates are relatively high, recurrence is frequent.