Atrioventricular Nodal Reentrant Tachycardia In Children Research Articles

Effect of Ablation Energy Source on Outcomes of Slow Pathway Modification for AVNRT in Children.

Selection of radiofrequency ablation (RF) or cryoablation (Cryo) for atrioventricular nodal re-entrant tachycardia (AVNRT) in children remains controversial due to a lack of contemporary comparison studies in this population. This study sought to compare outcomes of RF and Cryo for AVNRT in the pediatric population. AVNRT ablation outcomes were retrospectively analyzed utilizing the National Cardiovascular Data Registry IMPACT (Improving Pediatric and Adult Congenital Treatment) Registry from April 2016 to March 2019. Data from subjects 1 to 21 years of age undergoing elective first-time slow pathway (SP) modification for AVNRT were included. Exclusion criteria included<1 year of age, congenital heart disease, and >1 ablation target. Cases were analyzed by ablation energy: 1) RF only; 2) Cryo only; 3) radiofrequency ablation switching to cryoablation (RF→Cryo); and 4) cryoablation switching to radiofrequency ablation (Cryo→RF). The primary outcome was acute ablation failure. Secondary outcomes included in-hospital adverse events. Among 2,448 patients (mean age 13.6 ± 3.4 years, 60% female), RF only was employed in 43% (n=1,046), Cryo only in 49% (n=1,201), RF→Cryo in 6% (n=135), and Cryo→RF in 66 (3%). Acute ablation failure occurred in 1.3% (n=33), with no difference by energy source (1% in RF only, 1.5% in Cryo only, 1.5% in RF→Cryo, 3% in Cryo→RF; P=0.5). Atrioventricular (AV) block requiring permanent pacemaker did not occur in any group; transient AV block occurred in 0.4% of the cohort, with no difference by group. In this largest pediatric study of AVNRT ablation, RF and Cryo demonstrated comparable high acute success and rare documentation of AV block that did not result in temporary or permanent pacing. Longitudinal data are important for further comparison of these modalities with regard to recurrence risk and late complications.

Catheter ablation of orthodromic reciprocating tachycardia and atrioventricular nodal reentrant tachycardia in children with hypoplastic left heart syndrome.

Experience with catheter ablation of orthodromic reciprocating tachycardia (ORT) and atrioventricular nodal reentrant tachycardia (AVNRT) in young children with hypoplastic left heart syndrome (HLHS) is limited. We report the feasibility, safety, and outcomes of catheter ablation of ORT and AVNRT in children with HLHS. This was a retrospective review of patients with HLHS who underwent catheter ablation for reentrant supraventricular tachycardias (excluding atrial tachycardias) between 2005 and 2017 at a single center. Descriptive data including demographics, clinical history, procedural data, and outcomes were recorded. Ten children with HLHS underwent elevencatheter ablation procedures. Median age and weight at ablation were 2.7 years (range: 0.1-10.5) and 11.4 kg (range: 3.6-30.4), respectively. Tachycardia mechanism was AVNRT in four, ORT in five (two with preexcitation), and both in one. Acute procedural success was 100% and there was no spontaneous recurrence of tachycardia orpreexcitationin median 92 months (range: 21-175 months) follow-up. Five patients underwent subsequent EP studies at catheterization (intracardiac) or after surgery (via epicardial wires): three were noninducible, one after AVNRT ablation had inducible atrial tachycardia, and one after initial ORT ablation had inducible ORT at fenestration closure and underwent successful repeat ablation. Thus, long-term freedom from clinical tachycardia was 100% and from inducible AVNRT or ORT was 80%. Transcatheter ablation for ORT and AVNRT in children with HLHS can be performed with excellent acute and long-term success without major complications.

3D electronic anatomy mapping guided radiofrequency catheter ablation in 95 children with atrioventricular nodal reentrant tachycardia

Objective: To investigate the clinical features and evaluate the efficacy of radiofrequency catheter ablation (RFCA) guided by 3D electronic-anatomy mapping system (CARTO3 System) in children with atrioventricular nodal reentrant tachycardia (AVNRT). Methods: This was a retrospective case-controlled study. Data were collected from 95 children with AVNRT who underwent RFCA using CARTO3 System in the first hospital of Tsinghua University from January 2014 to December 2017. The onset age, characteristic of electrophysiology and anatomy feature of Koch triangle were analyzed. The efficacy and safety of ablation and X-ray fluoroscopy were compared with control 135 children with AVNRT who underwent RFCA without using CARTO3 System. The t test or the chi-square test was used for group comparison. Linear regression equation was established for correlation analysis. Results: The onset age of the 95 children (male 55, female 40; the average age (8.0±3.6) years) with AVNRT was (0.2-17.0) years and 23(24.2%) children were less than 3 years old. Electrophysiologic study showed that 84.2% (80 cases) was AVNRT-slow fast (SF), 11.6% (11 cases) AVNRT-slowslow and 4.2%(4 cases) AVNRT-fast slow. The phenomena of atrio-Hisian(AH) jump occurred in 65.3% and the interval of AH jump was (73.0±10.6) ms. The height of Koch triangle (CSo-His) was (22.3±5.8) mm and related with the weight of children (Y=0.171X+ 16.660, r(2)=0.224, P<0.001).The distance between the successful ablation target and the lowest point of His zone (ABL-His) was (11.7±2.6) mm. And there was no relation with the body weight(Y=-0.005X + 11.650, r(2)=0.001, P=0.780) and CSo-His (Y=0.072X+9.914, r(2)=0.030, P=0.171). The acute success rate was 97.9% (93/95) and recurrent rate was 5.4% (5/93) during follow-up. No obvious complication was reported. Compared with control group, the fluoroscopy time ((3.3±2.5) vs. (10.7±5.8) min, t=13.190, P<0.05), radiation dose ((5.4±4.9) vs. (15.5±6.3) mGy, t=13.660, P<0.05), and dose area product (514±445) vs. (2 478±415) mGy·cm(2), t=33.850, P<0.05) were decreased significantly. Conclusions: AVNRT-SF was the most common type of AVNRT. AVNRT incidence in infant and toddlers is lower than that in elder children. CSo-His is correlated with the body weight. ABL-His is relatively fixed. There is no correlation between ABL-His and the body weight and also no correlation between ABL-His and CSo-His. RFCA of AVNRT in children using the CARTO3 system is safe, effective and minimizes X-ray fluoroscopy.

Value of an old school approach: safety and long-term success of radiofrequency current catheter ablation of atrioventricular nodal reentrant tachycardia in children and young adolescents.

Radiofrequency current energy (RFC) ablation is still considered as the gold standard for atrioventricular nodal reentrant tachycardia (AVNRT). Success-rates for AVNRT ablation vary irrespective of the ablation technology and strategy. This study aimed to access safety, efficacy, and long-term outcome of RFC catheter ablation for the treatment of AVNRT in children and adolescents aged < 19years with special focus on modulation versus ablation of the AV nodal slow pathway (SP). A total number of 1143 patients (pts) < 19years were referred for invasive electrophysiological testing due to paroxysmal supraventricular tachycardia (SVT). Diagnosis of AVNRT was confirmed in 412 pts, and RFC-guided ablation was attempted in 386 pts (age 13.0 ± 3.5years). No permanent complications were observed. RFC application resulted in SP-ablation in 171/386 (44.3%) and in SP modulation in 208/386 (53.9%) children, whereas attempts for RFC treatment failed in 7 pts. Follow-up was completed for 396/412 patients (96.1%). Within a mean follow-up period of 54.9 ± 39.7months, in 51/379 pts (13.5%) AVNRT recurrence was observed. The median time until tachycardia recurrence was 19.5months. No difference for AVNRT recurrence was found comparing SP ablation versus SP modulation (p> 0.05), whereas the recurrence rate was significantly higher in patients with non-inducible SVT and therefore empiric SP treatment as compared to patients with inducible AVNRT (p= 0.01). RFC-guided ablation for AVNRT in children and adolescents is safe and leads to an acceptable long-term freedom from recurrences. SP modulation and SP ablation resulted in comparable acute and long-term success rates. Late AVNRT recurrences can occur even after years of freedom from tachycardia-related symptoms.

Long-termoutcomes following cryoablation of atrioventricular nodal reentrant tachycardia in children.

Atrioventricular nodal reentrant tachycardia (AVNRT) is a common tachyarrhythmia substrate inchildren, which is successfully treated by catheter ablation using radiofrequency or cryothermal energy. In recent years, cryoablation (Cryo) using electroanatomical system guidance is more commonly preferred for use in children in order to decrease the risk of an atrioventricular block. However, there are concerns regarding the long-term efficacy of Cryo in treating AVNRT. We aimed to evaluate the feasibility, safety, and long-term efficacy of Cryo for AVNRT in children. A total of 275 consecutive children above 4 years of age diagnosed with AVNRT were included in our study. The EnSite system (St. Jude Medical, Inc., St. Paul, MN, USA) was used to reduce or eliminate fluoroscopy. The study included 275 patients (148 females, age: 11.9 ± 3.6 years) undergoing catheter ablation forAVNRT from July 2012 to September 2016. Acute success was obtained in all (100%) patients with a mean procedure time of 140 ± 44 minutes. Fluoroscopy was used in only 12 (4.4%) patients. During a follow-up time of 25.6 ± 13.5 months (median: 23 months),AVNRT recurred in 12 of 279 (4.4%) of the patients. Age, sex, number of Cryo lesions, and catheter tip size (6-mm vs 8-mm) were not predictive for recurrence. In nine patients, a repeat ablation was successfully performed with cryoenergy. Cryo for AVNRT is a safe and effective procedure with excellent long-term outcomes. The use of electroanatomical systems during ablation significantly decreases exposure to fluoroscopy without compromising success.

Assessment of Atrioventricular Conduction Following Cryoablation of Atrioventricular Nodal Reentrant Tachycardia in Children

Early-onset transient atrioventricular block (AVB) is a rare occurrence following cryoablation of atrioventricular nodal reentrant tachycardia (AVNRT), despite lack of any AVB at the end of the procedure. The purpose of this prospective study was to assess AVB shortly after successful cryoablation of AVNRT in children. A 6-mm-tip cryocatheter was used in 39 procedures. An 8-mm-tip catheter was used in 11 procedures. Twelve-lead electrocardiograms (ECGs) and 24-hour ambulatory ECGs were performed 24 hours prior to the procedure and immediately following the procedure. All procedures were done using the EnSite system (St. Jude Medical, St. Paul, MN, USA) without fluoroscopy. Although nine (18%) patients developed variable degrees of transient AVB during the procedure, all of them had normal atrioventricular (AV) conduction at the end of the procedure and did not require any intervention. Four of these patients had variable degrees of transient AVB following the procedure despite having normal AV conduction at the end of the procedure. One developed Mobitz type I AVB, which lasted for 11.5 hours, and the other three experienced 2:1 AVB, which lasted for 2, 8, and 24 hours, respectively. All patients had complete resolution of the AVB, which was also documented with the 24-hour ambulatory ECGs after the procedure. Early transient AVB can develop following AVNRT cryoablation even if AV conduction is normal at the end of the procedure. Despite the transient AVB in the initial 24 hours after the procedure in some cases, there is no evidence for ongoing AV nodal dysfunction.

Single center experience of fluoroless AVNRT ablation guided by electroanatomic reconstruction in children and adolescents

Purpose: Anatomical considerations and risks related to x-ray exposure make atrio-ventricular nodal reentrant tachycardia (AVNRT) ablation in pediatric patients a concerning procedure. We aimed to evaluate the feasibility, safety and efficacy of performing fluoroless slow pathway cryoablation guided by the electroanatomic (EA) mapping in children and adolescents. Methods: Twenty-five consecutive patients (mean age 13.8±2.5 years) symptomatic for AVNRT were prospectively enrolled to right atrium EA mapping and electrophysiological study prior to cryoablation. Cryoablation was guided by slow pathway potential and performed using a 4-mm tip catheter. Results: Sustained slow-fast AVNRT was inducible in all the patients with a dual AV nodal physiology in 96%. Acute success was achieved in 100% of the patients with a median of 2 cryo-applications. Fluoroless ablation was feasible in 23 patients, while in 2 subjects 50 and 45 seconds of x-ray were needed due to difficult vascular accesses. After a mean follow-up of 27.5 months AVNRT recurred in 6 patients. All the recurrences were successfully treated with a second procedure. In 4 patients a fluoroless cryoablation with a 6-mm tip catheter was successfully performed, while in the remaining 2 patients a single pulse of 60 s of radiofrequency energy was applied under fluoroscopic monitoring. No complications occurred. Conclusions: Combination of EA mapping systems and cryoablation may allow to perform fluoroless slow pathway ablation for AVNRT in children and adolescents in the majority of patients. Fluoroless slow pathway cryoablation showed a high efficacy and safety comparable to conventional fluoroscopy guided procedures.

Single Center Experience of Fluoroless AVNRT Ablation Guided by Electroanatomic Reconstruction in Children and Adolescents

Anatomical considerations and risks related to x-ray exposure make atrioventricular nodal reentrant tachycardia (AVNRT) ablation in pediatric patients a concerning procedure. We aimed to evaluate the feasibility, safety, and efficacy of performing fluoroless slow-pathway cryoablation guided by the electroanatomic (EA) mapping in children and adolescents. Twenty-one consecutive patients (mean age 13.5 ± 2.4 years) symptomatic for AVNRT were prospectively enrolled to right atrium EA mapping and electrophysiological study prior to cryoablation. Cryoablation was guided by slow-pathway potential and performed using a 4-mm-tip catheter. Sustained slow-fast AVNRT was inducible in all the patients with a dual AV nodal physiology in 95%. Acute success was achieved in 100% of the patients with a median of two cryo-applications. Fluoroless ablation was feasible in 19 patients, while in two subjects 50 seconds and 45 seconds of x-ray were needed due to difficult progression of the catheters along the venous system. After a mean follow-up of 25 months, AVNRT recurred in five patients. All the recurrences were successfully treated with a second procedure. In three patients, a fluoroless cryoablation with a 6-mm-tip catheter was successfully performed, while in the remaining two patients, a single pulse of 60 seconds of radiofrequency energy was applied under fluoroscopic monitoring. No complications occurred. Combination of EA mapping systems and cryoablation may allow to perform fluoroless slow-pathway ablation for AVNRT in children and adolescents in the majority of patients. Fluoroless slow-pathway cryoablation showed a high efficacy and safety comparable to conventional fluoroscopy guided procedures.

Incidental Dual Atrioventricular Nodal Physiology in Children and Adolescents: Clinical Follow‐Up and Implications

Dual atrioventricular (AV) nodal physiology is a substrate for the development of AV nodal reentrant tachycardia (AVNRT). However, the risk of developing AVNRT in patients with dual AV nodal physiology is not known. The purpose of this study is to identify the risk of developing AVNRT in children and adolescents with incidental findings of dual AV nodal physiology after accessory pathway ablation. This is a single center retrospective study of patients who underwent intracardiac electrophysiology study at The Children's Hospital, Denver, from March 1993 to August 2008, with findings of dual AV nodal physiology after successful ablation of an accessory pathway. Follow-up was obtained by chart review with the primary outcome of recurrent supraventricular tachycardia. Extended clinical follow-up was also achieved through phone contact with patients or parents of patients. Mean age at initial electrophysiology study was 12.8 years (±3.7 years). Follow-up was obtained on all 66 patients for a mean duration of 3.1 years (±2.8 years). Mean age at follow-up was 15.8 years (±4.6 years). Recurrent supraventricular tachycardia occurred in nine of the 66 patients (13.6%). AVNRT was induced in two of the 66 patients (3.0%). This study supports the hypothesis that incidental dual AV nodal physiology does not predict AVNRT in children and adolescents with after successful accessory pathway ablation.

Pharmacological Therapy in Children with Nodal Reentry Tachycardia: When, How and How Long to Treat the Affected Patients

Atrio-ventricular nodal reentrant tachycardia (AVNRT) is a rare supra-ventricular tachycardia (SVT) in children and becomes more frequent in adolescents. Most of children with an AVNRT have a healthy heart thus rarely experiencing severe symptoms. Because of haemodynamic instability or risk of complications, recurrences of SVT may require a chronic therapy. Interruption of dual atrio-ventricular nodal physiology is the basic mechanism to terminate AVNRT. This may be achieved by using anti-arrhythmic drugs or through Radiofrequency catheter ablation (RF). We aim to review the literature on the use of anti-arrhythmic drugs for the management of AVNRT in children aged more than 1 year and discuss the recommended dosages and the duration of a long term therapy. In the absence of comparative trials of risks and benefits between pharmacological therapy and RF and because of a greater clinical experience with anti-arrhythmic drugs, these last but not the least continue to be first-line therapy in the management of most SVT in children. Trials on pharmacotherapy in children with SVT in general and AVNRT in particular are lacking, use of anti-arrhythmic drugs being extrapolated from adult literature. Although Adenosine is becoming more used since it is the safest and effective drug in the acute setting, Digoxin continue to be the drug of first choice. Beta-blockers and Class I anti-arrhythmic are the second choice drugs with Flecainide being the preferred anti-arrhythmic drug for treatment failures. Amiodarone is rarely used as a chronic therapy in resistant cases. With the new advances in the RF technology, this therapy is becoming more safe and effective for AVNRT in children. Therefore, additional well-designed controlled trials are needed to further evaluate the comparative efficacy of anti-arrhythmic drugs in the management of AVNRT in children, as well as to evaluate dosing and toxicity in various age groups and determine the duration of a chronic therapy as compared to a potential RF.