Validation of a novel automated signal analysis tool for ablation of Wolff-Parkinson-White Syndrome.

BACKGROUND: In previous pilot work we demonstrated that a novel automated signal analysis tool could accurately identify successful ablation sites during Wolff-Parkinson-White (WPW) ablation at a single center. OBJECTIVE: We sought to validate and refine this signal analysis tool in a larger multi-center cohort of children with WPW. METHODS: A retrospective review was performed of signal data from children with WPW who underwent ablation at two pediatric arrhythmia centers from 2008-2015. All patients with WPW ≤ 21 years who underwent invasive electrophysiology study and ablation with ablation signals available for review were included. Signals were excluded if temperature or power delivery was inadequate or lesion time was < 5 seconds. Ablation lesions were reviewed for each patient. Signals were classified as successful if there was loss of antegrade and retrograde accessory pathway (AP) conduction or unsuccessful if ablation did not eliminate AP conduction. Custom signal analysis software analyzed intracardiac electrograms for amplitudes, high and low frequency components, integrated area, and signal timing components to create a signal score. We validated the previously published signal score threshold 3.1 in this larger, more diverse cohort and explored additional scoring options. Logistic regression with lasso regularization using Youden's index criterion and a cost-benefit criterion to identify thresholds was considered as a refinement to this score. RESULTS: 347 signals (141 successful, 206 unsuccessful) in 144 pts were analyzed [mean age 13.2 ± 3.9 years, 96 (67%) male, 66 (45%) left sided APs]. The software correctly identified the signals as successful or unsuccessful in 276/347 (80%) at a threshold of 3.1. The performance of other thresholds did not significantly improve the predictive ability. A signal score threshold of 3.1 provided the following diagnostic accuracy for distinguishing a successful from unsuccessful signal: sensitivity 83%, specificity 77%, PPV 71%, NPV 87%. CONCLUSIONS: An automated signal analysis software tool reliably distinguished successful versus unsuccessful ablation electrograms in children with WPW when validated in a large, diverse cohort. Refining the tools using an alternative threshold and statistical method did not improve the original signal score at a threshold of 3.1. This software was effective across two centers and multiple operators and may be an effective tool for ablation of WPW.

A multicenter review of ablation in the aortic cusps in young people.

BACKGROUND: Ablation within the aortic cusp is safe and effective in adults. There are little data on aortic cusp ablation in the pediatric literature. We investigated the safety and efficacy of aortic cusp ablation in young patients. METHODS: A retrospective, descriptive study of aortic cusp ablation in five pediatric electrophysiology centers from 2008 to 2014 was performed. All patients <21 years of age who underwent ablation in the aortic cusps were included. Factors analyzed included patient demographics, procedural details, outcomes, and complications. RESULTS: Thirteen patients met inclusion criteria (median age 16 years [range 10-20.5] and median body surface area 1.58 m2 [range 1.12-2.33]). Substrates for ablation included: nine premature ventricular contractions or sustained ventricular tachycardia (69%), two concealed anteroseptal accessory pathways (APs) (15%), one Wolff-Parkinson-White with an anteroseptal AP (8%), and one ectopic atrial tachycardia (8%). Three-dimensional electroanatomic mapping in combination with fluoroscopy was used in 12/13 (92%) patients. Standard 4-mm-tip radiofrequency (RF) current was used in 11/13 (85%) and low-power irrigated-tip RF in 2/13 (15%). Angiography was used in 13/13 and intracardiac echocardiography was additionally utilized in 3/13 (23%). Ablation locations included: eight noncoronary (62%), three left (23%), and two right (15%) cusps. Ablation was acutely successful in all patients. At median follow-up of 20 months, there was one recurrence of PVCs (8%). There were no ablation-related complications and no valvular injuries observed. CONCLUSION: Arrhythmias originating from the coronary cusps in this series were successfully and safely ablated in young people without injury to the coronary arteries or the aortic valve.

Success rates in pediatric WPW ablation are improved with 3-dimensional mapping systems compared with fluoroscopy alone: a multicenter study.

INTRODUCTION: Three-dimensional mapping (3-D) systems are frequently used for ablation of supraventricular tachycardia. Prior studies have demonstrated radiation dosage reduction with 3-D, but there are no data on whether 3-D improves the efficacy of ablation of Wolff-Parkinson-White syndrome (WPW). We sought to determine if 3-D improves the success rate for ablation of WPW in children. METHODS: Multicenter retrospective study including patients ≤21 years of age with WPW undergoing ablation from 2008 to 2012. Success rates using the 2 techniques (3-D vs. fluoroscopy alone [FLUORO]) were compared. RESULTS: Six hundred and fifty-one cases were included (58% male, mean age 13 ± 4 years, 366 [56%] 3-D). Baseline characteristics including gender, weight, accessory pathway (AP) location, number of APs, and repeat ablation attempts were similar between the 2 groups (3-D and FLUORO) The 3-D group was slightly younger (12.7 ± 4.0 vs. 13.3 ± 4.0 years; P = 0.04) and less likely to undergo ablation utilizing cryoenergy (38 [10%] vs. 56 [20%]; P < 0.01). The 3-D group had a higher acute success rate of ablation (355 [97%] vs. 260 [91%]; P < 0.01). No differences were seen in recurrence (16 [5%] vs. 26 [9%]; P = 0.09) or complication rates (1 [0.3%] vs. 1 [0.4%]; P = 0.86) between the groups. On multivariable analysis, 3-D was shown to significantly improve success at ablation with an odds ratio of 3.1 (95% CI 1.44-6.72; P < 0.01). CONCLUSIONS: Use of 3-D significantly improved success rates for ablation of WPW in children. The increase in acute success associated with 3-D suggests it is an important adjunct for catheter ablation of WPW in children.

Effects of ventilation and catheter position on catheter movement on the tricuspid annulus during ablation in children.

INTRODUCTION: There are little data on the effect of catheter position and mechanical ventilation on ablation catheter stability during electrophysiology study in children. We sought to determine the magnitude of catheter movement with mechanical ventilation, the effect of ventilation maneuvers on catheter movement, and to compare the degree of movement observed between the right lateral (RL) and right posteroseptal (RPS) regions. METHODS: From June 2012 to June 2013, patients ≤ 21 years of age undergoing ablation for supraventricular tachycardia with CARTO® 3 (Biosense Webster, Diamond Bar, CA, USA) were included. During mapping the ablation catheter was placed in the RPS and RL regions and the magnitude of catheter movement (mm) was measured using CARTO® 3. Measurements were made during routine ventilation and with a maximal inspiration maneuver between end-expiration (ENDEX) and peak-inspiration (PEAKINS). RESULTS: Twenty-one patients were included: 12 males (57%), age 13 ± 3 years, weight 55 ± 14 kg. Indications for ablation were: 10 Wolff-Parkinson-White, seven atrioventricular node re-entry tachycardia, four concealed accessory pathway. Mechanical ventilation was used in all cases. The magnitude of catheter movement was 3.6 ± 1.7 mm with routine ventilation and 6.2 ± 4.1 mm between ENDEX and PEAKINS (P ≤ 0.01). Catheter movement was greater in the RL compared to the RPS region with routine ventilation (RL 4.3 ± 1.6 vs RPS 3.0 ± 1.5; P < 0.01) and between ENDEX and PEAKINS (RL 8.3 ± 4.7 vs RPS 4.0 ± 1.7; P < 0.01). CONCLUSIONS: Ventilation and catheter position both have significant impact on the degree of catheter movement during ablation. Movement was greatest in the RL position. This may partially explain the lower success rates of ablation in the RL region.

Ablating the anteroseptal accessory pathway-ablation via the right internal jugular vein may improve safety and efficacy.

PURPOSE: Ablation of anteroseptal accessory pathways have historically been associated with lower success rates and a higher risk of AV nodal injury due to close proximity to the compact AV node. We describe the technique of ablation of anteroseptal APs via the right internal jugular vein (RIJV). METHODS: A retrospective analysis of all patients undergoing EP study and ablation at the Children's Hospital at Montefiore from 2008 to 2011 for SVT and/or WPW was performed. All patients less than 21 years of age who underwent ablation from the RIJV for either WPW or a concealed accessory pathway located in the anteroseptal region were included. RESULTS: A total of 16 patients met inclusion criteria and were the subject of this analysis. Twelve patients had WPW (75%) and four had a concealed AP (25%). Ablation was acutely successful in 94% of patients (15/16). In one patient, ablation was deferred due to close proximity to the compact AV node and risk of AV nodal injury. Radiofrequency (RF) was used in 14 patients and cryoenergy in two patients. There was no difference in WB CL pre- and post-ablation (p = 0.19). There were no complications encountered. At a mean follow-up of 15 ± 12 months, there were no recurrences. CONCLUSION: Ablation of APs in the right anteroseptal region can safely and effectively be performed via the RIJV with a success rate of 94%. This technique should be considered for ablation of APs located in the anterior septum.

Characteristics of ventricular tachycardia arising from the inflow region of the right ventricle.

INTRODUCTION: Ventricular tachycardia (VT) arising from the right ventricular inflow (RVI) region is uncommon. There is minimal literature on the clinical and electrocardiographic characteristics of RVI VT. METHODS: A retrospective analysis of patients with RVI VT who underwent electrophysiology study between 2006 and 2011 was performed. Patients with structural heart disease (including arrhythmogenic right ventricular dysplasia) were excluded. RESULTS: Seventy patients underwent an electrophysiology study for VT arising from the right ventricle during the study period. Nine patients (13%) met the inclusion criteria for RVI VT and were the subject of this analysis. The median age was 46 years (range, 14-71), and VT cycle length was 295 milliseconds (range, 279-400 milliseconds). All VTs had an left bundle-branch block morphology. An inferiorly directed QRS axis was noted in 7 (78%) of 9 patients and a left superior axis in 2 (22%) of 9 patients. A QS or rS pattern was noted in all patients in aVR and V(1). A transition from S to R wave occurred in V(3) to V(5) in all patients, with 78% of the patients transitioning in V(4) or V(5). Ablation was attempted in 8 (89%) of 9 patients and was successful in 6 (67%) of 9 patients. Ablation was limited in all unsuccessful patients due to the proximity to the His and risk of complete heart block. CONCLUSIONS: Electrocardiographic findings of a left bundle-branch block with a normal QRS axis, QS or rS patterns in aVR and V(1), and late S to R transition (V(4)/V(5)) are commonly found in RVI VT. Because of the proximity to the His, ablation of RVI VT may be more challenging than that of right ventricular outflow tract VT.