Catheter ablation for supraventricular tachycardia and health resource utilization and expenditures: A propensity-matched cohort study.

BACKGROUND: Few data are available regarding temporal patterns of health resource utilization (HRU) and expenditures among patients undergoing catheter ablation for paroxysmal supraventricular tachycardia (PSVT). This study aimed to describe expenditures and HRU in patients with PSVT who underwent catheter ablation compared to a matched cohort of patients on medical therapy alone. METHODS: Using a large US administrative database, we identified adult patients (age 18 to 65 years) with a new PSVT diagnosis between 2008 and 2016. Propensity-score matching was used to assemble a PSVT cohort treated with ablation or medical therapy alone (N = 2556). Longitudinal trends in HRU and expenditures in the 3-years preceding and following PSVT diagnosis were compared. RESULTS: There were no significant differences in expenditures between groups except within the first year after PSVT diagnosis: $48,004 ablation vs. $17,560 medical therapy (p < 0.001). This difference was driven by procedural expenditures, where the mean cost of catheter ablation was $32,057 ± SD 26,737. In Years 2 and 3 post-ablation, HRU and expenditures decreased to the levels associated with the medical therapy group, although fewer ablation patients required any prescription for beta-blockers, calcium channel blockers, or anti-arrhythmic drugs (32% ablation vs. 42% medical therapy group, p < 0.001). CONCLUSION: Catheter ablation reduces medication burden in PSVT, yet health resource use and expenditures were similar beyond 2 years post-ablation when compared to PSVT patients on medical therapy alone. Additional studies are required to better understand drivers of these sustained health expenditures, and barriers to achieving cost-savings for a potentially curative procedure.

Temporal and geographical trends in women operators of electrophysiology procedures in the United States.

BACKGROUND: Cardiac electrophysiology (EP) has few women physicians. OBJECTIVE: The purpose of this study was to determine temporal and geographical trends in the proportion of women EP operators in the United States. METHODS: We extracted data from the Medicare Provider Utilization and Payment Database from 2013 to 2019 using procedure codes for atrial fibrillation (AF) ablation, supraventricular tachycardia/atrial flutter (SVT/AFL) ablation, and cardiac device implantation. The Medicare Provider Utilization and Payment Database excludes operators who perform ≤10 procedures annually for a given individual procedure code. The proportion of women operators was compared across the 7-year period. RESULTS: On average annually between 2013 and 2019, 5% (n = 187) of the 3524 EP operators were women. Procedure-specific analyses demonstrated a similarly low proportion of women EP operators across each procedure type. Despite a 137% increase in the total number of AF ablationists over the 7-year period, the proportion of women remained unchanged (P = .3966). The number of SVT/AFL ablationists and device operators remained constant over time as did the proportion of women operators (P = .9709 and .3583, respectively). In 2019, 10 states (20%) had no women EP operators who performed >10 of any given EP procedure annually, 20 states (39%) had no women who performed >10 of either AF or SVT/AFL ablation procedures annually, and 10 states (20%) had no women device operators who performed >10 of any given type of device implantation annually. CONCLUSION: Women EP operators remain underrepresented, and the proportion of women is stagnant even in areas of major clinical growth such as AF ablation. One-fifth of states had no women operators who performed >10 of any given EP procedure annually.

Cost Effectiveness Analysis and Payment Policy Recommendation-Population-Based Survey with Big Data Methodology for Readmission Prevention of Patients with Paroxysmal Supraventricular Tachycardia treated with Radiofrequency Catheter Ablation.

Recurrence of paroxysmal supraventricular tachycardia (PSVT) has been reported to be lower in patients treated with radiofrequency catheter ablation (RFCA) than in those who are not. Few population-based surveys have stated the cost-effectiveness related to this treatment. We, therefore, performed a nationwide retrospective study using National Health Insurance Research Database (NHIRD) data from 2001-2012 in Taiwan. The incidence of PSVT-related admissions was computed from patients' first admission for a primary PSVT diagnosis. There were 21,086 patients hospitalized due to first-time PSVT, of whom 13,075 underwent RFCA, with 374 recurrences (2.86%). In contrast, 1751 (21.86%) of the remaining 8011 patients who did not receive RFCA, most of whom had financial concerns, experienced PSVT recurrence. The relative PSVT recurrence risk in those who did not receive RFCA was 7.6 times (95%CI: 6.67-8.33) that of those who did undergo RFCA. In conclusion, the PSVT recurrence rate was much higher in patients who did not receive RFCA at their first admission. Furthermore, RFCA proved cost-effective, with the ratio of the incremental cost-effectiveness ratio (ICER) and gross domestic product (GDP) being only 1.15. To prevent readmission and avoid incremental cost, the authority could provide a financial supplement for every patient so that the procedure is performed, reducing the PSVT-recurrence life-years (disease-specific DALY).

Healthcare Resource Use and Expenditures in Patients Newly Diagnosed With Paroxysmal Supraventricular Tachycardia.

Information on paroxysmal supraventricular tachycardia (PSVT) patient characteristics and the associated economic burden of the disease is limited. Therefore, we sought to characterize newly diagnosed PSVT patients and quantify their healthcare resource use and expenditures. We used enrollment, demographic, and claims data from IBM MarketScan Research Database and Medicare Limited Data Set (LDS) to identify patients newly diagnosed with PSVT (ICD-9: 427.0; ICD-10: I47.1) from 10/1/2012 to 9/30/2016. Patients were required to be observable 1-year before and after index diagnosis. Patients were stratified by age (<65 years and ≥65 years), and propensity-matched to patients without PSVT. Expenditures and healthcare resource use were analyzed 1 year before and 1-year following index diagnosis. Among 49,316 patients <65 years and 23,954 patients ≥65 years, most were female (64% and 63%, respectively). Compared with matched controls, all PSVT patients had significantly more emergency department visits pre- and postdiagnosis, and more hospitalizations following diagnosis. Mean annual per patient expenditures paid by insurers were significantly higher in the year post-PSVT diagnosis, tripling for patients <65 years ($9,028 to $29,867) and nearly doubling for patients ≥65 years ($10,867 to $20,143). Spending for PSVT services accounted for 43% and 33% of the increase in expenditures in these patient-groups, respectively. Few patients had an ablation within 1 year of diagnosis, although ablations were more frequent in patients age <65 years (13% vs 3%). In conclusion, PSVT imposes a substantial economic burden, with increases in expenditures following initial diagnosis in both younger (<65 years) and older (≥65 years) patients who are not accounted for by cardiac ablation spending alone.

An Economic Analysis of the Systematic Use of Mapping Systems during Catheter Ablation Procedures: Single Center Experience.

INTRODUCTION: In this study we estimated the cost-effectiveness of adopting 3D Nonfluoroscopic Mapping Systems (NMSs) for catheter ablation (CA). METHODS: This study includes patients who underwent supraventricular tachycardia (SVT) CA and atrial fibrillation (AF) CA from 2007 to 2016. A comparison was conducted between a reference year (2007) and the respective years for the two types of procedure in which the maximum optimization of patients' exposure using NMSs was obtained. We compared the data of all SVT CA performed solely using fluoroscopy in 2007 (Group I) and all SVT CA procedures performed using fluoroscopy together with an NMS in 2011 (Group II). There was also an important comparison made between AF CA procedures performed in 2007 (Group III) and AF CA in 2012 (Group IV), where patients' treatment in both years included the use of an NMS but where the software and hardware versions of the NMS were different. Two cost-effectiveness analyses were carried out. The first method was based on the alpha value (AV): the AV is a monetary reference value of avoided unit of exposure and is expressed as $/mansievert. The second one was based on the value of a statistical life (VSL): the VSL does not represent the cost value of a person's life, but the amount that a community would be willing to pay to reduce the risk of a person's death. The costs estimated from these two methods were compared to the real additional cost of using an NMS during that type of procedure in our EP Lab. RESULTS: The use of NMS reduced the effective dose of about 2.3 mSv for SVT and 23.8 mSv for AF CA procedures. The use of NMS, applying directly AV or VSL values, was not cost-effective for SVT CA for the most countries, whereas the use of an NMS during an AF CA seemed to be cost-effective for most of them. CONCLUSIONS: In our analysis the cost-effectiveness of the systematic use of NMSs strongly depended on the AV and VSL values considered. Nonetheless, the approach seemed to be cost-effective only during AF CA procedures.

A Prospective Assessment of Optimal Mechanical Ventilation Parameters for Pediatric Catheter Ablation.

Catheter stability, an important factor in ablation success, is affected by ventilation. Optimal ventilation strategies for pediatric catheter ablation are not known. We hypothesized that small tidal volume and positive end-expiratory pressure are associated with reduced ablation catheter movement at annular positions. Subjects aged 5-25 years undergoing ablation for supraventricular tachycardia (SVT) or WPW at two centers from March 2015 to September 2016 were prospectively enrolled and randomized to receive mechanical ventilation with either positive end-expiratory pressure of 5 cm H2O (PEEP) or 0 cm H2O (ZEEP). Movement of the ablation catheter tip at standard annular positions was measured using 3D electroanatomic mapping systems under two conditions: small tidal volume (STV) (3-5 mL/kg) or large TV (LTV) (6-8 mL/kg). 58 subjects (mean age 13.8 years) were enrolled for a total of 266 separate observations of catheter movement. STV ventilation was associated with significantly reduced catheter movement, compared to LTV at all positions (right posteroseptal: 2.5 ± 1.4 vs. 5.2 ± 3.1 mm, p < 0.0001; right lateral: 2.7 ± 1.6 vs. 6.3 ± 3.5 mm, p < 0.0001; left lateral: 1.8 ± 1.0 vs. 4.3 ± 1.9 mm, p < 0.0001). The presence or absence of PEEP had no effect on catheter movement. In multivariable analysis, STV was associated with a 3.1-mm reduction in movement (95% CI 2.6-3.5, p < 0.0001), adjusting for end-expiratory pressure, annular location, and patient size. We conclude that STV ventilation is associated with reduced ablation catheter movement compared to a LTV strategy, independent of PEEP and annular position.

Clinical assessment and comparison of annotation algorithms in high-density mapping of regular atrial tachycardias.

BACKGROUND: High-density automated mapping of regular atrial tachycardias (ATs) requires accurate assessment of local activation times (LATs). OBJECTIVE: To evaluate high-density mapping of ATs and compare the accuracy of different automated LAT annotation algorithms. METHODS: Fifteen patients underwent AT ablation guided by the automated ConfiDENSEۛ high-density mapping module (Carto 3 v4) allowing manual reannotation (edited maps). For each AT, unedited automated maps were reconstructed offline by three algorithms: maximum unipolar slope (LATSlope ), bipolar peak (LATPeak ), and a new hybrid annotation algorithm (LATHybrid ). Five blinded experts were asked to define the (1) tachycardia mechanism, (2) ablation target, and (3) level of difficulty of these unedited maps. RESULTS: Twenty-one ATs (cycle length 300 ± 46 ms, activation points 955 ± 421) were successfully ablated using LATHybrid guided ablation with manual editing in a small number of points. At 6 months, 14 (93%) of the patients were free of AT recurrences. Unedited LATHybrid maps showed the highest accuracy in defining the tachycardia mechanism (LATHybrid : 49% vs. LATPeak : 27% vs. LATSlope : 28%, P < 0.001) and ablation target (LATHybrid : 65% vs. LATPeak : 39% vs. LATSlope : 31%, P < 0.001). Overall, LATHybrid -annotated maps were graded as "easier to interpret" by the experts (difficulty score 2.3 ± 0.9) versus LATPeak (2.8 ± 1) and LATSlope (3.2 ± 0.8) (P < 0.001). Only 12% of the LATHybrid maps were annotated as uninterpretable compared to 31% of LATSlope and 45% of the LATPeak maps (P < 0.001). CONCLUSION: Automated LATHybrid annotation allows better and easier recognition of the tachycardia mechanism compared to automated LATPeak and LATSlope algorithms, although fully automated mapping still requires further improvements.

Gender-related differences in outcomes and resource utilization in patients undergoing radiofrequency ablation of supraventricular tachycardia: results from Patients' Perspective on Radiofrequency Catheter Ablation of AVRT and AVNRT Study.

AIMS: The aim of this study was to describe gender-related differences in clinical presentation, radiofrequency ablation (RFA) outcomes, and healthcare resource utilization in a group of patients with atrioventricular nodal reciprocating tachycardia (AVNRT) and atrioventricular reciprocating tachycardia (AVRT). METHODS AND RESULTS: This was a single-centre, prospective, cohort study which enroled 82 patients undergoing RFA of AVNRT or AVRT. At baseline, all patients received a clinical assessment and completed questionnaires concerning: socioeconomic status, disease-specific symptoms (Patient Perception of Arrhythmia Questionnaire; PPAQ), health-related quality of life (HRQoL) (EQ-5D-3L), and healthcare resource utilization. Two months after RFA, the clinical assessment was repeated and subjects completed PPAQ and EQ-5D-3L. Follow-up was completed by 64 patients, 41 (64%) women. At baseline, there were no significant differences in baseline characteristics, except AVNRT prevalence, and HRQoL by gender but women reported higher severity of symptoms on PPAQ than men (2.8 vs. 2.4 points, P < 0.001). At 2 months after RFA, women still reported higher severity of symptoms (1.8 vs. 0 points; P = 0.02) on PPAQ and more heart skipping than men (54 vs. 13%; P = 0.0014); differences in EQ-5D-3L index and EQ-VAS were insignificant. There was no significant difference in healthcare resource utilization during the year preceding RFA, but antiarrhythmic drugs were significantly more often prescribed to women pre-procedure (30 vs. 8%; P = 0.022). CONCLUSION: There is a small but significant gender-related difference in outcome of RFA in patients with AVNRT or AVRT measured with a disease-specific instrument. No significant difference in HRQoL or access to healthcare resources between women and men was found.

Efectividad y seguridad de la ablación por radiofrecuencia en taquicardia supraventricular / Effectiveness and safety of radiofrequency ablation in supraventricular tachycardia

Antecedentes: Descripción de la condición de salud de interés: Las taquicardias paroxísticas supraventriculares, son ritmos rápidos y habitualmente regulares en los que alguna estructura del corazón por encima de la bifurcación del haz de Hiz es necesaria para su mantenimiento. Los tres tipos más frecuentes son las ta quicardias auriculares (dentro de las que se encuentra el flutter auricular), las taquicardias de reentrada nodal, y las taquicardias mediadas por una vía accesoria. Son arritmias de pronóstico benigno, aunque son típicamente sintomáticas, y crónicamente recidivantes, por lo que producen cierto grado de invalidez. Las estrategias terapéuticas más comúnmente utilizadas son la terapia farmacológica y la ablación por catéter. La ablación con catéter es una intervención que se realiza para corregir o modificar los trastornos del ritmo cardíaco. Consiste en producir - mediante la introducción de un catéter especial-una pequeña quemadura de entre 5-8 mm de diámetro en el interior del corazón, en el punto donde se origina la arritmia. La energía que origina el calentamiento de la punta del catéter de ablación se denomina radiofrecuencia. Si se consigue erradicar ese foco en su totalidad. En pacientes con taquicardia supraventricular, ¿cuál es la efectividad y seguridad de la ablación con catéter por radiofrecuencia en comparación con fármacos antiarrítmicos (amiodarona), betabloquedores (propanolol) y calcio antagonistas (verapamilo y diltiazem), para el mejoramiento de la calidad de vida, la prevención de recurrencia de la arritmia y la reintervención? La pregunta de investigación fue refinada y validada con base en: autorización de mercadeo de la tecnología para la indicación de interés (registro sanitario INVIMA), listado de medicamentos vitales no disponibles, cobertura de las tecnologías en el Plan Obligatorio de Salud (POS) (Acuerdo 029 de 2011), revisión de grupos terapéuticos (código ATC: Anatomical, Therapeutic, Chemical classification system), recomendaciones de guías de práctica clínica actualizadas, disponibilidad de evidencia sobre efectividad y seguridad (reportes de evaluación de tecnologías, revisiones sistemáticas de la literatura), uso de la tecnologías (listas nacionales de recobro, estadísticas de prescripción, etc), estudios de prevalencia/incidencia y carga de enfermedad y \r\nconsulta con expertos temáticos (especialistas clínicos), sociedades científicas y otros actores clave. No se identificaron otros comparadores relevantes para la evaluación. Criterios de elegibilidad de la evidencia: Criterios de inclusión: Población: Pacientes mayores de 18 años, con diagnóstico de Taquicardia \r\nSupraventricular (Taquicardias Paroxísticas Supraventriculares: taquicardia de reentrada nodal, taquicardias con participación de vía accesoria (Sindrome de Wolff-Parkinson-White), taquicardia auricular, y flutter auricular). Tecnología de interés: Ablación con catéter por radiofrecuencia. Metodología: Búsqueda de literatura, Búsqueda en bases de datos electrónicas. Conclusiones: Efectividad: la ablación con catéter por radiofrecuencia comparado con tratamiento farmacológico es una estrategia terapéutica efectiva para el tratamiento de las arritmias supraventriculares, con tasas de éxito inmediato posterior a la intervención cercanas al 100%, y de mantenimiento del ritmo sinusal de aproximadamente 80% vs. 35% con tratamiento farmacológico, hasta por 5 años. La ablación con catéter por radiofrecuencia tiene un impacto positivo en la calidad de vida y síntomas relacionados con la enfermedad; se demuestran diferencias significativas entre las evaluaciones antes y después del procedimiento de ablación, a diferencia de las evaluaciones en pacientes que recibieron terapia farmacológica. Seguridad: el procedimiento es seguro, en 3 de los 4 estudios, no se reportan complicaciones graves como bloqueo auriculoventricular ni derrame pericárdico.

First experience of monitoring with cardiac event recorder electrocardiography Omron system in childhood population for sporadic, potentially arrhythmia-related symptoms.

AIMS: To document symptomatic episodes of palpitations with traditional methods such as24 h Holter monitoring (HM) or loop recorders remains a big challenge in clinical practice. Clinical trials with patient-activated electrocardiography (ECG) recorders show increased diagnostic yield in such patients. However, studies in the paediatric population are limited. We want to present a first experience with an event-recording system Omron HeartScan in children with symptomatic palpitations. METHODS AND RESULTS: Thirty paediatric patients (age 4-16 years) were followed with the Omron at our centre. All patients had a normal echocardiogram, a normal baseline 12-lead ECG and a normal 24 h HM. Indications with regard to monitoring were palpitations (n = 30). Two of them also had episodes of pre-syncope. The average of palpitation episodes in the past 3 months was 13.2 ± 8.3. The mean age of the study population was 9.7 ± 2.3 years [17 males (56.7 %)]. In all patients (n = 30) a diagnostic event could be recorded with the studied system. Four patients were diagnosed with supraventricular tachycardia (SVT) and underwent catheter ablation. The remaining patients (n = 26; 87%) were diagnosed with sinus tachycardia. Two patients with SVT additionally had episodes of pre-syncope. None of the patients could be diagnosed with previous 24 h HM. CONCLUSION: This event recorder has a high diagnostic yield in the childhood population. The children enjoyed the ease of using the system under daily-life conditions. In this study the system was able to record a diagnostic event in all patients with palpitations.

The use of transtelephonic loop recorders for the assessment of symptoms and arrhythmia recurrence after radiofrequency catheter ablation.

Radiofrequency catheter ablation (RFA) is an effective treatment of arrhythmias. However, patients often remain symptomatic after the procedure. We aimed to assess the arrhythmia recurrence after successful RFA in relation to patients' symptoms using transtelephonic loop recorders. Thirty-six consecutive patients (age 50 +/- 14 years, 17 males/19 females) were enrolled after successful RFA for atrioventricular (AV) nodal reentrant tachycardia (n = 21), AV reentrant tachycardia (n = 8), atrial tachycardia (n = 2), atrial fibrillation/flutter (n = 4), and ventricular tachycardia (n = 1). During 23 +/- 6 days of follow-up, 679 events were recorded, 246 of which were true arrhythmic events, mostly (56%) asymptomatic. The vast majority of these true arrhythmic events were due to trivial arrhythmias (extrasystoles or sinus tachycardia), equally distributed among symptomatic and asymptomatic episodes. Arrhythmia relapse was shown in four patients, who had a total of nine episodes, eight of which were symptomatic. No high degree AV block was detected. Overall, symptom recurrence had low sensitivity (44%) and high specificity (95%) for the detection of any arrhythmia, and high sensitivity (89%) but low specificity (58%) for the detection of relapse. In conclusion, transtelephonic monitoring was a useful tool for the assessment of symptoms after RFA and its use may be reserved for the most symptomatic patients to detect a relapse or to reassure them for the benign nature of their symptoms.

Current case mix and results of catheter ablation of regular supraventricular tachycardia: are we giving unrealistic expectations to patients?

AIMS: Catheter ablation (CA) has become the treatment of choice for regular supraventricular tachycardia (SVT). The purpose of this study was to investigate whether the current clinical results in a large single centre are as good as success rates quoted to patients from published trials and national cardiology society websites. METHODS AND RESULTS: We recorded and analysed prospectively the acute and follow-up (FU) results of all CA procedures performed for SVT at our institution over a 2-year period. We compared our results with the success rates of 90-98% for CA quoted in the literature. We performed a total of 547 CA at our institution over 2 years, of which 389 (71%) were for regular SVT. Of these, 71 procedures (18%) were redo procedures. The overall acute procedural success rate was 96.1% (374/389). Follow-up data were available for 367 of 389 (94.3%) procedures. The overall 6-week success rate varied between 74.7 and 91.3% depending on the SVT type (average 83.9%). The FU success rates were lower for redo procedures (47/66, 71.2%) when compared with first ablation (de novo) procedures (261/301, 86.7%), P = 0.003. CONCLUSION: Published success rates are much better than current success rates in a large single centre. It is possible that the information regarding outcome given to patients during the consent process is not accurate.

Prospective assessment after pediatric cardiac ablation: fate of intracardiac structure and function, as assessed by serial echocardiography.

BACKGROUND: Catheter ablation puts cardiac valves at risk of damage, and children are of particular concern. METHODS: A multicenter prospective study was performed to assess the results and risks associated with radiofrequency (RF) ablation in children. Patients were aged 0 to 16 years with supraventricular tachycardia due to accessory pathway or atrioventricular node reentry, excluding patients with more than trivial congenital heart disease. A total of 481 patients were recruited into the prospective cohort and were followed up at 2, 6 and, 12 months after ablation. Complete echocardiograms were obtained before and at intervals after RF ablation, and they were reviewed by experts who were blinded with respect to diagnosis, outcome, pathway site, and study interval. RESULTS: Moderate valve insufficiency was quite rare (0.12%), but mild insufficiency was common, both before ablation (42.43%) and at 2 months after ablation (40.49%). Analysis of paired readings failed to demonstrate a tendency toward increased insufficiency of valves adjacent to ablation targets, with the exception of the tricuspid valve after the ablation of right freewall pathways and atrioventricular node reentry, but the degree of change was small. No clear changes in left ventricular systolic or diastolic function were observed, and dyskinesis was rare and not related to the ablation target. No intracardiac thrombosis was observed. CONCLUSIONS: Serious injury to cardiac valves due to RF ablation is very rare, but the tricuspid valve may be mildly affected in some cases. We identified no clear effect of RF ablation on cardiac wall motion or on left ventricular function.

Radiofrequency catheter ablation of supraventricular tachycardia in children and adolescents : feasibility and cost-effectiveness in a low-income country.

The objective of this study is to provide results and costs of catheter ablation in children and adolescents in a low-income country. Reports from first-world countries have demonstrated the cost-effectiveness of radiofrequency catheter ablation (RFCA) compared to medical treatment of supraventricular tachycardia (SVT). The study included 28 patients younger than 18 years of age with SVT in a pediatric cardiology unit in Guatemala. All patients underwent RFCA. Clinical outcome and cost-effectiveness of RFCA compared to continued medical treatment were the end points. Twenty-four patients had successful ablation (85.7%). Mean age at RFCA was 11.42 +/- 3.49 years. Three patients underwent a second ablation, increasing the success rate to 96.4%. One remaining patient is awaiting a second procedure. At a mean follow-up of 13.69 +/- 7.16 months, all 27 patients who had a successful ablation remained in sinus rhythm. Mean cost per procedure was 4.9 times higher than that of medical treatment. However, the estimated cost of catheter ablation equal that of medical therapy after 5.1 years and is 3.4 times less after 20 years. Radiofrequency catheter ablation of SVT in children and adolescents is safe and cost-effective compared to medical therapy. Resources must be judiciously allocated, especially in low-income countries, to treat the largest number of pediatric patients.

Prospective assessment after pediatric cardiac ablation: demographics, medical profiles, and initial outcomes.

INTRODUCTION: A multicenter prospective study was designed and implemented to assess the short- and longer-term results and risks associated with radiofrequency (RF) ablation in children. METHODS AND RESULTS: Patients recruited for the study were aged 0 to 16 years with supraventricular tachycardia due to accessory pathways or AV nodal reentrant tachycardia (AVNRT), excluding patients with nontrivial congenital heart disease. A national registry also was established, and contributing centers were encouraged to enroll all pediatric patients, aged 0 to 21 years, undergoing ablation at their center. This report summarizes acute results of these procedures. For analysis, subjects were divided into three groups: the prospective cohort (n = 481), cohort-eligible registry participants (n = 504), and not cohort eligible registry participants (n = 1,776). Prospectively enrolled cohort patients were similar to cohort-eligible patients in terms of demographic and other patient characteristics. Overall success rates for RF ablation were high (95.7%), with higher success rates for left-sided and particularly left free-wall pathways (97.8%) than right free-wall pathways (90.8%). Complications of both electrophysiologic study and RF ablation were infrequent (4.2% and 4.0%, respectively), and there were no deaths. AV block was uncommon overall (1.2%) and was limited to ablation in AVNRT (2.1%) and septal accessory pathways (3.0%). CONCLUSION: Despite the multicenter and prospective design, the study demonstrates high success rates and low complication rates, which are comparable to prior single-center retrospective studies. These results may serve as the current best benchmark for expected results in the pediatric population, aged 0 to 16 years, both in terms of acute success rates and the occurrence of complications.

Prospective assessment after pediatric cardiac ablation: recurrence at 1 year after initially successful ablation of supraventricular tachycardia.

OBJECTIVES: A multicenter prospective study was performed to assess the results and risks associated with radiofrequency ablation in children. This report focuses on recurrences following initially successful ablation. METHODS: Patients recruited for the study were aged 0 to 16 years and had supraventricular tachycardia due to accessory pathways or atrioventricular nodal reentrant tachycardia (AVNRT), excluding patients with more than trivial congenital heart disease. A total of 481 patients were recruited into the prospective cohort and were followed at 2, 6, and 12 months following ablation. RESULTS: There were 517 successfully ablated substrates out of 540 attempted (95.7%). Loss to follow-up for individual substrates was 3.3%, 10.6%, and 21.2% at 2, 6, and 12 months, respectively. Recurrence was observed in 7.0%, 9.2%, and 10.7% of these substrates at 2, 6, and 12 months, respectively (adjusted for loss to follow-up as an independent source of data censoring). Recurrence rate varied by substrate location (24.6% for right septal, 15.8% for right free wall, 9.3% for left free wall, and 4.8% for left septal), as well as for AVNRT versus all others (4.8% vs 12.9%) at 12 months. The recurrence rate was higher for substrates ablated using power control but was not a function of whether isoproterenol was used for postablation testing. CONCLUSIONS: Recurrence after initially successful ablation occurs commonly in children. It is least common after AVNRT ablation and most common following ablation of right-sided pathways. These results serve as a benchmark for the time course of recurrence following initially successful ablation of supraventricular tachycardia in children.

Prospective assessment after pediatric cardiac ablation: design and implementation of the multicenter study.

A multicenter prospective study was designed and implemented as an activity of the Pediatric Electrophysiology Society to assess the risks associated with radiofrequency ablation in children. Patients (age 0-15 years) with supraventricular tachycardia due to accessory pathways or atrioventricular nodal reentry were enrolled and studied prior to ablation and periodically by clinical evaluation, electrocardiogram (ECG), Holter monitor, and echocardiogram. In addition, a national registry was established, to which the contributing centers report all pediatric patients undergoing ablation at their center. Initial electrophysiological study tracings and all noninvasive studies undergo blinded outside review for quality control. Clinical endpoints were death, recurrence, proarrhythmia, and echocardiographic abnormality. A pilot study demonstrated excellent agreement concerning diagnoses of previously reported ablation patients between the reporting center and the blinded reviewer (kappa = 0.938 +/- 0.062). A total of 317 patients were enrolled in the ongoing study from April 1, 1999 to December 31, 2000. The success rate of ablations was 96% with a complication rate of 4.3% for electrophysiological study and 2.9% for the ablation procedure. Comparison of the registry group versus the study group shows that the groups are comparable in terms of patient characteristics, diagnoses, and the results of ablation making it less likely that the sample of prospectively enrolled patients is biased.

Accurate assessment of patient effective radiation dose and associated detriment risk from radiofrequency catheter ablation procedures.

BACKGROUND: Radiofrequency (RF) cardiac catheter ablation procedures may require extended fluoroscopic exposure resulting in elevated radiation risk. The aim of the present study was to accurately establish RF ablation radiation risk levels and to provide means for accurate patient risk estimation from studies performed in any electrophysiology laboratory. METHODS AND RESULTS: Fluoroscopy required during cardiac ablation was classified into 4 types identified by beam orientation and irradiated tissue: (1) posteroanterior exposure during catheter advancing from the groin to the heart, (2) posteroanterior heart exposure, (3) left anterior oblique heart exposure, and (4) right anterior oblique heart exposure. The duration of each exposure was monitored in 24 patients undergoing RF cardiac ablation. Dose per minute of fluoroscopy was measured at 15 organs/tissues for each projection with the use of anthropomorphic phantom and thermoluminescence dosimetry. The effective dose rate was 219, 144, 136, and 112 mu/min for groin-to-heart posteroanterior, posteroanterior, left anterior oblique, and right anterior oblique exposure, respectively. A typical ablation procedure results in a total effective dose of 8.3 mSv per hour of fluoroscopy. The average excess of fatal cancers was estimated to be 650 and 480 per million patients undergoing RF ablation requiring 1 hour of fluoroscopy for US and UK populations, respectively. The average risk for genetic defects was determined to be 1 per million births. CONCLUSIONS: Radiation risk from RF cardiac ablation is moderate compared with other complications, but it may highly exceed radiation risk from common radiological procedures. Efforts should be made toward minimization of patient radiation risk from RF ablation procedures.