Asymptomatic Ventricular Pre-excitation Research Articles

TRANSOESOPHAGEAL ELECTROPHYSIOLOGICAL STUDY IN PEDIATRIC PATIENTS WITH VENTRICULAR PRE–EXCITATION

Abstract Introduction The transoesophageal electrophysiological study (SETE) is a simple, semi–invasive and highly reliable test for risk stratification in patients with ventricular pre–excitation. In paediatric subjects, symptoms may be nonspecific or poorly reported; hence the usefulness of the study in guiding the therapeutic strategy. The guidelines also suggest performing it in all asymptomatic patients with ventricular preexcitation above 8 years of age.Purpose of the study: to evaluate the inducibility of re–entry tachycardia at SETE in paediatric patients with ventricular pre–excitation. Materials and Methods We observed 21 patients aged between a few days of life and 12 years (average age 11 years); 14 of them had constant and 7 intermittent pre–excitations. The latter were subjected to the study as they reported dubious symptoms either due to sports activities or due to a previous diagnosis of neonatal TPS. The study was performed by carrying out the protocols of continuous atrial stimulation at increasing frequencies, programmed atrial stimulation with single, double, and triple extra stimulus and atrial stimulation with burst. Results Of the 21 patients, 8 (38.1%) were inducible. Of the 14 patients with constant ventricular pre–excitation, 5 had tachycardia upon return to the study (35.7%), 4 of which were symptomatic due to previous TPS. Therefore, only one patient with constant and asymptomatic ventricular pre–excitation was inducible. Of the 7 patients with intermittent ventricular preexcitation (documented by Holter or exercise test), 3 developed TPS at SETE (42.8%): all these patients complained of heart palpitations but did not have a documented arrhythmia. On the contrary, all patients with intermittent ventricular preexcitation and asymptomatic were found to be non–inducible. In patients in whom it was possible to calculate the effective antegrade refractory period of the anomalous pathway, shorter refractory period showed greater inducibility. Non–sustained atrial fibrillation was induced in only two patients. Conclusions SETE demonstrates a good correlation between symptoms and inducibility especially in patients with intermittent ventricular pre–excitation. In fact, if the manifest pre–excitation disappears with growth in about a third of patients, the retrograde conduction capacity of the pathway often persists. The study also allows us to identify patients with constant pre–excitation but pathway at low risk.

Do children with asymptomatic ventricular preexcitation have similar quality of life as healthy children?

To our knowledge, no studies have assessed quality of life (QoL) in asymptomatic children with a preexcitation electrocardiogram pattern. To evaluate the QoL of children with asymptomatic Wolff-Parkinson-White (WPW) syndrome. This study involved QoL assessment of 31 children with asymptomatic preexcitation and 82 healthy children using the WHOQOL-BREF and the Pediatric Arrhythmia Related Score (PARS), a specific questionnaire that we have developed, which is related to patients' feelings and observations concerning arrhythmia. There were no significant differences between the two groups in all the measured domains; however, there were significant differences regarding general satisfaction with their health condition (P = 0.01). There were no differences in general satisfaction with the QoL, but WPW children more often experienced palpitations than the control group (P <0.001) and were more likely to feel sad (P = 0.046) and nervous (P = 0.04) compared to healthy children. The children with WPW were more dissatisfied with their health compared to healthy children. Although both groups of children had similar levels of satisfaction with their QoL, some areas of physical and psychological parameters of QoL were worse in WPW children. The PARS questionnaire is a useful tool as a disease-specific QoL instrument, which supplements the general questionnaire and aids in clinical practice and decision-making.

804 WOLF PARKINSON WHITE SYNDROME OR ASYMPTOMATIC VENTRICULAR PRE-EXITATION IN CHILDREN: EVALUATION OF ELECTROPHYSIOLOGICAL PROPERTIES CHANGES IN TWO DIFFERENT TIMING

Abstract Background In patients with Wolf Parkinson White (WPW) syndrome or asymptomatic ventricular pre-excitation (VP), electrophysiologic study (EPS) is recommended to assess and to stratify the risk of life - threatening arrhythmias and SCD. However, little information exist on the timing of EPS study. In particular, the electrophysiological properties variations of accessory pathway (AP) in patients with asymptomatic or symptomatic VP remain to be defined. Recently, the evolution of electrophysiological data was observed in a cohort of patients by including children and adults, although a transcatheter ablation (TCA) was performed during the evaluation among the two EPS. According to our knowledge, no study exists related to the changes over time in the conductive properties of an atrioventricular accessory pathway (AP) and arrhythmic vulnerability in the pediatric - young adult population. Aims The aim of our study was to investigate the evolution of clinical and electrophysiological datas of the manifest PV (intermittent or persistent), the arrhythmic vulnerability and any modifications in the features of AP anterograde conduction in symptomatic or asymptomatic children, examined on two separate timing, at least 2 years apart from one EPS to the next. Method This is a retrospective monocentric observational study performed at Bambino Gesu` Children's Hospital, Rome, Italy. Between January 2011 and July 2022, we enrolled forty-four children and young adults (32 male, mean age 10 years± 2,42) with manifest ventricular preexcitation underwent, as our standard management, at two electrophysiolgical studies (EPS, transesophageal and/or endocavitary), both at rest and during adrenergic stress (exercise testing or isoproterenol infusion) in two different timing (T0 and T1) within a minimal interval of 2 year. No transchateter ablation was performed between two EPS. Clinical and electrophysiological data were collected and compared. Results We observed a significant modification in atrioventricular accessory pathway conductive properties from T0 to T1 in basal study. In particular, at the baseline, preAVA value and 1/1 conduction VA time were respectively 306,59±43 and 292,61±61,7 and significatively decreased on occasion of second EPS evalutation (T1) (respectively to 279,51±41 with p 0,004 and 267,13±51,6, with p 0,003). Furthermore, an ARVT were induced in 14 patients in T1 respect 9 patient in T0 (p&amp;lt;0,03) and AF in 16 patients in T1 respect 7 patients in T0 (p 0,24). This results were not confirmed on adrenergic test during EPS evaluation. We also reported a clinically but not statistically relevant reduction of SPERRI time evaluated during EPS with stress test from T0 to T1 (from 251,44±47,9 to 206,9±36,7; p= 0,18). Conclusion There were significant and clinically rilevant changes of electrophysiological datas in young patients with symptomatic and asymptomatic VP underwent two EPS in two different timing. Therefore, in our opinion, a systematic evaluation with repeated EPS should be considered in this population.

Risk stratification of sudden cardiac death in subjects with asymptomatic ventricular preexcitation: diagnostic value of non-invasive and invasive methods

Abstract Introduction In subjects with asymptomatic ventricular preexcitation (AVP) guidelines recommend follow-up by non-invasive methods. However, in some patients accessory pathways (APs) show high-risk invasive parameters and risk of sudden death. Objectives To assess the association between the non-invasive and invasive risk stratification (NIRS and IRS) in AVP patients in our center. Material and methods Retrospective and observational study in 58 patients with AVP, underwent NIRS and IRS. Association between NIRS (electrocardiogram, holter and ergometry testing) and IRS variables (AERP ≤250 msec, SPERRI ≤250 msec, atrioventricular reentrant tachycardia or AF, multiple APs) from the electrophysiological study (EPS), and sensitivity and specificity of NIRS to predict a high-risk EPS were determined. Results Of patients with high-risk EPS (n=41), 55% had a previously low-risk NIRS (n=11) while 78% (n=30) had a high-risk NIRS (p=0.05). A low-risk NIRS had a sensitivity (S) 27% and specificity (E) 47% to predict a high-risk EPS. Conclusions In our population, 1 of every 2 patients with low-risk NIRS presented a high-risk IRS. The NIRS methods present low S and E for risk stratification in AVP patients. Funding Acknowledgement Type of funding sources: None.

The Risk of Sudden Death Associated with Symptomatic and Asymptomatic Ventricular Pre-excitation in Athletes

Abstract Sudden death (SD) in athletes is a potential avoidable dramatic scenario. When done regularly, cardiological evaluation increases the chances of diagnosing ventricular pre-excitation. Consequently, the following question arises: what is the real incidence of SD risk in athletes with Wolff-Parkinson-White (WPW) syndrome/pattern? This study included 84 consecutive patients diagnosed with WPW and was designed as a retrospective analysis of data acquired between 2011 and 2021 to answer this question. The patients were evaluated using a 12-lead electrocardiogram (ECG), echocardiography, stress test, and electrophysiological study (EPS). The SD risk linked to WPW was defined as ≥ 1 of the following: the anterograde effective refractory period (AERP) of the accessory pathway (AP) ≤ 250 ms, atrial fibrillation (AF) with the shortest RR pre-excited interval ≤ 250 ms, syncope during AF or atrioventricular reentry tachycardia. The athletes with WPW pattern (n=25) or syndrome (n=59) at risk of SD were identified and treated with radiofrequency ablation (RFA). The mean age was 19.83 (10–29) years; 66.6% were men. Seventeen athletes (n=17; 20.23%) were found with SD risk: 15 (n=15; 17.85%) in the WPW syndrome group and 2 (n=2; 2.38%) in the WPW pattern group. During the EPS, n=4 developed syncope: 1 during antidromic tachycardia and 3 during pre-excited AF. RFA was curative in 96.42% of cases. The EPS is mandatory to identify athletes with short AERP APs linked to an increased risk of SD. RFA is the intervention that settles the patients into a risk-free area, allowing resumption of sports shortly afterward.

P34 ASYMPTOMATIC VENTRICULAR PRE–EXCITATION WITH DISAPPEARANCE DURING EXERTION: ALWAYS AN INDEX OF BENIGNITY?

Abstract Introduction The disappearance of pre–excitation at high heart rates points to a low arrhythmic risk: why resort to electrophysiological studies anyway? Clinical Case L.S., a 12–year–old patient, performed an ECG for sports examination with evidence of ventricular pre–excitation from an asymptomatic left lateral accessory route (Fig. A). A 24 h ECG–Holter during training showed the disappearance of the pre–excitation at high frequencies (Fig. B) which is considered a low risk index. The patient underwent a transesophageal electrophysiological study (SETE) during which an effective refractory antegrade period of 228 ms of the pathway was objectified through atrial extrastimuli (*) (Fig. C: drive of atrial stimuli (*) followed by extrastimulus with conduction on an accessory route (E)). In addition, a 1: 1 conduction was observed on the atrial pathway up to at least 270 bpm (222 ms). The antegrade refractory period of the resting path was &amp;lt;250 ms and therefore identified a high–risk condition to be treated with ablation. Discussion The disappearance of pre–excitation at high heart rates is usually considered indicative of an accessory pathway with a long refractory period and therefore at low risk, however it must be sudden. According to European guidelines, the execution of invasive studies in asymptomatic patients who are employed in high–risk jobs or competitive sports has a class I B indication, but in the remaining asymptomatic cases the indication is IIa B. The Holter ECG alone or the stress test, with a careless evaluation of the disappearance of the pre–excitation (sudden vs progressive with minimal residual pre–excitation) would have erroneously led to labeling this accessory pathway at low risk. In the left lateral accessory pathways, with the increase of the HR, there can be a disappearance or pseudo–disappearance of the pre–excitation for anatomical reasons (being further away from the SA node) and for an increase in the AV conduction speed, not therefore for a long refractory period of the pathway. SETE is closer to the atrial side of the left accessory pathway and allows to correctly classify the risk. Conclusion SETE is a low–cost and minimally invasive method that should be considered as an integral part of the study of patients with asymptomatic ventricular pre–excitation even if non–invasive stratification indicates low risk.

Endocavitary electrophysiological study by percutaneous antecubital vein and without X-ray for risk stratification of asymptomatic ventricular pre-excitation in young athletes.

Athletes with asymptomatic ventricular pre-excitation (VP) should undergo electrophysiological study for risk stratification. We aimed to evaluate the feasibility, efficacy, safety and tolerability of an electrophysiological study using a percutaneous antecubital vein access and without the use of X-ray (ESnoXr). Methods: We collected data from all young athletes<18year-old with AVP, who underwent ESnoXr from January 2000 to September 2020 for evaluation of accessory pathway refractoriness and arrhythmia inducibility using an antecubital percutaneous venous access. Endocavitary signals were used to advance the catheter in the right atrium and ventricle. Results: We included 63 consecutive young athletes (mean age 14.6±1.9years, 46% male). Feasibility of the ESnoXr technique was 87% while in 13% fluoroscopy and/or a femoral approach were needed. Specifically, fluoroscopy was used in 7 cases to position the catheter inside the heart cavities with an average exposure of 43±38s while in 2 femoral venous access was needed. The mean procedural time was 35±11min. The exam was diagnostic in all patients, there were no procedural complications and tolerability was excellent. 53% of the patients had an accessory pathway with high refractoriness and no inducible atrio-ventricular reentry tachycardia: this subgroup was considered eligible to competitive sports and no event was observed during long-term follow-up (13.6±5.2years) without drug use. The others underwent catheter ablation. Conclusion. ESnoXr has been shown to be a feasible, effective, safe and well-tolerated procedure for the assessment of arrhythmic risk in a population of young athletes with asymptomatic VP.

Assessing and Managing Asymptomatic Ventricular Preexcitation in the Young Athlete

Assessing and Managing Asymptomatic Ventricular Preexcitation in the Young Athlete

Fluoroless catheter ablation of accessory pathways in adult and pediatric patients: a single centre experience.

Catheter radio-frequency ablation (RFA) and cryo-ablation (CRA) procedures are an effective and safe treatment options for adult and pediatric patients with accessory pathway (AP) mediated tachycardias. Non-fluoroscopic techniques during catheter ablation (CA) procedures reduce potentially harmful effects of radiation. Our aim was to investigate the efficacy and safety of completely fluoroless RFA and CRA procedures in pediatric and adult patients with APs. Consecutive patients with AP-related tachycardia and high risk asymptomatic ventricular pre-excitation were assessed in retrospective analysis. Three-dimensional (3D) electro-anatomical mapping (EAM) and intra-cardiac echocardiography (ICE) were used as principal imaging modalities. Fluoroscopy was not used during any stage of the procedures. Among 116 included patients (22.76 ± 16.1years, 68 patients < 19years), 60 had left-sided APs, 16 right-sided APs and 40 septal APs. Altogether, 96 had RFA and 20 CRA procedures. The acute success rates (ASR) of RFA and CRA were 97.9% and 95%, respectively (p = 0.43), with recurrence rates (RR) of 8.33% and 40%, respectively (p < 0.0001). The outcome difference was principally driven by lower RR with RFA in septal APs (9.1% vs. 38.9%, p = 0.025). Pediatric patients with APs (12.21 ± 3.76years) had similar procedural parameters and outcomes compared to adult patients. There were no procedure-related complications. In adult and pediatric patients with AP-related tachycardias, both CRA and RFA can be effectively and safely performed without the use of fluoroscopy. In addition, RFA resulted in better outcomes compared to CRA.

Risk-Stratification Strategy for Sudden Cardiac Death in the Very Young Children with Asymptomatic Ventricular Preexcitation.

Asymptomatic VPE refers to the presence of this abnormal ECG pattern in the absence of any symptoms. The natural history in these patients is usually benign, and most children (60%) with VPE are usually asymptomatic. However, Sudden Cardiac Death (SCD) has been reported to be the initial symptom in many patients too. The increased risk of SCD is thought to be due to the rapid conduction of atrial arrhythmias to the ventricle, via the AP, which degenerates into Ventricular Fibrillation (VF). The best method to identify high-risk patients with asymptomatic VPE for SCD is the characterization of the electrophysiological properties of the AP through an Electrophysiological Study (EPS). Also, catheter ablation of the AP with radiofrequency as definitive treatment to avoid SCD can be performed by the same procedure with high rates of success. However, the uncertainty over the absolute risk of SCD, the poor positive predictive value of an invasive EPS, and complications associated with catheter ablation have made the management of asymptomatic VPE challenging, even more in those children younger than 8-year-old, where there are no clear recommendations. This review provides an overview of the different methods to make the risk stratification for SCD in asymptomatic children with, as well as our viewpoint on the adequate approach to those young children not included in current guidelines.

Sudden Cardiac Death as the First Clinical Manifestation in Infants With Asymptomatic Ventricular Pre-excitation: Two Case Reports and Review of the Literature

Sudden Cardiac Death as the First Clinical Manifestation in Infants With Asymptomatic Ventricular Pre-excitation: Two Case Reports and Review of the Literature

Catheter ablation in ASymptomatic PEDiatric patients with ventricular preexcitation: results from the multicenter "CASPED" study.

As there are limited data about the clinical practice of catheter ablation in asymptomatic children and adolescents with ventricular preexcitation on ECG, we performed the multicenter "CASPED" (Catheter ablation in ASymptomatic PEDiatric patients with Ventricular Preexcitation) study. In 182 consecutive children and adolescents aged between 8 and 18years (mean age 12.9 ± 2.6years; 65% male) with asymptomatic ventricular preexcitation, a total of 196 accessory pathways (APs) were targeted. APs were right sided (62%) or left sided (38%). The most common right-sided AP location was the posteroseptal region (38%). Ablation was performed using radiofrequency (RF) energy (93%), cryoablation (4%) or both (3%). Mean procedure time was 137.6 ± 62.0min with a mean fluoroscopy time of 15.6 ± 13.8min. A 3D mapping or catheter localization system was used in 32% of patients. Catheter ablation was acutely successful in 166/182 patients (91.2%). Mortality was 0% and there were no major periprocedural complications. AP recurrence was observed in 14/166 patients (8.4%) during a mean follow-up time of 19.7 ± 8.5months. A second ablation attempt was performed in 20 patients and was successful in 16/20 patients (80%). Overall, long-term success rate was 92.3%. In this retrospective multicenter study, the outcome of catheter ablation for asymptomatic preexcitation in children and adolescents irrespective of antegrade AP conduction properties is summarized. The complication rate was low and success rate was high, the latter mainly depending on pathway location. The promising results of the study may have future impact on the ongoing risk-benefit discussion regarding catheter ablation in the setting of asymptomatic preexcitation in children and adolescents.

Asymptomatic ventricular pre-excitation: what management?

The management of asymptomatic patients with ventricular pre-excitation diagnosed occasionally is controversial. In fact, the lack of clinical arrhythmias does not necessarily define a benign condition: it could be possibly due to poor conduction over the accessory pathway or, conversely, to peculiar and individual conditions, which, even if the accessory pathway is capable of fast conduction, can prevent the onset of arrhythmias. These can occur unexpectedly during follow-up and may include malignant ventricular arrhythmias, although sudden death is very rare in this clinical scenario. An aggressive strategy aiming at extensive ablation in all cases with asymptomatic ventricular pre-excitation is not justified, as well as the "wait-and-see" approach. Clinically, it is important to accurately define the individual risk of any arrhythmia related to the accessory pathway, which may require treatment. For decades, the management of asymptomatic ventricular pre-excitation has been quite inhomogeneous among centers and in some cases it is still very different. Recently, a consensus document proposed the combined use of non-invasive and invasive diagnostic tools for accurate screening of these patients. If non-invasive methodologies are unable to demonstrate poor conduction over the accessory pathway, then an invasive approach is justified for arrhythmia risk definition and, if necessary, adequate therapy.

Asymptomatic Ventricular Pre-excitation: Between Sudden Cardiac Death and Catheter Ablation.

Debate about the best clinical approach to the management of asymptomatic patients with ventricular pre-excitation and advice on whether or not to invasively stratify and ablate is on-going. Weak evidence about the real risk of sudden cardiac death and the potential benefit of catheter ablation has probably prevented the clarification of action in this not infrequent and sometimes conflicting clinical situation. After analysing all available data, real evidence-based medicine could be the alternative strategy for managing this group of patients. According to recent surveys, most electrophysiologists invasively stratify. Based on all accepted risk factors - younger age, male, associated structural heart disease, posteroseptal localisation, ability of the accessory pathway to conduct anterogradely at short intervals of ≤250 milliseconds and inducibility of sustained atrioventricular re-entrant tachycardia and/or atrial fibrillation - a shared decisionmaking process on catheter ablation is proposed.

Sports Eligibility After Risk Assessment and Treatment in Children with Asymptomatic Ventricular Pre-excitation.

Many studies concern the management of young patients with symptomatic Wolff-Parkinson-White (WPW) syndrome, but little information exists on the significance and prognosis of ventricular pre-excitation (VPE) in asymptomatic children. The aim of the study was to evaluate the risk of sudden death in young athletes with asymptomatic VPE by transesophageal electrophysiological study (TEEPS) and their sports eligibility after the risk assessment and/or ablative treatment. Ninety-one asymptomatic children and adolescents underwent TEEPS both at rest and during adrenergic stress (exercise testing or isoproterenol infusion). After electrophysiological testing, patients were assessed in the 36months of follow-up. Thirty-three patients (36.3%) had a benign form of VPE and were allowed to participate in competitions. Ten patients (11%) were at borderline risk; thus, sport eligibility was evaluated individually. Forty-eight patients (52.7%) showed inducible sustained atrioventricular reentrant tachycardia and/or atrial fibrillation (AF), 11 of whom (12.1% of total population) had a potential risk of sudden cardiac death due to AF inducibility during physical stress. Forty-five young athletes underwent transcatheter ablation (TCA). TCA was interrupted in 12 patients (26.7%) because of the high procedural risk linked to septal accessory pathway (AP) location. There were no TCA-related complications, and all patients remained asymptomatic during follow-up. Most of the young athletes with asymptomatic VPE may be allowed to participate in competitive sports after an adequate risk assessment and/or ablative treatment. However, in our opinion, special care should be taken to avoid procedural complications, which are unacceptable in asymptomatic patients.

Ventricular pre-excitation: symptomatic and asymptomatic children have the same potential risk of sudden cardiac death

Children and adolescents with ventricular pre-excitation (VPE) are at increased risk for sudden cardiac death (SCD). Although antiarrhythmic therapy and catheter ablation are well established temporary or definitive treatments for patients with Wolff-Parkinson-White (WPW) syndrome, the optimal management of children with asymptomatic VPE remains to be clearly defined. On the basis of the most recent guidelines and recommendations, the aim of this study was to determine the electrophysiological characteristics of young patients with VPE and WPW syndrome to assess and compare their potential risk of SCD. We retrospectively investigated 124 consecutive young patients with VPE (51 with WPW syndrome and 73 asymptomatic) who underwent transoesophageal electrophysiological study. At baseline, atrioventricular reentrant tachycardia (AVRT) was induced in 13 WPW vs. 10 asymptomatic patients (25.5 vs. 13.7%, P = NS). Atrial fibrillation (AF) was induced in 13 WPW vs. 15 asymptomatic patients (25.5 vs. 20.5%, P = NS). A shortest pre-excited R-R interval (SPERRI) ≤250 ms during AF was found in four WPW vs. six asymptomatic patients (30.8 vs. 40%, P = NS). During isoproterenol infusion or stress testing, AVRT was induced in 31 of 44 WPW vs. 33 of 69 asymptomatic patients (70.4 vs. 47.8%, P = 0.018). Atrial fibrillation was induced in 12 of 44 WPW vs. 21 of 69 asymptomatic patients (27.3 vs. 30.4%, P = NS). A SPERRI ≤ 210 ms was found in 6 of 12 WPW vs. 10 of 21 asymptomatic patients (50 vs. 47.6%, P = NS). No statistically significant correlation was observed between accessory pathway location and symptoms, AVRT/AF inducibility, or mean APERP/SPERRI values. Children and adolescents with WPW syndrome have a higher rate of AVRT inducibility than asymptomatic patients. However, no differences between the two groups were found in atrial vulnerability and parameters related to the risk of SCD.

Cost-Effectiveness of Various Risk Stratification Methods for Asymptomatic Ventricular Pre-Excitation

Accessory pathways with "high-risk" properties confer a small but potential risk of sudden cardiac death. Pediatric guidelines advocate for either risk stratification or ablation in patients with ventricular pre-excitation but do not advocate specific methodology. We sought to compare the cost of differing risk-stratification methodologies in pediatric patients with ventricular pre-excitation in this single institutional, retrospective cohort study of asymptomatic pediatric patients who underwent risk stratification for ventricular pre-excitation. Institutional methodology consisted of stratification using graded exercise testing (GXT) followed by esophageal testing in patients without loss of pre-excitation and ultimately ablation in high-risk patients or patients who became clinically symptomatic during follow-up. A decision analysis model was used to compare this methodology with hypothetical methodologies using different components of the stratification technique and an "ablate all" method. One hundred and two pediatric patients with asymptomatic ventricular pre-excitation underwent staged risk stratification; 73% of patients were deemed low risk and avoided ablation and the remaining 27% ultimately were successfully ablated. The use of esophageal testing was associated with a 23% (p ≤0.0001) reduction in cost compared with GXT stratification alone and a 48% (p ≤0.0001) reduction compared with the "ablate all" model. GXT as a lone stratification method was also associated with a 15% cost reduction (p ≤0.0001) compared with the "ablate all" method. In conclusion, risk stratification of pediatric patients with asymptomatic ventricular pre-excitation is associated with reduced cost. These outcomes of cost-effectiveness need to be combined with the risks and benefits associated with ablation and risk stratification.

Abstract 9041: Cost Effective Risk Assessment of Asymptomatic Wolff Parkinson White Syndrome Patients

Background: Asymptomatic ventricular pre-excitation (aVPE) is a conduction abnormality that may result in sudden death resulting from rapid conduction down the accessory pathway during atrial fibrillation (AFib). The purpose of this study was to identify the most cost effective approach to risk assessing aVPE patients. Methods: A cost effectiveness analysis was performed using a decision tree model (TreeAge Pro software) comparing aVPE patients undergoing a transvenous electrophysiology study (TVEPS) vs. step wise risk assessment consisting of exercise stress test(EST), transesophageal electrophysiology study (TEEPS) and TVEPS if risk could not be determined. A TEEPS followed EST when VPE did not disappear in a single beat and TVEPS followed TEEPS when not effective inducing Afib or was risky (shortest preexcited RR interval &lt; 250 msc). Efficacy of EST was 15% and the ability of TEEPS at inducing Afib was 88%; with 78% having no risk (published results.) Sensitivity analysis investigated the impact of changes in the efficacy assumption on the cost effectiveness results. Costs were 2009 Medicare reimbursement rates with cost of EST $ 277, TEEPS $990, and TVEPS $4035. Results: The step wise approach involving EST, TEEPS and TVEPS when necessary is the most cost-effective method of identifying aVPE patients at risk with an expected cost of $2,174 compared to $4,035 for those initially undergoing TVEPS. Combining efficacy and cost data on these patients, this approach (EST- TEEPS - TVEPS) results in an average savings of $1,861 per patient. This step wise approach remained cost effective as long as TEEPS efficacy rate is &gt; 31% on patients not screened out at EST. Conclusions: This step wise approach (EST-TEEPS-TVEPS) is the most cost effective way to risk assessment of aVPE patient. This approach yields an average savings of $1,861 per patient.

Atrial Fibrillation Induction by Transesophageal Electrophysiology Studies in Patients with Asymptomatic Ventricular Preexcitation

Ventricular preexcitation is a conduction abnormality caused by an accessory pathway bridging the atria and ventricles. If the accessory pathway conducts rapidly during atrial fibrillation (AFib), sudden death may result. The purpose of this study was to determine the ability of transesophageal electrophysiology studies (TEEPS) to induce AFib in pediatric patients with asymptomatic ventricular preexcitation (aVPE). A retrospective review of patients with aVPE who had a TEEPS was conducted. Inclusion criteria were evidence of ventricular preexcitation on electrocardiogram; age <18 years; and no history of tachycardia, palpitations, or syncope. Data gathered included age, weight, height, form of sedation, and TEEPS results. If AFib was induced, patients were classified as at risk of sudden death if the shortest preexcited RR interval during AFib was <250 ms or no risk if ≥ 250 ms. A total of 26 patients met the inclusion criteria, with average age of 11.9 years, weight of 48.9 kg, and height of 149.2 cm. During the procedure, nine patients underwent conscious sedation (34.6%), and 17 underwent general anesthesia (65.4%). AFib was induced in 23 patients (88.5%), of whom 17 (73.9%) had no risk and six (26.1%) had risk. No statistical differences were noted in age, weight, height, or form of sedation when comparisons were made between AFib induction and no AFib induction. TEEPS induced AFib in 88.5% of patients. Age, weight, height, and form of sedation had no effect upon AFib inducibility. TEEPS is an effective modality to induce AFib in pediatric patients with aVPE.

Induction of Atrial Fibrillation with Adenosine during a Transesophageal Electrophysiology Study to Risk Stratify a Patient with Asymptomatic Ventricular Preexcitation

An asymptomatic adolescent male athlete was incidentally found to have ventricular preexcitation on electrocardiogram during a sports preparticipation physical. A transesophageal electrophysiology study (TEEPS) was performed after an exercise stress test failed to delineate the patient's risk of sudden cardiac death. The TEEPS was favored in this case over a transvenous electrophysiology study due to reduced invasiveness. The goal of the TEEPS was to place the patient into atrial fibrillation (AFib) and evaluate the shortest preexcited RR interval during AFib, thereby assessing the risk of his accessory pathway. Conventional pacing modalities were unable to induce AFib. During atrial burst pacing, adenosine was then administered, which successfully induced AFib. This case highlights adenosine's potential to induce atrial fibrillation during transesophageal electrophysiology studies when atrial pacing alone was unable to do so.