Effective Refractory Period Of Accessory Pathway Research Articles

Risk Assessment in Patients with Symptomatic and Asymptomatic Preexcitation (RASAP)

Abstract Background Controversy remains as to whether exercise stress test (EST) is sufficient for risk evaluation in patients with preexcitation. Purpose This study aims to clarify the usefulness of EST in risk stratification in both asymptomatic and symptomatic patients, presenting with preexcitation. Methods This prospective study includes consecutive asymptomatic and symptomatic patients with preexcitation, referred for risk assessment. All participants performed an incremental EST (bicycle), prior to an electrophysiology study (EPS). Primary data from the EST included loss of preexcitation during exercise and from EPS included measurement of accessory pathway effective refractory period (APERP), shortest preexcited RR interval (SPERRI), and inducible arrythmia with use of a beta-adrenergic receptor agonist if deemed necessary. Results One hundred and sixty-four patients (59 asymptomatic, 105 symptomatic) completed an EST and EPS. Forty-five patients (27%) demonstrated low-risk findings on EST, of which 19 were asymptomatic and 26 were symptomatic. Six patients with low-risk EST findings had SPERRI/APERP≤250 ms at EPS, two of them were asymptomatic. The sensitivity, specificity, positive and negative predictive value (PPV, NPV) and accuracy of low-risk EST for excluding patients with SPERRI/APERP≤250 ms were 29%, 91%, 80%, 48%, and 55% respectively. The number of patients with inducible arrhythmia at EPS was similar in the asymptomatic 36 (69%) and in the symptomatic 73 (61%) group. Conclusions Sudden loss of preexcitation during EST has a low sensitivity and low NPV in excluding high-risk APs. EPS with use of isoproterenol should be considered to accurately assess the risk of patients with preexcitation regardless of symptoms.Figure

Risk assessment in patients with symptomatic and asymptomatic pre-excitation.

Controversy remains as to whether the exercise stress test (EST) is sufficient for risk evaluation in patients with pre-excitation. This study aims to clarify the usefulness of EST in risk stratification in both asymptomatic and symptomatic patients presenting with pre-excitation. This prospective study includes consecutive asymptomatic and symptomatic patients with pre-excitation referred for risk assessment. All participants performed an incremental EST (bicycle) prior to an electrophysiology study (EPS). Primary data from the EST included loss of pre-excitation during exercise, and primary data from the EPS included the measurement of accessory pathway effective refractory period (APERP), shortest pre-excited RR interval (SPERRI), and inducible arrhythmia with the use of a beta-adrenergic receptor agonist if deemed necessary. One hundred and sixty-four patients (59 asymptomatic, 105 symptomatic) completed an EST and EPS. Forty-five patients (27%) demonstrated low-risk findings on EST, of which 19 were asymptomatic and 26 were symptomatic. Six patients with low-risk EST findings had SPERRI/APERP ≤ 250 ms at EPS, and two of them were asymptomatic. The sensitivity, specificity, positive predictive value, negative predictive value (NPV), and accuracy of low-risk EST for excluding patients with SPERRI/APERP ≤ 250 ms were 40, 91, 87, 51, and 60%, respectively. The number of patients with inducible arrhythmia at EPS was similar in the asymptomatic (36, 69%) and symptomatic (73, 61%) groups. Sudden loss of pre-excitation during EST has a low NPV in excluding high-risk APs. The EPS with the use of isoproterenol should be considered to accurately assess the risk of patients with pre-excitation regardless of symptoms (ClinicalTrials.gov Identifier: NCT03301935).

Mind the gap: Recurrence of ventricular pre-excitation after accessory pathway effective refractory period with short coupled paced stimuli.

Journal of Cardiovascular ElectrophysiologyEarly View EP ROUNDS Mind the gap: Recurrence of ventricular pre-excitation after accessory pathway effective refractory period with short coupled paced stimuli Nathan McConkey DO, Nathan McConkey DO Division of Cardiology, Penn State Hershey Medical Center, Heart and Vascular Institute, Hershey, Pennsylvania, USASearch for more papers by this authorAnkit Maheshwari MD, Corresponding Author Ankit Maheshwari MD [email protected] orcid.org/0000-0002-3096-3372 Division of Cardiology, Penn State Hershey Medical Center, Heart and Vascular Institute, Hershey, Pennsylvania, USA Correspondence Ankit Maheshwari, MD, Division of CardiologyPenn State Hershey Medical Center, Heart and Vascular Institute, 500 University Dr, Hershey, PA 17033, USA. Email: [email protected]Search for more papers by this author Nathan McConkey DO, Nathan McConkey DO Division of Cardiology, Penn State Hershey Medical Center, Heart and Vascular Institute, Hershey, Pennsylvania, USASearch for more papers by this authorAnkit Maheshwari MD, Corresponding Author Ankit Maheshwari MD [email protected] orcid.org/0000-0002-3096-3372 Division of Cardiology, Penn State Hershey Medical Center, Heart and Vascular Institute, Hershey, Pennsylvania, USA Correspondence Ankit Maheshwari, MD, Division of CardiologyPenn State Hershey Medical Center, Heart and Vascular Institute, 500 University Dr, Hershey, PA 17033, USA. Email: [email protected]Search for more papers by this author First published: 14 June 2023 https://doi.org/10.1111/jce.15971 Disclosures: None. Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL No abstract is available for this article. REFERENCE 1Josephson ME. Josephson's Clinical Cardiac Electrophysiology: Techniques and Interpretations. 5th ed. Wolters Kluwer; 2016. Early ViewOnline Version of Record before inclusion in an issue ReferencesRelatedInformation

Results of risk stratification and accessory pathway ablation in patients with asymptomatic Wolf-Parkinson-White pattern at 108 Military Central Hospital

Objective: To evaluate the electrophysiological characteristics, risk stratification and ablation outcomes in patients with asymptomatic Wolf-Parkinson-White pattern at 108 Military Central Hospital. Subject and method: A retrospective observational study on 45 asymptomatic Wolf-Parkinson-White patients underwent electrophysiology study and ablation by radiofrequency energy at Department of Cardiology, 108 Military Central Hospital, from December 2018 to December 2021. All patients were evaluated by electrophysiology study to stratify the risks. Indications of ablation was according to European Society of Cardiology guideline. Result: The average age of patients was 34.8 ± 15.1 years old. Majority of patients were men with the rate of 82.2%. The proportion of patients at high clinical risk was 31.1%. In electrophysiology study, the mean accessory pathway effective refractory period (APERP) was 215.5 ± 60.1 (in which 73.3% patients had APERP ≤ 240ms). Among patients with having spontaneous/ induced atrial fibrillation (22.2%), the mean shortest pre-excited R-R interval in atrial fibrillation (SPERRI) was 232 ± 81.2ms (80% of patients had SPERRI ≤ 250ms). The rate of patients with inducible atrioventricular reentrant tachycardia was 22.2%. There were 43 patients (95.55%) having indication for ablation (4.44% due to high-risk occupation and 91.11% due to high risk by electrophysiological study). The locations of accessory pathways included: 53.4% from left side (the most common region was anterior wall of mitral valve with 18.6%) and 46.6% from right side (14% from posterolateral wall of tricuspid valve). The mean number of attempt ablations before success was 3.1 times. The rate of successful ablation was 97.6%. There were no complications in our study sample. Conclusion: Among 45 patients with asymptomatic Wolf-Parkinson-White pattern, there were 95.55% patients having indication for ablation (4.44% due to high-risk occupation and 91.11% due to high risk by electrophysiological study). The locations of accessory pathways included: 53.4% from left side (18.6% from anterior wall of mitral valve) and 46.6% from right side (14% from posterolateral wall of tricuspid valve). The rate of successful ablation was 97.6%.

Electrophysiological guided accessory-pathway ablation strategy in children with asymptomatic WPW: it may not be enough to prevent sudden cardiac death.

Sudden cardiac death (SCD) may rarely occur among asymptomatic patients with Wolff-Parkinson-White (WPW) pattern. Risk stratification is based on electrophysiological study (EPS). We aimed to evaluate long-term efficacy of such a strategy in preventing SCD. Retrospective analysis of asymptomatic children with WPW who underwent EPS using isoproterenol. Patients considered at risk had inducible sustained atrial fibrillation or atrioventricular reentry tachycardia (AVRT) associated with the following: (1) accessory pathway (AP) effective refractory period or (2) 1:1 shortest cycle length along the AP or (3) shortest pre-excited R-R interval during AF ≤ 250ms. Fifty-one consecutive cases (7-18years, 12 ± 3) were identified, 40 (78%) with right and 11 (22%) with left AP. Twenty-eight (55%) were classified as high risk (HI) and 23 (45%) as low risk (LO), with no significant differences in demographic characteristics and AP locations. Ablation was performed in 20/28 HI and 11/23 LO patients (p 0.08), with no significant differences in acute success (20/20 versus 10/11, p 0.17) or recurrence (1/20 versus 2/10, p 0.15). Follow-up (46 ± 27months): ablated patients remained asymptomatic; among the 23 non-ablated, 18 (78%) remained asymptomatic, 5 (22%) were successfully ablated, and 5 (22%) presented events (4 AVRT, 1 SCD). Arrhythmic events did not differ significantly between non-ablated HR and LR (2/8 versus 3/15, p 0.29) and the SCD was in the LO group. More than 50% asymptomatic WPW children present high-risk AP properties. EPS-based risk stratification using isoproterenol was not able to identify increased risk of future events or SCD.

A Wolff-Parkinson-White (WPW) Electrocardiographic Pattern in Asymptomatic Patient – State-of-the-Art-Review

A comprehensive approach to asymptomatic adults with Wolff-Parkinson-White (WPW) pattern discovered incidentally on routine electrocardiography (ECG) is debatable. The objective of this review article is to update the most recent evidence on the management of young patients with asymptomatic WPW patterns. A substantial proportion of adults with WPW patterns on ECG may remain asymptomatic but the lifetime risk for fatal arrhythmias still exists. The inherent properties of the accessory pathway determine the risk of sudden cardiac death. A low-risk pathway is considered when the pre-excitation is intermittent on ambulatory monitoring or when it disappears completely or abruptly during exercise testing. On the other hand, a high-risk pathway in EP study is suggested by the presence of the shortest pre-excited RR interval (SPERRI) during atrial fibrillation of ≤ 250 ms or accessory pathway effective refractory period (APERP) ≤ 240 ms. The cardiac evaluation may thus be considered in asymptomatic patients with WPW to determine the individual risk for future symptomatic arrhythmia. A shared-decision making must be performed before offering catheter ablation whose procedural success rate is high.

Conduction Properties and Ablation of Adenosine Sensitive Accessory Pathways in Children.

Block in accessory pathway (AP) conduction with adenosine has been previously described. However, conduction characteristics of these APs has not been well defined to date. All patients with APs </ = 21years old who underwent an EP study from 2014 to 2017 were included in our study. Patients with adenosine sensitive APs were identified (group 1). Demographic and AP conduction characteristics were compared between group 1 and the entire cohort of patients. Local atrioventricular (AV) or ventriculoatrial (VA) time, cycle length and need for isoproterenol were compared to a control group matched by age and AP location (group 2). Student's t test, Wilcoxon rank sum, χ2 and Fisher's exact were used for analysis. Fourteen (7%) out of 207 patients had an adenosine sensitive AP. The median age of patients with adenosine sensitive APs was 11.8 (IQR 8.5-13.5) years vs. 14 (IQR 10.6-16.7) for the rest of the cohort (p = 0.04). Three of the 134 patients with preexcitation had adenosine sensitive APs (2%) vs. 11 of the 73 patients with concealed APs (15%) (p = 0.001). The median local AV/VA time at the site of successful ablation was longer in group 1 vs group 2 [78ms, IQR 62-116 vs. 31ms, IQR 30-38; p < 0.001]. Antegrade AP effective refractory period and total procedure time were longer in patients with adenosine sensitive APs (p = 0.03 & p = 0.04, respectively). Adenosine sensitive APs which occur in children are more often concealed. These APs have a longer conduction time at the site of successful ablation.

Characteristics of antegrade-only accessory pathways in children and adolescents.

There is minimal data regarding antegrade-only accessory pathways in young patients. Given evolving recommendations and treatments, retrospective analysis of the clinical and electrophysiologic properties of antegrade-only pathways in patients <21 years old was performed, with subsequent comparison of electrophysiology properties to age-matched controls with bidirectional pathways. Of 522 consecutive young patients with ventricular pre-excitation referred for electrophysiology study, 33 (6.3%) had antegrade-only accessory pathways. Indications included palpitations (47%), chest pain (25%), and syncope (22%). The shortest value for either the accessory pathway effective refractory period or the pre-excited R-R interval was taken for each patient, with the median of the antegrade-only group significantly greater than shortest values for the bidirectional group (310 [280-360] ms versus 270 [240-302] ms, p < 0.001). However, the prevalence of pathways with high-risk properties (effective refractory period or shortest pre-excited R-R interval <250 ms) was similar in both study patients and controls (13% versus 21%) (p = 0.55). Sixteen patients had a single antegrade-only accessory pathway and no inducible arrhythmia. Six patients had Mahaim fibres, all right anterolateral with inducible antidromic reciprocating tachycardia. However, 11 patients with antegrade-only accessory pathways and 3 with Mahaim fibres had inducible tachycardia due to a second substrate recognised at electrophysiology study. These included concealed accessory pathways (7), bidirectional accessory pathways (5), and atrioventricular node re-entry (2). Antegrade-only accessory pathways require comprehensive electrophysiology evaluation as confounding factors such as high-risk conduction properties or inducible Supraventricular Tachycardia (SVT) due to a second substrate of tachycardia are often present.

A Brief review of the risks and the stratification of sudden death in the ventricular Pre-excitation syndrome.

Objective: The diagnosis of ventricular preexcitation syndromes is often occasional and with underestimated risk, showing controversies in its stratification and indication of prophylactic ablation. This work aims to explore and summarize the data in the literature, exposing the authors’ conclusions regarding this review. Methods: The authors prepared this work based on the latest guideline of the European Society of Cardiology plus a search for articles published in MEDLINE whose titles related to sudden death from ventricular fibrillation in patients with ventricular preexcitation. Discussion: Sudden death secondary to preexcited atrial fibrillation with degeneration to ventricular fibrillation is the most feared event in Wolff-Parkinson-White syndrome, has an average annual incidence of 0.15 to 0.39%, affecting individuals with structurally normal heart. The noninvasive stratification methods do not demonstrate adequate efficacy, and an electrophysiological study is recommended for all cases at the time of diagnosis. The most severe criteria for sudden death are shortest preexcited RR interval ≤ 250 ms (SPERRI or SPRRI); accessory pathway effective refractory period (APERP) ≤ 250 ms; presence of multiple accessory bundles; shortest paced cycle length with preexcitation during atrial pacing ≤ 250ms (SPPCL); Ebstein anomaly; induction of sustained supraventricular tachycardia. Conclusion: The low rate of complications during the diagnostic exam as well as in the therapeutic procedure, added to the high percentage of success of radiofrequency ablation, leads to indicate early the execution of electrophysiological study as a more diligent and accurate measure in the reduction of sudden death events in patients with ventricular preexcitation syndromes.

Novel Assessment of Accessory Pathway Function in Patients with Wolff-Parkinson-White Syndrome.

Surrogates for the shortest pre-excited R-R interval in atrial fibrillation (SPERRI) such as the accessory pathway effective refractory period (APERP) and shortest pre-excited paced cycle length (SPPCL) are flawed assessments of accessory pathway function in patients with WPW. Multi-extrastimulus pacing may have the theoretical advantage of more accurately mimicking the clinical reality of atrial fibrillation and thus may serve to better assess accessory pathway function. This cross-sectional study included 25 consecutive patients, aged≤18years, undergoing electrophysiology study for WPW. The longest S1S2, S2S3, S3S4 coupling intervals at which the antegrade AP refractoriness occurred, SPERRI, and SPPCL were recorded. Induction of atrial fibrillation was attempted in all patients and induced in 8 (32%, 4 SPERRIbaseline (265ms±61ms), 4 SPERRIIsuprel (258ms±41ms)). At baseline, the lower value of the S3ERP or S4ERP (274ms±52ms) was lower than the SPPCL (296ms±54ms, p<0.0001) and APERP (296ms±41ms, p<0.0001). More patients had S3ERP or S4ERP≤250ms (12/25, 48%) compared to those with APERP≤250ms (2/25 8%), p=0.0016), SPPCL 5/24, 20%), p=0.008 or either (6/25, 24%), p=0.0143). With Isuprel, the lower value of the S3ERP or S4ERP (221ms±36ms) trended to be lower than the APERP (252ms±36ms, p=0.0001) and the SPPCL (266ms±57ms, p=0.001). With Isuprel, there was no statistical difference in the proportion of patients with S3ERP or S4ERP<250ms (12/16, 75%) compared to those with APERP≤250ms ((9/16, 56%), p=0.08), SPPCL≤250ms ((9/16, 56%), p=0.08), or either ((10/16, 63%), p=0.16). Multi-extrastimulus pacing protocols demonstrate that accessory pathways are less refractory than as defined by single extrastimulus pacing and straight decremental pacing.

Loss of ventricular preexcitation during noninvasive testing does not exclude high-risk accessory pathways: A multicenter study of WPW in children

Abrupt loss of ventricular preexcitation on noninvasive evaluation, or nonpersistent preexcitation, in Wolff-Parkinson-White syndrome (WPW) is thought to indicate a low risk of life-threatening events. The purpose of this study was to compare accessory pathway (AP) characteristics and occurrences of sudden cardiac arrest (SCA) and rapidly conducted preexcited atrial fibrillation (RC-AF) in patients with nonpersistent and persistent preexcitation. Patients 21 years or younger with WPW and invasive electrophysiology study (EPS) data, SCA, or RC-AF were identified from multicenter databases. Nonpersistent preexcitation was defined as absence/sudden loss of preexcitation on electrocardiogram, Holter monitoring, or exercise stress test. RC-AF was defined as clinical preexcited atrial fibrillation with shortest preexcited R-R interval (SPERRI) ≤ 250 ms. AP effective refractory period (APERP), SPERRI at EPS , and shortest preexcited paced cycle length (SPPCL) were collected. High-risk APs were defined as APERP, SPERRI, or SPPCL ≤ 250 ms. Of 1589 patients, 244 (15%) had nonpersistent preexcitation and 1345 (85%) had persistent preexcitation. There were no differences in sex (58% vs 60% male; P=.49) or age (13.3±3.6 years vs 13.1±3.9 years; P=.43) between groups. Although APERP (344±76 ms vs 312±61 ms; P<.001) and SPPCL (394±123 ms vs 317±82 ms; P<.001) were longer in nonpersistent vs persistent preexcitation, there was no difference in SPERRI at EPS (331±71 ms vs 316±73 ms; P=.15). Nonpersistent preexcitation was associated with fewer high-risk APs (13% vs 23%; P<.001) than persistent preexcitation. Of 61 patients with SCA or RC-AF, 6 (10%) had nonpersistent preexcitation (3 SCA, 3 RC-AF). Nonpersistent preexcitation was associated with fewer high-risk APs, though it did not exclude the risk of SCA or RC-AF in children with WPW.

Difficulties with invasive risk stratification performed under anesthesia in pediatric Wolff-Parkinson-White Syndrome

Children with Wolff-Parkinson-White Syndrome (WPW) are at risk for sudden death. The gold standard for risk stratification in this population is the shortest pre-excited RR interval during atrial fibrillation (SPERRI). The purpose of this study was to determine how closely measurements made in the electrophysiology laboratory in patients with WPW compared to SPERRI obtained during an episode of clinical pre-excited atrial fibrillation (Clinical-SPERRI). This was a subgroup analysis of a multicenter study of children with WPW. Subjects in our study (N = 49) were included if they had Clinical-SPERRI measured in addition to 1 or more of 3 surrogate measurements: SPERRI obtained during electrophysiological study (EP-SPERRI), accessory pathway effective refractory period (APERP), or shortest pre-excited paced cycle length with 1:1 conduction (SPPCL). Seventy percent of electrophysiological measurements were made with patients under general anesthesia. Clinical-SPERRI moderately correlated with EP-SPERRI (r = 0.495; P = .012). However, 24% of our patients with Clinical-SPERRI ≤250 ms would have been misclassified as having a low-risk pathway based on EP-SPERRI >250 ms. Clinical-SPERRI did not correlate with APERP or SPPCL (r < 0.3; P >.1). Mean EP-SPERRI, APERP, and SPPCL all were greater than Clinical-SPERRI. Electrophysiology laboratory measurements of pathway characteristics made with patients under general anesthesia do not correlate well with Clinical-SPERRI. Of APERP, SPPCL, and EP-SPERRI, only EP-SPERRI had moderate correlation with Clinical-SPERRI. This study questions the predictive ability of invasive risk stratification with patients under general anesthesia, given that 24% of patients with high-risk Clinical-SPERRI (≤250 ms) had EP-SPERRI that may be considered low risk (>250 ms).

Electrophysiological properties of asymptomatic children and adolescents with the Wolff-Parkinson-White electrocardiographic pattern

Optimal management in asymptomatic children and adolescents with the Wolff-Parkinson-White (WPW) electrocardiographic pattern is still debatable. The aim of this retrospective study was to evaluate the electrophysiological properties of asymptomatic children and adolescents with WPW. The medical records and procedural data of asymptomatic children and adolescents with the WPW electrocardiographic pattern who underwent invasive electrophysiological study (EPS) and catheter ablation between April 2012 and April 2018 were evaluated. In all, 149 consecutive, asymptomatic children and adolescents with WPW who underwent EPS were retrospectively investigated. In 39 (26.2%) of the patients, a shortest pre-excited R-R interval of ≤250 ms during atrial fibrillation or an accessory pathway effective refractory period of ≤270 ms was found. A total of 39 patients with high-risk antegrade conduction and 45 patients with inducible orthodromic atrioventricular re-entrant tachycardia underwent catheter ablation. In addition, 14 patients underwent catheter ablation due to family preference. High-risk antegrade conduction properties are exhibited by more than one-quarter of asymptomatic children and adolescents with WPW. Ablation should be considered as a first-line therapy in asymptomatic children and adolescents with high-risk WPW.

Risk Stratification of an Accessory Pathway Using Isoproterenol after Cardiac Arrest

A 43-year-old man presented after ventricular fibrillation cardiac arrest with evidence of pre-excited atrial fibrillation. Electrophysiology study with guideline-directed testing demonstrated a low risk accessory pathway effective refractory period, which became high-risk with isoproterenol infusion. This case represents a challenging scenario wherein a high-risk pathway may be misclassified using the currently indicated methods of risk stratification.

Life-Threatening Event Risk in Children With Wolff-Parkinson-White Syndrome: A Multicenter International Study.

This study sought to characterize risk in children with Wolff-Parkinson-White (WPW) syndrome by comparing those who had experienced a life-threatening event (LTE) with a control population. Children with WPW syndrome are at risk of sudden death. This retrospective multicenter pediatric study identified 912 subjects≤21 years of age with WPW syndrome, using electrophysiology (EPS) studies. Case subjects had a history of LTE: sudden death, aborted sudden death, or atrialfibrillation (shortest pre-excited RR interval in atrial fibrillation [SPERRI] of≤250 ms or with hemodynamic compromise); whereas subjects did not. We compared clinical and EPS data between cases and subjects. Case subjects (n= 96) were older and less likely than subjects (n= 816) to have symptoms or documented tachycardia. Mean age at LTE was 14.1 ± 3.9 years of age. The LTE was the sentinel symptom in 65%, consisting of rapidly conducted pre-excited atrial fibrillation (49%), aborted sudden death (45%), and sudden death (6%). Three risk components were considered at EPS: SPERRI, accessory pathway effective refractory period (APERP), and shortest paced cycle length with pre-excitation during atrial pacing (SPPCL), and all were shorter in cases than in control subjects. In multivariate analysis, risk factors for LTE included male sex, Ebstein malformation, rapid anterograde conduction (APERP, SPERRI, or SPPCL≤250 ms), multiple pathways, and inducible atrial fibrillation. Of case subjects, 60 of 86 (69%) had≥2 EPS risk stratification components performed; 22 of 60 (37%) did not have EPS-determined high-risk characteristics, and 15 of 60 (25%) had neither concerning pathway characteristics nor inducible atrioventricular reciprocating tachycardia. Young patients may experience LTE from WPW syndrome without prior symptoms or markers of high-risk on EPS.

Electrophysiological effects of desflurane in children with Wolff-Parkinson-White syndrome: a randomized crossover study.

We hypothesized that, compared with propofol, desflurane prolongs the antegrade accessory pathway effective refractory period (APERP) in children undergoing radiofrequency catheter ablation for Wolff-Parkinson-White (WPW) syndrome. In this randomized crossover study, children aged 4.1-16.1years undergoing radiofrequency catheter ablation for WPW syndrome were randomly divided into four groups according to the concentration of desflurane and anesthetics used in the first and the second electrophysiological studies (EPS). After induction of general anesthesia with propofol and tracheal intubation, they received one of the following regimens: 0.5 minimum alveolar concentration (MAC) desflurane (first EPS) and propofol (second EPS) (Des0.5-Prop group, n=8); propofol (first EPS) and 0.5 MAC desflurane (second EPS) (Prop-Des0.5 group, n=9); 1 MAC desflurane (first EPS) and propofol (second EPS) (Des1.0-Prop group, n=10); propofol (first EPS) and 1 MAC desflurane (second EPS) (Prop-Des1.0 group, n=9). Radiofrequency catheter ablation was performed upon completion of EPS. Sample size was determined to detect a difference in the APERP. Desflurane at 1.0 MAC significantly prolonged the APERP compared with propofol, but did not affect the sinoatrial conduction time, atrio-His interval or atrioventricular node effective refractory period. Supraventricular tachycardia was induced in all children receiving propofol, but not induced in 1 and 4 children receiving 0.5 MAC and 1.0 MAC desflurane, respectively. Desflurane enhances the refractoriness and may block the electrical conduction of the atrioventricular accessory pathway, and is therefore not suitable for use in children undergoing radiofrequency catheter ablation for WPW syndrome.

Evolution of Clinical and Electrophysiological Data in Children with a Preexcitation Syndrome.

With ablation, the follow-up of preexcitation syndrome now is difficult to assess. The purpose was to collect data of children with a preexcitation syndrome studied on two separate occasions within a minimal interval of 1 year. This is a retrospective chart review of 47 children initially aged 12 ± 4 years, who underwent two or more invasive electrophysiological studies (EPS) within 1-25 years of one another (6.3 ± 4.8) for occurrence of symptoms or new evaluation. Among initially symptomatic children (n = 25), four (19%) became asymptomatic and one presented life-threatening arrhythmia. Among asymptomatic children (n = 22), five became symptomatic (22.7%). Anterograde conduction disappeared in seven of 23 children with initially long accessory pathway-effective refractory period, but four of six had still induced atrioventricular reentrant tachycardia (AVRT). AVRT was induced at second EPS in three of 13 asymptomatic preexcitation syndrome with negative initial EPS. There were no spontaneous adverse events in the five children with criteria of malignancy at initial EPS; signs of malignancy disappeared in two. At multivariate analysis, AVRT at initial EPS was the only independent factor of symptomatic AVRT during follow-up. Absence of induced AVRT at initial EPS was the only factor of absence of symptoms and a negative study at the second EPS. There were no significant changes of data in children after 6.3 ± 4.8 years of follow-up. Most children with spontaneous/inducible AVRTs at initial EPS had still inducible AVRT at second EPS. Induced AF conducted with high rate has a relatively low prognostic value for the prediction of adverse events.

0272: Why accessory pathway refractory period can be shorter at esophageal electrophysiological study than at intracardiac study?

Preexcitation syndrome (PS) is a potential cause of sudden cardiac death; its prognostic assessment is a major issue. The aim was to assess the contribution of esophageal electrophysiological study (EPS) compared to intracardiac EPS for the prognostic evaluation in patients with PS. We conducted a prospective single-centre study between November 1 st , 2008 and December 1 st , 2014, in patients who underwent both esophageal and intracardiac EPS for a PS. Accessory pathway effective refractory period (APERP) and induction of sustained supraventricular tachyarrhythmias (SVT) were noted for both methods. 69 patients were included. 45 (65%) were males and mean age was 36±16 years. There were no significant differences in the induction of SVT between both methods. APERPs were significantly shorter at esophageal EPS compared to intracardiac EPS in control state (>40 ms) in 51% of patients, but APERPs did not decrease significantly after isoproterenol: in these patients with shorter APERP at esophageal EPS, age and gender was similar to other patients; APERPs in basal state were shorter than in patients with similar APERPs at both studies (255±43 vs 281±61)(p0.032), but APERPs after isoproterenol were similar (226±33 vs 231±45)(0.55); the shortening of APERP after infusion of isoproterenol was significantly less than in patients with similar APERPs at esophageal and intracardiac EPS (30±31ms vs 49±45 ms)(p<0.05). The sensitivity of esophageal EPS in prognostic assessment was 88% in control state, 100% during isoproterenol infusion. The area under ROC curve of transesophageal EPS in prognostic assessment based on APERP measurement was 0.74. Esophageal EPS was a reliable and sensitive method of prognostic assessment in patients with PS. APERP was shorter in 51% of patients but did not decrease significantly after isoproterenol at esophageal EPS compared to intracardiac EPS, indicating esophageal EPS-related stress.

Intermittent versus Persistent Wolff-Parkinson-White Syndrome in Children: Electrophysiologic Properties and Clinical Outcomes.

Intermittent Wolff-Parkinson-White (WPW) syndrome is considered to have a lower risk of sudden death. Fewer data exist regarding electrophysiologic (EP) characteristics and the natural history of intermittent WPW in children. All patients with WPW age 1-18 years at a single institution (1996-2013) were reviewed. Patients with intermittent preexcitation were compared to those with loss of preexcitation on Holter/exercise testing and those with persistent preexcitation. High-risk accessory pathway (AP) was defined as AP effective refractory period (APERP), block cycle length, or shortest preexcited RR interval during atrial fibrillation ≤250 ms. A total of 295 patients were included: 226 (76.6%) persistent, 39 (13.2%) intermittent, and 30 (10.2%) loss of preexcitation Holter/exercise. There were no differences in symptoms between groups. Median interquartile range APERP was significantly longer in intermittent WPW (380 [320, 488] ms vs 320 [300, 350] ms persistent, 310 [290, 330] ms loss of preexcitation Holter/exercise; P = 0.0008). At baseline, there was no difference between groups in frequency of high-risk pathways. However, when isoproterenol values were included, high-risk pathways were more frequent among patients with loss of preexcitation on Holter/exercise (54% vs 16% persistent, 11% intermittent; P = 0.005). There was one death in a patient with loss of preexcitation on exercise testing, no EP study, and prior drug use. A second patient with persistent WPW and APERP 270 ms required resuscitation following a methadone overdose. Intermittent preexcitation in children does not connote a lower risk AP by EP criteria or reduced symptoms. The low number of pediatric WPW patients who develop preexcited atrial fibrillation or sudden death warrants larger studies to investigate these outcomes.

0164: Evolution of preexcitation syndrome in children

Previous studies reported a spontaneous disappearance of preexcitation syndrome (PS) in patients with a long accessory pathway (AP) effective refractory period (ERP) and in children <12 years (y), but stability in children >12 y with inducible SVT and short AP-ERP. The purpose of the study was to collect the data of untreated children with a PS, studied 2 times at least one year of interval. 2 baseline electrophysiological studies (EPS) were performed within 1 to 25 years of one another (mean 6±years) in 39 children and teenagers, 17 boys, 22 girls, aged initially from 1 to 19 years (12.5±4), with overt PS. First EPS (EPS1) was indicated for syncope (n=4), atrioventricular reentrant tachycardias (AVRT)(n=17) or for asymptomatic PS (n=18). The protocol was similar, performed in control state (CS) and after isoproterenol. At EPS2, among patients studied for syncope at EPS1, 1 has still syncope, 2 have AVRT, 1 is asymptomatic. Among patients with AVRT at EPS1, 14 (82%) have still AVRT, 3 are asymptomatic. Among asymptomatic patients, 13 (72%) remain asymptomatic, 2 have AVRT, 3 have syncope. AVRT in children presenting initially with syncope or initially asymptomatic children occurred in 2/4 with inducible AVRT at EPS1. The higher rate conducted by AP was similar in CS and after isoproterenol at EPS2 (178±72bpm, 203±81) and at EPS1 (188±62, 237±83)(p<0.01). AP-ERP’s were similar in CS at EPS2 (283±68ms) and 1 (281±91.5) and tended to increase from 211±72 at ESP1 to 234±58ms at EPS2 (p<0.07) after isoproterenol. AP has lost anterograde conduction in 6 children with initially long APERP but all 5 children with initially inducible AVRT had still inducible AVRT. Two children with initially a long AP-ERP had shorter AP-ERP at EPS2. AVRT was induced at EPS2 in asymptomatic PS with initially negative EPS in 3 children. Contrary to previous studies, we did not find significant changes of clinical and electrophysiological data in children after a mean follow-up of 6±5 years. Most of children with spontaneous or inducible AVRT’s at the first evaluation have still inducible AVRT’s at the second evaluation. AP-ERP did not increase significantly.