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A 20-year-old man was resuscitated after ventricular fibrillation (VF). Electrocardiography revealed Wolff-Parkinson-White (WPW) syndrome. Intracoronary acetylcholine provocation (ACH test) testing was performed to induce VF secondary to the coronary vasospasm. The administration of acetylcholine to the coronary artery induced atrial fibrillation (AF) with preexcitation, followed by VF without coronary vasospasm. Electrophysiological studies revealed an accessory pathway managed by catheter ablation. Subsequent intracoronary ACH test induced the occurrence of AF without preexcitation. To our knowledge, this case report is the first to demonstrate the utility of the ACH test in confirming WPW syndrome as a cause of VF.

Competing Interests: Conflict of interest: None declared.

An 18-year-old female neutered Domestic Shorthair cat was referred for investigation of seizure-like episodes. Physical and neurological examination were unremarkable, as were systemic arterial blood pressure, cardiac troponin I, complete blood count and biochemistry profile. Diagnostic tests included transthoracic echocardiography which ruled out any structural cardiomyopathy, and electrocardiography which showed an underlying regular wide QRS-complex rhythm with pronounced shortening of the PR interval. Considering the findings, a diagnosis of suspected ventricular pre-excitation secondary to an accessory pathway was made. Further investigations were declined and, as no periods of tachycardia were seen on the five-minute electrocardiogram, no antiarrhythmic treatment was started., Competing Interests: Conflicts of Interest Statement The authors do not have any conflicts of interest to disclose., (Crown Copyright © 2024. Published by Elsevier B.V. All rights reserved.)

Background: T-wave memory (TWM) is a rare cause of T-wave inversion (TWI). Alterations in ventricular activation due to abnormal depolarization may cause repolarization abnormalities on the ECG, even if myocardial conduction returns to normal. These repolarization changes are defined as TWM. In our study, we aimed to determine the frequency of TWM development and the predictors affecting it in the pediatric population who underwent accessory pathway (AP) ablation due to Wolff-Parkinson-White (WPW) syndrome., Methods: The data of patients with manifest AP who underwent electrophysiological studies and ablation between 2015 and 2021 were retrospectively analyzed. The study included 180 patients who were under 21 years of age and had at least one year of follow-up after ablation. Patients with structural heart disease, intermittent WPWs, recurrent ablation, other arrhythmia substrates, and those with less than one-year follow-up were excluded from the study. The ECG data of the patients before the procedure, in the first 24 h after the procedure, three months, and in the first year were recorded. The standard ablation technique was used in all patients., Results: Postprocedure TWM was observed in 116 (64.4%) patients. Ninety-three patients (51.7%) had a right-sided AP, and 87 patients (48.3%) had a left-sided AP. The presence of posteroseptal AP was found to be significantly higher in the group that developed TWM. Of these patients, 107 (93.1%) patients showed improvement at the end of the first year. Preprocedural absolute QRS-T angle, postprocedural PR interval, and right posteroseptal pathway location were identified as predictors of TWM., Conclusion: The development of TWM is particularly associated with the right-sided pathway location, especially the right posteroseptal pathway location. The predictors of TWM are the preprocedural QRS-T angle, the postprocedural PR interval, and the presence of the right posteroseptal AP., (© 2024 Wiley Periodicals LLC.)

The ECG of a patient during sinus rhythm shows preexcited QRS pattern, with rS pattern in lead V1, transition in lead V2, and positive inferior leads. Following the stepwise algorithms, the location of accessory pathway (AP) was identified at anteroseptal region. However, the precordial transition in lead V2 indicates mid-septal or posteroseptal AP. The mismatch suggested multiple APs and 5 APs were identified by electrophysiologic study. This case highlights the importance of detailed analysis of ECG in order to achieve adequate ablation., Competing Interests: Declaration of competing interest None., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Introduction: Williams syndrome (WS) cases have been reported to have with 25-100 times greater increased risk of sudden cardiac death (SCD). SCD has been reported in cases without any evidence of structural cardiovascular anomalies. Wolff-Parkinson-White (WPW) syndrome is characterized by short PR interval and delta wave. Ventricular preexcitations can develop paroxysmal reentrant tachycardia through Kent bundle or less frequent atrial fibrillation and in some cases with accessory pathway effective refractory period (APERP) under 250 ms considered as risky and may lead to SCD. WS associated with WPW has not been reported before., Case Report: An 11-year-old male who had been followed up with WS was referred to pediatric cardiology outpatient clinic with the complaint of palpitation. Electrocardiographic examination showed short PR interval and delta wave in the ECG consistent with WPW. He underwent electrophysiological study (EPS). Basic measurements were performed, and APERP was found at 280 ms cycle atrial pacing. RF energy was delivered using a 4 mm tip nonirrigated radiofrequency (RF) ablation catheter where the best ventriculoatrial (VA) signals were received and the AP was abolished within few seconds., Discussion and Conclusions: Although, WPW cases are usually asymptomatic or related to SVT, the risk of SCD should not be ignored. Thus, all patients with WPW deserve an EPS for assessing the AP conduction properties. Due to the increased risk of SCD in patients with WS compared to general population, in the presence of concomitant WPW, these patients should be evaluated with EPS even if they do not have symptoms., (© 2024 Wiley Periodicals LLC.)

The main objective of this research work is to develop an effective mathematical model of cardiac conduction system using a heterogeneous whole-heart model. The model is in the form of a system of modified Van der Pol and FitzHugh-Nagumo differential equations capable of describing the heart dynamics. The proposed model extends the range of normal and pathological electrocardiogram (ECG) waveforms that can be generated by the model. The effects of the respiratory sinus arrhythmia (RSA) and the Mayer waves (MW) are both incorporated to modulate the intrinsic frequency of the main oscillator that represents the sinoatrial node. Also, three pathological conditions are incorporated into the model. The heart rate variability (HRV) phenomenon is incorporated into the synthetic ECGs produced which yields valuable information about the cardiovascular health and the performance of the autonomic nervous system. The spectral analysis of the generated RR tachogram delivers power spectrums that resemble those obtained from real recordings. Also, the proposed model generates synthetic ECGs that characteristic the three considered pathological conditions, namely, the tall T wave, the ECG with U wave, and the Wolff-Parkinson-White syndrome. In general, the significance of this research work is in developing a mathematical model that represents the interactions between different pacemakers and allows analysis of cardiac rhythms. To show the effectiveness and the accuracy of the presented model, the results are compared to published results. The proposed model can be a useful tool to study the influences of different physiological conditions on the profile of the ECG. The synthetic ECG signals produced can be used as signal sources for the assessment of diagnostic ECG signal processing devices.

Background: Published algorithms for accessory pathway localization in Wolff-Parkinson-White (WPW) syndrome are inaccurate in pediatric patients, especially for septal pathways., Objective: We aimed to develop a new algorithm that is sensitive for septal pathways and more applicable in pediatric patients., Methods: In 120 patients (mean age: 11.7 ± 3.9 years) who underwent catheter ablation for WPW syndrome, the candidate criteria for new algorithm were searched by comparing electrocardiography parameters and accessory pathway locations. A new algorithm was designed to increase the sensitivity for septal pathways. For validation, 142 patients (mean age: 15.8 ± 3.7 years) were additionally evaluated. New and published algorithms were applied to electrocardiography of 262 patients and the results were compared., Results: The new algorithm achieved its best discrimination by combining several parameters together in each step: (1) QRS polarity in V 1 and QRS shape in lead I for left/right discrimination, and (2) delta wave polarity in V 1 , QRS transition in precordial leads, and delta wave polarity in lead III for septal pathway screening. The new algorithm showed higher sensitivity for septal pathways (95.7%) than 7 published algorithms (average: 62.1%), with satisfactory positive predictive value (77.9%). Delta wave polarity in V 1 among septal pathways and QRS axis among right anteroseptal pathway showed age-related trend; this could be the reason for the lower accuracy in localizing septal pathways in children., Conclusion: The inaccuracy of published algorithms in pediatric patients is due to the age-related trend in the electrocardiography of septal pathways. The new algorithm was superior for localizing septal pathways in pediatric patients., (Copyright © 2020 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

The ability to estimate accessory pathway (AP) position enables pre-procedural planning, reduces mapping times, and improves risk estimates as part of the patient consent process. In this article, the nomenclature and important concepts of AP localization algorithms are outlined. An overview of three prominent algorithms is then provided. Each represents an era of invasive treatment of APs: surgical therapy, endocardial ablation, and contemporary electroanatomic mapping. In this manner, the premises, pitfalls, and evolution of AP localization algorithms are illustrated. In addition, the pertinent features of their work are distilled in a simplified topographic algorithm with the interventional electrophysiologist in mind., Competing Interests: Disclosure None., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Accessory pathways are present in 1 in 300 young individuals. They are often asymptomatic and potentially lethal arrhythmias may be the first presentation. During long-term follow-up, up to 20% of asymptomatic individuals with pre-excitation go on to develop an arrhythmia and the absence of traditional clinical and electrophysiological high-risk markers does not guarantee the "safe" nature of an accessory pathway. The widespread availability of permanent cure for the condition at low risk by catheter ablation, creates an incentive to screen for accessory pathways with a 12-lead ECG, particularly in individuals who are perceived to be at increased risk, such as athletes and high-risk professions. We review the existing literature on the assessment and management of accessory pathways (Wolff-Parkinson-White [WPW] syndrome) and discuss its implications for the young athletic population., (© 2020 The Authors. Clinical Cardiology published by Wiley Periodicals, Inc.)

The evaluation and treatment of wide QRS-complex tachycardia remains a challenge, and mismanagement is quite common. Diagnostic aids such as wide-complex tachycardia algorithms perform poorly in the real-life setting. The purpose of this review is to offer a simple clinical-electrocardiographic approach for the initial evaluation and management of the adult patient with stable wide-complex tachycardia that does not require recollection of complex guidelines or algorithms., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Background: Fasciculoventricular fibers (FVFs) are responsible for 1%-5% of cases of asymptomatic preexcitation on the surface electrocardiogram (ECG). Unlike ventricular preexcitation seen in Wolff-Parkinson-White (WPW) syndrome, FVFs are not associated with sudden cardiac death from preexcited atrial fibrillation., Objective: The purpose of this study was to identify surface ECG variables that differentiate FVFs from true WPW syndrome., Methods: This is a retrospective case-control study comparing surface ECG characteristics of patients diagnosed with FVFs (cases) with those of patients with WPW syndrome and anteroseptal accessory pathways (controls) via intracardiac electrophysiology testing at a single institution from 2005 to 2017., Results: Twenty-four cases of FVFs confirmed by intracardiac electrophysiology testing were identified and compared with 48 consecutive controls with WPW syndrome and anteroseptal accessory pathways. Patients with WPW syndrome were found to have significantly higher delta wave amplitudes (4.8 ± 2.0 mm vs 1.9 ± 1.3 mm; P < .001), shorter PR intervals (94.6 ± 12.5 ms vs 106.8 ± 13.2 ms; P < .001), and longer QRS intervals (133.6 ± 19.0 ms vs 118.7 ± 24.7 ms; P = .006) than did those with FVFs. Multivariable logistic regression analysis identified the delta wave amplitude as the only independent predictor of WPW syndrome (odds ratio 3.1 per 1-mm increase; bootstrapped 95% confidence interval 1.5-6.4; c statistic 0.90; P = .002)., Conclusion: The etiology of preexcitation in patients with an anteroseptal preexcitation pattern, whether because of a benign FVF or because of potentially serious WPW syndrome, can be noninvasively deduced using the surface ECG. A higher delta wave amplitude is an independent risk factor for the presence of WPW syndrome and can accurately distinguish WPW syndrome from a FVF with good test accuracy characteristics., (Copyright © 2019 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Background: Due to high rates of ablation at the time of diagnostic EP study, follow-up of the natural history of untreated pre-excitation syndrome has become difficult. We present patients in which such data is available and study the effect of initial age on the evolution., Methods: In this retrospective review, 126 patients, 47 aged ≤19 years, 79 aged more than>19 underwent 2 similar electrophysiological studies (EPS) within 1 to 25 years of one another (8.8 ± 6.8) for occurrence of symptoms or new evaluation. First EPS was indicated for syncope (10), atrioventricular re-entrant tachycardias (AVRT) (58), atrial fibrillation (AF) (5), spontaneous PS-related adverse event (7) or asymptomatic PS (46)., Results: Clinical data remained unchanged in 76 patients (60.3%). AVRT symptom was more frequently unchanged than other symptoms. Electrophysiological data remained unchanged in 105 patients (82%), but signs of initial malignant signs were variable with a disappearance in 53.5% of patients. At EPS1, AF induction was rarer in patients ≤19 years. Syncope had a low predictive value of malignant form. AVRT induction at EPS1 was not predictive of AVRT occurrence. Maximal rate over accessory pathway increased, but unexpected changes could occur. After multivariate analysis, data of first EPS were limited for the prediction of AVRT or adverse event; effect of age was not significant., Conclusions: Clinical data remained unchanged in 60.3% of patients and electrophysiological data in 82%. Initial age of evaluation did not change the modifications. Electrophysiological signs associated with sudden death varied over time. Clinical AVRT was inconstantly related to inducible AVRT (78.5%)., (Copyright © 2018 Elsevier Inc. All rights reserved.)

A number of rare cardiac diseases can be recognized by electrocardiogram (ECG). This article illustrates the clinical importance of ECG as a key diagnostic tool to detect Wolff-Parkinson-White syndrome and channelopathies, which are frequently diagnosed late after one or more affected family members have become victims of sudden cardiac death. These channelopathies include long QT syndrome, short QT syndrome, Brugada syndrome, and catecholaminergic polymorphic ventricular tachycardia. In addition, typical ECG findings are frequently present in patients with idiopathic ventricular tachycardia, arrhythmogenic right ventricular dysplasia, digitalis intoxication, hyperkalemia, acute cor pulmonale due to pulmonary embolism, as well as severe left ventricular hypertrophy as in hypertrophic cardiomyopathy.

Background: The majority of available data on the clinical course of patients with ventricular preexcitation in the ECG originates from tertiary centers. We aimed to investigate long-term outcomes in individuals from a primary care population with electrocardiographic preexcitation., Methods and Results: Digital ECGs from 328 638 primary care patients were collected during 2001 to 2011. We identified 310 individuals with preexcitation (age range, 8-85 years). Data on medication, comorbidity, and outcomes were collected from Danish nationwide registries. The median follow-up time was 7.4 years (quartiles, 4.6-10.3 years). Compared with the remainder of the population, patients with preexcitation had higher adjusted hazards of atrial fibrillation (hazard ratio [HR], 3.12; 95% confidence interval [CI], 2.07-4.70) and heart failure (HR, 2.11; 95% CI, 1.27-3.50). Subgroup analysis on accessory pathway location revealed a higher adjusted hazard of heart failure for a right anteroseptal accessory pathway (HR, 5.88; 95% CI, 2.63-13.1). There was no evidence of a higher hazard of death among individuals with preexcitation when looking across all age groups (HR, 1.07; 95% CI, 0.68-1.68). However, a statistically significant ( P =0.01) interaction analysis (<65 versus ≥65 years) indicated a higher hazard of death for patients with preexcitation ≥65 years (HR, 1.85; 95% CI, 1.07-3.18)., Conclusions: In this large ECG study, individuals with preexcitation had higher hazards of atrial fibrillation and heart failure. The higher hazard of heart failure seemed to be driven by a right anteroseptal accessory pathway. Among elderly people, we found a statistically significant association between preexcitation and a higher hazard of death., (© 2017 American Heart Association, Inc.)

Background: 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., Methods: 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., Results: 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., Conclusions: 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., (© 2016 Wiley Periodicals, Inc.)

Objective: To review the literature systematically to determine whether noninvasive or invasive risk stratification, such as with an electrophysiological study of patients with asymptomatic pre-excitation, reduces the risk of arrhythmic events and improves patient outcomes., Methods: PubMed, EMBASE, and the Cochrane Central Register of Controlled Trials (all January 1, 1970, through August 31, 2014) were searched for randomized controlled trials and cohort studies examining noninvasive or invasive risk stratification in patients with asymptomatic pre-excitation. Studies were rejected for low-quality design or the lack of an outcome, population, intervention, or comparator of interest or if they were written in a language other than English., Results: Of 778 citations found, 9 studies met all the eligibility criteria and were included in this paper. Of the 9 studies, 1 had a dual design-a randomized controlled trial of ablation versus no ablation in 76 patients and an uncontrolled prospective cohort of 148 additional patients-and 8 were uncontrolled prospective cohort studies (n=1594). In studies reporting a mean age, the range was 32 to 50 years, and in studies reporting a median age, the range was 19 to 36 years. The majority of patients were male (range, 50% to 74%), and <10% had structural heart disease. In the randomized controlled trial component of the dual-design study, the 5-year Kaplan-Meier estimates of the incidence of arrhythmic events were 7% among patients who underwent ablation and 77% among patients who did not undergo ablation (relative risk reduction: 0.08; 95% confidence interval: 0.02 to 0.33; P<0.001). In the observational cohorts of asymptomatic patients who did not undergo catheter ablation (n=883, with follow-up ranging from 8 to 96 months), regular supraventricular tachycardia or benign atrial fibrillation (shortest RR interval >250 ms) developed in 0% to 16%, malignant atrial fibrillation (shortest RR interval ≤250 ms) in 0% to 9%, and ventricular fibrillation in 0% to 2%, most of whom were children in the last case., Conclusions: The existing evidence suggests risk stratification with an electrophysiological study of patients with asymptomatic pre-excitation may be beneficial, along with consideration of accessory-pathway ablation in those deemed to be at high risk of future arrhythmias. Given the limitations of the existing data, well-designed and well-conducted studies are needed., (© 2015 by the American College of Cardiology Foundation, the American Heart Association, Inc., and the Heart Rhythm Society.)

Background: 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., Methods: 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., Results: 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., Conclusion: 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., (©2015 Wiley Periodicals, Inc.)

Purpose: The aim of this study was to investigate the accuracy of three algorithms in predicting accessory pathway locations in adult patients with Wolff-Parkinson-White syndrome in Turkish population., Methods: A total of 207 adult patients with Wolff-Parkinson-White syndrome were retrospectively analyzed. The most preexcited 12-lead electrocardiogram in sinus rhythm was used for analysis. Two investigators blinded to the patient data used three algorithms for prediction of accessory pathway location., Results: Among all locations, 48.5% were left-sided, 44% were right-sided, and 7.5% were located in the midseptum or anteroseptum. When only exact locations were accepted as match, predictive accuracy for Chiang was 71.5%, 72.4% for d'Avila, and 71.5% for Arruda. The percentage of predictive accuracy of all algorithms did not differ between the algorithms (p = 1.000; p = 0.875; p = 0.885, respectively). The best algorithm for prediction of right-sided, left-sided, and anteroseptal and midseptal accessory pathways was Arruda (p < 0.001). Arruda was significantly better than d'Avila in predicting adjacent sites (p = 0.035) and the percent of the contralateral site prediction was higher with d'Avila than Arruda (p = 0.013)., Conclusions: All algorithms were similar in predicting accessory pathway location and the predicted accuracy was lower than previously reported by their authors. However, according to the accessory pathway site, the algorithm designed by Arruda et al. showed better predictions than the other algorithms and using this algorithm may provide advantages before a planned ablation.

Important advances in the diagnosis and therapy of various arrhythmic disorders have been made in the last two decades. These, in turn, have necessitated a re-examination of current practice guidelines, with a view to deciding on optimal management of young patients with suspected or proven arrhythmia syndromes and in assessing the risk of adverse arrhythmic events during sport participation. There has also been a concomitant emphasis on identifying individuals at risk by nationwide screening programs using the ECG and excluding them from competitive sport. This review identifies some of these issues, looks at the data critically and offers some suggestions for current care and future research.

Unlabelled: The aim of study was to report different and unusual patterns of preexcitation syndrome (PS) noted in patients referred for studied for poorly-tolerated arrhythmias and their frequency. Electrophysiologic study (EPS) is an easy means to identify a patient with PS at risk of serious events. However the main basis for this diagnosis is the ECG which associates short PR interval and widening of QRS complex with a delta wave., Methods: ECGs of 861 patients in whom PS related to an atrioventricular accessory pathway (AP) was identified at electrophysiological study (EPS), were studied., Results: The most frequent unusual presentation (9.6%) was the PS presenting with a normal or near normal ECG, noted preferentially for left lateral AP and rarely for posteroseptal or right lateral location. More exceptional (0.1%) was the presence of a long PR interval, which did not exclude a rapid conduction over AP. The association of a complete AV block with symptomatic tachycardias was exceptional (0.3%) and was shown related to a rapid conduction over AP after isoproterenol. Most of the presented patients were at high-risk at EPS., Conclusion: The diagnosis of PS is not always evident and symptoms should draw attention to minor abnormalities and lead to enlarge indications of EPS, only means to confirm or not PS., (Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.)

Background: In school-based cardiovascular screening programs in Japan, Wolff-Parkinson-White (WPW) syndrome is diagnosed based on the presence of an electrocardiographic (ECG) delta wave without differentiation from the fasciculoventricular pathway (FVP), although the risk of sudden death is associated only with the former., Objective: The purpose of this study was to differentiate FVP patients among children diagnosed with WPW syndrome by ECG., Methods: Children who were diagnosed with WPW syndrome through school screening between April 2006 and March 2008 and had QRS width ≤120 ms were included. Patients with asthma and/or coronary heart disease were excluded. FVP and WPW syndrome were differentiated based on ECG responses to adenosine triphosphate (ATP) injection. Age, PR interval, QRS width, and Rosenbaum classification were compared among patients., Results: Thirty patients (median age 12.7 years, range 6.5-15.7 years) participated in the study. FVP was diagnosed in 23 patients (76.7%), and WPW syndrome in 7 (23.3%). In Rosenbaum type A patients, all six patients had WPW syndrome, whereas FVP was diagnosed in 23 of 24 and WPW syndrome was diagnosed in 1 of 24 of type B patients. Age, PR interval, and QRS width were not significantly different between the two conditions., Conclusion: ATP stress test was reliable in differentiating FVP from WPW syndrome. Although FVP is considered rare, the results of our study indicate that many WPW syndrome patients with QRS width ≤120 ms may actually have FVP. Patients categorized as type B are more likely to have FVP, whereas type A patients are most likely to have WPW syndrome., (© 2013 Heart Rhythm Society Published by Heart Rhythm Society All rights reserved.)

Background: Data on the results and clinical effect of an invasive risk stratification strategy in asymptomatic young patients with the Wolff-Parkinson-White electrocardiographic pattern are scarce., Methods and Results: Eighty-five consecutive patients aged<18 years with a Wolff-Parkinson-White pattern and persistent preexcitation at maximum exercise undergoing invasive risk stratification were retrospectively studied. Adverse accessory pathway (AP) properties were defined according to currently consented criteria as any of the following: shortest preexcited RR interval during atrial fibrillation/rapid atrial pacing≤250 ms (or antegrade effective refractory period≤250 ms if shortest preexcited RR interval was not available) or inducible atrioventricular re-entrant tachycardia. Age at evaluation was median 14.9 years. Eighty-two patients had a structurally normal heart and 3 had hypertrophic cardiomyopathy. A single manifest AP was present in 80, 1 manifest and 1 concealed AP in 4, and 2 manifest APs in 1 patient. Adverse AP properties were present in 32 of 85 patients (37.6%) at baseline and in additional 16 of 44 (36.4%) after isoproterenol. Ablation was performed in 41 of these 48 patients. Ablation was deferred in the remaining 7 for pathway proximity to the atrioventricular node. In addition, 18 of the low-risk patients were ablated based on patient/parental decision., Conclusions: Adverse AP properties at baseline were exhibited by 37.6% of the evaluated patients with an asymptomatic Wolff-Parkinson-White preexcitation persisting at peak exercise. Isoproterenol challenge yielded additional 36.4% of those tested at higher risk. Ablation was performed in a total of 69.4% of patients subjected to invasive risk stratification.

Unlabelled: We have studied the results of electrophysiological study (EPS) in patients with Wolff-Parkinson-White syndrome (WPW) and spontaneous adverse clinical presentation and determined whether isoproterenol added incremental value., Methods: EPS was performed in 63 patients with WPW and adverse clinical presentation at baseline. EPS was repeated after infusion of isoproterenol in 37 patients, including 25 without criteria for a malignant form at baseline., Results: Atrioventricular orthodromic tachycardia was induced 44%, antidromic tachycardia in 11%, atrial fibrillation (AF) in 68% at baseline. At baseline EPS, criteria for a malignant form (AF induction and shortest CL <250 ms) were noted in 60%; tachycardia was not inducible in 16%. All the patients met the criteria for a malignant form after isoproterenol., Conclusions: EPS at baseline missed 16% of patients at risk of life-threatening arrhythmias who had no inducible tachyarrhythmia and 40% without classical criteria for malignant form., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Aims: Orthodromic atrioventricular reentrant tachycardia (ORT) is the most common arrhythmia at electrophysiological study (EPS) in patients with pre-excitation. The purpose of the study was to determine the clinical significance and the electrophysiological characteristics of patients with inducible antidromic tachycardia (ADT)., Methods and Results: Electrophysiological study was performed in 807 patients with a pre-excitation syndrome in control state and after isoproterenol. Antidromic tachycardia was induced in 63 patients (8%). Clinical and electrophysiological data were compared with those of 744 patients without ADT. Patients with and without ADT were similar in term of age (33 ± 18 vs. 34 ± 17), male gender (68 vs. 61%), clinical presentation with spontaneous atrioventricular reentrant tachycardia (AVRT) (35 vs. 42%), atrial fibrillation (AF) (3 vs. 3%), syncope (16 vs. 12%). In patients with induced ADT, asymptomatic patients were less frequent (24 vs. 37%; <0.04), spontaneous ADT and spontaneous malignant form more frequent (8 vs. 0.5%; <0.001) (16 vs. 6%; <0.002). Left lateral accessory pathway (AP) location was more frequent (51 vs. 36%; P < 0.022), septal location less frequent (40 vs. 56%; P < 0.01). And 1/1 conduction through AP was more rapid. Orthodromic AVRT induction was as frequent (55.5 vs. 55%), but AF induction (41 vs. 24%; P < 0.002) and electrophysiological malignant form were more frequent (22 vs. 12%; P < 0.02). The follow-up was similar; four deaths and three spontaneous malignant forms occurred in patients without ADT. When population was divided based on age (<20/≥20 years), the older group was less likely to have criteria for malignant form., Conclusion: Antidromic tachycardia induction is rare in pre-excitation syndrome and generally is associated with spontaneous or electrophysiological malignant form, but clinical outcome does not differ.