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Altered ventricular depolarization due to manifest accessory pathway conduction (ie, Wolff-Parkinson-White syndrome) leads to repolarization abnormalities that persist after pathway ablation. The term T-wave memory (TWM) has been applied to these changes, as the postablation T-wave vector "remembers" the pre-excited QRS vector. In adults, these abnormalities can be misinterpreted as ischemia leading to unnecessary interventions. To date, no comprehensive studies have evaluated this phenomenon in the pediatric population.The purpose of this study was to define TWM in the pediatric population, identify preablation risk factors, and delineate the timeline of recovery.Pre- and postablation electrocardiograms (ECGs) in patients ≤25 years were analyzed over a 5-year period. Frontal plane QTc interval, T-wave axis, QRST angle, and T-wave inversions were used to identify patients with TWM. Univariate analysis was performed to determine the association of preablation ECG features with the outcome of TWM.TWM was present in 42% of pediatric patients, with resolution occurring within 3 months of ablation. Preablation QRS axis0° was a strong predictor of TWM (odds ratio [OR] 15.2; 95% confidence interval [CI] 5.7-40), followed by posteroseptal pathway location (right posteroseptal-OR 8.9; 95% CI 4.2-18.8; left posteroseptal-OR 6.1; 95% CI 1.7-22.3). The degree of pre-excitation had a modest association with the development of TWM. No adverse events were observed.TWM is less common in children compared to adults, and normalization occurred within 3 months postablation. The most predictive features for the development of TWM include a leftward pre-excited QRS axis and posteroseptal pathway location.

Background: In contrast to adults, in whom cardiac rhythm disorders are mainly conditioned by coronary artery disease, in children, arrhythmias are most often associated with inherited heart disorders. Catheter ablation (CA) has an important role in the management of cardiac arrhythmias, in adults and children. The aim of the study was to assess and compare the efficacy and safety of CA in children and adults with preexcitation syndrome. Methods: The study population comprised 43 adults and 43 children diagnosed with a Wolff-Parkinson-White syndrome (WPW). The mean age of the study population was 41 ± 15 years for adults and 14 ± 2.5 years for children. In all patients, an electrophysiological study and CA were performed. Analysis with respect to the procedure duration, fluoroscopy exposure time, location of accessory pathways (AP), immediate success rate and complications were performed. Results: Electrophysiological study revealed the most frequent presence of left-sided AP (56% in children and 70% in adults). The mean procedure duration was 96 ± 36 min and 106 ± 51 min in children and adults, respectively (p = NS). The mean fluoroscopy duration was 8.5 ± 4.3 min and 5.9 ± 5.8 min in children and adults, respectively p < 0.05. The CA procedure was successful in 40 out of 43 (93%) adults and in 36 out of 43 (83.7%) children (p = NS). In 2 (4%) children minor complications occurred. Conclusions: Ablation in children and adults are equally effective with respect to short-term clinical observation.

Background: Predicting an accessory pathway location is extremely important in pediatric patients. Aims: We designed a study to compare previously published algorithms by Arruda, Boersma, and Chiang. Methods: This multicenter study included patients who had undergone successful ablation of one accessory pathway. Analysis of resting 12-lead electrocardiograms was carried out. An aggregated prediction score was constructed on the basis of algorithm agreement, and a structured workflow approach was proposed. Results: The total population was 120 patients (mean age, 12.7 [± 3.6] years). The algorithm by Boersma had the highest accuracy (71.7%). The inter-rater agreement among the 3 reference algorithms, according to left-sided accessory pathway (AP) identification, was good between Boersma and Chiang (κ = 0.611; 95% confidence interval [CI], 0.468–0.753) but moderate between Arruda and Chiang and between Arruda and Boersma (κ = 0.566; 95% CI, 0.419–0.713 and κ = 0.582; 95% CI, 0.438–0.727, respectively). Regarding locations at risk of atrioventricular (AV) block, agreement was fair between Arruda and Chiang and between Boersma and Chiang (κ = 0.358; 95% CI, 0.195–0.520 and κ = 0.307; 95% CI, 0.192–0.422, respectively) but moderate between Arruda and Boersma (κ = 0.45; 95% CI, 0.304–0.597). On applying a first-step diagnostic evaluation, when concordance was achieved, we were able to correctly identify left-sided or non-left-sided ablation sites in 96.4% (n = 80) of cases. When concordance was achieved, correct prediction of risk/no risk of AV block was achieved in 92.2% (n = 59) of cases. Conclusions: An aggregated prediction score based on 3 reference algorithms proved able to predict an accessory pathway location very precisely and could be used to plan safely invasive procedures.

PURPOSE The correct estimation of accessory pathway (AP) localization from surface ECG is critical before the procedure. Our study aimed to detect the predictive value of the V1r + DIIq criterion for differentiating right- from left-sided paraseptal APs. METHODS We retrospectively included 58 patients with (Wolff-Parkinson-White) WPW syndrome and paraseptal APs who underwent successful catheter ablation (37 male, 21 female; mean age 34.4 ± 13.6 years). The V1r + DIIq criterion was calculated using the following formula: V1r + DIIq (mV) = initial r wave amplitude in V1 + q wave amplitude in DII. The combined criterion included V1r + DIIq

An 84-year-old woman with type B WPW with Ebstein anomaly was admitted with heart failure. She had rapid wide QRS tachcardia due to accessory pathway (AP) conduction associated with atrial fibrillation (AF). Since transesophageal echocardiography before catheter ablation showed a left atrial thrombus, ablation was performed using a 3D mapping system under AF. After marking the functional tricuspid anulus with intra-cardiac echocardiography, 3D intra-cardiac electrogram visualisation (ripple map) during AF enabled clear identification of location of the AP. After ablation, there was no complication of cerebral infarction, and the heart failure improved. This article is protected by copyright. All rights reserved.

Data is scarce regarding epicardial ablation in children. I herewith present a case of successful epicardial ablation in a child with previous unsuccessful attempts at endocardial ablation. This report could be used to guide further such attempts.

The optimal screening strategy to prevent sudden cardiac death (SCD) in athletes remains unknown. Pre-participation screening with electrocardiogram (ECG) remains controversial. The utility and accuracy of limb-lead (LL) ECG alone in identifying cardiac abnormalities associated with SCD has not been studied. This study was a comparative secondary data analysis, comparing the interpretation accuracy of 4 physicians evaluating publicly available ECGs of the most common cardiac conditions associated with SCD in athletes. Each physician interpreted a total of 100 ECGs: 50 normal ECGs (25 LL and 25 standard 12L) and 50 abnormal ECGs (25 LL and 25 standard 12L). The agreement between LL ECGs and 12L ECGs was assessed by Cohen's kappa coefficient and the accuracy of identifying an abnormal ECG was compared across LL and 12L ECGs using a chi-squared test. Inter-rater reliability was assessed by estimating the Fleiss's kappa coefficient. The sensitivity of LL ECG and 12L ECG was identical at 86%. The specificity of LL ECG was 75% (95% CI = 65% to 83%) and 12L ECG was 82% (95% CI = 73% to 89%). Substantial agreement was seen between LL ECG and 12L ECG interpretation across all readers (k = 0.63; 95% CI = 0.49 to 0.77). Interpretation accuracy was 81% (95% CI = 74% to 86%) and 84% (95% CI 78% to 89%) using LL ECG and 12L ECG, respectively (p = 0.43). In conclusion, the accuracy, sensitivity, and specificity were high and comparable for both LL ECG and 12L ECG in identifying cardiovascular conditions associated with SCD. Agreement between LL ECG and 12L ECG was substantial.

Background Wolff‐Parkinson‐White (WPW) syndrome is characterized by an anomalous accessory pathway (AP) that connects the atrium and ventricles, which can cause abnormal myocardial excitation and cardiac arrhythmias. The morphological and electrophysiological details of the AP remain unclear. The size and conductivity of the AP may affect conduction and WPW syndrome symptoms. Methods To clarify this issue, we performed computer simulations of antegrade AP conduction using a simplified wall model. We focused on the bundle size of the AP and myocardial electrical conductivity during antegrade conduction (from the atrium to the ventricle). Results We found that a thick AP and high ventricular conductivity promoted antegrade conduction, whereas a thin AP is unable to deliver the transmembrane current required for electric conduction. High ventricular conductivity amplifies transmembrane current. These findings suggest the involvement of a source‐sink mechanism. Furthermore, we found that high AP conductivity blocked antegrade conduction. As AP conductivity increased, sustained outward transmembrane currents were observed. This finding suggests the involvement of an electrotonic effect. Conclusions The findings of our theoretical simulation suggest that AP size, ventricular conductivity, and AP conductivity affect antegrade conduction through different mechanisms. Our findings provide new insights into the morphological and electrophysiological details of the AP., We performed computer simulations of antegrade accessory pathway (AP) conduction using a simplied wall model. We found that high AP conductivity blocked antegrade conduction. This finding suggests the involvement of an electrotonic effect.

Background This is a rare and challenging case of Wolff–Parkinson–White syndrome due to a posteroseptal accessory pathway located in the coronary sinus diverticulum. It is often difficult to precisely locate this type of accessory pathway, and the ablation procedure could be associated with collateral damage to the neighbouring coronary arteries. Case Presentation The patient was a 49-year-old female with Wolff–Parkinson–White syndrome who was referred for catheter ablation. She had had a previous unsuccessful attempt at ablation and had remained symptomatic despite drug therapy. The pre-procedural cardiac computed tomography scan revealed the presence of a diverticulum in the proximal coronary sinus. Using an advanced three-dimensional cardiac mapping system, the electroanatomic map of the diverticulum was created. The accessory pathway potential was identified within the diverticulum preceding the ventricular insertion. The accessory pathway was then successfully ablated using radiofrequency energy. Conclusion We have demonstrated that the advanced three-dimensional cardiac mapping system plays a very important role in guiding clinicians in order to precisely locate and safely ablate this type of challenging accessory pathway.

Ultra‐high‐resolution mapping is useful in the ablation of accessory pathways. However, in patients with accessory pathways in the coronary sinus (CS) diverticulum, treatment with endocardial ablation may be challenging. Patients suspected of having subepicardial accessory pathways may require the examination of the venous anomaly using CS angiography.

Aims Catheter ablation is recommended for symptomatic WPW-syndrome. Commonly perceived low recurrence rates were challenged recently. We sought to identify patient strata at increased risk. Method Of 12,566 patients enrolled at 52 German Ablation Registry sites from 2007 to 2010, 789 were treated for WPW-syndrome. Patients were included for symptomatic palpitations and tachycardia documentation. Follow-up duration was one year. Overall complications were defined as serious, access-related, and ablation-related. We adjudicated WPW-recurrence for re-ablation during follow-up. Risk strata included: admission for repeat ablation at registry entry; accessory pathway localization; antiarrhythmic medical treatment before the ablation. Results WPW-syndrome patients were 42.8 ± 16.2 years on average; 39.9% were women. A majority of 95.9% was symptomatic; in 84.4%, a tachycardia was documented. Seventy-six (9.6%) patients presented for repeat procedures. Accessory pathways were located in the left atrium (71.4%), right atrium (21.1%), septum (4.4%), or coronary sinus diverticula (2.1%). Prior antiarrhythmic medication was used in 43.7% of patients. No serious events occurred. The overall complication rate was 2.5% (ablation related 1.2%, access-related 1.3%). Major determinants for complications were presentation for re-ablation as registry index procedure (6.9% vs 2.2%; p = 0.016) and septal pathway location (left 2.0% vs septal 9.1%, p = 0.014). The overall re-ablation rate was 9.7%. Usage of prior antiarrhythmic medication was associated with higher recurrence rates (12.2% vs. 7.6%; p = 0.035). Conclusions Patients at higher complication risk may be identified by repeat procedure and septal pathway location. Prior antiarrhythmic medication was associated with higher recurrence rates. Our findings may help improving peri-procedural patient management and information.

Background It was reported that intravenous amiodarone might induce ventricular fibrillation for acute treatment in patients with atrial fibrillation (AF) and Wolff-Parkinson-White (WPW) syndrome. No study was done to assess its application comprehensively in this population. Methods This study was a retrospective analysis and undertaken by reviewing medical records and electronic databases to search for patients admitted with tachycardia resulting from WPW syndrome and AF, who have intravenously administrated amiodarone at the emergency department from January 2008 to June 2018. Results Thirty patients were involved in this study, of which 27 were males. The mean age of the patients was 47.8 ± 17.0 years. The mean systolic blood pressure and diastolic blood pressure were 111.9 ± 18.3 mmHg and 76.1 ± 14.6 mmHg, respectively. The mean heart rate was 171 (150-189) beats per minute. Half of the patients (53.3%) had no comorbidities, and only one had prior syncope. Nearly 17 patients (56.7%) started with a loading dose of 150 mg. No ventricular acceleration or VF developed. The incidence of hypotension was 3.3% (1/30). Eighteen patients (60.0%) restored to sinus rhythm by amiodarone with the conversion time of 486.0 (229.0-1278.0) minutes. Conclusions Intravenous amiodarone might be an alternative for acute treatment of AF and WPW syndrome in patients characterized by stable hemodynamics, relatively low admission heart rate, few comorbidities, elder age, and no prior syncope. The loading dosage of 150 mg appeared to be preferred, and the maintenance period was better to less than 12 hours. Monitoring and electrolyte correction were also necessary. It is essential to keep a defibrillator nearby during pharmacologic cardioversion.

Patients with the Wolff-Parkinson-White syndrome may experience benign and malignant arrhythmias, the most common being atrioventricular reentrant tachycardias. This arrhythmia may degenerate into atrial fibrillation, which can be conducted over an accessory pathway capable of exceptionally fast conduction to the ventricles and degenerate into ventricular fibrillation, leading to sudden cardiac death. These life-threatening events generally affect symptomatic patients in their third or fourth decade. Although rare, ventricular fibrillation may be the first clinical manifestation in subjects who are asymptomatic or unaware of their conditions. Electrophysiologic study may be useful to identify subjects at high risk of sudden cardiac death.

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 V1 and QRS shape in lead I for left/right discrimination, and (2) delta wave polarity in V1, 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 V1 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.

An 81-year-old woman was admitted to the emergency department for collapse. She has no known medical history. The clinical examination shows a heart rate oscillating between 160 and 180, a BP at 78/55 mm Hg, a GCS at 14 (E : 4, V : 4, M : 6), an oxygen saturation at 89%. She has cyanosis going from the feet to the knees. An ECG was done (see figure 1). Figure 1 ECG at the emergency department. What is your diagnosis ? 1. Ventricular tachycardia. 2. Ventricular fibrillation. 3. Wolff-Parkinson-White. …

The Holter electrocardiogram from an asymptomatic man shows intermittent preexcitation. At the lowest rates all the QRS complexes display a WPW pattern. As the rate increases, preexcitation fails to occur and all the QRS complexes become persistently narrow. With a further increase in sinus rate the WPW occurs on alternate beats and this alternation is maintained for a while. A careful analysis of the accessory pathway conduction in relation to sinus-cycle length and morphology of the prior beat strongly supports the supernormal conduction through the Kent bundle associated with linking as the key mechanism underlying the preexcitation on alternate beats.

A 56‐year‐old female with manifest Wolff‐Parkinson‐White (WPW) syndrome was sent to emergency room because of preexcited atrial fibrillation (AF) and became sinus rhythm after cardioversion. Then, she received catheter ablation of a left‐sided lateral accessory pathway. The patient immediately developed Wenckebach atrioventricular (AV) block and left bundle branch block (LBBB) during the initial ablation. The ECG still showed LBBB 1 hour after ablation. The LBBB became narrow QRS (The QRS complex in the electrocardiogram. The QRS complex includes the Q wave, R wave, and S wave) 1 day later. Two weeks later, Holter's ECG showed normal sinus rhythm with 1:1 AV conduction even at the maximum heart rate of 125 beats/min. Transient LBBB and poor AV nodal conduction could occur during ablation by the trans‐aortic approach., A 56‐year‐old female with manifest Wolff‐Parkinson‐White (WPW) syndrome was sent to emergency room because of atrial fibrillation with rapid wide QRS tachycardia and became sinus rhythm after cardioversion. After she received catheter ablation of a left‐sided lateral accessory pathway for 1 hour, the ECG showed LBBB, and the LBBB became narrow QRS 1 day later. Eliminating the accessory pathway could recover the AV nodal and His‐Purkinje conduction.

Background Although successful ablation of the accessory pathway (AP) eliminates atrial fibrillation (AF) in some of patients with Wolff‐Parkinson‐White (WPW) syndrome and paroxysmal AF, in other patients it can recur. Hypothesis Whether adding pulmonary vein isolation (PVI) after successful AP ablation effectively prevents AF recurrence in patients with WPW syndrome is unknown. Methods We retrospectively studied 160 patients (102 men, 58 women; mean age, 46 ± 14 years) with WPW syndrome and paroxysmal AF who underwent AP ablation, namely 103 (64.4%) undergoing only AP ablation (AP group) and 57 (35.6%) undergoing AP ablation plus PVI (AP + PVI group). Advanced interatrial block (IAB) was defined as a P‐wave duration of >120 ms and biphasic (±) morphology in the inferior leads, using 12‐lead electrocardiography (ECG). Results During the mean follow‐up period of 30.9 ± 9.2 months (range, 3‐36 months), 22 patients (13.8%) developed AF recurrence. The recurrence rate did not differ in patients in the AP + PVI group and AP group (15.5% vs 10.5%, respectively; P = .373). Univariable and multivariable Cox regression analyses showed that PVI was not associated with the risk of AF recurrence (hazard ratio, 0.66; 95% confidence interval, 0.26‐1.68; P = .380). In WPW patients with advanced IAB, the recurrence rate was lower in patients in the AP + PVI group vs the AP group (90% vs 33.3%, respectively; P = .032). Conclusions PVI after successful AP ablation significantly reduced the AF recurrence rate in WPW patients with advanced IAB. Screening of a resting 12‐lead ECG immediately after AP ablation helps identify patients in whom PVI is beneficial.

Danondisease is a rare genetic disorder with an X-linked dominant inheritance affecting both skeletal and cardiac muscle. Its characteristic cardiac phenotype consists on a severe, non-obstructive and concentric hypertrophic cardiomyopathy (HCM) usually associated with a Wolff-Parkinson-White (WPW) type preexcitation pattern. Whether this corresponds to the presence of an AV or another type of accessory pathways, such as fasciculoventricular pathways (FVP) remains controversial in the literature. However, we describe the case of a teenager with Danon disease and preexcitation who develops a first degree AV block without any change in his QRS morphology, fact that favors the hypothesis of the presence of a FVP. This finding has important clinical implications in the management and prognosis of these complex patients. The absence of an AV accessory pathway decreases their risk of potential SCD in the context of a fast atrial arrhythmia and their chances of having a reentrant AV tachycardia.

Background: Significant left ventricular dysfunction may arise in right-sided accessory pathways with ventricular preexcitation in the absence of recurrent or incessant tachycardia. This has just been realized and not enough attention has been paid to it. Methods: In the last 7 years, we identified 12 consecutive children with a diagnosis of ventricular preexcitation–induced dilated cardiomyopathy. This report describes the clinical and echocardiographic characteristics of the patients before and after ablation. Results: Dyssynchronous ventricular contraction was observed by M-mode echocardiography and two-dimensional strain analysis in all patients. The basal and middle segments of the interventricular septum became thin and moved similarly to an aneurysm, with typical bulging during the end of systole. The locations of the accessory pathways were the right-sided septum (n=5) and the free wall (n=7). Left ventricular synchrony was obtained shortly after ablation. The left ventricular function recovered to normal and the left ventricular end-diastolic diameter decreased gradually during follow-up. Conclusions: A causal relationship between ventricular preexcitation and the development of dilated cardiomyopathy is supported by the complete recovery of left ventricular function and reversed left ventricular remodeling after the loss of ventricular preexcitation. Preexcitation-related dyssynchrony was thought to be the crucial mechanism. Ventricular preexcitation–induced dilated cardiomyopathy is an indication for ablation with a good prognosis.

Three-dimensional transthoracic echocardiography (3DE)-derived heart models have not previously been utilized to guide catheter ablation. In this case report, we describe the creation of a 3DE model from transthoracic echocardiography, import of the model into CARTO3, and successful use of the model as a guide during mapping and ablation of a right lateral accessory pathway. We believe this technique represents a valuable alternative to the integration of computed tomography or magnetic resonance imaging-derived anatomic data, and that it has the potential to improve the definition of the atrioventricular valve annuli during catheter ablation of accessory pathways.

Accessory pathway (AP) mapping is currently based on point-by-point mapping and identifying if a local electrogram’s origin is atrial, pathway, or ventricular, which is time-consuming and prone to insufficient mapping. We sought to determine the feasibility of automated and high-density mapping to define AP location using open-window mapping (OWM), which does not rely on defining the electrogram’s origin but simply detects the sharpest local signal at each point. We enrolled 23 consecutive patients undergoing catheter ablation for atrioventricular reentrant tachycardia. High-density mapping was performed using OWM and ablation was performed. The successful site of ablation was determined by the loss of pathway function. OWM was 100% effective at identifying the successful site of ablation (average mapping time 7.3 ± 4.3 min.) Permanent AP elimination was achieved using a mean radiofrequency energy time of 18.5 ± 24.5 s/patient. Transiently successful ablations were 4.0 ± 1.8 mm from permanently successful sites and had lower contact force (5.1 ± 2.5 g vs. 11.7 ± 9.0 g; P = 0.041). Unsuccessful sites had similar contact force to permanently successful sites (12.2 ± 9.2 g vs. 11.7 ± 9.0 g; P = 0.856) but were 6.4 ± 2.0 mm away from successful sites. A novel technique of high-density, automated, and open-window mapping (OWM) effectively localizes APs without the need to differentiate the signal’s site of origin. These findings suggest that OWM can be used to rapidly and successfully map and ablate APs. Both distances from the pathway and contact force were shown to be important for pathway ablation.

Radiofrequency catheter ablation (RFCA) procedure is performed for many tachyarrhythmias. We performed successful RFCA in a 5-year-old child for supraventricular tachyarrhythmia and Wolff-Parkinson-White syndrome. Acute circumflex artery (CxA) occlusion occurred due to RFCA. After percutaneous balloon angioplasty was performed into the CxA, the patient was treated with systemic steroid to resolve myocardial edema. To the best of our knowledge, systemic steroid was used first time for acute coronary artery injury related myocardial ischemia.

Background Flecainide is a class Ic antidysrhythmic agent used to prevent and treat both ventricular and supraventricular tachycardias, including atrial fibrillation, atrioventricular nodal re-entrant tachycardia, and Wolff-Parkinson-White syndrome. Flecainide can cause serious side effects, including cardiac arrest, dysrhythmias, and heart failure. Despite its growing use, the presenting signs and symptoms of flecainide toxicity are not familiar to most clinicians. In particular, our patient's particular presentation of acute kidney injury (AKI) resulting in flecainide accumulation is high risk for missed diagnosis in the emergency department. Case Report A 58-year-old woman presented with altered mental status and hypoxia that was later found to be secondary to sepsis. Medical history was notable for atrial fibrillation, for which she was on flecainide. Laboratory results were notable for hypokalemia and an AKI. Her wide complex tachycardia on admission was ultimately attributed to flecainide toxicity in the setting of AKI. Six days after presentation, it was found that her flecainide level was in the toxic range at 2.02 μg/mL (normal range 0.20–1.00 μg/mL, toxic >1.50 μg/mL). Why Should an Emergency Physician Be Aware of This? Flecainide intoxication is rare but serious due to the potential for cardiogenic shock. Its diagnosis can be difficult, as the flecainide serum level may take days to result. This case demonstrates the necessity of keeping flecainide toxicity on the physician's differential for patients who are taking the drug, as well as what electrocardiogram findings suggest it as the etiology. Treatment can be lifesaving if initiated promptly.

ECG of patients with Wolf Parkinson White (WPW) syndrome may simulate other entities such as myocardial infarction, ventricular premature complexes, ventricular bigeminy, accelerated idioventricular rhythm, intermittent bundle branch block or electrical alternans. On the other hand, the opposite can also occur where these other conditions may simulate WPW. We present the case of a young patient referred for WPW ablation showing an incessant accelerated idioventricular rhythm mimicking preexcitation.

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.

Background: Several electrocardiographic (ECG) algorithms have been developed for predicting accessory pathway (AP) location in Wolff–Parkinson–White syndrome. However, their accuracy may be related to the manifested degree of preexcitation on ECG. Aims: Our goal was to assess the effect of the degree of preexcitation on the accuracy of 4 traditional AP localization algorithms and to compare them with the algorithm specifically designed for ECGs with maximal preexcitation (Pambrun) Methods: The study included 300 patients who underwent successful ablation of an overt atrioventricular AP. Resting and maximally preexcited ECGs obtained during incremental atrial pacing were assessed using 4 traditional AP localization algorithms: Xie, d’Avila, Iturralde, and Taguchi. Maximally preexcited ECGs were additionally assessed with the Pambrun algorithm. We compared the precision of the algorithms to predict accurate or anatomically adjacent AP location. Results: Theoverall accuracy of traditional AP localization algorithms using resting ECG ranged between 26% and 53.7% and improved to a range of 47.3% to 69.7% when adjacent locations were accepted. When used with maximal preexcitation, all algorithms had significantly higher accuracy, with a mean improvement of 14.3 and 15.6 percentage points for precise and adjacent sites, respectively. The Pambrun algorithm for maximally preexcited ECGs had the highest precision for both accurate and adjacent locations of the APs (89.7% and 97%, respectively). Conclusions: Greater preexcitation on ECG improved the accuracy of the traditional AP localization algorithms. The algorithm designed to use maximally preexcited ECGs has the best accuracy. Maximally preexcited ECG recordings should preferably be used in clinical practice to facilitate the ablation procedure.

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 ≤ 18 years, 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 (265 ms ± 61 ms), 4 SPERRIIsuprel (258 ms ± 41 ms)). At baseline, the lower value of the S3ERP or S4ERP (274 ms ± 52 ms) was lower than the SPPCL (296 ms ± 54 ms, p

Background To investigate the relationship between the location of accessory pathways, electrophysiologic characteristics, and ablation success in Wolfe-Parkinson-White (WPW) syndrome. Methods Electrophysiologic study was performed in 178 patients for a pre-excitation syndrome. Accessory pathway location, anterograde or retrograde conduction, ablation success, and recurrence rate were evaluated. Results Among 178 patients with WPW syndrome, the most frequent location of the accessory pathway was left lateral (39.3%) which had high ablation success rate (97%) and low recurrence rate (1%). A meaningful relationship exists between accessory pathway location and electrophysiologic characteristics. Ablation success rate was 89.7% and was statistically related to accessory pathway location. Recurrent occurred in 2.9% of our patients and was more frequent in right free wall and PJRT. Conclusions The location of accessory pathways has a great impact on conductivity, ablation success, and recurrence rate in WPW syndrome.

A 50-year-old man presented with general fatigue on exertion. Investigations revealed tachycardia-induced cardiomyopathy induced by Wolff-Parkinson-White syndrome and atrial fibrillation. He was successfully treated with catheter ablation. Cardiac magnetic resonance imaging revealed that delayed enhancement throughout the left ventricle disappeared within 2 months after ablation. (Level of Difficulty: Beginner.), Graphical abstract, A 50-year-old man presented with general fatigue on exertion. Investigations revealed tachycardia-induced cardiomyopathy caused by Wolff-Parkinson-White…

BACKGROUND: Wolff-Parkinson-White (WPW) syndrome is a relatively common arrhythmia affecting ~1-3/1000 individuals. Mutations in PRKAG2 have been described in rare patients in association with cardiomyopathy. However, the genetic basis of WPW in individuals with a structurally normal heart remains poorly understood. Sudden death due to atrial fibrillation (AF) can also occur in these individuals. Several studies have indicated that despite ablation of an accessory pathway, the risk of AF remains high in patients compared to general population. METHODS: We applied exome sequencing in 305 subjects, including 65 trios, 80 singletons, and 6 multiple affected families. We used de novo analysis, candidate gene approach, and burden testing to explore the genetic contributions to WPW. RESULTS: A heterozygous deleterious variant in PRKAG2 was identified in one subject, accounting for 0.6% (1/151) of the genetic basis of WPW in this study. Another individual with WPW and left ventricular hypertrophy carried a known pathogenic variant in MYH7. We found rare de novo variants in genes associated with arrhythmia and cardiomyopathy (ANK2, NEBL, PITX2, and PRDM16) in this cohort. There was an increased burden of rare deleterious variants (MAF

Background Both atrial fibrillation (AF) and early repolarization (ER) are highly prevalent in patients with Wolff–Parkinson–White (WPW) syndrome. Methods We retrospectively identified 123 WPW patients with manifest accessory pathway (mAP) and 105 patients with concealed accessory pathways (cAP) who underwent successful ablation of the APs. AF history prior to the ablation was investigated. The presence of ER was evaluated from the 12-lead electrocardiograms performed both before and immediately after the ablation. Patients were further followed up for AF occurrence after the AP ablation. Results Compared with cAP patients, WPW patients presented with higher incidence of previous AF, as well as ER after the AP ablation. Compared with those without AF history, WPW patients with comorbid AF were more prone to presenting ER, especially in the inferior leads, after the mAP ablation. Regression analysis suggested that the post-ablation ER in the inferior leads was strongly associated with AF in WPW patients [OR = 5.85; 95% confidence interval (CI): 2.29–14.96], even after adjusting for age and left atrial diameter (OR = 5.14; 95% CI: 1.80–14.74). Moreover, post-ablation inferior-lead ER was predictive of AF recurrence after mAP ablation during the follow-up of 22.6 ± 11.1 months. In comparison, ER was correlated with neither AF history nor AF recurrence in patients undergoing cAP ablation. Conclusions ER in the inferior leads after the mAP ablation is highly correlated with AF history and recurrence in WPW patients.

Background 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). Objective 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). Methods 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). Results 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 .1). Mean EP-SPERRI, APERP, and SPPCL all were greater than Clinical-SPERRI. Conclusion 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).

Objective: 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. Methods: 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. Results: 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. Conclusion: 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.

Wolff-Parkinson-White (WPW) has been associated with left ventricular noncompaction (LVNC) in children. Little is known about the prevalence of this association, clinical outcomes, and treatment options.Retrospective review of subjects with LVNC. LVNC was defined by established criteria; those with congenital heart disease were excluded. Electrocardiograms (ECGs) were reviewed for presence of pre-excitation. Outcomes were compared between those with isolated LVNC and those with WPW and LVNC.A total of 348 patients with LVNC were identified. Thirty-eight (11%) were found to have WPW pattern on ECG, and 84% of those with WPW and LVNC had cardiac dysfunction. In Kaplan-Meier analysis, there was significantly lower freedom from significant dysfunction (ejection fraction ≤ 40%) among those with WPW and LVNC (P.001). Further analysis showed a higher risk of developing significant dysfunction in patients with WPW and LVNC versus LVNC alone (hazard ratio 4.64 [2.79, 9.90]). Twelve patients underwent an ablation procedure with an acute success rate of 83%. Four patients with cardiac dysfunction were successfully ablated, 3 having improvement in function.WPW is common among children with LVNC and is associated with cardiac dysfunction. Ablation therapy can be safely and effectively performed and may result in improvement in function.