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Exertional syncope has been suggested to correlate with a cardiac aetiology, particularly when occurring in mid-stride. The aim of the study is to evaluate the incidence of cardiac disease among children presenting with exertional syncope, determine the influence of timing within activity, and determine the utility of genetic testing and implantable event monitors in the evaluation of cardiac syncope. The patients ≤18 years old with exertional syncope who underwent exercise stress testing between 2008 and 2019 were retrospectively included. Patients were assessed to be in one of three groups: mid-exertion (mid-stride syncope), peri-exertion (syncope during activity but not moving), and post-exertion (within minutes of the activity). A total of 334 patients were included; 46 % were mid-exertion, 18 % were peri-exertion, and 36 % were post-exertion. Thirteen patients (3.8 %) were diagnosed with cardiac syncope; n = 9 (69 %) mid-exertion. Only mid-exertional syncope was significantly associated with a cardiac diagnosis (OR: 2.6). Cardiac diagnoses included inherited arrhythmia syndromes (n = 9), abnormal coronary origins (n = 2), and supraventricular tachycardia (n = 2). Only catecholaminergic polymorphic ventricular tachycardia (n = 5) was associated with mid-exertional syncope (OR: 1.4). The definitive diagnostic test was exercise testing (n = 8), echocardiogram (n = 2), genetic testing (n = 1), ambulatory monitor (n = 1), and EKG (n = 1). Mid-stride syncope was more likely to result in a cardiac diagnosis, and exercise testing is the most common definitive test as catecholaminergic polymorphic ventricular tachycardia was the primary aetiology of exertional syncope in our cohort. Implantable event monitors and genetic testing could be helpful in ruling out cardiac disease.

BACKGROUND The ability of transesophageal three-dimensional echocardiography (3DE) to aid in pacemaker lead extraction has not yet been evaluated. 3DE provides real-time evaluation of intracardiac anatomy and the location of pacemaker leads in greater detail than either fluoroscopy or -two-dimensional echocardiography (2DE), aiding in the extraction of such leads, which can be potentially dangerous. We sought to investigate the feasibility and utility of 3DE to visualize intracardiac anatomy and pacemaker leads, and to assist in lead extraction procedures. METHODS We utilized 3DE in nine encounters for eight different patients, to visualize intracardiac anatomy and leads before, during, and after extraction to evaluate the feasibility and utility to aid in the procedure and evaluate for potential sequelae. RESULTS 3DE was able to identify pertinent intracardiac anatomy and leads in all cases. 3DE detected procedural complications or altered management in five of nine encounters (five of eight patients); this included detection of an avulsed papillary muscle, tricuspid valve leaflet damage, and cast/thrombus after lead removal, as well as adjustment of excess lead slack to avoid future valve damage, or risk stratification of lead removal. CONCLUSION 3DE is feasible and adds utility to lead extraction cases by visualizing intracardiac anatomy and leads beyond fluoroscopy or 2DE, providing real-time information during extraction, and identifying potential complications.

Bicuspid aortic valves (BAVs) are associated with accelerated valvular dysfunction. Increasing rates of conduction system disease are seen in patients with calcific tricuspid aortic valves (TAVs). However, little is known regarding the extent of conduction disorders in BAV patients. We sought to determine the extent of infra-hisian conduction pathology among patients with BAVs undergoing EP studies. We prospectively analyzed patients presenting to the EP laboratory from 2006 to 2017 at our institution. Thirty-three BAV patients had measured HV intervals. Each individual was matched by age and gender to two control patients. Clinical characteristics were collected and compared, and patients followed for outcomes. The BAV cohort had a mean age of 47.8 ± 17.2 years (range 19–76 years). Indications for referral to the EP lab in the BAV cohort included SVT ablation (n = 16), VT ablation (n = 10), and EP study for syncope, pre-syncope, or palpitations (n = 29). Patients with BAVs had a mean HV interval of 58.7 ms ± 18.6 ms, compared to a mean of 47.2 ms ± 9.6 ms for controls (p value = 0.0001). Over a 10-year follow-up period, 9 BAV patients (27%) went on to require permanent pacing compared to 6 patients (9%) in the control group (p value = 0.03). Compared to patients with TAVs presenting for EP evaluation, individuals with BAVs have longer HV intervals and a significantly increased requirement for pacemaker therapy over long-term follow-up. Closer monitoring of progressive conduction system disease in BAV patients may be warranted.

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).

Background Ventricular tachycardia (VT) is frequently encountered in patients with repaired and unrepaired congenital heart disease (CHD), causing significant morbidity and sudden cardiac death. Data regarding underlying VT mechanisms and optimal ablation strategies in these patients remain limited. Objective To describe the electrophysiologic mechanisms, ablation strategies, and long-term outcomes in patients with CHD undergoing VT ablation. Methods Forty-eight patients (mean age 41.3 ± 13.3 years, 77.1% male) with CHD underwent a total of 57 VT ablation procedures at two centers from 2000 to 2017. Electrophysiologic and follow-up data were analyzed. Results Of the 77 different VTs induced at initial or repeat ablation, the underlying mechanism in 62 (81.0%) was due to scar-related re-entry; the remaining included four His-Purkinje system-related macrore-entry VTs and focal VTs mainly originating from the outflow tract region (8 of 11, 72.7%). VT-free survival after a single procedure was 72.9% (35 of 48) at a median follow-up of 53 months. VT-free survival after multiple procedures was 85.4% (41 of 48) at a median follow-up of 52 months. There were no major complications. Three patients died during the follow-up period from nonarrhythmic causes, including heart failure and cardiac surgery complication. Conclusion While scar-related re-entry is the most common VT mechanism in patients with CHD, importantly, nonscar-related VT may also be present. In experienced tertiary care centers, ablation of both scar-related and nonscar-related VT in patients with CHD is safe, feasible, and effective over long-term follow-up.

The subcutaneous implantable cardioverter defibrillator (S-ICD) has become a valid alternative to the traditional transvenous implantable cardioverter defibrillator (ICD) in patients who do not require antitachycardia/antibradycardia pacing or cardiac resynchronization therapy.1 The absence of intravascular or intracardiac components removes several complications of transvenous systems that make it particularly favorable in younger patients. Limiting factors in children have been the relatively large size of the pulse generator, concerns of device erosion, and a mandatory distance between sensing electrodes.

Background An increasing number of adults with congenital heart disease (CHD) are undergoing catheter ablation for atrial fibrillation (AF). Data on ablation strategy and outcomes in CHD are limited. Rhythm control is often believed to be of greater importance among patients with complex CHD. Objective The purpose of this study was to examine the safety and efficacy of AF ablation in adult patients with CHD. Methods A multicenter retrospective analysis was performed of CHD patients undergoing AF ablation. Clinical data were collected, including AF and CHD type, procedural data, and outcomes. Patients were divided into 3 groups (simple, moderate, and severe) based on CHD complexity, as defined by the 2014 PACES/HRS (Pediatric and Congenital Electrophysiology Society/Heart Rhythm Society) consensus statement. One-year procedural success was defined as freedom from recurrent AF, off antiarrhythmic drugs (complete) or off/on previously failed antiarrhythmic drugs (partial). Results Overall, 84 CHD patients (mean age 51.5 ± 12.1 years; 65.5% male; 45.2% with paroxysmal AF) undergoing AF ablation (51 simple, 22 moderate, 11 severe complexity) were included. Pulmonary vein isolation was performed in 80 (95.2%), of whom 30 (35.7%) underwent pulmonary vein isolation alone. Overall, complete and complete/partial freedom was achieved at 1 year in 53.1% and 71.6%, respectively, with no significant differences between those with simple, moderate, or severe complexity. There were no major complications and 7 minor complications, and 2 patients died during follow-up. Conclusion There are dramatic differences in the degree of CHD complexity among patients referred for AF ablation. When performed at experienced centers, AF ablation is safe and effective even among patients with the most complex forms of CHD.

The Advisor™ HD Grid mapping catheter (Abbott Laboratories; Chicago, IL) allows for bipolar electrogram collection in both orthogonal and perpendicular planes, unique when compared to traditional and branch catheters. Experience in pediatric patients and congenital heart disease (CHD) is limited. The purpose of this work was to evaluate the utility and safety of the Advisor™ HD Grid mapping catheter in pediatric and CHD populations.Retrospective review of all pediatric patients and those with CHD (regardless of age) at Children's Hospital Colorado and University of Colorado undergoing electrophysiologic study in which the Advisor™ HD Grid mapping catheter was utilized.Sixty-five procedures in 60 patients (N = 31 female (47.6%), median age 17 years (15-24.1)) were included. Patients had CHD in 30 procedures (46.1%). Eight-eight arrhythmia substrates were mapped including atrial flutter/intra-atrial reentrant tachycardia (N = 33), focal atrial tachycardia (N = 20), isolated PVCs (N = 10), accessory pathways (N = 9), atrioventricular nodal reentrant tachycardia (N = 7), right ventricular substrate mapping (N = 7), and ventricular tachycardia (N = 2). Median time per map was 11.8 (7.5-20.1) min with 3.2 (± 1.7) maps per procedure and a median of 2634 (1767-7654) points used per map. Patients with CHD required more maps (p 0.001) and points per map (p 0.001). Ablation was successful in 92.4% of procedures.The Advisor™ HD Grid mapping catheter is safe and effective in the pediatric and congenital heart disease population. A wide variety of arrhythmia substrates can be mapped with high point density and low mapping time.

Background:Genetic variants in calsequestrin-2 (CASQ2) cause an autosomal recessive form of catecholaminergic polymorphic ventricular tachycardia (CPVT), although isolated reports have identified arrhythmic phenotypes among heterozygotes. Improved insight into the inheritance patterns, arrhythmic risks, and molecular mechanisms ofCASQ2-CPVT was sought through an international multicenter collaboration.Methods:Genotype-phenotype segregation inCASQ2-CPVT families was assessed, and the impact of genotype on arrhythmic risk was evaluated using Cox regression models. Putative dominantCASQ2missense variants and the established recessive CASQ2-p.R33Q variant were evaluated using oligomerization assays and their locations mapped to a recent CASQ2 filament structure.Results:A total of 112 individuals, including 36 CPVT probands (24 homozygotes/compound heterozygotes and 12 heterozygotes) and 76 family members possessing at least 1 presumed pathogenicCASQ2variant, were identified. AmongCASQ2homozygotes and compound heterozygotes, clinical penetrance was 97.1% and 26 of 34 (76.5%) individuals had experienced a potentially fatal arrhythmic event with a median age of onset of 7 years (95% CI, 6–11). Fifty-one of 66CASQ2heterozygous family members had undergone clinical evaluation, and 17 of 51 (33.3%) met diagnostic criteria for CPVT. Relative toCASQ2heterozygotes,CASQ2homozygote/compound heterozygote genotype status in probands was associated with a 3.2-fold (95% CI, 1.3–8.0;P=0.013) increased hazard of a composite of cardiac syncope, aborted cardiac arrest, and sudden cardiac death, but a 38.8-fold (95% CI, 5.6–269.1;PCASQ2missense variants evaluated exhibited filamentation defects, but only p.R33Q convincingly failed to dimerize. Structural analysis revealed that 3 of these 6 putative dominant negative missense variants localized to an electronegative pocket considered critical for back-to-back binding of dimers.Conclusions:This international multicenter study ofCASQ2-CPVT redefines its heritability and confirms that pathogenic heterozygousCASQ2variants may manifest with a CPVT phenotype, indicating a need to clinically screen these individuals. A dominant mode of inheritance appears intrinsic to certain missense variants because of their location and function within the CASQ2 filament structure.

The primary goal of this study was to evaluate the implant experience and midterm results of subcutaneous implantable cardioverter-defibrillators (S-ICDs) in pediatric patients and those with congenital heart disease.The S-ICD was developed to avoid the lead-related complications associated with transvenous systems. The absence of intravascular or intracardiac components offers potential advantages to pediatric patients and those with congenital heart disease.This international, multicenter, retrospective, standard-of-care study was conducted through the PediatricCongenital Electrophysiology Society. Complications at 30 and 360 days, inappropriate shocks, and delivery of appropriate therapy were assessed.The study included 115 patients with a median follow-up of 32 (19 to 52) months. Median age was 16.7 years (14.8 to 19.3 years), 29% were female, and 55% had a primary prevention indication. Underlying disease substrate was cardiomyopathy (40%), structural heart disease (32%), idiopathic ventricular fibrillation (16%), and channelopathy (13%). The complication rate was 7.8% at 30 days and 14.7% at 360 days. Overall, inappropriate shocks occurred in 15.6% of patients, with no single clinical characteristic reaching statistical significance. At implant, 97.9% of patients had successful first shock conversion with 96% requiring ≤65 J. Appropriate therapy was delivered to 11.2% of patients with an annual incidence of 3.9% and an acute first shock conversion success rate of 92.5%.This study found that in a heterogeneous population of pediatric patients and those with congenital heart disease, the S-ICD had comparable rates of complications, inappropriate shocks, and conversion efficacy compared with previously published studies on transvenous systems in similar populations.

Introduction Eleven-year-old male presented with nonsustained ventricular tachycardia presented for ablation of ventricular tachycardia located on the left lateral wall that is likely associated with anterolateral papillary muscle. Although he was asymptomatic, his atria have become dilated over time thus he was scheduled for a catheter ablation. Echocardiographic-fluoroscopic fusion imaging has shown transseptal puncture using this technology is safe and required less time in crossing the atrial septum; however, fusion imaging with 3D echocardiography overlay of left ventricular papillary muscle onto fluoroscopy has not been used in ventricular tachycardia ablations. Purpose The purpose of this clinical case was to evaluate the application of this new technology of echocardiography-fluoroscopy fusion imaging to guide left ventricular tachycardia ablation. Methods Echocardiographic-fluoroscopic fusion imaging was used for transseptal puncture and a 3D echocardiographic image of the left ventricle with anterolateral papillary muscle was overlaid onto fluoroscopy (Figure 1). The radiofrequency catheter was used to ablate the left anterolateral papillary muscle. With fused imaging, the ablation catheter was seen at the left anterolateral papillary muscle, and care was taken to prevent perforation of the lateral wall of the left ventricle. Results With fusion imaging of the left anterolateral papillary muscle overlaid onto fluoroscopy, the lateral wall of the left ventricular was also delineated. The catheter was easily visualized with fusion imaging to prevent perforation of the left ventricle while radiofrequency ablation was performed (Figure 1). Discussion 3D echocardiography provides excellent soft tissue definition of the lateral wall of the left ventricle and papillary muscle while fluoroscopy provides clear visualization of the ablation catheter. The ability of fusion imaging to overlay the 3D echocardiographic images onto fluoroscopy allowed for easy visualization of the anterolateral papillary muscle while the radiofrequency ablation was performed to avoid lateral wall perforation of the left ventricle. Future studies of echocardiographic-fluoroscopic fusion imaging should evaluate the potential to reduce procedure time and improve patient outcomes. Abstract P635 Figure.

Background Electrical and right ventricular (RV) mechanical dyssynchrony has been previously described in pediatric pulmonary arterial hypertension (PAH), but less is known about the relationship between electrical dyssynchrony and biventricular function. In this study we applied cardiac magnetic resonance (CMR) imaging to evaluate biventricular size and function with a focus on left ventricular (LV) strain mechanics in pediatric PAH patients with and without electrical dyssynchrony. Methods Fifty-six children with PAH and comprehensive CMR evaluation were stratified based on QRS duration z -score, with electrical dyssynchrony defined as z -score ≥2. Comprehensive biventricular volumetric, dyssynchrony, and strain analysis was performed. Results Nineteen PAH patients had or developed electrical dyssynchrony. Patients with electrical dyssynchrony had significantly reduced RV ejection fraction (35% vs 50%, p = 0.003) and greater end-diastolic (168 vs 112 ml/m 2 , p = 0.041) and end-systolic (119 vs 57, ml/m 2 , p = 0.026) volumes. Patients with electrical dyssynchrony had reduced RV longitudinal strain (–14% vs –19%, p = 0.007), LV circumferential strain measured at the free wall (–19% vs –22%, p = 0.047), and the LV longitudinal strain in the septal region (–10% vs –15%, p = 0.0268). LV mechanical intraventricular dyssynchrony was reduced in patients with electrical dyssynchrony at the LV free wall (43 vs 19 ms, p = 0.019). Conclusions The electrical dyssynchrony is associated with the reduced LV strain, enlarged RV volumes, and reduced biventricular function in children with PAH. CMR assessment of biventricular mechanical function with respect to QRS duration may help to detect pathophysiologic processes associated with progressed PAH.

Objectives 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. Background Children with WPW syndrome are at risk of sudden death. Methods 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 atrial fibrillation (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. Results 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. Conclusions Young patients may experience LTE from WPW syndrome without prior symptoms or markers of high-risk on EPS.

Cardiac resynchronization therapy (CRT) is used as an adjunctive therapy in adults with advanced heart failure but remains less commonly applied in pediatric patients. Further, CRT is traditionally conducted via biventricular transvenous pacing from the right ventricle and coronary sinus to activate the left ventricle and improve electromechanical synchrony; however, triventricular pacing, in which a third ventricular lead is utilized to activate an additional ventricular location, has been shown to be a feasible therapeutic alternative to typical CRT in patients with advanced heart failure or nonresponders. Limited adult studies involving triventricular pacing have been performed to date but no pediatric data are available. Thus, we present the case of a 12-month-old patient with congenital complete heart block and subsequent pacemaker-induced cardiomyopathy in whom triventricular epicardial pacing was applied in an effort to increase the available knowledge.

The feasibility of transesophageal 3-dimensional echocardiography to reduce fluoroscopy in pacemaker lead placement has not yet been evaluated. This clinical vignette demonstrates the ability of 3-dimensional echocardiography to visualize intracardiac anatomy and the pacemaker lead and to guide positioning of the lead into the right atrial appendage, thus reducing fluoroscopy by nearly 50%. (Level of Difficulty: Advanced.), Graphical abstract, The feasibility of transesophageal 3-dimensional echocardiography to reduce fluoroscopy in pacemaker lead placement has not yet been evaluated…

Background Atrial undersensing despite normal atrial lead parameters and high amplitude electrograms has been described in adult patients as a consequence of atrial amplifier saturation. Repetitive inputs cause amplifier ringing and undersensing occurs as a consequence of quiet timer blanking. High amplitude ventricular electrograms can also result in atrial blanking secondary to cross-chamber effect. This has not been described in pediatric patients or epicardial pacing systems and specific risk factors are not known. We describe five cases of atrial undersensing in pediatric and congenital heart disease patients with epicardial dual-chamber systems and high ventricular lead outputs. Methods This was a retrospective cohort study of all patients with dual-chamber pacing systems cared for at the Heart Institute at Children's Hospital Colorado. Results Five cases of atrial undersensing with normal atrial lead parameters were found. All were epicardial systems with acceptable lead parameters at implantation and Medtronic (Medtronic, Inc., Minneapolis, MN, USA) generators with unipolar leads. Ventricular pacing outputs were elevated at presentation, median 5.5 V (5-7.5). Presenting symptoms were exercise intolerance (four) and detection on routine monitoring (one). Successful interventions included reduction in ventricular lead pacing output (one), programming of rate response (two), and implantation of an alternative generator manufacturer (two). Conclusion Atrial undersensing secondary to amplifier ringing and quiet timer blanking is an uncommon presentation but may be clinically important in patients with unipolar epicardial atrial leads and high pacing outputs from ventricular leads.

Background: Patients with tetralogy of Fallot (TOF) have increased risk of atrial arrhythmias. Hypothesis: A measure of atrial dispersion, the P-wave vector magnitude (Pvm), can identify patients at risk for perioperative atrial flutter (AFL) or intra-atrial re-entrant tachycardia (IART) in a large TOF cohort. Methods: We performed a blinded, retrospective analysis of 158 TOF patients undergoing pulmonary valve replacement between 1997 and 2015. History of AFL/IART was documented using electrocardiogram, Holter monitor, exercise stress test, implanted cardiac device, and electrophysiology study. P-R intervals, Pvm, QRS duration, and QRS vector magnitude were assessed from resting sinus-rhythm 12-lead electrocardiograms and identification of those with AFL/IART was determined. Results: Fourteen patients (8.9%) were found to have AFL/IART. Pvm, QRS duration, and QRS vector magnitude significantly differentiated those with AFL/IART from those without on univariate analysis: 0.09±0.04 vs 0.18±0.07 mV, 161.3±21.9 vs 137.7±31.4ms, and 1.2 (interquartile range, 1.0-1.2) vs 1.6 mV (1.0-2.3), respectively (P < 0.05 for each). The Pvm had the highest area under the ROC curve (0.88) and was the only significant predictor on multivariate analysis, with odds ratio of 0.02 (95% confidence interval: 0.01-0.53). P-R duration, MRI volumes, and right-heart hemodynamics did not significantly differentiate those with vs those without AFL/IART. Conclusions: In TOF patients undergoing pulmonary valve replacement, Pvm has significant value in predicting those with perioperative AFL/IART. These clinical features may help further evaluate TOF patients at risk for perioperative atrial arrhythmias. Prospective studies are warranted.

AIMS: Catecholaminergic polymorphic ventricular tachycardia (CPVT) is an ion channelopathy characterized by ventricular arrhythmia during exertion or stress. Mutations in RYR2-coded Ryanodine Receptor-2 (RyR2) and CASQ2-coded Calsequestrin-2 (CASQ2) genes underlie CPVT1 and CPVT2, respectively. However, prognostic markers are scarce. We sought to better characterize the phenotypic and genotypic spectrum of CPVT, and utilize molecular modelling to help account for clinical phenotypes. METHODS AND RESULTS: This is a Pediatric and Congenital Electrophysiology Society multicentre, retrospective cohort study of CPVT patients diagnosed at

Bicuspid aortic valves (BAVs) are associated with accelerated valvular dysfunction. Increasing rates of conduction system disease are seen in patients with calcific tricuspid aortic valves (TAVs). However, little is known regarding the extent of conduction disorders in BAV patients. We sought to determine the extent of infra-hisian conduction pathology among patients with BAVs undergoing EP studies.We prospectively analyzed patients presenting to the EP laboratory from 2006 to 2017 at our institution. Thirty-three BAV patients had measured HV intervals. Each individual was matched by age and gender to two control patients. Clinical characteristics were collected and compared, and patients followed for outcomes.The BAV cohort had a mean age of 47.8 ± 17.2 years (range 19-76 years). Indications for referral to the EP lab in the BAV cohort included SVT ablation (n = 16), VT ablation (n = 10), and EP study for syncope, pre-syncope, or palpitations (n = 29). Patients with BAVs had a mean HV interval of 58.7 ms ± 18.6 ms, compared to a mean of 47.2 ms ± 9.6 ms for controls (p value = 0.0001). Over a 10-year follow-up period, 9 BAV patients (27%) went on to require permanent pacing compared to 6 patients (9%) in the control group (p value = 0.03).Compared to patients with TAVs presenting for EP evaluation, individuals with BAVs have longer HV intervals and a significantly increased requirement for pacemaker therapy over long-term follow-up. Closer monitoring of progressive conduction system disease in BAV patients may be warranted.

Purpose Identify administrative claims-based algorithms for capturing out-of-hospital ventricular arrhythmias (VA) and cardiac arrests (CA) due to cardiac causes in the pediatric population with high positive-predictive value (PPV). Methods Within a single pediatric center, a retrospective cohort of patients hospitalized or seen in the emergency room for VA or CA were identified from the electronic health records. Eligible encounters were blindly reviewed and linked to administrative data, including ICD-9/ICD-10 codes. Test characteristics, including PPV, for different diagnostic and procedure codes were generated using a 50% training sample. The gold standard was definite or suspected out-of-hospital VA or CA due to cardiac cause verified based on clinical criteria. Algorithms with the highest PPV were then applied to a 50% validation sample to validate performance. Results From 2004-2017, 598 encounters met eligibility criteria. 174 (29%) had an outcome of interest, with remainder being an inpatient event or CA due to other cause. Within the training sample (n = 263), VA codes in primary position had a PPV 94% (95%CI 81%-99%) with low sensitivity (44%, 95%CI 33%-56%). CA codes in any position or VA codes in nonprimary positions had low PPV (18%-19%, 31% respectively). Applying the top three performing algorithms to the validation sample (n = 252) yielded similar PPV values. Conclusions Contrary to adults, algorithms including a CA code do not perform well for identifying out-of-hospital VA and CA due to cardiac cause in the pediatric populations. Researchers should be aware of the potential implications for future pediatric drug safety studies for these outcomes.

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.

Purpose The authors conducted this scoping review to (1) provide a comprehensive evaluation and summation of published literature reporting on interprofessional substance use disorder (SUD) education for students in health professions education programs and (2) appraise the research quality and outcomes of interprofessional SUD education studies. Their goals were to inform health professions educators of interventions that may be useful to consider as they create their own interprofessional SUD courses and to identify areas of improvement for education and research. Method The authors searched 3 Ovid MEDLINE databases (MEDLINE, In-Process & Other Non-Indexed Citations, and Epub Ahead of Print), Embase.com, ERIC via FirstSearch, and Clarivate Analytics Web of Science from inception through December 7, 2018. The authors used the Medical Education Research Study Quality Instrument (MERSQI) to assess included studies' quality. Results The authors screened 1,402 unique articles, and 14 met inclusion criteria. Publications dated from 2014 to 2018. Ten (71%) included students from at least 3 health professions education programs. The mean MERSQI score was 10.64 (SD = 1.73) (range, 7.5-15). Interventions varied by study, and topics included general substance use (n = 4, 29%), tobacco (n = 4, 29%), alcohol (n = 3, 21%), and opioids (n = 3, 21%). Two studies (14%) used a nonrandomized 2-group design. Four (29%) included patients in a clinical setting or panel discussion. Ten (72%) used an assessment tool with validity evidence. Studies reported interventions improved students' educational outcomes related to SUDs and/or interprofessionalism. Conclusions Interprofessional SUD educational interventions improved health professions students' knowledge, skills, and attitudes toward SUDs and interprofessional collaboration. Future SUD curriculum design should emphasize assessment and measure changes in students' behaviors and patient or health care outcomes. Interprofessional SUD education can be instrumental in preparing the future workforce to manage this pressing and complex public health threat.

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.

Introduction Vectorcardiography (VCG) may have predictive value in Tetralogy of Fallot (TOF) patients undergoing ventricular arrhythmia inducibility (VAI) electrophysiology studies (EPs). Materials and methods Blinded, retrospective analyses of 37 adult TOF patients undergoing EPs prior to pulmonary valve replacements were performed (21 female, median age 37 years). VAI was evaluated from EPs and resting 12-lead electrocardiograms, respectively using QRS and heart rate adjusted Q-T intervals, spatial QRS-T angles (peaks), T-wave and QRS-wave (QRSwave vc) component vector root mean squares. Differences were assessed (Student t-tests, Mann Whitney U-tests, Analysis of Variance). Relative risks were calculated. Results 16 patients had VAI (6 monomorphic, 10 polymorphic). Only the QRSwave vc showed significant differences between those with and without VAI, 10.5 ± 2.4 dmV vs. 13.9 ± 4.5 dmV, respectively (p = 0.002), area under the ROC curve of 0.78 and relative risk of 2.52. Conclusion VCG evidence of depolarization differences was significant between TOF patients with and without inducible VA.

BACKGROUND Axillary implant location is an alternative implant location in patients for cardiac implantable electronic devices (CIEDs) for the purposes of improved cosmetic outcome. The impact from the patient's perspective is unknown. The purpose of this study was to compare scar perception scores and quality of life (QOL) in pediatric patients with axillary CIED implant location versus the standard infraclavicular approach. METHODS This is a multicenter prospective study conducted at eight pediatric centers and it includes patients aged from 8 to 18 years with a CIED. Patients with prior sternotomy were excluded. Scar perception and QOL outcomes were compared between the infraclavicular and axillary implant locations. RESULTS A total of 141 patients (83 implantable cardioverter defibrillator [ICD]/58 pacemakers) were included, 55 with an axillary device and 86 with an infraclavicular device. Patients with an ICD in the axillary position had better perception of scar appearance and consciousness. Patients in the axillary group reported, on average, a total Pediatric QOL Inventory score that was 6 (1, 11) units higher than the infraclavicular group, after adjusting for sex and race (P = 0.02). CONCLUSIONS QOL is significantly improved in axillary in comparison to the infraclavicular CIED position, regardless of device type. Scar perception is improved in patients with ICD in the axillary position.

Background Ventricular tachyarrhythmias are the most common cause of death in patients with repaired tetralogy of Fallot (TOF), but predicting those at risk remains a challenge. An electrophysiology study (EPS) has been proposed to risk stratify patients with TOF. Objective We sought to evaluate a perioperative EPS-guided approach to risk stratify patients with TOF undergoing pulmonary valve replacement (PVR) and guide concomitant cryoablation. Methods A prospective cohort study of patients with TOF undergoing an EPS at the time of PVR from 2006 to 2017 was conducted at 2 centers. Patients inducible at the time of pre-PVR had undergone concomitant cryoablation in addition to PVR. A repeat post-PVR EPS was performed in those initially inducible to guide implantable cardioverter-defibrillator (ICD) implantation. Results Of 70 patients who underwent a pre-PVR EPS, 34 (49%) had inducible sustained ventricular tachycardia (VT): 25 monomorphic VT and 9 polymorphic VT. Among patients undergoing cryoablation, 14 (45%) had inducible VT and underwent ICD implantation. During a mean follow-up period of 6.1 ± 3.2 years, 3 patients (21%) had appropriate ICD shocks for symptomatic VT. There was an average of 2.3 shocks (range 1–4 shocks), and the mean time to first shock post–device implantation was 3.6 years (range 2.9–4.3 years). Among patients with negative pre- or post-PVR EPS results, 2 had VT requiring radiofrequency ablation and/or subsequent ICD implantation. There were no arrhythmic deaths. Conclusion A pre-PVR EPS identified patients with higher-risk TOF undergoing PVR. Despite empirical VT cryoablation at the time of PVR, a high percentage of patients remained inducible for VT. In this high-risk cohort, post-PVR EPS evaluation is important to identify patients at risk of VT despite cryoablation.

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 atrial fibrillation (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.

We report the clinical course of a female child with a normal karyotype and chromosomal microarray who presented as an infant with clinical findings consistent with congenital polyvalvular disease (CPVD). This clinical entity describes patients with multiple congenitally dysplastic valves, often showing nodular or cystic malformation in at least two cardiac valves. This patient then developed medically refractory multifocal ventricular arrhythmia and required radiofrequency ablation at seven months of age. She had good tachycardia control but became symptomatic with right heart failure related to progressive tricuspid, pulmonary, and mitral valve dysfunction necessitating multivalvular replacement at 21 months of age.