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Cardiac amyloidosis is a rare cause of cardiomyopathy, reported exclusively in adults. We report the first known case presenting in childhood. A 12-year-old boy presented with syncope and diagnosed with ventricular non-compaction by echocardiography. Eventual genetic testing confirmed a TTR gene mutation associated with hereditary transthyretin amyloidosis.

In view of the increasing complexity of both cardiovascular implantable electronic devices (CIEDs) and patients in the current era, practice guidelines, by necessity, have become increasingly specific. This document is an expert consensus statement that has been developed to update and further delineate indications and management of CIEDs in pediatric patients, defined as ≤21 years of age, and is intended to focus primarily on the indications for CIEDs in the setting of specific disease categories. The document also highlights variations between previously published adult and pediatric CIED recommendations and provides rationale for underlying important differences. The document addresses some of the deterrents to CIED access in low- and middle-income countries and strategies to circumvent them. The document sections were divided up and drafted by the writing committee members according to their expertise. The recommendations represent the consensus opinion of the entire writing committee, graded by class of recommendation and level of evidence. Several questions addressed in this document either do not lend themselves to clinical trials or are rare disease entities, and in these instances recommendations are based on consensus expert opinion. Furthermore, specific recommendations, even when supported by substantial data, do not replace the need for clinical judgment and patient-specific decision-making. The recommendations were opened for public comment to Pediatric and Congenital Electrophysiology Society (PACES) members and underwent external review by the scientific and clinical document committee of the Heart Rhythm Society (HRS), the science advisory and coordinating committee of the American Heart Association (AHA), the American College of Cardiology (ACC), and the Association for European Paediatric and Congenital Cardiology (AEPC). The document received endorsement by all the collaborators and the Asia Pacific Heart Rhythm Society (APHRS), the Indian Heart Rhythm Society (IHRS), and the Latin American Heart Rhythm Society (LAHRS). This document is expected to provide support for clinicians and patients to allow for appropriate CIED use, appropriate CIED management, and appropriate CIED follow-up in pediatric patients.

Background Chronic right ventricular (RV) apical pacing in patients with congenital complete atrioventricular block (CCAVB) is associated with left ventricle (LV) dyssynchrony and dysfunction. Hence, alternative pacing sites are advocated. The aim of this study was to compare LV function using STE in selected patients with LV epicardial pacing (LVEp) vs. RV transvenous pacing (RVSp). Methods This was a single center, retrospective study in patients with CCAVB who underwent permanent pacemaker implant at age ≤ 18 years. Age- and gender-matched patients with a normal heart anatomy and function served as control group. LV function was comprehensively assessed by conventional 2D Echocardiography and speckle tracking echocardiography (STE). Results: We included 24 patients in the pacemaker group [27.6% male, mean age of 17.1 at last follow-up, follow-up duration of 8.7 years, RVSp (n = 9; 62.5%)] compared to 48 matched healthy controls. Shortening fraction (SF) and ejection fraction (EF) were normal and similar between cases and controls. However, STE detected abnormal LV function in the pacemaker group compared to controls. The former demonstrated lower/abnormal, PLS Myo (-12.0 ± 3.3 vs. -18.1 ± 1.9, p < 0.001) and PLS endo (-16.1 ± 4.1 vs. -21.7 ± 1.7, p < 0.001). STE parameters of LV function were significantly more abnormal in LVEp vs. RVSp subgroup as demonstated by lower values for PLS Myo (-10.1 ± 3.2 vs. -13.1 ± 2.9, p = 0.03) and PLS Endo (-13.8 ± 4.4 vs. -17.5 ± 3.3, p = 0.03). Conclusions: LV dysfunction was better adjudicated by STE than 2D echocardiographic measurements (EF and SF) in our selected patients with CCAVB and permanent pacemaker. Furthermore, STE demonstrated that transvenous RV septal pacing was associated with better LV systolic function preservation than LV epicardial pacing for comparable post-implant intervals.

In view of the increasing complexity of both cardiovascular implantable electronic devices (CIEDs) and patients in the current era, practice guidelines, by necessity, have become increasingly specific. This document is an expert consensus statement that has been developed to update and further delineate indications and management of CIEDs in pediatric patients, defined as ≤21 years of age, and is intended to focus primarily on the indications for CIEDs in the setting of specific disease categories. The document also highlights variations between previously published adult and pediatric CIED recommendations and provides rationale for underlying important differences. The document addresses some of the deterrents to CIED access in low- and middle-income countries and strategies to circumvent them. The document sections were divided up and drafted by the writing committee members according to their expertise. The recommendations represent the consensus opinion of the entire writing committee, graded by class of recommendation and level of evidence. Several questions addressed in this document either do not lend themselves to clinical trials or are rare disease entities, and in these instances recommendations are based on consensus expert opinion. Furthermore, specific recommendations, even when supported by substantial data, do not replace the need for clinical judgment and patient-specific decision-making. The recommendations were opened for public comment to Pediatric and Congenital Electrophysiology Society (PACES) members and underwent external review by the scientific and clinical document committee of the Heart Rhythm Society (HRS), the science advisory and coordinating committee of the American Heart Association (AHA), the American College of Cardiology (ACC), and the Association for European Paediatric and Congenital Cardiology (AEPC). The document received endorsement by all the collaborators and the Asia Pacific Heart Rhythm Society (APHRS), the Indian Heart Rhythm Society (IHRS), and the Latin American Heart Rhythm Society (LAHRS). This document is expected to provide support for clinicians and patients to allow for appropriate CIED use, appropriate CIED management, and appropriate CIED follow-up in pediatric patients.

Appropriate non-invasive assessments (ECHO/ECG) of cardiac resynchronization pacing therapy (CRT) among younger patients (pts) with/without (w/wo) congenital heart disease (CHD) are not established. Ejection fraction (EF) and QRS can be unreliable due to anatomy, surgical repairs, and pre-existing pacemakers (PM). This study correlates updated non-invasive studies, including newer strain values, with clinical and invasive hemodynamic assessments of CRT response in the young. Sixteen pts (mean age 18.5 ± 6 years, 10/16 with pre-existing pacemakers) underwent CRT for heart failure (NYHA II-III). CHD included septal defects and Tetralogy of Fallot. Assessment of CRT efficacy was based on clinical findings, direct catheterization studies [pressures, contractility indices (dP/dt-max)], ECG changes, and ECHO studies [including updated global (GLS), left atrial strain (LAS), and sphericity indices] pre- and at 1-month and 1-year post-CRT. After 1 year following CRT, all pts improved (II-III to I-II) in clinical NYHA status. Contractility (dP/dt) increased (932 ± 351 vs 561 ± 178.7 mmHg-sec [p = 0.001]). QRS duration shortened only among pts with pre-existing PM (160 ± 25 vs 134 ± 25 ms [p = 0.02]). Standard ECHO parameters, including chamber dimensions and EF, showed no appreciable changes from pre-CRT values. However, endocardial GLS [(- 6.4 vs. - 9.6%) p = 0.0003] and LAS [(- 5.8 vs - 9.3%) p = 0.02] values significantly improved. Although CRT is applicable to younger pts, accurate non-invasive evaluations of response are lacking. This study establishes that newer strain values better correlate with clinical and hemodynamic changes over other parameters and offer more appropriate assessments of CRT response.

Cardiac amyloidosis is a rare cause of cardiomyopathy, reported exclusively in adults. We report the first known case presenting in childhood. A 12-year-old boy presented with syncope and diagnosed with ventricular non-compaction by echocardiography. Eventual genetic testing confirmed a TTR gene mutation associated with hereditary transthyretin amyloidosis.

In view of the increasing complexity of both cardiovascular implantable electronic devices (CIEDs) and patients in the current era, practice guidelines, by necessity, have become increasingly specific. This document is an expert consensus statement that has been developed to update and further delineate indications and management of CIEDs in pediatric patients, defined as ≤21 years of age, and is intended to focus primarily on the indications for CIEDs in the setting of specific disease categories. The document also highlights variations between previously published adult and pediatric CIED recommendations and provides rationale for underlying important differences. The document addresses some of the deterrents to CIED access in low- and middle-income countries and strategies to circumvent them. The document sections were divided up and drafted by the writing committee members according to their expertise. The recommendations represent the consensus opinion of the entire writing committee, graded by class of recommendation and level of evidence. Several questions addressed in this document either do not lend themselves to clinical trials or are rare disease entities, and in these instances recommendations are based on consenus expert opinion. Furthermore, specific recommendations, even when supported by substantial data, do not replace the need for clinical judgment and patient-specific decision-making. The recommendations were opened for public comment to Pediatric and Congenital Electrophysiology Society (PACES) members and underwent external review by the scientific and clinical document committee of the Heart Rhythm Society (HRS), the science advisory and coordinating committee of the American Heart Association (AHA), the American College of Cardiology, (ACC) and the Association for European Paediatric and Congenital Cardiology (AEPC). The document received endorsement by all the collaborators and the Asia Pacific Heart Rhythm Society (APHRS), the Indian Heart Rhythm Society (IHRS), and the Latin American Heart Rhythm Society (LAHRS). This document is expected to provide support for clinicians and patients to allow for appropriate CIED use, appropriate CIED management, and appropriate follow-up in pediatric patients.

Background: Pacing sites vary among symptomatic patients with congenital complete heart block (CHB) with right ventricle (RV) apex (Ap) and outflow tract (OT), both of which alter contractility, as commonly-cited lead implant locations. However, controversy exists as to the best site based on only ECHO-derived ejection fraction (EF) as a marker for contractility. With recent ECHO updates, the question now arises if use of other indices of left (L) V function offer advantages in comparing function between pacing sites. Objective: To compare newer LV functional ECHO …

Guidelines for the implantation of cardiac implantable electronic devices (CIEDs) have evolved since publication of the initial ACC/AHA pacemaker guidelines in 1984 [ 1 ]. CIEDs have evolved to include novel forms of cardiac pacing, the development of implantable cardioverter defibrillators (ICDs) and the introduction of devices for long term monitoring of heart rhythm and other physiologic parameters. In view of the increasing complexity of both devices and patients, practice guidelines, by necessity, have become increasingly specific. In 2018, the ACC/AHA/HRS published Guidelines on the Evaluation and Management of Patients with Bradycardia and Cardiac Conduction Delay [ 2 ], which were specific recommendations for patients >18 years of age. This age-specific threshold was established in view of the differing indications for CIEDs in young patients as well as size-specific technology factors. Therefore, the following document was developed to update and further delineate indications for the use and management of CIEDs in pediatric patients, defined as ≤21 years of age, with recognition that there is often overlap in the care of patents between 18 and 21 years of age. This document is an abbreviated expert consensus statement (ECS) intended to focus primarily on the indications for CIEDs in the setting of specific disease/diagnostic categories. This document will also provide guidance regarding the management of lead systems and follow-up evaluation for pediatric patients with CIEDs. The recommendations are presented in an abbreviated modular format, with each section including the complete table of recommendations along with a brief synopsis of supportive text and select references to provide some context for the recommendations. This document is not intended to provide an exhaustive discussion of the basis for each of the recommendations, which are further addressed in the comprehensive PACES-CIED document [ 3 ], with further data easily accessible in electronic searches or textbooks.

Symptomatic, circulatory collapse occurred in an unvaccinated child with repaired congenital heart and a backup pacemaker during an Influenza B viral infection with complete atrioventricular block and pacemaker non-capture. Ventricular arrhythmias occurred during her collapse. Atrioventricular conduction recovered within 24 hours. Influenza-associated cardiac inflammation can adversely affect patients with repaired CHD. Proactive immunisation is strongly recommended.

Although postoperative complete heart block is a relatively rare complication after cardiac surgery for congenital heart disease in the current era, it has significant repercussions if there is no recovery of atrioventricular conduction in the early postoperative period. Insertion of a permanent pacemaker in an infant, child or adolescent remains an important medical decision considering all potential adverse physical and physiological side effects commonly associated with device implant among these younger patients. In this review, the current incidence, morbidity and mortality of postoperative complete heart block is presented as well as contributing anatomical and perioperative risk factors along with potential therapies and long-term sequelae of this unwanted complication.

A 14-year-old female was referred for severe pulmonary valve insufficiency after undergoing radiofrequency ablation for a right ventricular outflow tract tachycardia that originated in the proximal pulmonary artery at 10 years of age. Clinical records indicated that ablation was guided solely by electrograms and electroanatomical mapping. Due to myocardial tissue extensions, mapping failed to identify the level of the pulmonary valve annulus, which resulted in delivery of energy on the valve proper and into the pulmonary artery. She developed severe pulmonary valve insufficiency and moderate proximal pulmonary artery stenosis necessitating intravascular stent placement 4 years later with an associated transcatheter valve. Although the nonfluoroscopic approach during ablation has gained wide acceptance for use in children, this report highlights the benefits of adjunctive imaging to identify the precise location of the pulmonary valve when ablation therapy is contemplated in the right ventricle outflow tract.

Background: Pacemaker implantation is recommended in symptomatic patients with congenital complete heart block (CHB) with either an epicardial (epi) or transvenous (TV) approach depending on patient age / size. However, there is a paucity of data on updated left ventricle (LV) functional indices between the two approaches. Objective: Our aim was to compare LV function using speckle strain imaging in patients with LV Epi vs. best site right (R) TV pacing Methods: This was a single center, retrospective study of patients with isolated CHB …

Objectives The purpose of this study was to use direct cardiac resynchronization therapy (CRT)-paced contractility (dP/dt-max) response as a pre-implantation evaluation among patients with congenital heart disease (CHD) and follow clinical parameters and contractility indexes after CRT implantation. Background Patients with CHD often develop early heart failure with few therapeutic options, leading to heart transplantation (HT). Unfortunately, guidelines for CRT do not apply, and function evaluations by cardiac ultrasound are often inaccurate among CHD anatomies. Therefore, which CHD patients would benefit from CRT remains an enigma. Methods From 1999 to 2015, 103 CHD patients with New York Heart Association (NYHA) functional class II to IV were listed for HT; 40 patients on optimal medical therapy were referred for paced contractility response cardiac catheterization before CRT consideration. If dP/dt-max improved ≥15% from baseline, these “responders” were given the option of CRT with continued follow-up after implantation. Results Of 40 patients studied, 26 (65%) (age 22 ± 8.2 years; 9 of 26 [35%] single or systemic right ventricle; 17 of 26 [65%] with pacemakers) met criteria for possible hemodynamic benefit and underwent CRT implantation. All 26 patients improved in NYHA functional classification: 5 of 26 patients (19%) were later relisted for HT (4 to 144 months, mean 55 months) after CRT implantation, whereas 21 of 26 (81%) continued with improved NYHA functional class (12 to 112 months, mean 44 months) later. A repeat dP/dt-max study following long-term CRT showed stable function or continued contractility improvement. Conclusions Heart failure is common among CHD patients, and therapies are limited. CRT guidelines do not address clinical and anatomic issues of CHD. Short-term paced contractility response testing identifies those CHD patients who are likely to respond to CRT regardless of anatomy.

BACKGROUND Patients with congenital heart defects (CHD) often present more challenges to pacing therapy due to anatomy than those without CHD. The lumenless, 4.1Fr diameter M3830 pacing lead (Medtronic, Inc., Minneapolis, MN, USA), approved for use in 2005, has, to date, reported to have excellent short-term (

Accelerated junctional rhythm has been reported in children in the setting of acute rheumatic fever; however, we describe a hitherto unreported case of isolated junctional tachycardia in a child with streptococcal pharyngitis, not meeting revised Jones criteria for rheumatic fever. A previously healthy, 9-year-old girl presented to the emergency department with complaints of sore throat, low-grade fever, and intermittent chest pain. She was found to have a positive rapid streptococcal antigen test. The initial electrocardiogram showed junctional tachycardia with atrioventricular dissociation in addition to prolonged and aberrant atrioventricular conduction. An echocardiogram revealed normal cardiac anatomy with normal biventricular function. The patient responded to treatment with amoxicillin for streptococcal pharyngitis. The junctional tachycardia and other electrocardiogram abnormalities resolved during follow-up.

A preterm infant with a ventricular septal defect and facial dysmorphisms. ### Prenatal and Birth Histories ### Presentation After birth, the infant was admitted to the NICU because of prematurity. He required supplemental oxygen through a nasal cannula for a brief period (

African American (AA) adults are reported to have lower levels of cardiorespiratory fitness (CRF) as compared to Caucasian adults. CRF is linked to cardiovascular morbidity and mortality. We hypothesized that the disparities start early in childhood. This was a retrospective analysis of the cardiopulmonary exercise test (CPET). We included normal healthy children, ≤ 18 years of age, who had normal electrocardiograms and normal cardiac function. We excluded patients with congenital heart disease, obesity and suboptimal exercise test. The entire cohort was divided into two groups based on race (Caucasian vs. AA) and then further subcategorized by gender. The cohort of 248 patients had a mean ± SD age of 14.4 ± 2.1 years. 158 (60.8%) were males and 158 (60.8%) were Caucasians. Oxygen consumption was higher among Caucasian children when compared to the AA children (48.7 ± 7.9 vs. 45.4 ± 7 mL/kg/min, p = 0.01). This racial disparity continued to persist when comparisons were performed separately for girls and boys. Upon comparing the four groups, the AA females were found to have the lowest values of VO2max, exercise time and METS (p = 0.001). Thus, in conclusion, the AA children have significantly lower level of CRF, as measured by VO2max and exercise time. The racial disparity is independent of gender. African American females show the lowest level of aerobic capacity. The findings of our study suggest that the racial disparity in the CRF levels seen in the adult population may begin early in childhood.

Background Standard, 5–7-Fr diameter pacing leads (PLs) can adversely affect atrioventricular valve (AVV) and venous (superior vena cava [SVC], innominate [INN]) integrities. Although chronic pacing/sensing performances have been reported on the steroid-eluting, lumenless, 4.1-Fr PL (Model 3830, Medtronic Inc., Minneapolis, MN, USA), comparative valve and venous effects are largely unknown. Methods Patients (n = 134) were divided into two PL groups: Group 1 (n = 65, Model 3830) and Group 2 (n = 69, various 5–7 Fr models) and followed up to 9 years postimplant. Patient demographics, clinical findings, valve function, and venous dimensions were reviewed. Statistical significance was defined as P < 0.05. Results Patient implant age (mean 16.4 years vs 17.3 years), presence of congenital heart defect (CHD), and preexisting valve issues were comparable between groups. New or worsening valve insufficiency occurred in 12% of Group 1 patients (mean follow-up 4.3 ± 2.8 years) and 27% of Group 2 patients (mean follow-up 6.2 ± 3.5 years; P < 0.05). Significant SVC or INN narrowing was found in 11 % of Group 1 and 24% of Group 2 patients (P = 0.0004). All Group 1 patients

Vena caval obstruction (VCO) is a common complication after vascular manipulation for congenital heart disease. Long-term efficacy of stent therapy for relief of VCO and long-term stent patency with and without intrastent transvenous pacing leads (TPLs) is not well described. This was a retrospective review of patients treated for VCO, including those who received intrastent TPLs, between 1995 and 2012. Patient demographics, diagnoses, vascular pressure gradients, and vessel diameters were analyzed. Forty-one patients (mean age 23.5 ± 10.3 years) with and without congenital heart disease underwent stent implantation, 26 of whom also received intrastent TPLs. Short-term stent implantation success in relieving obstructions was 93%. Poststent vascular pressure gradients and percentage vascular narrowing significantly improved (from 6.2 ± 4.5 to 1.1 ± 1.6 mm Hg and from 63.1 ± 19.5% to 18.0 ± 17.1%, respectively, p0.05). On follow-up in 38 of 41 patients from 0.2 to 18 years (median 6.0), all survived; 6 (14%) required stent reintervention. Freedom from reintervention was 87% at 15 years. Patients with short-term procedural failure were at higher risk for stent reintervention. Among 27 patients with intrastent TPLs, freedom from reintervention was 96%. In 26 patients with follow-up catheterization, intrastent intimal proliferation was not significantly associated with TPL but was higher in the superior vena cava-innominate vein junction compared with other stent locations (p 0.05). In conclusion, stent therapy for VCO can be successfully and safely performed with good long-term results. Pre-pacing lead stent placement for VCO is effective in allowing TPL placement with encouraging long-term patency.

Designed as effective therapy for patients with symptomatic bradycardia, implantable cardiac pacemakers initially served to improve symptoms and survival. With initial applications to the elderly and those with severe myocardial disease, extended longevity was not a major concern. However, with design technology advances in leads and generators since the 1980s, pacemaker therapy is now readily applicable to all age patients, including children with congenital heart defects. As a result, emphasis and clinical interests have advanced beyond simply quantity to quality of life. Adverse cardiac effects of pacing from right ventricular apical or epicardial sites with resultant left bundle branch QRS configurations have been recognized. As a result, and with the introduction of newer catheter-delivered pacing leads, more recent studies have focused on alternative or select pacing sites such as septal, outflow tract, and para-bundle of His. This is especially important in dealing with pacemaker therapy among younger patients and those with congenital heart disease, with expected decades of artificial cardiac stimulation, in which adverse myocellular changes secondary to pacing itself have been reported. As a correlate to these alternate or select pacing sites, applications of left ventricular pacing, either via the coronary sinus, intraseptal or epicardial, alone or in combination with right ventricular pacing, have gained interest for patients with heart failure. Although cardiac resynchronization pacing has, to date, had limited clinical applications among patients with congenital heart disease, the few published reports do indicate potential benefits as a bridge to cardiac transplant.

Society Guidelines PACES/HRS Expert Consensus Statement on the Recognition and Management of Arrhythmias in Adult Congenital Heart Disease Developed in Partnership Between the Pediatric and Congenital Electrophysiology Society (PACES) and the Heart Rhythm Society (HRS). Endorsed by the Governing Bodies of PACES, HRS, the American College of Cardiology (ACC), the American Heart Association (AHA), the European Heart Rhythm Association (EHRA), the Canadian Heart Rhythm Society (CHRS), and the International Society for Adult Congenital Heart Disease (ISACHD) Paul Khairy, MD, PhD, FRCPC (Chair),* George F. Van Hare, MD, FACC, FHRS (Co-Chair),y Seshadri Balaji, MBBS, PhD,y Charles I. Berul, MD, FHRS,y Frank Cecchin, MD, FACC,z Mitchell I. Cohen, MD, FACC, FHRS,y Curt J. Daniels, MD, FACC,** Barbara J. Deal, MD, FACC,y Joseph A. Dearani, MD, FACC,* Natasja de Groot, MD, PhD,{ Anne M. Dubin, MD, FHRS,y Louise Harris, MBChB, FHRS, Jan Janousek, MD, PhD,{ Ronald J. Kanter, MD, FHRS,y Peter P. Karpawich, MD, FACC, FAHA, FHRS,y James C. Perry, MD, FACC, FHRS,* Stephen P. Seslar, MD, PhD,y Maully J. Shah, MBBS, FHRS,y Michael J. Silka, MD, FACC, FAHA,x John K. Triedman, MD, FACC, FHRS,y Edward P. Walsh, MD, FACC, FHRS,y and Carole A. Warnes, MD, FRCP, FACC, FAHA** Pediatric and Congenital Electrophysiology Society (PACES) representative; yHeart Rhythm Society (HRS) representative; zAmerican College of Cardiology (ACC) representative; xAmerican Heart Association (AHA) representative; {European Heart Rhythm Association (EHRA) representative; Canadian Heart Rhythm Society (CHRS) representative; International Society for Adult Congenital Heart Disease (ISACHD) representative

Recognition and Management of Arrhythmias in Adult Congenital Heart Disease: Executive Summary Developed in partnership between the Pediatric and Congenital Electrophysiology Society (PACES) and the Heart Rhythm Society (HRS). Endorsed by the governing bodies of PACES, HRS, the American College of Cardiology (ACC), the American Heart Association (AHA), the European Heart Rhythm Association (EHRA), the Canadian Heart Rhythm Society (CHRS), and the International Society for Adult Congenital Heart Disease (ISACHD)

Objective The objective of this study was to develop quality metrics (QMs) relating to the ambulatory care of children after complete repair of tetralogy of Fallot (TOF). Design A workgroup team (WT) of pediatric cardiologists with expertise in all aspects of ambulatory cardiac management was formed at the request of the American College of Cardiology (ACC) and the Adult Congenital and Pediatric Cardiology Council (ACPC), to review published guidelines and consensus data relating to the ambulatory care of repaired TOF patients under the age of 18 years. A set of quality metrics (QMs) was proposed by the WT. The metrics went through a two-step evaluation process. In the first step, the RAND-UCLA modified Delphi methodology was employed and the metrics were voted on feasibility and validity by an expert panel. In the second step, QMs were put through an "open comments" process where feedback was provided by the ACPC members. The final QMs were approved by the ACPC council. Results The TOF WT formulated 9 QMs of which only 6 were submitted to the expert panel; 3 QMs passed the modified RAND-UCLA and went through the "open comments" process. Based on the feedback through the open comment process, only 1 metric was finally approved by the ACPC council. Conclusions The ACPC Council was able to develop QM for ambulatory care of children with repaired TOF. These patients should have documented genetic testing for 22q11.2 deletion. However, lack of evidence in the literature made it a challenge to formulate other evidence-based QMs.

Background Supraventricular tachycardia (SVT) in children can be successfully terminated using catheter ablation techniques; however, chronic, true success may be less. Sensed tachycardia (ST) is common following ablation and the differentiation from true arrhythmia recurrences can be challenging. Methods Records of all patients ≤18 years who underwent successful ablation for simple forms of SVT and followed-up for at least a year between 2002 and 2012 were reviewed. Patients with congenital heart disease, atrial muscle tachycardia, and associated ventricular tachycardia were excluded. The diagnostic utility of commonly performed tests was assessed. Results Among the 205 eligible subjects, 202 underwent successful ablation (98.5%), of who five were lost to follow-up before 1 year. The early success rate (6 weeks postablation) and mid-term success rate (1 year postablation) were high (97.5% and 87.4%, respectively) whereas the chronic success (5 years postablation) was only 75%. Although true arrhythmia recurrence was significantly higher in the young (mean 11.5 years vs 13.5 years, P = 0.03) and males (P = 0.02), the presence of diffuse, right-sided fibers was the only independent predictor of true recurrence (odds ratio = 2.7, P = 0.03, 95% confidence interval 1.1, 6.8). Significant ST was reported by 111 patients (56%). The 30-day ambulatory event monitor had the highest sensitivity (71%) when compared to exercise test (19%) and electrocardiogram (24%) in identifying true arrhythmia recurrence. Conclusions Acute and early success may not guarantee chronic ablation success. Postablation, symptomatic patients can be most effectively evaluated using ambulatory event monitoring; however, true recurrence may still be missed and requires closer monitoring.

Although transcatheter arrhythmia ablation (TCA) has been performed in children for over two decades, guidelines for routine use of post-ablation transthoracic echocardiography (TTE) are absent. We sought to determine the efficacy of TTE after apparently uneventful TCA procedures in detecting adverse findings and identify predisposing factors. A retrospective review of clinical and procedural data on patients who underwent TCA for supraventricular arrhythmias from 2000 to 2015 was performed. Pre- and post-ablation TTE data were reviewed. All patients were followed at 1 week, 6 and 12 months post-TCA. A repeat TTE was performed at 12 months on patients in whom post-TCA abnormalities were found. Patients were divided into two groups: those with and without adverse TTE findings and comparative analysis between variables was performed. Data on 252 patients, 52% males, mean age 14 ± 3 years were analyzed. New onset or worsening atrioventricular valve regurgitation occurred in 17 (6.7%), a small pericardial effusion in 3 (1.2%) and worsened ventricular function in 2 patients (0.8%). Patients in the complication group had higher mean number of ablations (22.6 ± 15.3 vs. 16.8 ± 9.2, p 0.001) and required longer duration of ablation (sec) (254.6 ± 256.4 vs. 180.9 ± 158.9, p

The purpose of this study was to use direct cardiac resynchronization therapy (CRT)-paced contractility (dP/dt-max) response as a pre-implantation evaluation among patients with congenital heart disease (CHD) and follow clinical parameters and contractility indexes after CRT implantation.Patients with CHD often develop early heart failure with few therapeutic options, leading to heart transplantation (HT). Unfortunately, guidelines for CRT do not apply, and function evaluations by cardiac ultrasound are often inaccurate among CHD anatomies. Therefore, which CHD patients would benefit from CRT remains an enigma.From 1999 to 2015, 103 CHD patients with New York Heart Association (NYHA) functional class II to IV were listed for HT; 40 patients on optimal medical therapy were referred for paced contractility response cardiac catheterization before CRT consideration. If dP/dt-max improved ≥15% from baseline, these "responders" were given the option of CRT with continued follow-up after implantation.Of 40 patients studied, 26 (65%) (age 22 ± 8.2 years; 9 of 26 [35%] single or systemic right ventricle; 17 of 26 [65%] with pacemakers) met criteria for possible hemodynamic benefit and underwent CRT implantation. All 26 patients improved in NYHA functional classification: 5 of 26 patients (19%) were later relisted for HT (4 to 144 months, mean 55 months) after CRT implantation, whereas 21 of 26 (81%) continued with improved NYHA functional class (12 to 112 months, mean 44 months) later. A repeat dP/dt-max study following long-term CRT showed stable function or continued contractility improvement.Heart failure is common among CHD patients, and therapies are limited. CRT guidelines do not address clinical and anatomic issues of CHD. Short-term paced contractility response testing identifies those CHD patients who are likely to respond to CRT regardless of anatomy.

Background The early ECG repolarization QRS pattern (ERp), with J-point elevation of 0.1 mV in two contiguous inferior and/or lateral leads, can be associated with ventricular arrhythmias among adults. The significance of an ERp in the young is unknown. Objective The purpose of this study was to assess the prevalence of ERp among young patients (pts), describe and correlate the characteristics with clinical presentations and any arrhythmias. Methods This was a 1 y retrospective review of ECGs obtained from patients referred specifically for documented arrhythmias, possible arrhythmia-related symptoms or sports clearance. ECGs were analyzed for ERp (J-point, ascending/horizontal patterns, location) and correlated with presenting complaints. Results Of 301 patient ECGs, an ERp was found in 177 (59%), (pts age 11.7 ± 4.3 y); 54% male; 23% Caucasian. Of these, 6 pts had a family history of sudden cardiac death. Arrhythmias (72% atrial) occurred in 22 pts. Only 3 pts had ventricular arrhythmias (1 successfully ablated). The ascending ST segment and elevated J-point occurred in 77% and 51% of pts with and without arrhythmias respectively. In 73% of all pts, the ERp location was in inferior/lateral leads. Neither gender, ethnicity, large J-point, lead location, nor the combination of a horizontal ST segment with large J-point correlated with any arrhythmias. Conclusions ERp, especially the diffuse ascending pattern, is common among the young, in those of European ethnicity, found equally in both genders, and with no apparent correlation with atrial nor ventricular arrhythmias.

Patients with congenital heart defects (CHD) often present more challenges to pacing therapy due to anatomy than those without CHD. The lumenless, 4.1Fr diameter M3830 pacing lead (Medtronic, Inc., Minneapolis, MN, USA), approved for use in 2005, has, to date, reported to have excellent short-term (6 years) lead performance. Unfortunately, very long-term performance is unknown, especially among CHD patients and with implants at alternate pacing (AP) sites. This study reports a 10-year clinical experience with the M3830 lead.Records of patients who received the M3830 lead were reviewed: patient demographics, implant techniques and locations, sensing and pacing characteristics, impedances (Imp), and any complications at implant and follow-up.From 2005 to 2015, 141 patients (ages 2-50, mean 20.1 years, 57% males) received 212 leads: atrial 115; ventricle 97. CHD was present in 62% of patients. Leads were inserted at AP sites in 96% of patients. Postimplant follow-up was from 3 months to 10 years (mean 56.3 months). Comparative implant versus follow-up values (mean ± standard deviation) were available on 196 leads (92.5%), showing persistently low (1 v @ 0.4-0.5 ms) pacing thresholds (P = 0.57). Sensing was also comparable (atrial leads, P = 0.41; ventricular leads, P = 0.9). Impedances differed (P0.05) but remained within the normal range. Two A leads became dislodged and one was repositioned while two other leads (1 A, 1 V) were extracted. There are no differences observed in the pacing characteristics between the CHD and non-CHD groups on follow-up.The 4.1Fr lumenless pacing lead shows ease of implant regardless of CHD or AP site, excellent very long-term (10 years) stability, and performance indices with a very low rate of complications.

Background: Cryoablation (Cryo) has augmented radiofrequency (RF) as the ablation energy choice for most supraventricular tachycardias (SVT). Although initial acute results and more recent, but limited, 3‐36-month follow-up studies have been reported, more longer follow-up information is required to determine actual efficacy. Methods: Data from patients with structurally normal hearts who underwent reentrant forms of SVT ablation at our institution from January 2005 to December 2009 were reviewed. These included demographics, clinical and electrophysiologic findings, and ablative energies used. Following apparent acute success, all patients were then reevaluated for any potential recurrences of SVT or preexcitation up to 5 years later. Results: A total of 155 patients (83 male) were reviewed (mean age 13.4 ± 3.7 years). Ablations were predominantly right-sided (75%). Atrioventricular reciprocating tachycardia was seen in 74% and atrioventricular node reciprocating tachycardia (AVNRT) in 17% of patients. For concerns of atrioventricular node integrity, Cryo ± RF was user-preferred for anteroseptal accessory fiber locations and AVNRT. Acute success rate was 98% and chronic 83.2% over the next 5 years. Among patients with accessory pathways, recurrence was pathway number and location dependent: significantly higher (P < 0.05) if they were right anterior-anteroseptal, multiple, or with a broad-distribution pattern. There were no significant differences in recurrence rates with use of RF or its combination with Cryo. Conclusion: Radiofrequency ablation and Cryo are both effective therapies for pediatric patients. Although use of Cryo with RF in combination may enhance safety while affording comparable success, risk of recurrence still persists in the current era among patients depending on accessory pathways connection location and characteristics. (PACE 2012; 35:711‐717)

Objective. Intraatrial Mustard baffle repair of dextro-transposition of the great arteries (d-TGA) is vulnerable to complications, typically obstruction and leaks. Because patients often require pacemakers or intracardiac electrophysiology studies (EPS)/ablation for arrhythmias, narrowed or obstructed baffles restrict cardiac access hindering intracardiac procedures. Current guidelines recommend clinical as well as comprehensive transthoracic echocardiographic/Doppler (TTE) studies to identify baffle problems. This study reviews the effectiveness of these guidelines in detection of baffle issues pre-EPS catheterization and need for ancillary vascular interventions. Design. Data from all patients with repaired d-TGA referred for hemodynamic catheterization or EPS between 1995 and 2009 at our institution were reviewed, including symptoms and TTE findings. Obstruction was defined as either a disturbed color Doppler flow or mean velocity >1 m/s above the mitral valve or directly measured pressure gradient >4 mm Hg or more than 50% baffle diameter narrowing by venography. Results. Of 59 patients (34 pacemaker, 9 ablation, 16 routine hemodynamic) ages 8–39 years (mean 22.8), only three (5%) had symptoms of obstruction. However, baffle complications were found in 33 patients (56%), some with more than one problem: superior vena cava (SVC) obstruction in 32, inferior VC in two and leak in four. Baffle stenting was required in 24 patients and leak closure in two. Precatheterization TTE was available in 51 patients and showed 34% sensitivity, 61% specificity, 63% negative predictive value, and only 37% positive predictive value in recognizing baffle complications when compared with the actual catheterization findings. Conclusion. This study reports that baffle complications in patients with d-TGA following Mustard operation are more common than previously reported. However, comprehensive TTE and clinical symptoms are not effective enough to recognize these complications. Suspicion of and better noninvasive imaging prior to catheterization is required.

Chronic right ventricular (RV) pacing is associated with deleterious effects on cardiac function. In an observational multicentre study in children with isolated atrioventricular (AV) block receiving chronic ventricular pacing, the importance of the ventricular pacing site on left ventricular (LV) function was investigated. Demographics, maternal autoantibody status and echocardiographic measurements on LV end-diastolic and end-systolic dimensions and volumes at age 1 year) for isolated AV block. LV fractional shortening (LVFS) and, if possible LV ejection fraction (LVEF) were calculated. Linear regression analyses were adjusted for patient characteristics. From 27 centres, 297 children were included, in whom pacing was applied at the RV epicardium (RVepi, n = 147), RV endocardium (RVendo, n = 113) or LV epicardium (LVepi, n = 37). LVFS was significantly affected by pacing site (p = 0.001), and not by maternal autoantibody status (p = 0.266). LVFS in LVepi (39 ± 5%) was significantly higher than in RVendo (33 ± 7%, p < 0.001) and RVepi (35 ± 8%, p = 0.001; no significant difference between RV-paced groups, p = 0.275). Subnormal LVFS (LVFS < 28%) was seen in 16/113 (14%) RVendo-paced and 21/147 (14%) RVepi-paced children, while LVFS was normal (LVFS ≥ 28%) in all LVepi-paced children (p = 0.049). These results are supported by the findings for LVEF (n = 122): LVEF was

Innovative, nonthoracotomy, catheter-delivered therapies have redefined the approach to and treatment of congenital heart defects. Starting in the 1960s with the creation of an opening in the atrial septum to permit effective blood mixing and improve oxygen saturation in cyanotic infants, interventional cardiac procedures continue to replace many of the time-honored surgeries that were the mainstay of repair or correction for infants and children with heart defects. Now as those children reach adulthood and still require modifications of their defects, catheter-based interventions are becoming more important. This article examines some of the more recent applications of device therapy currently available to patients with congenital heart, including heart failure, septal defects, vascular problems and heart valves. Device use in deference to surgery, risks and benefits as well as complications associated with such catheter-delivered therapies are discussed.

Purpose: United States approval of the Model 3830, 4.1-French (Fr) diameter, lumenless, pacing lead (Medtronic Inc., Minneapolis, MN, USA) in patients under 17 years of age, and those with congenital heart disease (CHD), was in 2005. To date, long-term performance at alternative pacing sites (APS) is limited and chronic efficacy comparisons with more established leads is lacking. The purpose of this study was to evaluate these factors. Methods: Implant and follow-up data on leads were compared: group 1 (non-3830 leads) and group 2 (Model 3830 leads). These included acute and chronic sensing and pacing, impedances, implant sites, and complications. Groups were compared using Fischer's exact test, paired, and nonpaired t-tests, with significance defined at P < 0.05. Results: A total of 119 patients (ages 5–48 years) received 171 leads: group 1 (n = 80) and group 2 (n = 91). At implant, there were no differences in patient age, CHD, sensing, or pacing thresholds between groups. Implant lead impedances differed between groups but all were within normal values for each lead design. Chronic data showed no difference in sensing, pacing thresholds, or impedances. There were five (6%) early lead dislodgements in group 1 and one (1%) in group 2. APS were achieved in group 2 with mean 1.6 ± 1.3 minutes fluoroscopy time. Conclusion: The new 4.1-Fr lumenless lead shows similar performance indices to established leads even at APS, yet is thinner and achieves APS with technical ease, permitting more efficient chronic pacing in children and all patients with CHD. (PACE 2010; 33:1467–1474)

Tachyarrhythmias can occur at any age from the developing fetus through adulthood. However, in deference to adult-onset ischemic cardiac issues, abnormal heart rhythms occurring in the young are often due to developmental alterations of the cardiac conduction tissue, genetically-inherited changes of myocardial cellular ion membrane properties and both pre- and post-surgical repair of associated structural congenital heart anatomical defects. And different from adults, abnormal rhythms occurring in the young can spontaneously disappear with progressive patient growth. Both supra- and ventricular tachyarrhythmias occur in the young although atrial rhythm abnormalities far exceed those of the ventricle. In both, pharmacologic therapies to alter tissue conduction and refractoriness remain the mainstay for initial intervention in the infant and young child, reserving more invasive and potentially harmful ablation therapies for drug-refractory cases. The purpose of the review is to present common and uncommon tachyarrhythmias which can occur in the fetus and throughout infancy. Emphasis will be placed on their electrocardiographic identification, recognition of any associated structural congenital heart defects and recommended pharmacologic management. Drug therapies will be divided according to mechanism of action and discussions of which particular agent is potentially best-suited to treat which specific tachyarrhythmia. A listing of current pharmacologic agents used in the young with appropriate dosages is included.