Ventricular Functional Analysis in Congenital Complete Heart Block Using Speckle Tracking: Left Ventricular Epicardial Compared to Right Ventricular Septal Pacing.

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 the 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, Peak Longitudinal Strain myocardial (PLS Myo) [- 12.0 ± 3.3 vs. - 18.1 ± 1.9, p < 0.001] and Peak Longitudinal Strain endocardial (PLS endo) [- 16.1 ± 4.1 vs. 1.7 ± 1.7, p < 0.001]. STE parameters of LV function were significantly more abnormal in LVEp vs. RVSp subgroup as demonstrated 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). CONCLUSION: STE was more sensitive in detecting subtle differences in LV function relative to standard conventional 2D echocardiography (SF and EF) in selected patients with CCAVB and a 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.

Cardiac Amyloidosis in a Child Presenting with Syncope: The First Reported Case and a Diagnostic Dilemma.

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.

Assessing Non-invasive Studies to Evaluate Resynchronization Pacing Effectiveness in the Young.

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.

2021 PACES expert consensus statement on the indications and management of cardiovascular implantable electronic devices in pediatric patients.

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.

2021 PACES expert consensus statement on the indications and management of cardiovascular implantable electronic devices in pediatric patients: Executive summary.

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.

2021 PACES expert consensus statement on the indications and management of cardiovascular implantable electronic devices in pediatric patients.

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.

Influenza associated with circulatory collapse and atrioventricular block in an unvaccinated child with repaired CHD.

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.

Comparative Cardiorespiratory Fitness in Children: Racial Disparity May Begin Early in Childhood.

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.

Pulmonary damage following right ventricular outflow tachycardia ablation in a child: When electroanatomical mapping isn't good enough.

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.

Ten-Year Clinical Experience with the Lumenless, Catheter-Delivered, 4.1-Fr Diameter Pacing Lead in Patients with and without Congenital Heart.

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 (<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. METHODS: 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. RESULTS: 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 (P < 0.05) 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. CONCLUSIONS: 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.

Utility of Echocardiography in Detecting Silent Complications After Pediatric Catheter Ablations.

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 < 0.001). TCA location (including coronary sinus), energy source, arrhythmia substrate, and a trans-septal approach were noncontributory to any adverse findings. Routine post-ablation TTE uncovers asymptomatic self-resolving abnormalities that typically do not require any intervention.

Junctional tachycardia in a child with non-rheumatic fever streptococcal pharyngitis.

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.

Optimizing paced ventricular function in patients with and without repaired congenital heart disease by contractility-guided lead implant.

BACKGROUND: This study evaluates the concept of optimizing ventricular pacing in regard to functional cardiac response. Lead implant based on physiologic variables of contractility at various sites was performed in patients with and without congenital heart disease (CHD). Since right ventricular apical pacing may adversely alter contractility and myocellular function, septal and outflow tract pacing have been advocated. However, there are few studies in the young and essentially none in those with CHD. METHODS: A total of 113 consecutive patients with and without repaired CHD, aged two to 51 (median 16), some with preexisting epicardial pacemakers, underwent transvenous pacemaker implant using standard sensing/pacing indices plus measurements of pressures, QRS, and contractility responses at each of five predefined potential ventricular implant sites: apex, inflow-, low-, mid-, and infundibular/outflow-septal with each patient serving as his/her own control. Implant was at the site of best contractility with active-fixation, low-threshold steroid-eluting leads. RESULTS: Measured contractility indices varied up to 31% (mean 12%) between sites per patient. Septal regions (mid-, inflow-, and low-) were associated with the most optimal and right ventricular epicardial showed the worst contractility (P < 0.05) responses. Apex was optimal in some CHD patients. Threshold and sensing were comparable up to 11 years (mean 7) postimplant regardless of septal site. CONCLUSION: There is no single "sweet spot" for optimal ventricular pacing, and the best implant sites are patient and CHD variable. Current lead designs ensure chronic stability/performance regardless of site. Proactive contractility-guided pacing implant can optimize chronic paced ventricular function.

Comparative Chronic Valve and Venous Effects of Lumenless versus Stylet-Delivered Pacing Leads in Patients with and Without Congenital Heart.

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 <12 years of age showed normal while 50% of those from Group 2 exhibited stunted SVC or INN growth (P < 0.05). CONCLUSION: The lumenless, 4.1-Fr diameter PL offers improved clinical benefits, better AVV integrity, and venous development compared with larger 5-7-Fr diameter PL and should be considered especially in younger patients with/without CHD.

Improving pacemaker therapy in congenital heart disease: contractility and resynchronization.

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.

Testing efficacy in determination of recurrent supraventricular tachycardia among subjectively symptomatic children following "successful" ablation.

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.

Indications for Cardiac Resynchronization Therapy in Patients with Congenital Heart Disease.

Heart failure in patients with congenital heart disease (CHD) stems from unique causes compared with the elderly. Patients with CHD face structural abnormalities and malformations present from birth, leading to altered cardiac function and potential complications. In contrast, elderly individuals primarily experience heart failure due to age-related changes and underlying cardiovascular conditions. Cardiac resynchronization therapy (CRT) can benefit patients with CHD, although it presents numerous challenges. The complexities of CHD anatomy and limited access to appropriate venous sites for lead placement make CRT implantation demanding.