New Guidelines of Pediatric Cardiac Implantable Electronic Devices: What Is Changing in Clinical Practice?

Guidelines are important tools to guide the diagnosis and treatment of patients to improve the decision-making process of health professionals. They are periodically updated according to new evidence. Four new Guidelines in 2021, 2022 and 2023 referred to pediatric pacing and defibrillation. There are some relevant changes in permanent pacing. In patients with atrioventricular block, the heart rate limit in which pacemaker implantation is recommended was decreased to reduce too-early device implantation. However, it was underlined that the heart rate criterion is not absolute, as signs or symptoms of hemodynamically not tolerated bradycardia may even occur at higher rates. In sinus node dysfunction, symptomatic bradycardia is the most relevant recommendation for pacing. Physiological pacing is increasingly used and recommended when the amount of ventricular pacing is presumed to be high. New recommendations suggest that loop recorders may guide the management of inherited arrhythmia syndromes and may be useful for severe but not frequent palpitations. Regarding defibrillator implantation, the main changes are in primary prevention recommendations. In hypertrophic cardiomyopathy, pediatric risk calculators have been included in the Guidelines. In dilated cardiomyopathy, due to the rarity of sudden cardiac death in pediatric age, low ejection fraction criteria were demoted to class II. In long QT syndrome, new criteria included severely prolonged QTc with different limits according to genotype, and some specific mutations. In arrhythmogenic cardiomyopathy, hemodynamically tolerated ventricular tachycardia and arrhythmic syncope were downgraded to class II recommendation. In conclusion, these new Guidelines aim to assess all aspects of cardiac implantable electronic devices and improve treatment strategies.

Prevalence and Clinical Significance of Intraventricular Conduction Disturbances in Hospitalized Children.

Introduction: Data on the prevalence and clinical significance of interventricular conduction disturbances (IVCDs) in children are scarce. While incomplete right bundle branch blocks (IRBBBs) seem to be the most frequent and benign findings, complete bundle blocks and fascicular blocks are often seen in children with congenital/acquired cardiac conditions. This study aims to delineate the prevalence and the diagnostic accuracy of IVCD in children admitted to a paediatric cardiology unit. Methods: Children admitted to the paediatric cardiology unit between January 2010 and December 2020 who had an ECG were included in the study. IVCDs were diagnosed according to standard criteria adjusted for age. Results: Three thousand nine hundred and ninety-three patients were enrolled. The median age was 3.1 years (IQR: 0.0-9.2 years), and 52.7% were males. IVCDs were present in 22.5% of the population: 17.4% of the population presented with IRBBBs, 4.8% with a complete right bundle branch block (CRBBB), 0.1% with a complete left bundle branch block (CLBBB), 0.2% with a left anterior fascicular block (LAFB) and 0.2% with a combination of CRBBB and LAFB. Also, 26% of children with congenital heart disease had an IVCD, and 18% of children with an IVCD had previous cardiac surgery. The overall sensitivity of IVCD in detecting a cardiac abnormality was 22.2%, with a specificity of 75.5%, a PPV of 83.1% and an NPV of 15.1%, but the values were higher for CLBBB and LAFB. Conclusions: IVCDs were present in one-fifth of children admitted to the cardiology unit. IRBBB was the most frequent disturbance, while CRBBB, CLBBB and fascicular blocks were much rarer, though they had a higher predictive value for cardiac abnormalities.

Single-Chamber and Dual-Chamber Pacemaker Devices in Adults with Moderate and Complex Congenital Heart Disease: A Single Tertiary Referral Center Experience.

The number of device implantation procedures has increased in adult patients with congenital heart disease (ACHD). Despite significant improvements in materials and implantation techniques, these patients are exposed to higher risk of device related complications than general population. Herein, we describe our single tertiary referral center experience on transvenous pacemaker (PM) implantation and follow-up in adult patients with moderate and complex congenital heart disease (CHD) as limited data are available on long-term outcome. We considered all adults with moderate and complex CHD aged more than 16 years who underwent transvenous single-chamber and dual-chamber PM implant for sinus node dysfunction or atrioventricular block between January 2013 to December 2022 at our Unit. Seventy-one ACHD patients were included in the study (mean age 38.6 ± 15.2 years, 64% with moderate CHD, 36% with complex CHD). Among 32 patients implanted with a dual chamber PM (DDD PM), 4 devices were reprogrammed in VDD mode, 3 in VVI and 2 in AAI mode during follow-up because of lead dysfunction or permanent atrial arrhythmia. In addition, 26 patients had a single chamber PM (AAI or VVI PM) and 13 patients had single-lead pacing system with a free-floating atrial electrode pair (VDD PM). Just one of 13 single-lead VDD PM was reprogrammed in VVI mode due to a low atrial sensing. In DDD PM group, 10 re-interventions were needed due to lead dysfunction (8 cases) and lead-related infective endocarditis (2 cases). Only 3 patients in the single-lead PM group developed lead dysfunction with 2 re-interventions needed, but no infective endocarditis was reported. The rate of long-term complications is high in moderate and complex ACHD with transvenous PM devices, and it is mainly lead-related. In our experience, the less leads implanted, the less complications will occur. Considering the heterogeneity of the ACHD population, transvenous single-chamber or dual-chamber PM device implantation should always be tailored on the single patient, balancing risks and benefits in this complex population.

Contact allergy to subcutaneous implantable cardioverter defibrillator in a child with Brugada syndrome.

Allergic reactions to components of cardiac implantable electronic devices are rare and often go undiagnosed, which can lead to a misdiagnosis of device infection. Contact allergy to subcutaneous implantable cardioverter defibrillator (S-ICD) is extremely rare. In this report, we present a case of cobalt-related contact allergy in a pediatric patient with Brugada syndrome who underwent S-ICD implantation.

Combined subcutaneous implantable cardioverter defibrillator and pacemaker devices in complex congenital heart disease: a single-center experienced based study.

BACKGROUND: Subcutaneous implantable cardioverter defibrillators (S-ICD) are widely accepted therapy in congenital heart disease (CHD) patients at risk of life-threatening ventricular arrhythmias or sudden cardiac death (SCD) when pacing is not required. Occasionally, pacemaker (PM)-dependent CHD patients will subsequently develop an indication for a cardioverter defibrillator. The use of S-ICD in complex CHD patients who have had already PM devices implanted implies some specific considerations, as the safety for these patients in unknown and recommendations among physicians may vary widely. METHODS: We review the data and studied the indications for S-ICD in complex CHD with previous PM and discuss its usefulness in clinical practice. RESULTS: From a large cohort of 345 patients enrolled in the S-ICD Monaldi care registry, which encompass all the patients implanted in the Monaldi Hospital of Naples, we considered 11 consecutive complex CHD patients (10M/1F aged 40.4 ±18.4 years) who underwent S-ICD implant after a previous PM implant, from February 2015 to October 2022. Mean follow-up was 25.5 ± 22 months. All the patients showed a good compliance to the device system with no complications (infections or skin erosions). CONCLUSIONS: In complex CHD with already implanted PM devices, S-ICD implant appears to be a safe alternative to PM upgrading to transvenous ICD system, avoiding abandoned leads or life-threatening lead extraction. However, there are important issues with regard to testing and programming that need to be addressed at the time of implantation.

Contact force sensing radiofrequency catheter ablation guided by electroanatomic mapping in pediatric patients with permanent junctional reciprocating tachycardia: A case series.

Limited data are available on the use of irrigated contact force (CF) catheters for radiofrequency (RF) ablation of permanent junctional reciprocating tachycardia (PJRT) in children. We considered five consecutive pediatric patients with diagnosis of PJRT who underwent RF ablation with irrigated CF catheter guided by electroanatomic mapping, obtaining a low number of RF pulses and minimal fluoroscopy exposure. High CF values are not necessary to obtain effective RF lesions and successful ablation.

Diagnosis and treatment of fetal and pediatric age patients (0-12 years) with Wolff-Parkinson-White syndrome and atrioventricular accessory pathways.

Overt or concealed accessory pathways are the anatomic substrates of ventricular preexcitation (VP), Wolff-Parkinson-White syndrome (WPW) and paroxysmal supraventricular tachycardia (PSVT). These arrhythmias are commonly observed in pediatric age. PSVT may occur at any age, from fetus to adulthood, and its symptoms range from none to syncope or heart failure. VP too can range from no symptoms to sudden cardiac death. Therefore, these arrhythmias frequently need risk stratification, electrophysiologic study, drug or ablation treatment. In this review of the literature, recommendations are given for diagnosis and treatment of fetal and pediatric age (≤12 years) WPW, VP, PSVT, and criteria for sport participation.

Remote monitoring of implantable loop recorders reduces time to diagnosis in patients with unexplained syncope: a multicenter propensity score-matched study.

Background: There are little data on remote monitoring (RM) of implantable loop recorders (ILRs) in patients with unexplained syncope and whether it confers enhanced diagnostic power. Objective: To evaluate the effect of RM in ILR recipients for unexplained syncope for early detection of clinically relevant arrhythmias by comparison with a historical cohort with no RM. Methods: SyncRM is a propensity score (PS)-matched study prospectively including 133 consecutive patients with unexplained syncope and ILR followed up by RM (RM-ON group). A historical cohort of 108 consecutive ILR patients with biannual in-hospital follow-up visits was used as control group (RM-OFF group). The primary endpoint was the time to the clinician's evaluation of clinically relevant arrhythmias (types 1, 2, and 4 of the ISSUE classification). Results: The primary endpoint of arrhythmia evaluation was reached in 38 patients (28.6%) of the RM-ON group after a median time of 46 days (interquartile range, 13-106) and in 22 patients (20.4%) of the RM-OFF group after 92 days (25-368). The PS-matched adjusted ratio of rates of arrhythmia evaluation was 2.53 (95% confidence interval, 1.32-4.86) in the RM-ON vs. RM-OFF group (p = 0.005). Conclusion: In our PS-matched comparison with a historical cohort, RM of ILR patients with unexplained syncope was associated with a 2.5-fold higher chance of evaluations of clinically relevant arrhythmias as compared with biannual in-office follow-up visits.

Triple Antiarrhythmic Therapy in Newborns with Refractory Atrioventricular Reentrant Tachycardia.

Atrioventricular reentrant tachycardia (AVRT) is the most common form of supraventricular tachycardia in newborns. AVRT is sometimes refractory to conventional antiarrhythmic therapy. We describe our experience about the use of the triple combination of flecainide + propranolol + amiodarone as third-line regimen for refractory and recurrent AVRT in newborns. We considered a series of 14 patients who had failed both first-line and second-line therapy and were treated using the combination of flecainide + propranolol + amiodarone. Transoesophageal electrophysiologic study (TES) was performed to test the effectiveness of medical therapy during hospitalization and to try to reduce the amount of therapy, after amiodarone wash-out, before 1 year of age. TES was repeated at 1 year of age to test the spontaneous resolution of the arrhythmia after treatment discontinuation. Rhythm control was achieved in all 14 patients. At a mean age of 9.3 ± 2 months, AVRT was not inducible by TES in 11/12 amiodarone-free patients. At a mean age of 14.1 ± 3 months, AVRT was still inducible in 7/12 patients after interrupting the entire antiarrhythmic therapy (58.3%). Triple combination was effective as third-line option to suppress AVRT refractory to single and double antiarrhythmic therapy, with no significant adverse events. Our experience suggests that triple therapy could be maintained for a short-term treatment, discontinuing amiodarone before 1 year of age to avoid long-term side effects. Newborns who needed triple therapy appear to have a lower chance of accessory pathway disappearance at 1 year of age. TES could be useful for risk stratification of recurrences at the time of drug discontinuation in infants considered to be at higher risk of recurrent AVRT.

Implantable Loop Recorder with Long Sensing Vector: Safety, Acceptability, and Sensing Performance in Pediatric Patients.

Implantable loop recorders (ILRs) are effective tools for detecting arrhythmias by long-term continuous heart rhythm monitoring. Benefits have been demonstrated even in pediatric patients. ILR with a long sensing vector has recently been designed to improve signal quality in terms of P wave visibility and R wave amplitude. However, there are no data on its use in pediatric patients. We considered a series of pediatric patients implanted with a long sensing vector ILR. Sensing performance, including R wave amplitude and P wave visibility, device-related complications, and diagnostic yield were collected. During follow-up, each patient guided by his/her parents/guardians was also asked to complete a brief questionnaire to assess patient acceptability of the device. Twenty-five consecutive pediatric patients (mean age 11.3 ± 3.5 years, 72% male) were enrolled. The insertion success rate was 100% on the first attempt with no complications. The median amplitude of the R wave was 1.15 mV (interquartile range, 1.01-1.42) with no significant differences between patients aged ≤ or > 10 years (p = 0.726) and between female and male (p = 0.483). P wave was classified as 'always visible' in 24/25 patients (96%). ILR was generally well accepted and tolerated by all involved patients. During a median follow-up of 297 days (117-317), we achieved in 5 patients a correlation between symptoms and rhythm disorders (20%) and ruled out significant arrhythmias in 6 symptomatic children (24%). Long sensing vector ILR showed to be well accepted, with good signal quality and an excellent safety profile even in pediatric patients.

Severe Lymphatic Disorder and Multifocal Atrial Tachycardia Treated with Trametinib in a Patient with Noonan Syndrome and SOS1 Mutation.

Noonan syndrome (NS) is a multisystemic disorder caused by germline mutations in the Ras/MAPK cascade, causing a broad spectrum of phenotypical abnormalities, including abnormal facies, developmental delay, bleeding diathesis, congenital heart disease (mainly pulmonary stenosis and hypertrophic cardiomyopathy), lymphatic disorders, and uro-genital abnormalities. Multifocal atrial tachycardia has been associated with NS, where it may occur independently of hypertrophic cardiomyopathy. Trametinib, a highly selective MEK1/2 inhibitor currently approved for the treatment of cancer, has been shown to reverse left ventricular hypertrophy in two RIT1-mutated newborns with NS and severe hypertrophic cardiomyopathy. Severe lymphatic abnormalities may contribute to decreased pulmonary compliance in NS, and pulmonary lymphangiectasias should be included in the differential diagnosis of a newborn requiring prolonged oxygen administration. Herein we report the case of a pre-term newborn who was admitted to our unit for the occurrence of severe respiratory distress and subentrant MAT treated with trametinib.

Subcutaneous finger cardioverter-defibrillator in low weight paediatric patients: a case series.

Placement of traditional transvenous implantable cardioverter defibrillator (ICD) system in low-weight children is often difficult because of their vessel size, the elevated risk of lead malfunction and failure, children's growth and various anatomic constraints, creating the need for alternative solutions. Subcutaneous array leads combined with an abdominally placed ICD device can minimize the surgical approach. In this case series, we analyse the data behind indications for subcutaneous finger cardioverter defibrillator (SFCD) and discuss the preliminary clinical experience in low-weight children. We considered 4 consecutive children (mean age 3.9 years, range 3-5.5 years, mean body weight 17.6 Kg, range 14-23 Kg) who underwent SFCD implant from April 2016 to August 2020. All patients showed a good compliance to the device system with no complications (infections or skin erosions). No patients experienced in the observation period (mean time 44.5±21.5 months) sustained ventricular arrhythmias requiring shocks. No inappropriate shocks released by the device occurred. No significant changes were observed in LET (lowest energy tested) performed around 24 months of follow-up. All patients showed a good compliance and stable atrio-ventricular sensing and pacing thresholds. In smaller children in whom a transvenous approach is not feasible or not possible for anatomic reasons, the SFCD appears to be a safe method to prevent SCD with little surgical trauma and preservation of an intact vascular system, providing an adequate bridge to transvenous ICD or subcutaneous ICD implant late in the life.

Wearable cardioverter-defibrillator (life-vest): A feasible bridging treatment in adult congenital heart disease.

BACKGROUND: Wearable cardioverter-defibrillators (WCDs) are currently used in patients at temporarily heightened risk for sudden cardiac death (SCD) who are temporarily unable to receive an implantable cardioverter-defibrillator (ICD). WCD can safely record and terminate life-threatening arrhythmias through a non-invasive electrode-based system. The current clinical indications for WCD use are varied and keep evolving as experience with this technology increases. METHODS: We reviewed and explored the data behind indications for WCD use and discuss its usefulness in congenital heart disease (CHD) patients. RESULTS: We considered 8 consecutive patients (mean age 35.25 years, range 18-51 years, average duration of WCD use 4 months, range 3-6 months) with complex CHD, in which a WCD was used between June 2018 and January 2022. No sustained ventricular arrhythmias requiring shocks were recorded in the observation period. No inappropriate shocks were recorded. All the patients showed a good compliance and a very high mean wear time per day (21.2 ± 1 h a day). Four patients implanted a permanent device (3 CRT-D, 1 ICD), three underwent cardiac surgery at the end of the WCD period and one is still on the waiting list for the operation. CONCLUSIONS: Larger trial could confirm the possible conceivable benefit from an extended use of the WCD in certain populations with complex CHD as in our case series, especially in patients with life-treating ventricular arrhythmias waiting for surgery for residual cardiac defects or in the early phases following the surgical/hemodynamic interventions, patients with tachycardiomyopathy expected to improve after the arrhythmias are removed and patients awaiting implantation of an ICD at high risk due to active infection.

Cardiac resynchronization therapy-defibrillator implantation guided by electroanatomic mapping in a young adult patient with congenital heart disease.

Cardiac resynchronization therapy-defibrillator (CRT-D) implantation is a therapeutic option for adult patients with congenital heart disease (CHD), bundle branch block, reduced ejection fraction and symptoms of heart failure. A new implantation approach guided by the electroanatomic mapping (EAM) has been developed to overcome some issues of the standard technique: non-responder patients, high x-ray exposure and use of iodinated contrast medium for coronary sinus angiography. This approach has not been previously described in the CHD population. We report a case of EAM-guided approach for CRT-D implantation in a young adult patient with CHD.

Subcutaneous implantable cardioverter defibrillator in children and adolescents: results from the S-ICD "Monaldi care" registry.

BACKGROUND: Implantable cardioverter defibrillators (ICD) are widely accepted therapy in children and adolescents who are survivors of cardiac arrest or for high-risk patients with inheritable channelopathies, cardiomyopathies, or congenital heart disease. Initial experience with subcutaneous ICD (S-ICD) systems has shown a high efficacy in adults. However, the use of S-ICD in children and adolescents implies some specific considerations, as the safety for these patients is unknown and recommendations among physicians may vary widely. METHODS: We reviewed the data and studied the indications for S-ICD in children and adolescents and discuss the preliminary clinical experience. RESULTS: From a cohort of 297 patients enrolled in the S-ICD "Monaldi care" registry that encompass all the patients implanted in the Monaldi Hospital of Naples, we considered 21 consecutive children and adolescents (mean age 13.9 years, range 8-18 years, mean body weight 59.3 kg, range 38-100 kg) who underwent S-ICD implant from April 2014 to June 2020. Mean follow-up was 41.9±21.9 months. Only one patient presented, 6 weeks after implantation, skin erosion at the inferior parasternal incision that resolved after antibiotic therapy, without the necessity of any system revision. Two patients experienced appropriate shocks and four inappropriate shocks, due to T wave oversensing or atrial arrhythmia. Only one patient, with arrhythmogenic right ventricular dysplasia, required a system revision after 36 months of the first implantation and then a reintervention with a replacement of the S-ICD by a conventional ICD system. CONCLUSIONS: Our experience suggests that the S-ICD device can be used in some children over the age of 8 as well as adults, with a similar rate of unwanted side effects, and early evidence of apparent efficacy.

Prognostic Relevance of Thyroid Disorders in Adults With Congenital Heart Disease.

Adults with congenital heart disease (ACHD) are frequently affected by thyroid diseases (TDs). However, the clinical relevance of TD in ACHD remains unknown. We aimed to describe the prevalence of TD in the ACHD population and to ascertain whether TD are associated with worse outcome. Patients with ACHD >18 years attending our tertiary center for a day-case between 2014 and 2019 were included. Clinical data between patients' first visit and December 2020 were collected. Primary end point was a combination of death, hospitalization for heart failure (HF), and new-onset of arrhythmic events. Secondary end points were each part of the primary outcome as separate end points. A total of 495 patients with ACHD (32.2 [24.5 to 45.6] years; 54% women) were included. Median follow-up was 9.4 (4.5 to 13.1) years. The prevalence of TD was 30%. TD group showed worse clinical status, as demonstrated by N-terminal pro b-type natriuretic peptide values (243.5 [96.5 to 523] vs 94 [45 to 207] pg/ml, p <0.001) and New York Heart Association class (27% vs 13% in class III to IV, p <0.0001) with higher incident rate of adverse events at follow-up (4.45 [3.43 to 5.69] % vs 1.29[0.94 to 1.75] % per person-year, p <0.001). TD were independently associated with higher risk of death (hazard ratio [HR] 4.1, p = 0.009), arrhythmic events (HR 3.8, p <0.0001), and hospitalization for HF (HR 8.02, p <0.0001). There was a fourfold increased risk of primary end point in the TD group even after propensity score matching for clinical variables including age, gender, disease complexity, physiological stage, previous palliative surgery, ventricular function, pulmonary arterial hypertension, cyanosis, and presence of systemic right ventricle (HR 4.47, p <0.0001). In conclusion, TD are predictive of adverse outcome in the ACHD population. Routine screening of thyroid function during follow-up in this population may be helpful to identify those with higher risk of death, arrhythmias, and HF.

The Risk of Sudden Unexpected Cardiac Death in Children: Epidemiology, Clinical Causes, and Prevention.

"Sudden unexplained death (SUD) is a tragic event for both the family and community, particularly when it occurs in young individuals. Sudden cardiac death (SCD) represents the leading form of SUD and is defined as an unexpected event without an obvious extracardiac cause, occurring within 1 hour after the onset of symptoms. In children, the main causes of SCD are inherited cardiac disorders, whereas coronary artery diseases (congenital or acquired), congenital heart diseases, and myocarditis are rare. The present review examines the current state of knowledge regarding SCD in children, discussing the epidemiology, clinical causes, and prevention strategies."

A frightening giant QRS complex in a 3-months-old infant.

A 3-months-old infant was urgently admitted for drowsiness and lack of appetite started 24 h before. The ECG showed sinus rhythm with a prolonged AV interval (200 ms) and very large QRS complexes (280 ms) due to Flecainide overdosing following incorrectly administration for poor communication between parents resulted in both giving a dose to the infant. Flecainide serum level was 1.2µg/ml, confirming the diagnosis of an accidental drug intoxication. The patient started continue hydration with a close monitoring. Three hours later a significant narrowing of the QRS complex (150 ms) was observed, then over the following 24 h, the QRS almost completely normalized.