Lead and generator dysfunction in children and adolescents with epicardial pacemaker and implantable cardioverter defibrillator systems: The challenge of early recognition.

BACKGROUND: A major issue of cardiac implantable electronic device therapy in pediatric patients is the high incidence of lead dysfunctions and associated reinterventions. This study aims to analyze the timing and mode of generator and lead dysfunction. METHODS: Retrospective single-center analysis of 283 children and young adults with an epicardial pacemaker or implantable cardioverter defibrillator therapy from 1998 to 2018. RESULTS: Mean age at implant was 6.1 years (SD ± 5.8 years) and median follow-up 6.4 years (IQR, 3.4-10.4 years) with a total of 1998.1 patient-years of cardiac device therapy. A total of 120 lead-related complications were observed in 82 patients (29.0%). They were detected by device interrogation (n = 86), symptoms (n = 13), intraoperative findings (n = 7), routine chest radiography (n = 5), routine ECG (n = 4), patient alert sound by device (n = 3), and physical examination (n = 2). It was possible to find the date of the event on the device memory in 21 out of 120 lead dysfunctions (18%) with a median time interval between occurrence and detection of 1.3 months (IQR, 0.2-5.0 months). Moreover, 20 generator-related complications were found in 13 patients. CONCLUSIONS: Early recognition of lead and generator dysfunction remains challenging in pediatric patients. As symptoms are relatively rare conditions in the context of PM and ICD dysfunction, close patient monitoring is mandatory, even in asymptomatic patients with a good clinical course. To further improve the safety of pediatric pacing systems, more durable epicardial electrodes are desirable.

Inducibility of atrioventricular nodal reentrant tachycardia and ectopic atrial tachycardia in children under general anesthesia.

BACKGROUND: In children, invasive electrophysiological studies (EPS) and radiofrequency catheter ablations (RFA) of supraventricular tachycardia (SVT) are often performed under general anesthesia. Atrioventricular nodal reentrant tachycardia (AVNRT) and ectopic atrial tachycardia (EAT) must be inducible during EPS as reliable diagnosis and subsequent therapy are not possible in sinus rhythm. This study aims to assess the problem of noninducible AVNRT and EAT under general anesthesia. METHODS AND RESULTS: Anesthesia protocols of 166 patients undergoing EPS were retrospectively analyzed. 122 AVNRT patients were compared to 22 whose tachycardia was not inducible but probably due to an AVNRT mechanism. Another 16 patients with inducible EAT were compared to 6 whose EAT appeared on surface ECG but not during EPS. Demographic characteristics were similar among all groups. Inducibility did not differ (p = .42) between AVNRT patients with inhalational anesthesia (sevoflurane and/or nitrous oxide) and patients with intravenous anesthesia (propofol with/without remifentanil). The EAT group exhibited lower inducibility under intravenous anesthesia (64%) than under inhalational (88%), however without significance (p = .35). CONCLUSION: Tachycardia induction succeeds with similar frequency under both inhalational and intravenous general anesthesia in children with AVNRT. In children with EAT, inhalational anesthesia is associated with a trend towards better inducibility.

Antiarrhythmic Medication in Neonates and Infants with Supraventricular Tachycardia.

Supraventricular tachycardia (SVT) is the most common arrhythmia in neonates and infants, and pharmacological therapy is recommended to prevent recurrent episodes. This retrospective study aims to describe and analyze the practice patterns, effectiveness, and outcome of drug therapy for SVT in patients within the first year of life. Among the 67 patients analyzed, 48 presented with atrioventricular re-entrant tachycardia, 18 with focal atrial, and one with atrioventricular nodal re-entrant. Fetal tachycardia was reported in 27%. Antiarrhythmic treatment consisted of beta-receptor blocking agents in 42 patients, propafenone in 20, amiodarone in 20, and digoxin in 5. Arrhythmia control was achieved with single drug therapy in 70% of the patients, 21% needed dual therapy, and 6% triple. Propafenone was discontinued in 7 infants due to widening of the QRS complex. After 12 months (6-60), 75% of surviving patients were tachycardia-free and discontinued prophylactic treatment. Patients with fetal tachycardia had a significantly higher risk of persistent tachycardia (p: 0.007). Prophylactic antiarrhythmic medication for SVT in infancy is safe and well tolerated. Arrhythmia control is often achieved with single medication, and after cessation, most patients are free of arrhythmias. Infants with SVT and a history of fetal tachycardia are more prone to suffer from persistent SVT and relapses after cessation of prophylactic antiarrhythmic medication than infants with the first episode of SVT after birth.

Pacemaker Implantation in Neonates and Infants: Favorable Outcomes with Epicardial Pacing Systems.

The implantation of pacemakers (PM) in neonates and infants requires particular consideration of small body size, marked body growth potential, and the decades of future pacing therapy to be expected. The aim of this study is to quantify the complications of implantation and outcome occurring at our center and to compare these with other centers. Retrospective analysis of 52 consecutive patients undergoing PM implantation at a single tertiary care center within the first year of life. PMs were implanted at a median age of 3 months (range 0-10 months). Structural heart defects were present in 44 of 52 patients. During a median follow-up time of 40.4 months (range 0.1-114 months), measurements for sensing, pacing thresholds, and lead impedance remained stable. No adverse pacing effect was observed in left ventricular function or dimensions over time. There were 20 reoperations in 13 patients at a median time of 4.7 years (range 0.05-8.2 years) after implantation, for end of battery life (n = 10), lead dysfunction (n = 3), device dislocation (n = 3), infection (n = 3), and diaphragmatic paresis (n = 1). No PM-related mortality occurred. Epicardial pacemaker implantation in neonates and infants is an invasive but safe and effective procedure with a relatively low risk of complications. Our current implantation technique and the use of bipolar steroid-eluting electrodes, which we prefer to implant on the left ventricular apex, lead to favorable long-term results.

Radiofrequency catheter ablation for supraventricular tachycardia in a paediatric population: characteristics of tachycardia mechanisms in a subpopulation with early onset.

BACKGROUND: In children, the first episode of supraventricular tachycardia occurs at various ages. The aim of this study is to describe age-specific tachycardia mechanisms, clinical findings, and outcome in a contemporary cohort of paediatric patients with supraventricular tachycardia. METHODS: Retrospective analysis of 531 consecutive patients with structurally normal hearts under the age of 18 years who underwent invasive electrophysiological study for supraventricular tachycardia. The study population was divided into two groups, early-onset group (n = 57) and late-onset group (n = 474), according to the age of the occurrence of the first tachycardia before or after the age of 12 months. RESULTS: Accessory pathway-mediated tachycardia was more common (82.5 versus 50.1%, p < 0.001) and the proportion of left-sided accessory pathways was more pronounced (74.5 versus 53.7%, p = 0.01) in the early-onset group than in the late-onset group. The antegrade and retrograde refractory periods of the accessory pathways were similar in both groups, but pre-excitation was more common in the early-onset group (50.9 versus 31.9%, p = 0.007). Typical atrioventricular nodal re-entrant tachycardia was more common (36.7 versus 7.0%, p < 0.001) in the late-onset group. There was no difference among the two groups regarding overall outcome. CONCLUSION: Accessory pathway-mediated re-entrant tachycardia is the most common mechanism of recurrent supraventricular tachycardia in infants with structurally normal hearts who are later referred to an electrophysiological study. These pathways often cause pre-excitation and tend to be located on the left side whereas their refractory period is not different from that of patients with late-onset tachycardia.

Long-term outcome of epicardial implantable cardioverter-defibrillator systems in children: results justify its preference in paediatric patients.

Aims: The question of whether transvenous or epicardial implantable cardioverter defibrillator (ICD) system is more beneficial in children and adolescents is controversially discussed. We sought to analyse the long-term outcome after implantation of ICDs using epicardial pacing/sensing and pleural shock leads. Methods and results: Retrospective analysis of 31 consecutive patients undergoing a total of 55 implantations of epicardial/pleural ICD systems below 20 years of age. Median age at implantation was 11.4 years (range 2.2-20) and median follow-up 57 months (range 0.4-127). The ICDs were implanted for primary (n = 17) and for secondary prevention (n = 14). The first defibrillation threshold at implantation was ≤25 J in 94% of the implant procedures. Appropriate shocks occurred in 6 of 31 patients. Inappropriate shocks occurred in 4 of 31 patients triggered by lead fracture, T-wave oversensing, sinus tachycardia, and atrial fibrillation. Freedom from first ICD discharge was 81, 71, and 71% at 3, 6, and 9 years, respectively. Reoperation was indicated in 16 of 31 patients for lead failure (n=11), end of battery life (n=10), generator migration (n=1) and recall (n=1); freedom from reoperation was 74 and 55% at 3 and 6 years. Conclusion: Paediatric epicardial/pleural ICD therapy is feasible, effective, and safe both in the short-term as well as in the long-term perspective at the price of relatively frequent surgical revisions. They do not generally result in an increased burden of inappropriate shocks. This ICD system meets the needs of the paediatric population and can be recommended as a first choice in this age group.

Management of postoperative junctional ectopic tachycardia in pediatric patients: a survey of 30 centers in Germany, Austria, and Switzerland.

Postoperative junctional ectopic tachycardia (JET) is a frequent complication after pediatric cardiac surgery. Current recommendations on how and when to treat JET are inconsistent. We evaluated the management strategies of postoperative JET in German-speaking countries. We sent an online survey to 30 centers of pediatric cardiology that perform surgery for congenital heart defects in Germany (24), Austria (4), and Switzerland (2). The survey asked 18 questions about how and in what treatment sequence postoperative JET was managed. All 30 centers completed the survey (100% return rate). There was general agreement that the management of JET is based on administration of antiarrhythmic drugs, body surface cooling, and temporary pacing. Many centers presented treatment algorithms based on published literature, all centers named amiodarone as the first drug of choice. Significant disagreement was found concerning the timing and sequential order of additional therapeutic measures and particularly about the dosing of amiodarone and the role of R-wave synchronized atrial pacing. CONCLUSION: This survey reveals that from center to center, the treatment of postoperative JET may vary substantially. Future work should focus on those treatment modalities where a high rate of variation is found. Such studies may be of value to achieve commonly adopted treatment recommendations. What is known: • Treatment of postoperative junctional ectopic tachycardia is predominantly based on administration of antiarrhythmic drugs, therapeutic cooling, and temporary pacing. • Amiodarone is the antiarrhythmic drug of choice in this context. What is new: • Dosing and duration of administration of amiodarone differ relevantly from center to center. • The sequential order of drug administration, therapeutic cooling, and pacing is not consistent.

Transseptal puncture for radiofrequency catheter ablations of left-sided arrhythmias in a paediatric population.

Puncturing the atrial septum is frequently used in adults. In children, the transseptal puncture is less common, technically more demanding, and the rate of complications is not well described. We studied the feasibility and safety of this procedure in a retrospective analysis of 157 consecutive children undergoing transseptal puncture for radiofrequency catheter ablation of left atrial targets in two tertiary-care centres between 2005 and 2013. The median age of the patients at intervention was 12.5 years (1.1-18 years), with median weight of 42 kg (range 9.0-97.0 kg). Pre-excitation was found in 102 procedures, accessory pathway with exclusively retrograde conduction in 41, focal atrial tachycardia in nine, left-sided permanent junctional/reciprocating tachycardia-like accessory pathways in three, and atypical atrioventricular nodal re-entry tachycardia in two. All the procedures were guided by fluoroscopy. Additional imaging by transoesophageal echocardiography was used in three patients. Successful transseptal puncture was possible in 99.4% of the cases, ablation in 97.4%. The median time, including mapping and radiofrequency ablation, was 120 minutes (range 60-450), the median fluoroscopy time 10.8 minutes (range 1.8-75), and the median radiation dose 3 Gy cm2 (range 0.3-35). In total, five patients (3.2%) had a recurrent arrhythmia during the observation period of a median of 40 months (range 1-103). No complications associated with the transseptal puncture were observed. Transseptal puncture is a feasible and safe procedure in children. This access allows successful and efficient radiofrequency ablation of arrhythmia of the left atrium in the vast majority of the patients and might be considered as the first-line approach in this population.

Transseptal Puncture Guided by Three-Dimensional Electroanatomical Mapping: Early Experience Using a Simplified Approach in Adults with Congenital Heart Disease.

AIMS: The widespread use of three-dimensional (3D) mapping systems and echocardiography in the field of cardiac electrophysiology has made it possible to perform transseptal punctures (TSP) with low or no fluoroscopy. However, such attempts in adults with congenital heart disease (ACHD) who have previously undergone surgical or interventional treatment are limited. Therefore, we sought to explore the feasibility and safety of an approach to perform zero- or low-fluoroscopy TSP in ACHD patients undergoing left atrial cardiac ablation procedures. METHODS AND RESULTS: This study included 45 ACHD patients who underwent TSP for ablation of left-sided tachycardias (left atrium or pulmonary venous atrium). Computed tomography (CT) of the heart was performed in all patients prior to ablation. 3D mapping of the right-sided heart chambers before TSP was used to superimpose the registered anatomy, which was subsequently used for the mapping-guided TSP technique. TSP was performed with zero-fluoroscopy in 27 patients, and the remaining 18 patients had a mean fluoroscopy exposure of 315.88 ± 598.43 µGy.m2 and a mean fluoroscopy duration of 1.9 ± 5.4 min. No patient in this cohort experienced TSP-related complications. CONCLUSION: Our study describes a fluoroscopy-free or low-dose fluoroscopy approach for TSP in ACHD patients undergoing catheter ablation of left-sided tachyarrhythmias who had been previously treated surgically or interventionally due to congenital heart defects. By superimposing 3D electroanatomic mapping with cardiac CT anatomy, this protocol proved to be highly effective, feasible and safe.

Arrhythmias and Clinical Outcomes in a Swiss Multicenter Cohort of Patients With Dextro-Transposition of the Great Arteries and Atrial Switch.

Background Data on the incidence of arrhythmias, associated cardiac interventions, and outcome in patients with dextro-transposition of the great arteries and atrial switch are scarce. Methods and Results In this multicenter analysis, we included adult patients with dextro-transposition of the great arteries and atrial switch regularly followed up at 3 Swiss tertiary care hospitals. The primary outcome was a composite of left ventricular assist device, heart transplantation, and death. The secondary outcome was occurrence of ventricular tachycardia, ventricular fibrillation, or sudden cardiac death. We identified 207 patients (34% women; median age at last follow-up, 35 years) with dextro-transposition of the great arteries and atrial switch. Arrhythmias occurred in 97 patients (47%) at a median age of 22 years. A pacemaker or an implantable cardioverter-defibrillator was implanted in 39 (19%) and 13 (6%) patients, respectively, and 33 (16%) patients underwent a total of 51 ablation procedures to target 60 intra-atrial re-entry tachycardias, 4 atrioventricular nodal re-entry tachycardias, and 1 atrial fibrillation. The primary outcome occurred in 21 patients (10%), and the secondary outcome occurred in 18 patients (9%); both were more common in patients with concomitant ventricular septum defect than in those without (hazard ratio [HR], 3.06 [95% CI, 1.29-7.27], P=0.011; and HR, 3.62 [95% CI, 1.43-9.18], P=0.007, respectively). Conclusions In patients with dextro-transposition of the great arteries and atrial switch reaching adulthood, arrhythmias occur in almost half of patients, and associated rhythm interventions are frequent. One-tenth of those patients do not survive until the age of 35 years free from left ventricular assist device or heart transplantation, and the outcome is worse in patients with concomitant ventricular septum defect.

[Intergenerational care of patients with tachycardiac arrhythmias]. / Generationenübergreifende Betreuung von Patienten mit tachykarden Rhythmusstörungen.

Within the last decades the treatment options for patients with arrhythmias have developed from a purely conservative drug treatment to a really curative treatment with removal of the arrhythmogenic substrate by continuously more sophisticated possibilities in the sense of electrophysiological techniques and ablation. Parallel to this, special outpatient departments of cardiac rhythmology for the care of patients with ion channelopathies have also become established in pediatric cardiology centers. Their task is the intergenerational care of whole families, with the aim of primarily preventing malignant arrhythmias by appropriate counselling and guidance.

Paediatric and adolescent athletes in Switzerland: age-adapted proposals for pre-participation cardiovascular evaluation.

High-level sports competition is popular among Swiss youth. Even though preparticipation evaluation for competitive athletes is widespread, screening strategies for diseases responsible for sudden death during sport are highly variable. Hence, we sought to develop age-specific preparticipation cardiovascular evaluation (PPCE) proposals for Swiss paediatric and adolescent athletes (under 18 years of age). We recommend that all athletes practising in a squad with a training load of at least 6 hours per week should undergo PPCE based on medical history and physical examination from the age of 12 years on. Prior to 12 years, individual judgement of athletic performance is required. We suggest the inclusion of a standard 12-lead electrocardiogram (ECG) evaluation for all post-pubertal athletes (or older than 15 years) with analysis in accordance with the International Criteria for ECG Interpretation in Athletes. Echocardiography should not be a first-line screening tool but rather serve for the investigation of abnormalities detected by the above strategies. We recommend regular follow-up examinations, even for those having normal history, physical examination and ECG findings. Athletes with an abnormal history (including family history), physical examination and/or ECG should be further investigated and pathological findings discussed with a paediatric cardiologist. Importantly, the recommendations provided in this document are not intended for use among patients with congenital heart disease who require individualised care according to current guidelines.

Magnetic resonance imaging of patients with epicardial leads: in vitro evaluation of temperature changes at the lead tip.

PURPOSE: The aim of this study was to systematically investigate the potential heating effects of magnetic resonance imaging (MRI) in the presence of epicardial leads, which are connected to a device or abandoned, using a series of in vitro measurements. METHODS: The heating effects of MRI in a 1.5-T scanner were measured at the lead tip in a gel-filled tank. First, a transvenous lead (5086-45 cm, Medtronic) was compared with an epicardial lead (4968-35 cm, Medtronic) with and without connection to an MR-conditional pacemaker. Then, experiments were conducted using various lengths of epicardial leads exposed to MRI. RESULTS: (1) A temperature rise of + 2.5 °C was observed for the transvenous lead attached to an MRI-conditional pacemaker. The epicardial lead attached to the same pacemaker showed four times higher heating. (2) The transvenous lead without pacemaker showed four times higher heating, and the epicardial lead without pacemaker showed 30 times higher heating. (3) The epicardial lead coiled to 20 cm length without pacemaker showed 9 times higher heating. (4) Experiments with various lengths of epicardial leads showed that the shorter the leads were, the smaller was the heating effect. CONCLUSION: Standard clinical MRI investigations may result in pronounced heating at the tip of epicardial electrodes. Epicardial leads, which are not connected to a pacemaker and thus mimicking abandoned leads, may even result in a more pronounced rise in temperature at the lead tip. Therefore, current epicardial pacing systems may carry a substantial risk of inducing thermal damage of the neighboring tissue during MRI scanning.

Surgical correction of scoliosis in children with congenital heart failure (Fontan circulation): case report and literature review.

Patients with Fontan circulation represent a significant cardiorespiratory risk during spinal surgery. We report about two patients with severe scoliosis and Fontan circulation and their successful operative treatment. The case report will be compared with the national and international literature.

Fractally coated myocardial pacemaker leads in children.

UNLABELLED: We report our single centre experience with a new fractally coated myocardial unipolar lead (ELC35UP; Biotronik) in 96 pediatric patients (59% male, 41% female). Congenital heart disease (CHD) was associated in 89%. The age at implantation ranged between 2 days and 19 years, median for children with CHD 7.8 years, without CHD 4.7 years. Twenty percent of the children were younger than one year at implantation. Mean follow-up was 30 months (1-57 months). We compared our findings with a steroid eluting epicardial lead (CapSure EPI 4968; Medtronic) in 46 children with comparable age and sex-distribution. We found a lead survival of 87% after 57 months in the ELC35UP group (steroid lead: 87% after 129 months). Pacing energy thresholds were equal after 12 months (median 3.0 microjoules), but the sensing characteristics of the fractally coated lead was significantly superior to the steroid eluting lead with median R waves of 7.0 mV (steroid lead: 3.5 mV) after 12 months. Children with myocardial scar tissue requiring pacemaker therapy after surgery of CHD showed no differences in sensing and pacing thresholds in comparison to children with congenital rhythm disorders. The fractally coated screw-in lead offers technical advantages concerning the subxiphoidal implantation procedure. CONCLUSION: Fractally coated ventricular screw-in leads represent a feasible alternative to the common steroid eluting leads- especially in children requiring pacemaker therapy after surgery for CHD.

Postoperative arrhythmia in patients with bidirectional cavopulmonary anastomosis.

OBJECTIVES: Bidirectional cavopulmonary anastomosis (BDCPA) is part of the staged Fontan palliation for congenital heart defects with single-ventricle morphology. The aim of this study was to describe incidence and characteristics of early postoperative arrhythmias in patients undergoing BDCPA. METHODS: Retrospective analysis of 60 patients undergoing BDCPA at the age of <12 months from 2001 to 2008 at a single centre. Arrhythmias were subclassified in sinus bradycardia, premature atrial/ventricular contraction, supraventricular tachycardia and atrioventricular block. The groups were compared according to age at operation and diagnosis. Postoperative follow-up data were included until Fontan completion. RESULTS: Postoperative arrhythmia was observed in 20 patients: 12 temporary and 8 persisting until hospital discharge. Sinus bradycardia is a common postoperative arrhythmia and occurred in 16 patients (9 transient, 7 persistent until hospital discharge). One patient undergoing BDCPA and a Damus-Kaye-Stansel procedure had a persisting first-degree atrioventricular block. The occurrence of a postoperative arrhythmia was independent of age and diagnostic group (hypoplastic left heart vs non-hypoplasic left heart). After hospital discharge, five of the eight arrhythmia resolved spontaneously resulting in 2 patients with sinus bradycardia and 1 patient with a first-degree AV block immediately before the Fontan completion was undertaken. CONCLUSIONS: Postoperative arrhythmias in patients with BDCPA occur early after surgery and are temporary. Severe and life-threatening arrhythmias are rare although the interventions are complex and the patients very young. The most common arrhythmia is sinus bradycardia.