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Sudden cardiac death is the most common mode of death during childhood and adolescence in hypertrophic cardiomyopathy, and identifying those individuals at highest risk is a major aspect of clinical care. The mainstay of preventative therapy is the implantable cardioverter-defibrillator, which has been shown to be effective at terminating malignant ventricular arrhythmias in children with hypertrophic cardiomyopathy but can be associated with substantial morbidity. Accurate identification of those children at highest risk who would benefit most from implantable cardioverter-defibrillator implantation while minimising the risk of complications is, therefore, essential. This position statement, on behalf of the Association for European Paediatric and Congenital Cardiology (AEPC), reviews the currently available data on established and proposed risk factors for sudden cardiac death in childhood-onset hypertrophic cardiomyopathy and current approaches for risk stratification in this population. It also provides guidance on identification of individuals at risk of sudden cardiac death and optimal management of implantable cardioverter-defibrillators in children and adolescents with hypertrophic cardiomyopathy.

Antiarrhythmic medication (AM) is commonly used to prevent supraventricular tachycardia (SVT) recurrence in infants. Our aim was to determine whether a shorter duration of AM is sufficient to prevent atrioventricular reentrant tachycardia (AVRT) recurrence and evaluate risk factors for recurrence of SVT after discontinued AM.This multicenter cohort study included all infants diagnosed with SVT in the five university hospitals in Finland between 2005 and 2017. Those diagnosed between 2005 and 2012 received AM for 12 months (group 1), and those diagnosed between 2013 and 2017 received AM for 6 months (group 2). A total of 278 infants presented with AVRT (group 1, n = 181; group 2, n = 97), and the median AM duration was 12.0 months (interquartile range [IQR] 11.4–13.4) and 7.0 months (IQR 6.0–10.2), respectively. Propranolol was the most frequently used first-line AM (92% and 95%). Recurrence-free survival rates were over 88% until 12 months after AM prophylaxis in both groups, without any statistically significant difference between them. Independent risk factors for recurrence of SVT after discontinuation of AM were need of combination AM (HR 2.2, 95% CI 1.14–4.20), Wolff-Parkinson-White (WPW) syndrome (HR 2.4, 95% CI 1.25–4.59), and age over 1 month at admission (HR 2.2, 95% CI 1.12–4.48). Conclusion: Shortening AM duration in infants from 12 to 6 months does not seem to lead to more frequent SVT recurrence. The risk factors for recurrence of SVT were WPW syndrome, need of combination AM, and age over 1 month. What is Known:• Despite the evidence of spontaneous resolution of supraventricular tachycardia episodes in infants, the antiarrhythmic medication is often continued for up to twelve months.• The optimal approach for duration of antiarrhythmic medication remains unknown.. What is New:• Shortening the duration of antiarrhythmic medication in infants with supraventricular tachycardia does not seem to increase the risk of subsequent recurrence.• Infants whose arrhythmia was successfully controlled with monotherapy were the group least likely to have recurrence after discontinuation of antiarrhythmic medication.

Objectives:Patients with univentricular heart defects require lifelong imaging surveillance. Recent advances in non-invasive imaging have enabled replacing these patients’ routine catheterisation. Our objective was to describe the safety and cost savings of transition of a tertiary care children’s hospital from routine invasive to routine non-invasive imaging of low-risk patients with univentricular heart defects.Methods:This single-centre cohort study consists of 1) a retrospective analysis of the transition from cardiac catheterisation (n = 21) to CT angiography (n = 20) before bidirectional Glenn operation and 2) a prospective study (n = 89) describing cardiac magnetic resonance before and after the total cavopulmonary connection in low-risk patients with univentricular heart defects.Results:Pre-Glenn: The total length of CT angiography was markedly shorter compared to the catheterisation: 30 min (range: 20–60) and 125 min (range: 70–220), respectively (p < 0.001). Catheterisation used more iodine contrast agents than CT angiography, 19 ± 3.9 ml, and 10 ± 2.4 ml, respectively (p < 0.001). Controlled ventilation was used for all catheterised and 3 (15%) CT angiography patients (p < 0.001). No complications occurred during CT angiography, while they emerged in 19% (4/21) catheterisation cases (p < 0.001). CT angiography and catheterisation showed no significant difference in the radiation exposure.Pre-/post-total cavopulmonary connection: All cardiac magnetic resonance studies were successful, and no complications occurred. In 60% of the cardiac magnetic resonance (53/89), no sedation was performed, and peripheral venous pressure was measured in all cases. Cost analysis suggests that moving to non-invasive imaging yielded cost savings of at least €2500–4000 per patient.Conclusion:Transition from routine invasive to routine non-invasive pre-and post-operative imaging is safely achievable with cost savings.

Background: Congenitally corrected transposition of the great arteries (ccTGA) is a rare disease of unknown cause. We aimed to better understand familial recurrence patterns. Methods: An international, multicentre, retrospective cohort study was conducted in 29 tertiary hospitals in 6 countries between 1990 and 2018, entailing investigation of 1043 unrelated ccTGA probands. Results: Laterality defects and atrioventricular block at diagnosis were observed in 29.9% and 9.3%, respectively. ccTGA was associated with primary ciliary dyskinesia in 11 patients. Parental consanguinity was noted in 3.4% cases. A congenital heart defect was diagnosed in 81 relatives from 69 families, 58% of them being first-degree relatives, including 28 siblings. The most prevalent defects in relatives were dextro-transposition of the great arteries (28.4%), laterality defects (13.6%), and ccTGA (11.1%); 36 new familial clusters were described, including 8 pedigrees with concordant familial aggregation of ccTGA, 19 pedigrees with familial co-segregation of ccTGA and dextro-transposition of the great arteries, and 9 familial co-segregation of ccTGA and laterality defects. In one family co-segregation of ccTGA, dextro-transposition of the great arteries and heterotaxy syndrome in 3 distinct relatives was found. In another family, twins both displayed ccTGA and primary ciliary dyskinesia. Conclusions: ccTGA is not always a sporadic congenital heart defect. Familial clusters as well as evidence of an association between ccTGA, dextro-transposition of the great arteries, laterality defects and in some cases primary ciliary dyskinesia, strongly suggest a common pathogenetic pathway involving laterality genes in the pathophysiology of ccTGA.

Introduction Congenitally corrected transposition of the great arteries (ccTGA) is a rare disease of unknown aetiology. We aimed to better understand familial recurrence pattern. Methods An international, multicentre, retrospective cohort study was conducted in 29 tertiary hospitals in 6 countries between 1990 and 2018, leading to investigate 1043 unrelated ccTGA probands. Results Atrioventricular block at diagnosis and laterality defects were observed in 35.4% and 29.9%, respectively. ccTGA associated with primary ciliary dyskinesia in 10 patients. Parental consanguinity was noted in 3.4% cases. A congenital heart defect was diagnosed in 81 relatives from 69 families, 58% of them being first-degree relatives, including 28 siblings. The most prevalent defects in relatives were dextro-transposition of the great arteries (d-TGA: 28.4%), laterality defects (13.6%) and ccTGA (11.1%); 36 new familial clusters were described, including 8 pedigrees with concordant familial aggregation of ccTGA, 19 pedigrees with familial co-segregation of ccTGA and d-TGA and 9 familial co-segregation of ccTGA and laterality defects. In one family there was co-segregation of ccTGA, d-TGA and heterotaxy syndrome in 3 distinct relatives. Conclusion ccTGA is not always a sporadic congenital heart defect. Familial clusters as well as evidence of an association between ccTGA, d-TGA, laterality defects and in some cases primary ciliary dyskinesia strongly suggest a common pathogenetic pathway involving laterality genes in the pathophysiology of ccTGA.

The field of electrophysiology (EP) in paediatric cardiology patients and adults with congenital heart disease is complex and rapidly growing. The current recommendations for diagnostic and invasive electrophysiology of the working group for Cardiac Dysrhythmias and Electrophysiology of the Association for European Paediatric and Congenital Cardiology acknowledges the diveristy of European countries and centers. These training recommendations can be fulfilled in a manageable period of time, without compromising the quality of training required to become an expert in the field of paediatric and congenital EP and are for trainees undergoing or having completed accredited paediatric cardiologist fellowship. Three levels of expertise, the training for General paediatric cardiology EP, for non-invasive EP and invasive EP have been defined. This Association for European EP curriculum describes the theoretical and practicsal knowledge in clinical EP; catheter ablation, cardiac implantable electronic devices, inherited arrhythmias and arrhythmias in adults with congenital heart defects for the 3 levels of expertise.

Background Catheter ablation has become the preferred treatment for common supraventricular tachycardia (SVT) in children and adolescents, but long-term follow-up data on pediatric patients remain limited. Methods To provide follow-up data, we created a population-based prospective pediatric catheter ablation registry in 1997. All patients underwent clinical follow-up at 1 month and 1 year after the procedure. The follow-up data were completed with a single questionnaire in 2010. Results Of 318 patients, 289 (91%) required one to three procedures for successful ablation. A total of 211 (66%) patients had an accessory pathway, 97 (31%) atrioventricular nodal reentrant tachycardia, and 10 (3%) atrial tachycardia. Two (0.6%) of the 318 patients had serious complications: the first had a complete atrioventricular block and required a pacemaker, while the second had a hemopericardium, which was treated with drainage. A successful ablation procedure was followed by a recurrence in 18 (6%) patients during childhood. In addition, two patients had atrial fibrillation and one had a focal atrial tachycardia as adults after a successful ablation procedure during childhood. Moreover, 12 (4%) patients, who had undergone a successful ablation, complained of increased heart rate after exercise compared to their status before the procedure. Conclusion In our cohort study of 318 pediatric patients, with a mean follow-up of 5 years, SVT ablation was successful for 91% of the patients. Arrhythmia recurred in 6% of the patients. The increased sinus rate following radiofrequency ablation, observed in 4% of pediatric patients, constitutes a new finding, which warrants attention in other patient series.

Epinephrine Infusion in Diagnosis of CPVT. Introduction: A test involving intravenous infusion of epinephrine has been proposed as a method alternative to exercise stress test in diagnosis of catecholaminergic polymorphic ventricular tachycardia (CPVT). We aimed at estimating the predictive value of intravenous epinephrine administration in CPVT patients with frequent exercise-induced ventricular ectopy. Methods and Results: We recruited 81 subjects, including 25 CPVT-linked ryanodine receptor 2 (RYR2) mutation carriers, 11 genetically undefined CPVT patients, and 45 unaffected family members. All subjects underwent a maximal exercise stress test and an intravenous epinephrine infusion test. Exercise stress test was positive in 25 (31%) patients including 14 of 25 (56%) established RYR2-mutation carriers and all 11 (100%) genetically undefined CPVT patients. Epinephrine infusion induced arrhythmias in 3 (12%) RYR2-mutation carriers, 4 (36%) genetically undefined CPVT patients, and 1 (2%) unaffected family member. A total of 18 exercise stress test positive patients did not respond to intravenous epinephrine administration, whereas only 1 epinephrine test responder had a normal exercise stress test. Thus, if exercise stress test is used as a standard, the sensitivity of the epinephrine infusion test is 28% and specificity is 98%. Conclusions: Intravenous epinephrine infusion has low sensitivity and may not be considered as an alternative method for a maximal exercise stress test in diagnosis of CPVT. (J Cardiovasc Electrophysiol, Vol. 23, pp. 194-199, February 2012)

Objectives: Junctional ectopic tachycardia (JET) is a serious, haemodynamically compromising tachyarrhythmia associated with paediatric cardiac surgery, with a reported mortality up to 14%. The incidence, risk factors and outcome of this tachyarrhythmia were evaluated in this population-based, case-control patient cohort. Methods: A total of 1001 children, who underwent open-heart surgery during a 5-year period, were retrospectively analysed. The patients with haemodynamically significant tachycardia were identified, and their postoperative electrocardiograms were analysed. Three controls matched with the same type of surgery were selected for each patient with JET. Results: JETwas diagnosed in 51 patients (5.0%). These patients had longer cardiopulmonary bypass time (138 vs 119 min, p = 0.002), higher body temperature (38.0 vs 37.4 8C, p = 0.013) and higher level of postoperative troponin-T (3.7 vs 2.1 m gl 1 , p < 0.001) compared with controls. They also needed longer ventilatory support (3 vs 2 days,p = 0.004) and intensive care stay (7 vs 5 days,p < 0.001) as well as use of noradrenaline (23/51 vs 35/130, p = 0.019). Ventricular septal defect (VSD) closure was part of the surgery in 33/51 (64.7%) of these patients. The mortality was 8% in the JET group and 5% in the controls (p = 0.066). In the logistic regression model, JET was not an independent risk factor for death (p = 0.557). Conclusions:The incidenceof JETwas 5.0% in this large paediatric open-heart surgery patientgroup. Compared with controls, thesepatients had longer cardiopulmonary bypass time and higher level of troponin-T, possibly reflecting the extent of surgical trauma. However, the tachycardia was not an independent risk factor for death. # 2010 European Association for Cardio-Thoracic Surgery. Published by Elsevier B.V. All rights reserved.

Background: Automatic threshold measurement and output adjustment are used as default settings in modern pacemakers. The purpose of the study was to assess Atrial Capture Management (ACM) of Medtronic pacemakers in pediatric patients. Methods: Forty children were enrolled in two centers. Median age was 9.8 years (range 0.8–17.5 years). Half had undergone surgery for congenital heart defects; 45% of patients had an epicardial atrial lead. The pacing indication was atrioventricular block in 82% of patients and sinus node disease in 18%. Manually determined atrial thresholds and ACM measurements were compared. Results: ACM measurements were within the expected variation in 37/40 (93%) of the patients. In one patient the threshold was 0.625-V lower manually than with ACM. One patient had too high an intrinsic atrial rate for ACM to be able to measure threshold. The mean threshold at 0.4 ms was 0.69 ± 0.32 V manually and 0.68 ± 0.35 V with ACM (two-tailed paired t-test, P = 0.52) in all patients. The mean difference was 0.012 V (95% confidence interval: −0.027, 0.053). The mean endocardial threshold was 0.70 ± 0.36 V manually and 0.69 ± 0.38 V with ACM; epicardial threshold was 0.67 ± 0.27 V manually and 0.68 ± 0.32 V with ACM. The difference between the measurements was 0.012 V for endocardial and 0.014 V for epicardial leads. No atrial arrhythmias due to ACM measurements were observed. Conclusions: ACM measures atrial thresholds reliably in pediatric patients with both endocardial and epicardial leads, allowing its use in both. Constant high intrinsic atrial rate may prevent automatic threshold measurement in young children. (PACE 2010; 33:309–313)

WOS: 000368445700024 PubMed ID: 25995398 We read with great interest the EP wire report entitled ‘How are arrhythmias managed in the paediatric population in Europe? Results of the European Heart Rhythm Survey’ by HernandezMadrid et al. 1 On behalf of the Arrhythmias and Electrophysiology Working Group of the Association for European Pediatric and Congenital Cardiology (AEPC), we would like to comment on the methodology and content of the article. The EHRA Research Network Centers do not include any of the dedicated paediatric centresproviding interventional electrophysiological therapy. This creates a major sampling errorand negatesthe validityof the conclusions of the survey. By including the paediatric centres, we would expect the results to be markedly different. The conclusion that paediatric catheter ablations in Europe are mainly performed by adult electrophysiology teams is not justified.

Introduction: The naturally poor survival of pulmonary atresia with ventricular septal defect (PA+VSD) has improved due to evolved perioperative and surgical treatment. Studies including PA+VSD patients, both with and without major aortopulmonary collateral arteries (MAPCAs), with extensive follow-up are scarce. This nationwide study aimed to investigate survival and surgical treatment in PA+VSD patients with and without MAPCAs. Methods: Study comprised 109 PA+VSD patients born in Finland between 1970 and 2007. We reviewed retrospectively medical records and operative reports through December 2011, as well as first available angiograms and preoperative angiograms prior to repair attempt. Results: The median follow-up time for the total study population, including also patients who died during the follow-up, was 11.4 years (IQR 0.8 - 21.1). The incidence of PA+VSD, which could be determined reliably from 1995 to 2007, was 6.1 per 100 000 live births. Although the patients with (n = 43) or without MAPCAs (n = 66) showed no difference in survival (p = 0.74), the patients without MAPCAs had better probability to achieve repair (64% vs. 28%, p < 0.0001). The bigger size of true central pulmonary arteries assessed by McGoon index at first angiogram [HR 0.66 (CI95% 0.49 - 0.88) per 0.5 McGoon index units, p = 0.006] and achievement of repair [HR 0.07 (CI95% 0.03 - 0.17), p < 0.0001] improved the overall survival. After successful repair survival was 93% at 1 year and 91% from 2 years on. Palliated patients, instead, had survival at 1, 5, 10, and 20 years of age of 55%, 42%, 34%, and 20% respectively. However, patients with right ventricle - pulmonary artery connection and septal fenestration had better survival than rest of the palliated patients (p = 0.001). Palliation with a systemic-pulmonary artery shunt increased McGoon index by 41% (p < 0.0001). Conclusions: The patients with MAPCAs had higher risk to remain palliated than patients without, although their survival was similar. Survival of PA+VSD was influenced by the initial size of true central pulmonary arteries and whether repair was achieved. Although palliative procedures may not improve the final outcome of PA+VSD, palliative surgery may have a role in its treatment.

OBJECTIVES: Treatment of pulmonary atresia with ventricular septal defect (PA + VSD) has evolved during recent decades, but it still remains challenging. This study evaluated 41-year experience of outcome, survival and treatment of PA + VSD patients. METHODS: Patient records and angiograms of 109 patients with PA + VSD born in Finland between 1970 and 2007, and treated at the Children's Hospital, Helsinki University Central Hospital, were retrospectively analysed in this nationwide study. RESULTS: Of the 109 patients, 66 (61%) had simple PA + VSD without major aortopulmonary collateral arteries (MAPCAs). Although we observed no difference in overall survival between those with or without MAPCAs, the patients without MAPCAs had better probability to achieve repair (64 vs 28%, P

Background— Inherited long-QT syndrome (LQTS) is associated with risk of sudden death. We assessed the clinical course and the fulfillment of current treatment strategies in molecularly defined pediatric LQTS type 1 and (LQT1) and type 2 (LQT2) patients. Methods and Results— Follow-up data covering a mean of 12 years were collected for 316 genotyped LQT1 and LQT2 patients aged 0 to 18 years. No arrhythmic deaths occurred during the follow-up. Finnish KCNQ1 and KCNH2 founder mutations were associated with fewer cardiac events than other KCNQ1 and KCNH2 mutations (hazard ratio [HR], 0.33; P =0.03 and HR, 0.16; P =0.01, respectively). QTc interval ≥500 ms increased the risk of cardiac events compared with QTc P =0.001). Treatment with β-blocker medication was associated with reduced risk of first cardiac event (HR, 0.23; P =0.001). Noncompliant LQT2 patients were more often symptomatic than compliant LQT2 patients (18% and 0%, respectively; P =0.03). Treatment with implantable cardioverter defibrillator was rare (3%) and resulted in reinterventions in 44% of cases. Conclusions— Severe cardiac events are uncommon in molecularly defined and appropriately treated pediatric LQTS mutation carriers. β-Blocker medication reduces the risk of cardiac events and is generally well tolerated in this age group of LQTS patients.

Viral infections are the most common causes of myocarditis in children. Chronic myocardial injury may develop following an immune or autoimmune reaction triggered or maintained by an infection, or can be part of a systemic autoimmune disease. Although many of the children having developed myocarditis are symptomless, initial symptoms may include cardiac insufficiency, arrhythmias and sudden death. The diagnosis requires a clinical suspicion as well as laboratory and imaging studies. Recovery from myocarditises often takes place spontaneously, but some result in the development of dilated cardiomyopathy (DCM).

Catheter ablation has become the preferred treatment for common supraventricular tachycardia (SVT) in children and adolescents, but long-term follow-up data on pediatric patients remain limited.To provide follow-up data, we created a population-based prospective pediatric catheter ablation registry in 1997. All patients underwent clinical follow-up at 1 month and 1 year after the procedure. The follow-up data were completed with a single questionnaire in 2010.Of 318 patients, 289 (91%) required one to three procedures for successful ablation. A total of 211 (66%) patients had an accessory pathway, 97 (31%) atrioventricular nodal reentrant tachycardia, and 10 (3%) atrial tachycardia. Two (0.6%) of the 318 patients had serious complications: the first had a complete atrioventricular block and required a pacemaker, while the second had a hemopericardium, which was treated with drainage. A successful ablation procedure was followed by a recurrence in 18 (6%) patients during childhood. In addition, two patients had atrial fibrillation and one had a focal atrial tachycardia as adults after a successful ablation procedure during childhood. Moreover, 12 (4%) patients, who had undergone a successful ablation, complained of increased heart rate after exercise compared to their status before the procedure.In our cohort study of 318 pediatric patients, with a mean follow-up of 5 years, SVT ablation was successful for 91% of the patients. Arrhythmia recurred in 6% of the patients. The increased sinus rate following radiofrequency ablation, observed in 4% of pediatric patients, constitutes a new finding, which warrants attention in other patient series.

The cardiac state and the prevalence of high blood pressure (BP) were analyzed in 21 pediatric patients (mean age 5.3 +/- 5.3 years) on chronic peritoneal dialysis (CPD), the aim being to specify the impact of hypervolemia in the etiology of hypertension. C- and N-terminal atrial natriuretic peptide (ANP-C, ANP-N) were measured as possible additional markers of hypervolemia. Baseline investigations were carried out 0.2 years after initiation of PD, and repeated after 0.9 +/- 0.2 years. Fifty-two percent of the patients had high BP, and in 40% the nocturnal BP decline was decreased. Left ventricular hypertrophy was present in 45%, but the systolic and diastolic functions of the heart were not impaired. Left ventricular mass correlated significantly with the severity of hypertension and with ANP-N (r = 0.79, P0.01 and r = 0.66, P0.01, Spearman rank correlation). Significant correlations were also found between the severity of hypertension and ANP-N and ANP-C (r = 0.82, P0.01 and r = 0.66, P0.01, Spearman rank correlation). High BP and cardiac impairment were more frequent in the younger and nephrectomized patients in whom volume overload seemed to be the most-important etiological factor. Our results suggest further that an ANP-N over 3.0 nmol/l combined with hypertension is strongly indicative of volume overload in patients on PD.

Objectives: Few data exist for long-term results after the Senning operation for transposition of the great arteries. Sinus node dysfunction and systemic ventricular dysfunction have been the main problems. We evaluated risk factors for late death and the incidence of late death, sinus node dysfunction, and right ventricular dysfunction in 100 patients. Methods: The study was a retrospective analysis with a mean follow-up time of 12.8 ± 3.1 years. No patients were lost to follow-up. Patients were divided in 2 groups according to ventricular septal defect (73 simple, 27 complex). The electrocardiogram, ambulatory electrocardiogram, echocardiogram, and chest radiograph were reviewed for each patient. Results: The overall mortality rate was 10%. The actuarial survival was 90% (simple) and 78% (complex); the probability of staying in sinus rhythm was 34% and 7%, and the probability of normal right ventricular function was 52% and 39%, respectively, 15 years after operation. The incidence of sinus node dysfunction increased gradually over time, although the incidence of right ventricular dysfunction increased rapidly after 10 years of follow-up. Late deaths, arrhythmias, and right ventricular dysfunction were significantly more frequent in the complex group. Right ventricular dysfunction and active arrhythmias were risk factors for late death. Conclusion: Long-term follow-up after the Senning operation shows increasing incidence of sinus node dysfunction and right ventricular dysfunction over time. Deteriorating right ventricular function is a major concern. Its early recognition and initiation of appropriate management to preserve cardiac function is an important follow-up goal. (J Thorac Cardiovasc Surg 1999;117:488-95)

Pulmonary atresia with intact ventricular septum (PA+IVS) is a rare congenital cardiac malformation which is associated with ventriculocoronary arterial communications from the right ventricle. We present a case of PA+IVS with a bilateral atresia of the coronary ostia, and thus, a completely right ventricular-dependent coronary circulation followed up by fetal echocardiography. Eventually the infant died of myocardial infarction at 2 days of age.

In children with structurally normal hearts, the mechanisms of arrhythmias are usually the same as in the adult patient. Some arrhythmias are particularly associated with young age and very rarely seen in adult patients. Arrhythmias in structural heart disease may be associated either with the underlying abnormality or result from surgical intervention. Chronic haemodynamic stress of congenital heart disease (CHD) might create an electrophysiological and anatomic substrate highly favourable for re-entrant arrhythmias. As a general rule, prescription of antiarrhythmic drugs requires a clear diagnosis with electrocardiographic documentation of a given arrhythmia. Risk-benefit analysis of drug therapy should be considered when facing an arrhythmia in a child. Prophylactic antiarrhythmic drug therapy is given only to protect the child from recurrent supraventricular tachycardia during this time span until the disease will eventually cease spontaneously. In the last decades, radiofrequency catheter ablation is progressively used as curative therapy for tachyarrhythmias in children and patients with or without CHD. Even in young children, procedures can be performed with high success rates and low complication rates as shown by several retrospective and prospective paediatric multi-centre studies. Three-dimensional mapping and non-fluoroscopic navigation techniques and enhanced catheter technology have further improved safety and efficacy even in CHD patients with complex arrhythmias. During last decades, cardiac devices (pacemakers and implantable cardiac defibrillator) have developed rapidly. The pacing generator size has diminished and the pacing leads have become progressively thinner. These developments have made application of cardiac pacing in children easier although no dedicated paediatric pacing systems exist.

Background AutoCapture™ (AC) of St. Jude Medical (SJM; St. Paul, MN, USA) pacemakers provides beat-to-beat ventricular capture verification and allows low-amplitude pacing. There has been concern about evoked response signal (ERS) amplitude decreasing over time, leading to discontinuation of AC. The purpose of this study was to evaluate the long-term performance of AC in infants with epicardial pacing leads. Methods Data on 16 newborns with congenital complete atrioventricular block (CCAVB) implanted with a SJM Microny pacemaker between January 1998 and December 2004 were collected. The ERS at discharge, at 12 ± 2 months, and long-term AC performance were analyzed retrospectively. The median follow-up time was 5.3 years (range 0.4–8.6 years), the end point of follow-up being either lead or generator exchange. Results AC could be activated in all patients at discharge; the median ERS was 9.3 mV (3.7–19.0 mV). At 12 ± 2 months, the median ERS measured 4.6 ± 3.6 mV (n = 13), showing a significant decrease (P = 0.002) and leading to discontinuation of AC in three (23%) of 13 patients. AC use was possible in eight patients and long-term use in six patients. Conclusions In epicardially paced CCAVB newborns, the ERS amplitude decreased significantly during the first year. ERS decrease was the most common reason for AC failure. At 1-year follow-up, AC was functional in only 53% of patients, although it could originally be activated in all patients. During the first year of follow-up, special attention to AC parameters is recommended in this subgroup of pediatric pacemaker patients.

Objective. The aim of the study was to evaluate the cardiopulmonary exercise tolerance in children and adolescents after chest irradiation and anticancer chemotherapy. Methods. We studied 30 subjectively asymptomatic patients aged 8 to 25 years treated for pediatric malignancies with chest irradiation (XRT) ± chemotherapy. The median interval since XRT was 7 (range, 2 to 13) years. The median XRT dose for mediastinum and/or lungs was 2550 (range, 1000 to 5100) cGy. The median cumulative dose of anthracyclines was 250 (range, 0 to 480) mg/m2. Cardiac function and exercise tolerance were evaluated by electrocardiography, echocardiography, radionuclide cineangiography, and exercise test with gas exchange analysis. Results. The patients differed from normal controls in systolic indices of myocardial function. In echocardiography, the left ventricular contractility was abnormal in 14/30 patients. In radionuclide cineangiography, the left ventricular ejection fraction was subnormal in 6/30 patients, and in 9/30 patients the rise in ejection fraction during exercise was inadequate ( Conclusions. XRT and anticancer chemotherapy very often lead to late cardiopulmonary toxicity and impaired exercise tolerance. Although in most cases this toxicity seemed to be mild and subclinical, the long-term clinical sequels merit further evaluation.

AutoCapture™ (AC) of St. Jude Medical (SJM; St. Paul, MN, USA) pacemakers provides beat-to-beat ventricular capture verification and allows low-amplitude pacing. There has been concern about evoked response signal (ERS) amplitude decreasing over time, leading to discontinuation of AC. The purpose of this study was to evaluate the long-term performance of AC in infants with epicardial pacing leads.Data on 16 newborns with congenital complete atrioventricular block (CCAVB) implanted with a SJM Microny pacemaker between January 1998 and December 2004 were collected. The ERS at discharge, at 12 ± 2 months, and long-term AC performance were analyzed retrospectively. The median follow-up time was 5.3 years (range 0.4-8.6 years), the end point of follow-up being either lead or generator exchange.AC could be activated in all patients at discharge; the median ERS was 9.3 mV (3.7-19.0 mV). At 12 ± 2 months, the median ERS measured 4.6 ± 3.6 mV (n = 13), showing a significant decrease (P = 0.002) and leading to discontinuation of AC in three (23%) of 13 patients. AC use was possible in eight patients and long-term use in six patients.In epicardially paced CCAVB newborns, the ERS amplitude decreased significantly during the first year. ERS decrease was the most common reason for AC failure. At 1-year follow-up, AC was functional in only 53% of patients, although it could originally be activated in all patients. During the first year of follow-up, special attention to AC parameters is recommended in this subgroup of pediatric pacemaker patients.

Surgical strategy to construct a two-coronary system for a patient with anomalous origin of left coronary artery from pulmonary artery (ALCAPA) has evolved with time. Limited long-term follow-up data are available on these children. We report population-based follow-up in children operated on for ALCAPA. In total, 29 patients underwent aortic reimplantation of ALCAPA between 1979 and 2006. Twenty (69%) children were repaired with direct aortic implantation, five (17%) with a modified tubular extension technique, and four (14%) patients with an intrapulmonary baffling technique. Early postoperative mortality (30 days) was 17%. No late mortality (30 days) was detected. The median length of follow-up was 11 years (range 10 months-27 years). Global left ventricular function by echocardiography (M-mode) was within normal limits (30%) in all patients one year after operation. Functionally, 80% of patients were classified in NYHA class I, 20% in NYHA II, and 0% in NYHA classes III/IV at the time of the last examination. Excellent results with good long-term outcome can be achieved in infants with ALCAPA using reimplantation techniques. Normalization of cardiac function is expected within the first year in all operative survivors with a patent coronary system.

Background: The aim of the study was to evaluate the safety and reliability of automatic ventricular pacing threshold measurement, the Medtronic Capture Management™ (CM), in children with epicardial pacing leads. CM has not been recommended for use with epicardial leads due to lack of pertinent data. Methods: During a 2-year study period, 34 children (mean age 6.1 years, range 0 days to 17.7 years) with epicardial leads were prospectively enrolled. The CM measurements were compared with in-office ventricular pacing threshold measurements. Thirty bipolar and five unipolar epicardial leads were assessed. Results: CM measurements were successful and reliable in 30 out of 35 leads (86%). The mean threshold with CM was 1.16 V (95% CI 1.07–1.26 V), and with standard measurement was 1.18 V (95% CI 1.09–1.28 V), at a pulse width of 0.40 ms. The reasons for failure were evoked response undersensing in two cases (5.7%), and high intrinsic rate in one case. High pacing thresholds prevented accurate CM measurements in two cases. Conclusions: CM automatic threshold measurements are consistent with standard ventricular pacing threshold measurements in children with epicardial leads. We recommend a period of monitoring CM performance before programming it to adjust output according to automatic threshold measurements, in order to find the patients in whom it does not work. The CM feature provides increased pacing safety when it measures well (86% of leads). A larger study is needed to prove the tendency for extending battery life in children with epicardial leads.

Increased QT dispersion and loss of sinus rhythm were both associated with sudden cardiac death in patients with transposition of the great arteries after Mustard and Senning operations at the early and late postoperative periods. A combination of increased QT dispersion with loss of sinus rhythm increases the positive predictive value for sudden cardiac death in patients with transposition of the great arteries after Mustard and Senning procedures.

Objective: To compare the efficacy and safety of amrinone and a combination of dopamine and nitroglycerin in neonates after reconstructive surgery for transposition of the great arteries. Design: A prospective, randomized, double-blind study. Setting: Pediatric intensive care unit in a university hospital. Participants: Thirty-five neonates with transposition of the great arteries. Interventions: A loading dose of amrinone, 2 mg/kg, followed by a maintenance infusion of 7.5 μg/kg/min, were administered to 16 neonates before separation from cardiopulmonary bypass. The remaining 19 patients were administered a combination of dopamine, 5 μg/kg/min, and nitroglycerin, 1 μg/kg/min. An open-label epinephrine infusion was administered in both groups as required. Measurements and Main Results: The circulatory state of the patients was evaluated from 4 to 18 hours after cardiopulmonary bypass. The systemic blood flow index, calculated using the Fick principle, was higher in the amrinone group (1.7 ± 0.5 L/min/m2 (mean ± SD]) compared with the dopamine-nitroglycerin group (1.4 ± 0.4 L/min/m2; p < 0.04). The systemic vascular resistance in the amrinone group was lower (26 ± 8 Wood units × m2) than in the dopamine-nitroglycerin group (35 ± 12 Wood units × m2; p < 0.02). The oxygen extraction ratio was higher in the dopamine-nitroglycerin group (0.34 ± 0.08) compared with the amrinone group (0.28 ± 0.06; p < 0.02). Lower platelet counts were observed in the amrinone group, but no difference in hemorrhagic complications was seen between the groups. Conclusion: With the dosage regimen used, supplemented with epinephrine, amrinone provides a higher cardiac output and more favorable oxygen dynamics than a combination of dopamine and nitroglycerin.

Objectives: To compare the effectiveness and safety of amrinone and a combination of dopamine and nitroglycerin in infants after reconstructive surgery for congenital heart disease. Design: A prospective, randomized, double-blind study. Setting: Pediatric intensive care unit in a university hospital. Participants: Thirty-two infants with complete atrioventricular septal defect. Interventions: Amrinone loading dose, 2 mg/kg, followed by a maintenance infusion, 7.5 μg/kg/min, was given to 17 infants before separation from cardiopulmonary bypass. The remaining 15 patients received a combination of dopamine, 5 μg/kg/min, and nitroglycerin, 1 μg/kg/min. Measurements and Main Results: The circulatory state of the patients was evaluated from 4 to 18 hours after cardiopulmonary bypass. The systemic blood flow index, calculated using the Fick principle, was higher in the amrinone group (2.5 ± 0.7 L/min/m2) compared with the dopamine-nitroglycerin group (2.0 ± 0.6 L/min/m2, mean ± SD). The pulmonary blood flow index in the amrinone group was higher (2.9 ± 0.6 L/min/m2) than in the dopaminenitroglycerin group (2.2 ± 0.6 L/min/m2); no significant difference was noted in the mean pulmonary artery pressure. The oxygen extraction ratio was higher in the dopamine-nitroglycerin group (0.41 ± 0.07) compared with the amrinone group (0.34 ± 0.08). Despite lower platelet counts in the amrinone group, no hemorrhagic complications were seen in any patient. Conclusions: With this dosage regimen, amrinone provides a higher cardiac output, more favorable oxygen dynamics, and lower pulmonary vascular resistance than dopamine and nitroglycerin.

We present a series of 43 infants with neonatal herpes simplex virus infection treated at the Children's Hospital, University of Helsinki, during a 16-year period from 1970 to 1985. Twelve mothers (28%) had a history of genital herpes during pregnancy, and two had had labial herpes infection. Eight infants (19%) were delivered by cesarean section. In 14 (33%) infants symptoms appeared within 24 hours and in 26 (61%) they appeared within 7 days. The presenting symptoms were neurologic in 79%, cutaneous in 30%, respiratory in 19%, cyanosis/pallor/grayish skin in 16%, irritability in 12% and fever in 7%. Herpes simplex virus was detected most early and frequently in pharyngeal swabs, in one-third on Postnatal Days 2 to 5. Cerebrospinal fluid contained an increased amount of protein and/or pleocytosis in 72%. Abnormal electroencephalographic background activity appeared in 56% and electrical paroxysms in 41%. Six infants (14%) died, 9 (21%) were damaged severely and 6 (14%) were moderately or mildly damaged. Poor prognosis was associated with acute maternal illness at delivery, prematurity, visceral involvement and/or electrical paroxysms in the electroencephalograms. This study underlines the occurrence of intrauterine transmission of herpes virus, infections with neurologic manifestations, early symptomatology and the need for prompt diagnosis, brain biopsy in selected patients and antiviral therapy in neonates with herpes virus infection.

The most demanding patient population on peritoneal dialysis (PD) consists of children under 2 years of age. Their growth is inferior to that of older children and maintaining euvolemia is difficult, especially in anuric patients. In this prospective study reported here, we enrolled 21 patients2 years of age (mean 0.59 years) at onset of PD and monitored their uremia parameters and evaluated their nutrition. Since no good instrument currently exists for estimating intravascular volume status, we used traditional blood pressure measurements, echocardiography, and N-terminal atrial natriuretic peptide measurements. Growth was compared with midparental height. Metabolic control was good. Long-term hypertension was seen in 43% of the patients, but left ventricular hypertrophy decreased during the study period. Mean weekly urea Kt/V was 3.38 +/- 0.66 and creatinine clearance was 49 +/- 20 L/week per 1.73 m(2). Catch-up growth was documented in 57% of the patients during PD. However, these children did not attain their midparental height at the end of PD at a mean age of 1.71 years. Although favorable metabolic control and good growth were achieved during PD, these children lagged in term of their midparental height. We conclude that several instruments are needed for determining the management of intravascular volume status and that the control of calcium-phosphorus status is demanding.