Prenatal diagnosis, associated findings and postnatal outcome of fetuses with truncus arteriosus communis (TAC).

PURPOSE: To assess the spectrum of associated anomalies, the intrauterine course, postnatal outcome and management of fetuses with truncus arteriosus communis (TAC) METHODS: All cases of TAC diagnosed prenatally over a period of 8 years were retrospectively collected in two tertiary referral centers. All additional prenatal findings were assessed and correlated with the outcome. The accuracy of prenatal diagnosis was assessed. RESULTS: Thirty nine cases of TAC were diagnosed prenatally. Mean gestational age at first diagnosis was 22 weeks (range 13-38). Two cases were lost follow-up. Correct prenatal diagnosis of TAC was made in 87.5% and of TAC subtype in 90.5%. Prenatal diagnosis was incorrect in three cases: one newborn had aortic atresia with ventricular septal defect (VSD) postnatally, one had hypo-plastic right ventricle with dextro transposition of the great arteries (d-TGA) with coarctation of the aorta and a third newborn had tetralogy of fallot (TOF) with abnormal origin of the left pulmonary artery arising from the ascending aorta postnatally. These 3 cases were excluded from further analysis. In 26.5% of cases, TAC was an isolated finding. 38.2% of fetuses had additional chromosomal anomalies. Among them, microdeletion 22q11.2 was most common with a prevalence of 17.6% in our cohort. Another 3 fetuses were highly suspicious for non-chromosomal genetic syndromes due to their additional extra-cardiac anomalies, but molecular diagnosis could not be provided. Major cardiac and extra-cardiac anomalies occurred in between 8.8% and 58.8%, respectively. Predominantly, extra-cardiac anomalies occurred in association with chromosomal anomalies. Additionally, severe IUGR occurred in 17.6%. There were 14 terminations of pregnancy (41.2%), 1 (2.9%) intrauterine fetal death, 5 postnatal deaths (14.7%) and 14 (41.2%) infants were alive at last follow-up. Intention-to-treat survival rate was 70%. Mean follow-up among survivors was 42 months (range 6-104). Postoperative health status among survivors was excellent in 78.6%, but 46.2% needed repeated re-interventions due to recurrent pulmonary artery or conduit stenosis. The other 21.4% of survivors were significantly impaired due to non-cardiac problems. CONCLUSION: Truncus arteriosus communis is a rare and complex cardiac anomaly that can be diagnosed prenatally with high precision. TAC is frequently associated with chromosomal and extra-cardiac anomalies, leading to a high intrauterine and postnatal loss rate due to terminations and perioperative mortality. Without severe extra-cardiac anomalies, postoperative health status is excellent, independent of the subtype of TAC, but the prevalence of repeated interventions due to recurrent stenosis is high.

Prenatal diagnosis, associated findings and postnatal outcome of fetuses with truncus arteriosus communis (TAC).

PURPOSE: To assess the spectrum of associated anomalies, the intrauterine course, postnatal outcome and management of fetuses with truncus arteriosus communis (TAC) METHODS: All cases of TAC diagnosed prenatally over a period of 8 years were retrospectively collected in two tertiary referral centers. All additional prenatal findings were assessed and correlated with the outcome. The accuracy of prenatal diagnosis was assessed. RESULTS: 39 cases of TAC were diagnosed prenatally. Mean gestational age at first diagnosis was 22 weeks (range, 13-38). Two cases were lost follow-up. Correct prenatal diagnosis of TAC was made in 21 of 24 (87.5%) cases and of TAC subtype in 19 of 21 (90.5%) cases. Prenatal diagnosis of TAC was incorrect in three cases: one newborn had aortic atresia with ventricular septal defect postnatally, one had hypoplastic right ventricle with dextro Transposition of the Great Arteries with coartation of the aorta and a third newborn had Tetralogy of Fallot with abnormal origin of the left pulmonary artery arising from the ascending aorta postnatally. These three cases were excluded from further analysis. In 9 of 34 (26.5%) cases, TAC was an isolated finding. 13 (38.2%) fetuses had additional chromosomal anomalies. Among them, microdeletion 22q11.2 was most common with a prevalence of 17.6% in our cohort. Another 3 fetuses were highly suspicious for non-chromosomal genetic syndromes due to their additional extra-cardiac anomalies, but molecular diagnosis could not be provided. Major cardiac and extra-cardiac anomalies occurred in 3 (8.8%) and in 20 (58.8%) cases, respectively. Predominantly, extra-cardiac anomalies occurred in association with chromosomal anomalies. Additionally, severe IUGR occurred in 6 (17.6%) cases. There were 14 terminations of pregnancy (41.2%), 1 (2.9%) intrauterine fetal death, 5 postnatal deaths (14.7%) and 14 (41.2%) infants were alive at last follow-up. Intention-to-treat survival rate was 70%. Mean follow-up among survivors was 42 months (range, 6-104). Postoperative health status among survivors was excellent in 11 (78.6%) infants, but 5 (46.2%) of them needed repeated re-interventions due to recurrent pulmonary artery or conduit stenosis. The other 3 (21.4%) survivors were significantly impaired due to non-cardiac problems. CONCLUSION: TAC is a rare and complex cardiac anomaly that can be diagnosed prenatally with high precision. TAC is frequently associated with chromosomal and extra-cardiac anomalies, leading to a high intrauterine and postnatal loss rate due to terminations and perioperative mortality. Without severe extra-cardiac anomalies, postoperative short- and medium-term health status is excellent, independent of the subtype of TAC, but the prevalence of repeated interventions due to recurrent stenosis is high.

Prenatal diagnosis of absent pulmonary valve syndrome from first trimester onwards: novel insights into pathophysiology, associated conditions and outcome.

OBJECTIVE: To assess the spectrum of associated anomalies, intrauterine course and outcome in fetuses with absent pulmonary valve syndrome (APVS). METHODS: All cases with a prenatal diagnosis of APVS at two centers over a period of 13 years were analyzed retrospectively. APVS was diagnosed in the presence of rudimentary or dysplastic pulmonary valve leaflets with to-and-fro blood flow in the pulmonary trunk on color and pulsed-wave Doppler ultrasound. Data on demographic characteristics, presence of associated conditions, Doppler studies and pregnancy outcome were reviewed. RESULTS: During the study period, 40 cases of APVS were diagnosed prenatally. Thirty-seven (92.5%) cases were associated with tetralogy of Fallot (TOF) and three (7.5%) had an intact ventricular septum. Patency of the ductus arteriosus (DA) was found in 17/37 (45.9%) TOF cases and in all three cases with an intact ventricular septum. Mean gestational age at diagnosis was 19.7 (range, 12-34) weeks with 10 (25.0%) cases (all with TOF) diagnosed in the first trimester. TOF was an isolated finding in 15 (37.5%) cases. Chromosomal anomalies, cardiac defects and extracardiac anomalies were present in 18 (45.0%), four (10.0%) and three (7.5%) cases, respectively. Among the 40 cases, there were 19 (47.5%) terminations of pregnancy, six (15.0%) intrauterine deaths, four (10.0%) neonatal deaths and 11 (27.5%) survivors. Patency of the DA, reversed flow during atrial contraction in the ductus venosus, umbilical artery or fetal middle cerebral artery, and hydrops/increased nuchal translucency thickness were significantly associated with non-survival. All 10 cases diagnosed in the first trimester had a patent DA and abnormal Doppler parameters, eight had hydrops and/or increased nuchal translucency, six were associated with trisomy 13 or 18 and none survived. CONCLUSION: APVS diagnosed in the first trimester is significantly associated with TOF, patency of the DA, abnormal Doppler parameters, lethal trisomies and intrauterine mortality. Cases of APVS with isolated TOF and agenesis of the DA have a better outcome than those with additional anomalies, with > 80% survival. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Regulation of anion transport across the uterine epithelium of Gallus domesticus.

For egg shell production, cations, primarily Ca(2+), and anions, primarily HCO(3)(-), must be secreted across the uterine epithelium. Because alterations of HCO(3)(-) transport influence Ca(2+) secretion, the present study was performed to gain insight into the regulation of anion transport (i.e., chloride and HCO(3)(-) transport) across the egg shell gland of the domestic chicken. To this purpose, unstripped uterus epithelia were mounted in modified Ussing chambers and electrogenic [i.e., short circuit current (I(sc))] and electroneutral anion transport were measured. Stimulating adenylate cyclases by forskolin, thereby enhancing the intracellular cyclic adenosine monophosphate( )(cAMP) concentration, evoked 2 patterns of I(sc) responses. Under HCO(3)(-)-buffered conditions, some of the tissues (3/8) showed an increase of I(sc), whereas in others (5/8) a decrease of I(sc) was observed in the presence of the drug. The I(sc) increase existed in HCO(3)(-) secretion because under HCO(3)(-)-free conditions forskolin stimulated only an I(sc) decrease. In addition, methazolamide, a blocker of carboanhydrases, significantly reduced baseline I(sc). The forskolin-induced decrease of I(sc) presented a Cl(-) absorption. In the absence of HCO(3)(-), forskolin yielded only an I(sc) decrease and the transepithelial flux of (36)Cl(-) was reduced. In the presence of mucosal 5-nitro-2-(3-phenylpropylamino) benzoic acid, a nonselective blocker of chloride channels, forskolin-induced I(sc) decrease was inhibited. In addition to cAMP, the regulatory influence of neurons or prostaglandins on baseline I(sc) and anion transport was investigated. Neither tetrodotoxin, a blocker of neuronal Na(+) conductances, electrical field stimulation, nor indomethacin, a blocker of cyclooxygenases, influenced the baseline I(sc) or anion transport. In summary, these data show effects of forskolin (i.e., cAMP) on anion transport across the egg shell gland of the domestic chicken: HCO(3)(-) secretion (supporting Ca(2+) mineralizing of the egg shell) and Cl(-) absorption. Neurons or prostaglandins did not influence the anion transport.

Stem cells in pediatric heart failure.

Pediatric heart failure could be a target for regenerative therapy. Stem cell-based therapy has the potential to provide functional cardiomyocytes. Whereas adult stem cells have shown no or only minimal therapeutic benefit in adults with no evidence of transdifferentiation, embryonic stem cells can differentiate to any cell type, including cardiomyocytes. However, ethical concerns and immunological problems are associated with embryonic stem cells derived from the inner cell mass of blastocysts. Recently, somatic cells could be reprogrammed to a pluripotent state (i.e. induced pluripotent stem cells) with the help of transcription factors. This technique removes ethical and probably also immunological concerns. Nevertheless extensive experimental research will be necessary before cell replacement strategies become clinically applicable. Because the underlying pathophysiology differs significantly with age, caution is warranted extrapolating data obtained in experimental models of cardiac ischemia and clinical studies in adults to the pediatric population. Pediatric heart failure has a good prognosis if causal therapy is possible. However, some forms of congenital heart disease and especially dilated cardiomyopathy still have limited therapeutic options. Almost half of children with symptomatic cardiomyopathy receive a transplant or die within two years. The authors will review the relevant stem cell sources for cell-based treatments. And, given the differences of the underlying diseases between adult and pediatric patients with heart failure, it is contemplated which condition of pediatric patients with heart failure is most likely to benefit and which cell type would be appropriate.

[Hypothermia-induced ECG changes: characteristic, but not specific]. / Hypothermieinduzierte EKG-Veränderungen: charakteristisch, aber nicht spezifisch.

Hypothermia-induced J­ or so-called Osborn waves can be detected under therapeutic hypothermia in approximately 20-40% of cases. The occurrence of J­waves in the context of the targeted temperature management after cardiopulmonary resuscitation is characteristic, but not pathognomonic for hypothermia. An electrocardiographic diagnosis under hypothermia after cardiac arrest should always be done with caution due to the various hypothermia-associated electromechanical changes of the myocardium.

Exercise during pregnancy and its impact on mothers and offspring in humans and mice.

Exercise during pregnancy has beneficial effects on maternal and offspring's health in humans and mice. The underlying mechanisms remain unclear. This comparative study aimed to determine the long-term effects of an exercise program on metabolism, weight gain, body composition and changes in hormones [insulin, leptin, brain-derived neurotrophic factor (BDNF)]. Pregnant women (n=34) and mouse dams (n=44) were subjected to an exercise program compared with matched controls (period I). Follow-up in the offspring was performed over 6 months in humans, corresponding to postnatal day (P) 21 in mice (period II). Half of the mouse offspring was challenged with a high-fat diet (HFD) for 6 weeks between P70 and P112 (period III). In period I, exercise during pregnancy led to 6% lower fat content, 40% lower leptin levels and an increase of 50% BDNF levels in humans compared with controls, which was not observed in mice. After period II in humans and mice, offspring body weight did not differ from that of the controls. Further differences were observed in period III. Offspring of exercising mouse dams had significantly lower fat mass and leptin levels compared with controls. In addition, at P112, BDNF levels in offspring were significantly higher from exercising mothers while this effect was completely blunted by HFD feeding. In this study, we found comparable effects on maternal and offspring's weight gain in humans and mice but different effects in insulin, leptin and BDNF. The long-term potential protective effects of exercise on biomarkers should be examined in human studies.

[Sensorineural loss of hearing in lower registers as the main symptom of Lyme disease]. / Symmetrische Tieftonschwerhörigkeit als Hauptsymptom einer Neuroborreliose.

In a 9-year-old boy with sudden sensorineural loss of hearing in the lower registers in both ears, serology showed elevated levels of antibodies against Borrelia burgdorferi and examination of the CSF revealed a positive antibody index against Borrelia burgdorferi. The boy was treated with antibiotics for 2 weeks. Audiometry performed 4 weeks after treatment was completely normal. Inner ear involvement in Lyme disease has often been discussed. Treating these patients with antibiotics may lead to an improvement in some.

Intracardiac rhabdomyomas producing symptoms in infancy: the role of radiofrequency catheter ablation.

BACKGROUND: Cardiac rhabdomyomas, although benign, may produce symptoms related to arrhythmia or mechanical obstruction. Surgical excision is the therapy of choice for symptomatic rhabdomyomas in infancy. PATIENTS AND METHODS: Two infants with intracardiac rhabdomyomas producing symptoms underwent radiofrequency catheter ablation of the tumour. In patient 1 the diagnosis of multiple rhabdomyomas associated with recurrent supraventricular tachyarrhythmias and foetal hydrops was made in utero. After birth, several antiarrhythmic agents were administered, without successful suppression of the tachyarrhythmia. At seven months of age, the infant had one large residual tumour on the left atrial aspect of the anterior mitral valve leaflet with associated pre-excitation and re-entrant supraventricular tachyarrhythmia suggestive of a left-sided pathway. Catheter ablation of the accessory pathway was performed via a retrograde femoral arterial approach, targeting the earliest site of ventricular activation. Patient 2 presented as a neonate with multiple rhabdomyomas, one of which, measuring 15 mm × 15 mm, was producing severe mitral valve inflow obstruction resulting in symptoms of heart failure due to a large left-to-right shunt at atrial level and persistent pulmonary hypertension. Via the femoral vein, a 5F ablation catheter was advanced across the atrial septum, and the tumour directly ablated. RESULTS: Echocardiography performed 24 hours later demonstrated alteration in tumour morphology, with the development of a large central echolucent area, followed by progressive tumour shrinkage in both infants. Patient 1 was discharged at 24 hours, and patient 2 at seven days post-ablation, without symptoms. Follow-up at four weeks confirmed further tumour shrinkage. CONCLUSION: Transcatheter tumour ablation may be beneficial in selected infants and children.

[Pulmonary hypertension in grown-ups with congenital heart disease: Recommendations of the Cologne Consensus Conference 2016]. / Pulmonale Hypertonie bei Erwachsenen mit angeborenen Herzfehlern: Empfehlungen der Kölner Konsensus-Konferenz 2016.

The 2015 European Guidelines on Diagnosis and Treatment of Pulmonary Hypertension are also valid for Germany. The guidelines contain detailed recommendations for different forms of PH, and specifically address PH associated with congenital heart disease (CHD). However, the practical implementation of the European Guidelines in Germany requires the consideration of several country-specific issues and already existing novel data. This requires a detailed commentary to the guidelines, and in some aspects an update already appears necessary. In June 2016, a Consensus Conference organized by the PH working groups of the German Society of Cardiology (DGK), the German Society of Respiratory Medicine (DGP) and the German Society of Pediatric Cardiology (DGPK) was held in Cologne, Germany. This conference aimed to solve practical and controversial issues surrounding the implementation of the European Guidelines in Germany. To this end, a number of working groups was initiated, one of which was specifically dedicated to PH in grown-ups with congenital heart disease (GUCH). This article summarizes the results and recommendations of this working group.

Identification and characterisation of a novel KCNQ1 mutation in a family with Romano-Ward syndrome.

Romano-Ward syndrome (RWS), the autosomal dominant form of the congenital long QT syndrome, is characterised by prolongation of the cardiac repolarisation process associated with ventricular tachyarrhythmias of the torsades de pointes type. Genetic studies have identified mutations in six ion channel genes, KCNQ1, KCNH2, SCN5A, KCNE1 and KCNE2 and the accessory protein Ankyrin-B gene, to be responsible for this disorder. Single-strand conformation polymorphism (SSCP) analysis and subsequent DNA sequence analysis have identified a KCNQ1 mutation in a family that were clinically conspicuous due to several syncopes and prolonged QTc intervals in the ECG. The mutant subunit was expressed and functionally characterised in the Xenopus oocyte expression system. A novel heterozygous missense mutation with a C to T transition at the first position of codon 343 (CCA) of the KCNQ1 gene was identified in three concerned family members (QTc intervals: 500, 510 and 530 ms, respectively). As a result, proline 343 localised within the highly conserved transmembrane segment S6 of the KCNQ1 channel is replaced by a serine. Co-expression of mutant (KCNQ1-P343S) and wild-type (KCNQ1) cRNA in Xenopus oocytes produced potassium currents reduced by approximately 92%, while IKs reconstitution experiments with a combination of KCNQ1 mutant, wild-type and KCNE1 subunits yielded currents reduced by approximately 60%. A novel mutation (P343S) identified in the KCNQ1 subunit gene of three members of a RWS family showed a dominant-negative effect on native IKs currents leading to prolongation of the heart repolarisation and possibly increases the risk of malign arrhythmias with sudden cardiac death.

Left ventricular diastolic function in infants, children, and adolescents. Reference values and analysis of morphologic and physiologic determinants of echocardiographic Doppler flow signals during growth and maturation.

OBJECTIVES: The aim of this study was to set up reference values for Doppler flow-derived left ventricular filling parameters and to evaluate physiologic determinants of changes in signal expression related to maturation. BACKGROUND: In left ventricular diastolic function studies, age-related modulations in signal expression are observed. Assuming degenerative myocardial changes to be absent during childhood and adolescence, the determinants of these modulations must be different from those suspected in adults. METHODS: Pulsed wave Doppler signals from the mitral valve tip region were recorded in 329 healthy subjects aged 2 months to 39 years. Multiple linear regression was used to evaluate statistical relations between Doppler flow signals and stroke volume in the mitral valve area. RESULTS: Increasing early filling time velocity integral throughout maturation caused a decrease in atrial filling fraction from 0.34+/-0.06 to 0.24+/-0.04 (p < 0.005). Peak flow velocities during atrial systole decreased from infancy to adolescence (66+/-15 to 41+/-10 cm/s). Main effects on signal modulation were caused by heart rate, stroke volume and mitral ring area with a linear model fit (R2) of 0.79 for early filling phase (E)-time velocity integral, 0.6 for atrial filling phase peak velocity 0.84 for total E duration and 0.73 for E deceleration time. Atrial filling phase-time velocity integral, albeit significantly dependent on heart rate, was stable throughout growth. CONCLUSIONS: During infancy and childhood, the stroke volume crossing the mitral valve is a main modulator for early filling phase (E)-time velocity integral and diastolic time intervals during early filling, whereas atrial filling phase parameters are mainly dependent on heart rate. This results in a more pronounced atrial filling during infancy and childhood.

[Electrical heart diseases--therapy during childhood and adolescence]. / Elektrische Herzerkrankungen--Behandlung im Kindes- und Jugendalter.

With increasing experience, radiofrequency catheter ablation of tachyarrhythmia substrates has become first choice therapy for children >4 years of age with recurrent tachyarrhythmia. In younger patients, the risks associated with the procedure (typically procedure-related AV block or possible coronary artery damage) have to be weighed against the natural history of the tachyarrhythmia substrate, and the degree of control achieved with pharmacologic agents. Ablation for postoperative arrhythmias is more complicated, and associated with lower success rates and a higher rate of recurrence (of the same or a new tachyarrhythmia) despite acute procedural success. In this setting, catheter ablation has to be considered in conjunction with further surgery or the use of a defibrillator as a backup device to prevent arrhythmia-related sudden death. Also in inherited arrhythmias as in long QT syndrome and Brugada syndrome, implantable defibrillators have to be considered as a possible therapeutic option for patients with a higher risk for sudden cardiac death, irrespective of age.

Electrophysiologic effects and efficacy of intravenous propafenone in terminating atrioventricular reentrant tachycardia in children.

In pediatric patients with atrioventricular reentrant tachycardia, intravenous propafenone exhibits its electrophysiologic effects in a dose-dependent manner by slowing or blocking retrograde conduction at the accessory connection. The high drug efficacy (81%) in terminating tachycardia is not dependent on patient age or retrograde conduction properties of the accessory connection.

The index of pulmonary vascular disease in children with congenital heart disease: relationship to clinical and haemodynamic findings.

OBJECTIVE: We asked whether a scoring system [index of pulmonary vascular disease (IPVD)] that quantifies the individual pulmonary vascular pathology would relate to postoperative survival in patients with congenital heart disease and pulmonary hypertension (PH). METHODS: Lung biopsy specimens from 28 patients at a median age of 6 months (1 month to 21 years) were analysed qualitatively and morphometrically. The IPVD and other morphometric parameters were related to haemodynamic findings and survival. RESULTS: Mean pulmonary artery pressure (PAP) was 44 mmHg (15-72 mmHg), and the resistance to pulmonary perfusion was 5 U x m(2) (0.9-14 U x m(2)). There were three early (in-hospital) and three late deaths during the follow-up period of 2.5 years (6 months to 7 years). Incipient plexiform lesions were observed in one infant with trisomy 21 and complete atrioventricular septal defect (cAVSD). An IPVD score above the upper critical limit (>2.2) was not observed during the first year of life. On discriminant analysis, morphometric parameters could not predict mortality ( P=0.08). CONCLUSIONS: The IPVD is not helpful to predict surgical mortality during the first year of life. Patients with trisomy 21 and cAVSD may show advanced pulmonary vascular disease in infancy.

Fetal magnetocardiography: the clinician's viewpoint.

The fetal magnetocardiogram (FMCG) can be reliably recorded from approximately the 15th week of gestation onwards. The MCG has the ability to accurately record cardiac time intervals, and to provide a real-time recording that reflects cardiac electrical activity. Standardisation of the recording, signal processing, and measurement techniques can result in data that is reproducible, and when combined with the establishment of normal values for different gestational ages can be of clinical application universally, particularly in selected groups of patients at risk of potentially lethal arrhythmias.

Transhepatic approach for catheter ablation of accessory pathway in a child with complex congenital heart disease.

We report on a 22-month-old boy with drug-resistant atrioventricular reentrant tachycardia and complex structural heart disease consisting of right atrial isomerism, mirror image orientation of the intrathoracic veins, hemi-azygos continuation to the left superior vena cava, separate drainage of the hepatic veins into the left-sided atrium, congenitally corrected transposition, pulmonary atresia, and atrial and ventricular septal defects. Access to the heart for radiofrequency (RF) ablation was obtained by percutaneous puncture of a hepatic vein, the left internal jugular vein, and femoral artery. The accessory pathway was localised to the free wall of the left-sided AV groove and successfully ablated. There were no procedure-related complications. RF ablation of an accessory pathway is feasible in young children with complex structural heart disease and abnormal systemic venous return. In such patients access to the heart must be planned with knowledge of the anatomy and judicious use of the hepatic venous approach.

HIPAA compliance readiness assessment: a case study.

Centura Health, a faith-based, not-for-profit IDS headquartered in Denver, Colorado, recently undertook a rapid assessment to determine its readiness to comply with the standards mandated by the Health Insurance Portability and Accountability Act (HIPAA) of 1996. The assessment process consisted of a business-impact assessment, compilation of results, a gap analysis, and a preliminary business case. The business-impact assessment involved a series of interviews. For the business case, results of the business-impact assessment were compared with the related HIPAA standard to determine the current level of compliance and develop an action plan, for approval by the project steering committee, to correct deficiencies. The HIPAA readiness assessment uncovered numerous areas in which Centura needed to implement changes, particularly with respect to ensuring the security and privacy of patients' paper records.

[Inborn long QT-syndrome in childhood: clinical presentation and treatment]. / Angeborene Long-QT-Syndrome im Kindesalter: Klinische Präsentation und Behandlung.

During the last decade, the understanding of the long QT-syndrome (LQTS) as an inherited arrhythmogenic disease has dramatically increased. The LQTS has been recognized to be a heterogeneous family of ion-channel disorders caused by numerous mutations in at least six distinct gene loci, thus, explaining the prolongation of the myocardial repolarization. Consecutive studies of the LQTS advanced our knowledge of pathophysiology, clinical course and possible therapeutic impact. As a genetically determined disorder the clinical manifestation of the LQTS naturally starts in childhood. In 34% of the children, syncope or cardiac arrest was found to occur before the age of 15 years. In addition, 54% of all LQTS patients who died from sudden cardiac death were less than 20years old. Most cases in children are identified by the detection of a prolonged QT interval while evaluating unexplained cases of syncope or by family investigations of an index patient. In children more than in adults, however, normal values of QT interval duration are dependent from age, gender, heart rate and circadian variations. Therefore, the moreover applied correction formulas for the QT interval to heart rate ratio have to be used with caution in the pediatric setting. A useful and reliable tool for the analysis of QT duration, QT patterns, and its circadian variation is multilead digital Holter recordings. The determination of the diagnosis is based on clinical findings according to the criteria of the "International LQTS Registry". Genetic investigations, however, are actually diagnostic in about 50% of the patients, but are not effective as a clinical screening tool. The genetically determined LQTS types (LQT1-LQT6) differ significantly in terms of reaction to triggering stimuli that may induce life-threatening arrhythmias and their response to treatment. In LQT1, physical stress will more likely induce Torsades de Pointes than in the LQT3, which is more sensitive to emotional stress. The typical LQTS treatment is life-long medication with beta blocking agents; however, in LQT3 patients with mutations in the cardiac sodium channel gene, treatment with mexiletine may have advantages. In order to prevent bradycardia or by short-long sequences inducible torsades, the use of implantable pacemakers is recommended. Stellectomy to minimize cardiac adrenergic susceptibility has proven to be less effective in children. Recently, the rapid technical improvement of implantable defibrillators led to a more frequent use of these devices in children. In order to sufficiently manage pediatric LQTS patients in the future and to reduce the risk of sudden cardiac death due to inherited arrhythmias, a national and international multicenter approach is necessary.

[Cryoenergy for the ablation of arrhythmogenic paraseptal substrates in children and adolescents with heart rhythm disorders]. / Kryoenergie zur Ablation arrhythmogener paraseptaler Substrate bei Herzrhythmusstörungen im Kindes- und Jugendalter.

BACKGROUND AND OBJECTIVE: Cryoablation is safe for the ablation of substrates in proximity to the AV node, because the initial lesion is reversible. We report our results of cryoablation in a transregional center for ablation in children and adolescents. PATIENTS AND METHODS: Data on 39 children and adolescents (4 - 18 years of age) who had been treated with cryo energy were analyzed retrospectively. The diagnosis was AV nodal reentry tachycardia (AVNRT; n = 30), para-Hisian accessory pathway (AP; n = 6) and congenital junctional ectopic tachycardia (JET; n = 4). In addition to non-inducibility, the targeted endpoint for AP-ablation was a missing or decremental concentric retrograde conduction, for ablation of AVNRT the endpoint was no slow pathway, no AH jumps and no echo-beats. The median follow-up was 3 years (270 - 1919 days). RESULTS: The targeted endpoint was reached in 35/39 patients (90 %), in four patients (10 %) RF energy had to be applied. A recurrence occurred in 7/35 (20 %) successfully treated patients. Two patients had a pre-excitation again after AP ablation, but no symptoms. Thus, 28/35 patients (80 %) remained asymptomatic after cryoablation, and 26/35 (74 %) are definitively cured, regarding all follow-up data. The subgroup of AVNRT patients does not differ from the entire group. There was no AV block in the cryoablation group. CONCLUSIONS: Cryoablation is very safe and effective for the definitive treatment of arrhythmias in children and adolescents. The price for the high safety is a reduced efficacy and a higher recurrence rate.