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Long QT syndrome (LQTS) is an inherited arrhythmic disorder associated with sudden cardiac death (SCD). This study aimed to identify the clinical and molecular genetic risk factors that contribute to major arrhythmic events (MAEs) in patients with genetically confirmed childhood onset LQTS 1–3. This study was a retrospective double-center study. An MAE was defined as the occurrence of SCD, aborted SCD, appropriate implantable cardioverter defibrillator discharge, or sustained ventricular tachycardia. During a median follow-up of 4.6 years (range 0.1–24.3 years), MAEs occurred in 18 (17.8%) of 101 patients diagnosed with LQTS at a median of 7.7 years (range 0.0–18.0 years) despite the use of beta-blockers in 91.6% of patients at the last follow-up. A multivariate analysis identified a genetic diagnosis of LQTS2 and LQTS3 and variants within the KCNH2 S5-loop-S6 pore region as independent risk factors for MAEs, independent of the QTc value or a history of syncope detected from a univariate analysis. MAEs occur frequently in childhood onset LQTS despite beta-blocker treatment. A detailed molecular genetic diagnosis can contribute to the arrhythmia risk stratification and optimize the use of preventive measures in this vulnerable patient population.

Introduction:Cardiopulmonary exercise testing represents the diagnostic tool for determining cardiopulmonary function. Especially in small children, exercise testing is extremely challenging. To address this problem, field testing has been implemented using small mobile devices. This study aims at using this protocol for developing normal values for cardiopulmonary exercise testing in very young children.Material and methods:Healthy children aged 4–8 years were recruited. All children were tested according to an outdoor protocol, in which they were instructed to walk, then run slowly, then a little harder and at last run at full speed. Each step lasted for 2 minutes, except the last step, in which the children were instructed to maintain as long as possible.Results:A total of 104 children (64 female/35 male, mean age 6.6 years) performed outdoor cardiopulmonary exercise testing using a mobile device. Almost all tests were completed successfully (95%). Despite a predominance of female study subjects, anthropometric values did not differ between boys and girls. V̇O2peak/kg, respiratory exchange ratio, VT1, heart rate at VT1, and time of exercise were also comparable between sexes. Generally, a tendency of higher maximal oxygen uptake could be observed in older children.Conclusion:Open field mobile cardiopulmonary exercise testing represents a novel approach in very young children. In this study, we were able to determine normal values of maximal oxygen uptake and OUES/kg for 4–8-year-old children. The method is easy to achieve and safe.

Introduction:Telemedicine gained an increasing use throughout the last years. Lifestyle tools like the Apple watch seem to have an increasing spread even in remote areas and underdeveloped regions. The increasing availability of these tools offers the chance to use the health care functions of these devices to improve provision of professional medical care. First data on the use of the Apple Watch as a remote monitoring device in children have been reported, showing good acceptability and usability of the Apple Watch for symptom monitoring in children. This study aimed to evaluate the accuracy of the Apple Watch iECG in comparison to a standard 12-lead ECG in pre-term babies.Methods:In this prospective, single-arm study, consecutive preterm neonates hospitalised in Leipzig University Hospital neonatal ICU were eligible. A 12-lead ECG and an iECG using Apple Watch 4 were performed. iECG and 12-lead ECG measurements were performed by a paediatric cardiologist. Cardiac rhythm was classified and amplitudes and timing intervals were analysed for comparability.Results:Fifty preterm neonates, gestational week (23–36 weeks), and body weight (0.65–3.09 kg) were enrolled. Overall good quality and excellent correlation of the Apple Watch generated iECG in comparison to the standard 12-lead ECG could be demonstrated (p < 0.001). When interpreted by a paediatric cardiologist, a correct rhythm classification could be done in 100% of cases.Conclusion:The Apple Watch iECG seems to be a valuable tool to record an ECG comparable to lead I of the standard 12-lead ECG even in pre-term neonates. With a widespread availability and excellent connectivity, the Apple Watch iECG function may provide practitioners with a tool to send an iECG for interpretation to a paediatric cardiac specialist.

This study evaluates the accuracy of iECGs in comparison to the gold standard ECG in adult patients with congenital heart disease and recommends the appropriate iECG derivation based on the patient's characteristics.In 106 adults (51 female, 55 male) with congenital heart disease, a gold standard 12-lead ECG was recorded, followed by three iECGs with the Apple Watch series 4, which correspond to Einthoven leads I, II, and III. Two experienced and independent cardiologists analyzed the time intervals, amplitudes, and polarities of the ECG parameters as well as the rhythm type and correlated the patient characteristics with the iECG parameters.The iECG parameters of all three iECG leads correlate strongly with those of the gold standard ECG, with exception of the P and T wave durations. We demonstrated that the informative value of the individual iECGs was independent of the patient's characteristics, in particular the heart axis, anatomy, and situs, even if the quality of the Einthoven III-like derivation was partially inadequate. The automatic rhythm analysis of the Apple Watch and the heart rhythm classification of a standard ECG analyzed manually by a cardiologist corresponded in 77%.iECG recordings of adults with congenital heart disease provide comparable results with Einthoven recordings I, II, and III of the 12-lead ECG and current data encourage the use of the Apple Watch not only in patients with structurally normal hearts but also in patients with congenital heart disease.

Reflex vasovagal-or cardioinhibitory syncope is known to be a major cause of recurrent syncope in children. The mechanism of vasovagal syncope (VVS) is an interaction between a vagally mediated bradycardia or asystole and a more or less manifest vasodilatory component. Although pacing is not advisable as a standard approach in patients with VVS, it remains a treatment option of last resort in exceptionally severe cases, or patients with contraindication or refractoriness to drug therapy and life style changes. To effectively avoid VVS in these patients, the pacemaker has to both prevent bradycardia and to compensate for the vasodilatory component. Therefore, this study aimed to evaluate a simple pacemaker setting (VVI pacing with hysteresis) with the potential to prevent VVS in affected children.Clinical data of patients, who were presented to the Department for Pediatric Cardiology, Heart Center Leipzig, in the period of 2001-2017 for cardiac pacemaker implantation for cardioinhibitory syncope or pallid breath-holding spells, were collected retrospectively.Eleven pediatric patients, median age 2.7 (0.8-17) years, were included. Pacemaker settings are depicted. In 10 out of 11 patients, an entire abolishment of syncope could be achieved (P = .002).The presented VVI pacing with hysteresis seems to be a promising pacemaker setting in pediatric patients with cardioinhibitory syncope who need a pacemaker. Unnecessary ventricular stimulation is effectively avoided, while cardiac output is preserved during cardioinhibition, by providing a sufficient paced heart rate, compensating for the often present vasodilatory component.