D-Transposition of the great arteries with restrictive foramen ovale in the fetus: the dilemma of predicting the need for postnatal urgent balloon atrial septostomy.

OBJECTIVE: Restrictive foramen ovale (FO) in dextro-transposition of the great arteries (d-TGA) with intact ventricular septum may lead to severe life-threatening hypoxia within the first hours of life, making urgent balloon atrial septostomy (BAS) inevitable. Reliable prenatal prediction of restrictive FO is crucial in these cases. However, current prenatal echocardiographic markers show low predictive value, and prenatal prediction often fails with fatal consequences for a subset of newborns. In this study, we described our experience and aimed to identify reliable predictive markers for BAS. METHODS: We included 45 fetuses with isolated d-TGA that were diagnosed and delivered between 2010 and 2022 in two large German tertiary referral centers. Inclusion criteria were the availability of former prenatal ultrasound reports, of stored echocardiographic videos and still images, which had to be obtained within the last 14 days prior to delivery and that were of sufficient quality for retrospective re-analysis. Cardiac parameters were retrospectively assessed and their predictive value was evaluated. RESULTS: Among the 45 included fetuses with d-TGA, 22 neonates had restrictive FO postnatally and required urgent BAS within the first 24 h of life. In contrast, 23 neonates had normal FO anatomy, but 4 of them unexpectedly showed inadequate interatrial mixing despite their normal FO anatomy, rapidly developed hypoxia and also required urgent BAS ('bad mixer'). Overall, 26 (58%) neonates required urgent BAS, whereas 19 (42%) achieved good O2 saturation and did not undergo urgent BAS. In the former prenatal ultrasound reports, restrictive FO with subsequent urgent BAS was correctly predicted in 11 of 22 cases (50% sensitivity), whereas a normal FO anatomy was correctly predicted in 19 of 23 cases (83% specificity). After current re-analysis of the stored videos and images, we identified three highly significant markers for restrictive FO: a FO diameter < 7 mm (p < 0.01), a fixed (p = 0.035) and a hypermobile (p = 0.014) FO flap. The maximum systolic flow velocities in the pulmonary veins were also significantly increased in restrictive FO (p = 0.021), but no cut-off value to reliably predict restrictive FO could be identified. If the above markers are applied, all 22 cases with restrictive FO and all 23 cases with normal FO anatomy could correctly be predicted (100% positive predictive value). Correct prediction of urgent BAS also succeeded in all 22 cases with restrictive FO (100% PPV), but naturally failed in 4 of the 23 cases with correctly predicted normal FO ('bad mixer') (82.6% negative predictive value). CONCLUSION: Precise assessment of FO size and FO flap motility allows a reliable prenatal prediction of both restrictive and normal FO anatomy postnatally. Prediction of likelihood of urgent BAS also succeeds reliably in all fetuses with restrictive FO, but identification of the small subset of fetuses that also requires urgent BAS despite their normal FO anatomy fails, because the ability of sufficient postnatal interatrial mixing cannot be predicted prenatally. Therefore, all fetuses with prenatally diagnosed d-TGA should always be delivered in a tertiary center with cardiac catheter stand-by, allowing BAS within the first 24 h after birth, regardless of their predicted FO anatomy.

Fabrication of InVO4/SnWO4 heterostructured photocatalyst for efficient photocatalytic degradation of tetracycline under visible light.

In the present study, novel InVO4/SnWO4 nanocomposites with different concentrations of SnWO4 were successfully prepared using a facile hydrothermal technique and investigated employing a wide range of analytical methods for efficient photocatalytic degradation of tetracycline (TC). X-ray diffraction analysis showed the presence of the orthorhombic phases of both InVO4 and SnWO4 in the composite catalyst. Dispersion of SnWO4 nanoplates over the InVO4 nanosheets enhanced the synergistic interactions, improving the separation of charge carriers and their transfer. Furthermore, the formation of heterostructure expanded the absorption range and promoted visible light harvesting. The TC degradation efficiency of InVO4/SnWO4 nanocomposite (5 mg loading of SnWO4) reached 97.13% in 80 min under visible light, with the kinetic rate constants 5.51 and 7.63 times greater than those of pure InVO4 and SnWO4, respectively. Additionally, the scavenger results proved that hydroxyl radicals and holes played a significant role in the photodegradation of TC. Furthermore, the electrochemical impedance spectroscopy (EIS) and transient photocurrent response analysis showed enhanced e-/h+ partition efficiency. Thus, the formation of heterostructure with strong synergistic interactions can effectively transfer the excited charge carriers and shorten the reunion rate. Accordingly, the InVO4/SnWO4 nanocomposites exhibited remarkable photocatalytic performance due to the increased number of charge carriers on the surface.

Visible-light-driven indium vanadium oxide nanosheets supported bismuth tungsten oxide nanoflakes heterostructure as an efficient photocatalyst for the tetracycline degradation.

The development of excellent photocatalysts is of great significance for the efficient photocatalytic degradation process, however, the low carrier separation efficiency and poor light absorption ability typically limit the performance of photocatalysts. Herein, a visible light responsive heterostructure composed with indium vanadium oxide nanosheets supported bismuth tungsten oxide nanoflakes (InVO4/Bi2WO6) was synthetized through in-situ hydrothermal method. Further, the photocatalytic activity was performed for tetracycline (TC) under visible light illumination. The InVO4/Bi2WO6 heterostructure builds a strong interface between InVO4 and Bi2WO6 to hinder reunion of photoinduced charge carriers, and provides the sensitive agents for the removal of TC. In particular, the InVO4/Bi2WO6 photocatalyst prepared by taking 5.0 mg of Bi2WO6 shows the highest degradation of TC about 97.42% in 72 min. The quenching experiments identified that hydroxyl radicals, and holes dominated in the photocatalytic process. Furthermore, the optimized nanocomposite is stable even after four cycles, which exposes the excellent photostability and reusability of the photocatalyst. In addition, a plausible degradation pathway and mechanism of TC over InVO4/Bi2WO6 nanocomposite is also projected.

[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.

Device therapy to prevent sudden death in patients with structural heart disease.

The advent of the implantable cardioverter defibrillator has provided clinicians with a potential tool to prevent sudden arrhythmic death. When considering patients with structural heart disease, long-term follow-up data have suggested that this is indeed an important cause of late mortality. It is essential therefore to undertake follow-up studies to identify high risk individuals or disease categories that are associated with sudden cardiac death (SCD), and to elucidate the specific risk factors that may be associated with this complication. We provide a brief update on the current state of knowledge in this challenging and rapidly developing field.

Risk stratification in young patients with channelopathies.

Identifying the young patient at risk of malignant arrhythmias and sudden cardiac death remains a challenge. It is increasingly recognised that sudden death, syncope and aborted cardiac arrest at a young age in patients with a structurally normal heart may be the result of various ion channel disorders - the channelopathies. The approach to risk stratification involves a combination of the clinical presentation, taken in conjunction with the family history, genetic testing, invasive electrophysiological studies or other provocative tests where appropriate and feasible. A logical approach to risk stratification in some of the commoner channelopathies seen in paediatric practice is presented.

Rapid development of life-threatening complete atrioventricular block in Kearns-Sayre syndrome.

Kearns-Sayre syndrome is a rare mitochondrial disorder with defined diagnostic criteria. Knowledge of these diagnostic criteria and early diagnosis are important to ensure periodic electrocardiograms for identification of cardiac conduction disorders, which are the most important prognostic factor of the disease. We report on a 9-year-old girl with rapid development of a life-threatening complete atrioventricular block within 10 months and discuss the importance and time interval of regular electrocardiograms. Our patient survived by placing a temporary transvenous pacemaker lead followed by permanent pacemaker implantation a few days later.

Device therapy in children: current indications.

The implantable cardioverter defibrillator has achieved increasing acceptance in paediatric cardiologic practice. Concurrent with technological advances which have made the devices more versatile, easier to implant and to program, there has been a fundamental breakthrough in our understanding of genetic and inherited arrhythmia syndromes in the last decade. This in turn has led to investigations into risk stratification, with the aim of choosing high risk candidates for timely device therapy. The second group of young patients with a risk of sudden death are those who have had a previous repair of a structural heart defect. Given that sudden arrhythmic death is the commonest cause of mortality in this population, it behoves the practising paediatric cardiologist to be aware of the current recommendations for device implantation in this population. In this manuscript, we summarise the current state of our understanding of the risk factors for sudden death, and identify possible candidates for ICD implantation.

Paediatric electrophysiologic studies: how and what with?

Catheter ablation of arrhythmias in children has become standard practice virtually worldwide. Successful and safe ablation has been made possible by a combination of factors. These include increased operator experience, a better understanding of the natural history of a wide variety of arrhythmias, advances in technology such as smaller catheters, the routine use of various three-dimensional mapping systems, and the development of alternative energy sources. It is also not uncommon to perform multiple catheter intervention procedures (ablation +/- intravascular stent implantation +/- device closure of residual shunts +/- elective pacemaker or device implantation) during a single session. It is important to bear in mind that arrhythmia recurrence is commoner in children in general, and that this is particularly the case with postoperative (scar-related arrhythmias). Despite acute success, long-term follow-up is mandated for this subgroup of patients.

The diagnostic yield from implantable loop recorders in children and young adults.

BACKGROUND: Syncope and palpitations occur frequently in young patients. Noninvasive diagnostic testing may be inconclusive. AIM: To assess the diagnostic yield of implantable loop recorders in young patients. PATIENTS AND METHODS: Thirty-three young patients underwent implantation of a loop recorder for long-term monitoring of cardiac rhythm, to establish symptom-rhythm correlation. They belonged to one of three subgroups: those with structurally normal heart, normal electrocardiogram at rest, and negative family history (n = 16); patients with structural heart disease and previous surgical repair (n = 11), and patients with proven or suspected primary electrical disease (n = 6). A combination of automatic and patient-activated recordings was used to monitor cardiac rhythm during symptomatic episodes. RESULTS: There were no procedural complications. Diagnostic electrograms could be obtained in all patients. A high degree of symptom-rhythm correlation was established. In 8/33 patients, no recurrence of symptoms was observed either until end of battery life of the device (n = 4) or until last follow-up (n = 2). Specific cardiac therapy was required, based on rhythms recorded by the device in 15 patients (until last follow-up). This consisted of catheter ablation of a tachyarrhythmia (n = 7), pacemaker implantation or upgrade (n = 5) or ICD implantation (n = 5). In the remaining patients (n = 10), recurrence of symptoms was associated with a normal electrocardiogram, and in two of these patients a non-cardiac diagnosis was made. CONCLUSIONS: In selected patients, the implantable loop recorder provides valuable diagnostic information to guide further therapy.

Transcatheter recanalization of acutely occluded modified systemic to pulmonary artery shunts in infancy.

BACKGROUND: There are few data on successful recanalization of acutely occluded modified aortopulmonary shunts in infants in whom the major component of pulmonary flow is shunt-dependent. PATIENTS AND METHODS: Seven infants (age range 6 days to 7 months) with modified (polytetrafluoroethylene) aortopulmonary shunts (central shunt n = 6, modified Blalock-Taussig shunt n = 1), in whom acute shunt occlusion was documented following surgery (interval from shunt surgery 2-6 days) underwent emergency cardiac catheterization with a view to reopening the shunt. Anterograde right ventricle to pulmonary artery flow was present in three patient; two other had additional aortopulmonary collateral vessels, and intravenous prostaglandin E (PGE1) infusion was restarted in three infants to achieve or maintain ductal patency. All occluded shunts could be crossed with a 4F endhole catheter and various guidewire combinations. Balloon dilation was performed using a balloon with the same nominal diameter as the shunt (5 or 6 mm). RESULTS: All shunts were successfully recanalized. Two infants with recurrent cyanotic episodes underwent stent implantation in the right ventricular outflow tract (RVOT) during the same procedure. One infant required shunt revision 24 h following balloon angioplasty, during which a small clot was evacuated from the distal end of the shunt. An immediate improvement in oxygen saturation could be documented in all patients. In the remaining six infants, shunt patency was confirmed at follow-up, until further definitive repair. One infant died of non-cardiac causes, while awaiting definitive repair. CONCLUSIONS: This small series demonstrates that acutely occluded shunts can be successfully recanalized, and that patency can be maintained until further definitive surgery in the majority of infants.

Aerosolized iloprost in the treatment of pulmonary hypertension in extremely preterm infants: a pilot study.

BACKGROUND: In premature infants with preterm prolonged rupture of membranes, death after birth is often due to persistent pulmonary hyper-tension. PATIENTS: Aerosolized iloprost was used to treat pulmonary hypertension due to prolonged preterm rupture of fetal membranes (7-56 days) in four extremely low-birthweight neonates (23-25 weeks' gestation, weight 448-645 g) under spontaneous breathing supported by nasal continuous positive airway pressure. METHOD: Inhalation dose was 2 microg/kg b.w. and between 44 and 65 inhalations were performed in each patient starting within the first hour of life over a total of several days. Single inhalations lasted 5 min and were not repeated until 60 min had elapsed. RESULTS: After the first inhalation, the PaO2/FiO2 mean ratio increased from 65 (range 35-114) to 194 (148-250) mmHg and oxygenation requirements decreased within the next 7 days. Echocardiography similarly showed reduction in pulmonary resistance. We observed no severe side effects on blood pressure or prolonged bleeding time during inhalation. CONCLUSIONS: Iloprost inhalation might therefore be an additional treatment for improving oxygenation in cases of persistent pulmonary hypertension in extremely low-birthweight infants under spontaneous breathing. Further randomized clinical studies are required to establish the role of iloprost in this setting.

Central venous catheters in children and neonates (Part 2) - Access via the internal jugular vein.

Central venous access via the internal jugular vein (IJV) is safe, relatively easy and very commonly used in infants and children undergoing cardiac surgery for congenital heart disease. Because of the wide range of anatomical variations an ultrasound-guided technique is advantageous in many cases, in particular in patients who have had previous punctures or those in whom difficulties are anticipated for various reasons. The right internal jugular vein is the preferred vein for central venous access as it offers straight access to the superior vena cava. The rate of complications - insertion-related as well as long term - are lower compared to the femoral and the subclavian access.

Transcatheter closure of symptomatic aortopulmonary window in an infant.

An aortopulmonary window is a rare congenital cardiac defect. In the majority of symptomatic neonates and infants, primary surgical repair is the treatment of choice. In selected infants, catheter closure of the defect with a device may be feasible. We report on the successful closure of an AP window in a 12 month old infant, using a 6mm Amplatzer septal occluder. The procedure and follow-up were uneventful.

Central venous catheters in children and neonates (Part 3) - Access via the femoral vein.

BACKGROUND: Central venous access via the femoral vein (FV) is safe, relatively easy and very usual in infants and children undergoing cardiac surgery for congenital heart disease. It has a low insertion-related complication rate. RESULTS: It is therefore a good choice for short-term central venous lines and a preferred insertion site for less experienced staff. The maintenance-related complications of thrombus formation and infections are higher compared to the internal jugular and the subclavian venous access. CONCLUSIONS: Some of these complications are reduced by the use of heparin bonded catheters, routine use of antibiotics, and timely removal of these lines in patients with persistent signs of infection but without another focus being defined.

The Amplatzer duct occluder for PDA closure: indications, technique of implantation and clinical outcome.

Following its introduction into clinical practice, the Amplatzer duct occluder (ADO) has achieved a definite place in the armamentarium of the interventional cardiologist for the closure of moderate to large sized PDAs. The device combines ease of use, including retrievability and repositioning when required, and a high occlusion rate (>99% complete occlusion of PDA within 6 months of implant, with the majority of occlusions occurring within 24 hours of implant). Possible complications, such as device embolization, protrusion of the retention disc of the device into the aorta producing aortic obstruction, or obstruction of a branch pulmonary artery by the device are also uncommon and can be avoided by choosing the appropriate sized device (with the pulmonary end of the device being 2mm larger in diameter than the minimum measured ductal diameter), and paying scrupulous attention to technique of deployment. The device can be safely deployed in infants >3.5 kg, and can currently close PDAs of upto 11 to 12mm in minimum diameter. A brief description of the device, the technique of implantation, and the clinical results to date are provided.