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Supplemental Digital Content is available in the text., Background: Hypertrophic cardiomyopathy is the leading cause of sudden cardiac death (SCD) in children and young adults. Our objective was to develop and validate a SCD risk prediction model in pediatric hypertrophic cardiomyopathy to guide SCD prevention strategies. Methods: In an international multicenter observational cohort study, phenotype-positive patients with isolated hypertrophic cardiomyopathy 70% prediction accuracy and incorporates risk factors that are unique to pediatric hypertrophic cardiomyopathy. An individualized risk prediction model has the potential to improve the application of clinical practice guidelines and shared decision making for implantable cardioverter defibrillator insertion. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT0403679.

Background/Aim: Convalescent plasma collected from COVID-19 survivors contains antibodies against receptor binding domains with potent antiviral activity. The use of this therapy for COVID-19 is still under investigation, as the pathophysiological and immunological mechanisms responsible for the evolution of the disease have not been fully identified. Patients and Methods: In this retrospective observational study, we included all patients with a confirmed SARS-Cov-2 infection based on positive RT-PCR testing, who received convalescent plasma treatment in addition to standard therapy, between 17.05.2020 and 27.11.2020, following hospitalization in the Anaesthesia and Intensive Care Unit of the Sibiu County Emergency Clinical Hospital, Romania. Results: Convalescent plasma therapy of patients with SARS-Cov-2 infection and severe forms of the disease (requiring only high-flow oxygen therapy or non-invasive ventilation) significantly improved inflammatory markers (CRP, fibrinogen) and ventilatory parameters (SaO2, paO2, paO2/FiO2) reducing the need of supplemental oxygen delivery (p

Introduction: Diagnosing diastolic dysfunction (DD) non-invasively in children is challenging as no validated pediatric diagnostic algorithm is available. The aim of this study is to use machine learning (ML) to identify a model that integrates echocardiographic measurements to predict invasive hemodynamic markers of DD in children. Methods: We enrolled children with Kawasaki disease, heart transplant, aortic stenosis, and coarctation of the aorta undergoing left heart catheterization. We obtained simultaneous invasive and echo DD measurements. We applied random forest (RF) algorithms to develop separate models for each cath marker (time constant of isovolumic relaxation (Tau), LVEDP, and -dP/dt max) and used demographics, diagnosis, and echo features as inputs. Model approximation was done using a regression tree with the top ranked features of each RF model to improve model interpretability (Figure 1). Spearman correlations were also assessed. Results: 59 children were included. Spearman correlations were low. However, the RF models' adjusted R 2 values in predicting Tau, LVEDP, and -dP/dt max are 0.62, 0.51, and 0.83, respectively. A representative ML-generated tree for LVEDP is shown in Figure 2. The most important features were propagation velocity (Vp) for Tau; E/Vp ratio for LVEDP; and systolic global longitudinal strain rate for -dP/dt max. Model approximation showed that a Vp < 42 cm/s predicted a Tau > 39 ms, and an E/Vp > 2.4 predicted an LVEDP > 13 mmHg. Conclusions: Predicting invasively measured diastolic parameters with echo data may be improved using ML algorithms. Model approximation may help better interpret the complex interactions in ML models.

Introduction: Unplanned intervention before stage 2 palliation (S2P) in patients with single ventricle (SV) lesions with dual unobstructed outflows palliated with pulmonary artery banding (PAB) is common. The factors contributing to intervention and its association with successfully undergoing S2P are unclear. Hypothesis: Early intervention is more common when PAB is placed at a younger age and with a lower initial PAB pressure gradient. Methods: Retrospective single center study of patients with SV lesions undergoing PAB between Jan 2000 and Dec 2020. Association with reintervention and successful S2P was modeled using exploratory cause-specific hazard regression. A multivariable model was developed adjusting for clinical and statistically relevant predictors. The cumulative proportion of patients undergoing intervention were summarized using a competing risk model. Results: A total of 77 patients - 53% female, 86% term and 12% syndromic - underwent PAB at median (IQR) 47 (24-66) days and 3.73 (3.2-4.5) kg. Within 18 months of PAB, 60 (78%) reached S2P, 9 (12%) died, 1 (1%) transplanted and 7 (9%) were alive without S2P. Intervention occurred in 18 (23%) prior to S2P (10/18) or death (4/18); 16 (21 %) occurred within 6 months of PAB. Intervention included PAB adjustment (n=7), conversion to DKS/BTT shunt (n=5), balloon atrial septostomy (n=4) and addition of a BTT shunt (n=2). Repeat intervention was required in 4 patients. Intervention was associated with genetic syndrome (p= 0.03) and lower weight at PAB (p=0.02) but not with age at PAB, pre/postoperative oxygen saturation, PAB length or gradient. Presence of genetic syndrome was the only risk factor associated with not reaching S2P (p=0.02). Conclusions: Intervention is common following PAB and associated with presence of genetic disorder or smaller patient size. Children with genetic syndrome aiming to undergo S2P are at higher risk for intervention and death and may benefit from alternate treatment strategy.

Background: Ventricular torsion is important in assessment of the systolic and diastolic function especially in single ventricle (SV) but is poorly studied. Objective: We aimed to a) examine serial changes in SV torsion, and b) examine its association with CMR data and exercise performance. Methods: We retrospectively studied SV patients after Fontan completion. Speckle-tracking echocardiography was used to evaluate serial changes in ventricular mechanics; strain, torsion, and untwist. CMR volumetric data and cardiopulmonary exercise data closest to echocardiograms were obtained. The most recent follow up echocardiographic and CMR data were compared to data before Fontan. Results: 45 SV patients (27 LV, 12 RV, and 6 co dominant) were studied. Demographics, echocardiographic, CMR, and exercise data are shown in table 1. Mean time at follow up echo from time of Fontan was 12.8 (10.6-16.6) years. Follow up echocardiograms showed reduced global longitudinal strain [-17.5(-6.5 to-19.5) vs -19.8 (-12 to -23%), p=0.01], circumferential strain [-15.7 (-8.4 to - 20.7) vs [-18.9 (-11.2 to -25.0), p=0.009], reduced torsion [5.5°/cm (-6.1 to 17.8) vs 8.1°/cm (-9.7 to18.5) vs, p=0.03], decreased apical rotation [6.5°/cm (-11.3 to 18.1) vs 5.1°/cm (-21.2 to 19.7), p=0.02] with no significant change in basal rotation compared to the echo at time of Fontan. Single RV had lower net torsion compared to single LV [2.7°/cm (-2.5.1 to 13.1) vs 6.1°/cm (-6.3 to 19.5) vs, p=0.03]. Mean interval between echocardiograms and exercise testing and CMR were 3.5±2.2 and 5.6±1.8 months respectively. Torsion and untwist rates correlated with peak oxygen consumption (r=0.64, -0.41, p=0.01, 0.04 respectively) but did not correlate with ventricular volumes or ejection fractions. Conclusion: In long term follow up post Fontan, SV torsion is decreased due to decreased apical rotation, worse in single RV, and is associated with decreased exercise capacity.

Diagnosing left ventricular diastolic dysfunction (DD) noninvasively in children is difficult as no validated pediatric diagnostic algorithm is available. The aim of this study is to explore the use of machine learning to develop a model that uses echocardiographic measurements to explain patterns in invasively measured markers of DD in children.Children at risk for developing DD were enrolled, including patients with Kawasaki disease, heart transplantation, aortic stenosis, and coarctation of the aorta when undergoing clinical left heart catheterization. Simultaneous invasive pressure measurements were made using a high-fidelity catheter (time constant of isovolumic relaxation [Tau, τ], left ventricular end-diastolic pressure, and maximum negative rate of pressure change) and echocardiographic DD measurements. Spearman correlations were performed for each echocardiographic feature with invasive markers to understand pairwise relationships. Separate random forest (RF) models were implemented to assess all echocardiographic features, key demographic data, and clinical diagnosis in predicting invasive markers. A backward stepwise regression model was simultaneously implemented as a comparative conventional reference model. The relative importance of all parameters was ranked in terms of accuracy reduction. Model approximation was then performed using a regression tree with the top-ranked features of each RF model to improve model interpretability. Regression coefficients of the linear models were presented.Fifty-nine children were included. Spearman correlations were generally low. The RF models' performance measures were noninferior to those of the linear model. However, the linear model's regression coefficients were unintuitive. The highest ranked important features for the RF models were propagation velocity for Tau, E/propagation velocity ratio for left ventricular end-diastolic pressure, and systolic global longitudinal strain rate for maximum negative rate of pressure change.Estimating individual components of DD can potentially improve the noninvasive assessment of pediatric DD. Although pairwise correlations measured were weak and linear regression coefficients unintuitive, approximated machine learning models aided in understanding how echocardiographic and invasive parameters of DD are related. This machine learning approach could help in further development of pediatric-specific diagnostic algorithms.

The nitroxyl radical 1-methyl-2-azaadamantane N-oxyl (Me-AZADO) exhibits magnetic bistability arising from a radical/dimer interconversion. The transition from the rotationally disordered paramagnetic plastic crystal, Me-AZADO, to the ordered diamagnetic crystalline phase, (Me-AZADO)2, has been conclusively demonstrated by crystal structure determination from high-resolution powder diffraction data and by solid-state NMR spectroscopy. The phase change is characterized by a wide thermal hysteresis with high sensitivity to even small applied pressures. The molecular dynamics of the phase transition from the plastic crystal to the conventional crystalline phase has been tracked by solid-state (1H and 13C) NMR and EPR spectroscopies.

Background Right ventricular (RV) dilation from pulmonary valve regurgitation (PR) is common after intervention(s) for pulmonary stenosis (PS) or atresia and intact ventricular septum (PA/IVS). It is not well established whether PR and RV dilation have similar effects on RV function and exercise capacity in these patients compared to patients after repair of tetralogy of Fallot (rToF). The aims of this study were to compare exercise tolerance, RV function and myocardial mechanics in non-ToF versus rToF children with significantly increased and comparable RV volumes. Methods Thirty PS or PA/IVS children after intervention(s) with significant PR and RV dilation (non-ToF group) were retrospectively matched for RV end-diastolic volume index (RVEDVi) and age with 30 rToF patients. Clinical characteristics, RV function by echocardiography and CMR, ECG and exercise capacity were compared between groups. Results The groups were well matched for RVEDVi and age. Global RV function (RVEF: 48.7 ± 6.4% vs. 48.5 ± 7.2%, P = .81) and exercise capacity (% predicted peak VO2:82.5 ± 17.7% vs. 75.6 ± 20.4%, P = .27) were similarly reduced between groups. RVEDVi correlated inversely with RVEF in both groups (non-ToF:r = −0.39, P = .04, rToF:r = −0.40, P = .03). QRS duration was wider in rToF patients, and in both groups inversely correlated with RVEF (non-ToF:r = −0.77, P Conclusions Global RV function and exercise capacity are similarly reduced in non-ToF and rToF patients with severely dilated RV, after matching by RVEDVi, suggesting a comparable impact of RV dilation on RV global function. The significance of reduced RV longitudinal function and worse dyssynchrony in rToF patients require further exploration.

A synthetic strategy featuring dicyanometalates [M(CN)2]- (M = Ag, Au) as N-coordinating ditopic linkers connecting partially blocked FeII centers has been employed to produce heterometallic hexanuclear complexes, which exhibit spin-crossover (SCO) behavior at the FeII sites. The reaction between tris(2-pyridylmethyl)amine (tpma)-capped FeII ions and [Ag(CN)2]- proceeded with partial decomposition of the dicyanoargentate and led to the formation of {[Fe(tpma)]4(μ-CN)2[μ-Ag(CN)2]2}(ClO4)4·3H2O (1), in which both [Ag(CN)2]- and CN- act as bridging ligands, and the opposite [Ag(CN)2]- bridges are engaged in a pronounced argentophilic d10-d10 interaction. In an analogous synthesis, the more stable [Au(CN)2]- species remained intact and furnished the complex {[Fe(tpma)]2[μ-Au2(CN)4]2} (2), which features two FeII centers bridged by two [Au2(CN)4]2- dimers. The use of S,S'-bis(2-pyridylmethyl)-1,2-thioethane (bpte) as a mixed-donor, N2S2-coordinating capping ligand yielded {[Fe(bpte)]2[μ-Au2(CN)4]2} (3), with a structure analogous to that of 2. Variable-temperature magnetic susceptibility measurements revealed that complexes 1-3 exhibit an onset of SCO above 350 K. Measurements above 400 K further confirmed the occurrence of a gradual spin-state conversion for complex 2.

Mitral valve disease in pediatric cardiology is complex and can involve a combination of annular, leaflet, chordae tendineae and papillary muscle abnormalities. Transthoracic two-dimensional echocardiography (2DE) remains the primary diagnostic imaging technique utilized in pediatric surgical planning. However, given that the mitral valve is a three-dimensional (3D) structure, the addition of 3D echocardiography (3DE) to better define the mechanisms of stenosis and/or regurgitation is advantageous. Transthoracic 3DE technology has improved with advances in probe technology and ultrasound scanners, producing images with good spatial resolution and adequate temporal resolution. Specifically, the addition of pediatric 3D transducers with higher frequencies and a smaller footprint provides better 3DE imaging in children. Improved efficiency of 3DE acquisition and analysis allow 3D assessment of the mitral valve to be more easily integrated by the sonographer, the cardiologist and the surgeon in mitral valve assessment. This improvement was also made possible by the postprocessing software optimization. In this method paper, we aim to describe the transthoracic 3DE assessment of the mitral valve in children and its use in the surgical planning of pediatric mitral valve disease. Firstly, the 3DE assessment begins by selecting the correct probe and by obtaining a view of the mitral valve. Then, the appropriate data acquisition method should be selected based on the individual patient. Next, optimization of the data set is critical in order to properly balance spatial and temporal resolution. During live scanning or following acquisition, the data set can be cropped using innovative tools that allow the user to quickly obtain an infinite number of cut planes or volumetric reconstructions. The cardiologist and surgeon can view the mitral valve en face; thus, accurately reconstructing its morphology in order to support medical or surgical planning. Finally, a review of some clinical applications is proposed, showing examples in pediatric mitral valve managements.

Despite the development of imagistic methods, the differential diagnosis of a right atrial mass may be difficult to be established, the most common pathologies which should be taken in consideration being represented by thrombus, tumors, prominent crista terminalis, or vegetation of infectious endocarditis. In this study, we present the case of a 63-year-old man with chronic kidney disease, in hemodialysis (HD) with a silicone central venous catheter (CVC) with the incidental transthoracic echocardiography (transthoracic echocardiogram, TTE) finding of a tumoral mass of 35x26 mm in the right atrium (RA), not related with the catheter, which was diagnosed as right atrial myxoma and underwent surgical excision. After reviewing the histopathology probe, the diagnosis of right atrial thrombus was confirmed. In conclusion, differentiating intracardiac right atrial masses (RAMs) could may prove challenging. In our patient, clinical presentation and the preoperative investigations could not differentiate the right atrial thrombus from a myxoma, and only the postoperative histopathology diagnosis was able to guide correct diagnosis.

Paragangliomas are extremely rare neuroendocrine tumors. We report a case of a 44-year-old man with hypertension who presented a tumoral mass located retroperitoneally at the aortic bifurcation which included both the common iliac arteries and the posterior left iliac vein, who experienced an unpredictable intraoperative cardiac arrest with electromechanical dissociation at 5 min after laparotomy. After successful resuscitation and hemodynamic stability, the lesion was fully excised. In the course of tumor manipulation, the patient developed a major hypertensive crisis with peak systolic blood pressure over 280 mmHg. Pathologic examination revealed the presence of diffuse proliferation of large and medium-sized mature adipocytes consistent with paraganglioma diagnosis. The patient was discharged at home on the seventh postoperative day. He did not present evidence of recurrence at the one-year follow-up. In conclusion, paragangliomas can require particular management due to their location but also due to their capacity to discharge substances which might induce life-threatening intraoperative complications.

Fetal and neonatal hypertrophic cardiomyopathy is a complication of gestational diabetes and usually follows a benign course. In this report, we present a rare case of a newborn of a diabetic mother with severe ventricular hypertrophy who developed myocardial infarction confirmed by elevated cardiac enzymes, electrocardiographic changes, and subendocardial ischemia on cardiac magnetic resonance imaging. Follow-up revealed complete functional myocardial recovery with normalisation of ventricular systolic and diastolic functions on serial echocardiograms.