The clinical data of patients with total anomalous pulmonary venous connection who underwent repair in our centre in the past 13 years were reviewed. In this study, we systemically reviewed our experience in the optimal surgical strategy for patients with total anomalous pulmonary venous connection, aiming to provide evidence for clinical decision-making.

From January 1, 2009, to December 31, 2021, 122 patients undergoing surgical treatment for total anomalous pulmonary venous connection in our hospital were enrolled. Among them, 18 patients with single ventricle repair were excluded from the study. Multivariate analysis was used to determine the risk factors for early and late death and the risk factors for pulmonary vein obstruction.

There were 64 males and 40 females. The median age at surgery was 107 days (range, 25 days–788 days), the median weight at surgery was 4.8 kg (range, 3 kg–22 kg), and the median follow-up was 59 months (range, 0–150 months). Seven patients died early after surgery and six died late after discharge. Multivariable analysis indicated that prolonged cardiopulmonary bypass time was the only independent risk factor for early postoperative mortality. Multivariate analysis did not identify risk factors for late death. Emergency surgery, preoperative moderate and severe pulmonary hypertension, and prolonged cardiopulmonary bypass time were independent risk factors for postoperative pulmonary vein obstruction.

Early and long-term late outcomes of repair in patients with total anomalous pulmonary venous connection have been encouraging. Postoperative pulmonary vein obstruction remains a major problem for specialists worldwide. Pulmonary vein obstruction should be considered in children with preoperative emergency surgery, moderate to severe pulmonary hypertension and prolonged cardiopulmonary bypass time, and regular follow-up is necessary.

Feeding difficulties after congenital heart surgery are a common concern for caregivers of children with CHD. Insight into the intricacies of their experience is lacking. With a better understanding, healthcare providers can continue to optimize the approach and support mechanisms for these families. This study will explore the psychosocial impacts on caregivers, define barriers to care, and identify areas to improve their care.

This mixed-methods study combined semi-structured interviews with surveys. Purposive sampling targeted caregivers of a child who underwent heart surgery and was discharged with alternative enteral feeding access. A hybrid inductive-deductive methodology was used to analyse interview transcripts. Survey scores were compared to interview content for concordance.

Fifteen interviews were conducted with socio-demographically diverse caregivers. Feeding difficulties were often identified as their greatest challenge, with the laborious feeding schedule, sleep deprivation, and tube management being common contributors. Most caregivers described feeling overwhelmed and worried. Time-intensive feeding schedules and lack of appropriate childcare options precluded caregivers’ ability to work. Barriers to care included imperfect feeding education, proximity of specialist clinics, and issues with medical supply companies. Caregiver proposals for improved care addressed easing the transition home, improving emotional support mechanisms, and intensifying feeding therapy for expedited tube removal.

This study describes the psychosocial toll on the caregiver, typical barriers to care, and ideas for improved provision of care. These themes and ideas can be used to advance the family-centered approach to feeding difficulties after heart surgery.

The clinical data of patients with subaortic stenosis who underwent surgical treatment in our centre in the past 12 years were reviewed. The short-term and long-term clinical outcomes were analyzed, and the long-term outcomes of different surgical methods for subaortic stenosis were compared to determine the optimal surgical treatment strategy for subaortic stenosis.

From December 2010 to December 2022, 90 patients undergoing surgical treatment for subaortic stenosis in our hospital were enrolled. There were 55 males and 35 females with a median age of 72 (46,132) months and an average surgical weight of (21.35 ± 15.84) kg. According to the operation method, 90 patients were divided into group A (50 patients with simple subaortic membrane resection) and group B (40 patients with subaortic membrane and muscle resection or modified Konno procedure).

There were three early deaths (3.33%). One late death occurred in group B. There was no significant difference in long-term survival rate between the two groups (p = 0.904). The preoperative left ventricular outflow tract pressure gradient in group B was (91.56 ± 36.98) mm Hg, which was higher than that in group A(51.13 ± 36.04)mm Hg(p < 0.001). There was no significant difference in immediate postoperative left ventricular outflow tract pressure gradient between group B [(5.44 ± 8.43) mm Hg] and group A [(7.82 ± 13.44) mm Hg] (p = 0.343). In the long-term follow-up, left ventricular outflow tract pressure gradient in group B was (5.86 ± 9.53) mm Hg, which was not statistically significant compared with group A (8.83 ± 14.52) mm Hg (p = 0.294). Eleven patients with moderate or greater aortic regurgitation (group A/group B: 3/8) underwent simultaneous aortic valvuloplasty. In group B, moderate or greater aortic regurgitation was significantly improved immediately after operation (p = 0.013) and was not significantly aggravated in long-term follow-up (p = 0.083), and there was no significant improvement in group A after operation and long-term follow-up.

According to the different anatomical lesions of left ventricular outflow tract, the individualised surgical treatment strategy for patients with subaortic stenosis can achieve good long-term outcomes. The long-term survival rate and freedom from reoperation due to late left ventricular outflow tract obstruction after simple subaortic membrane resection and extended left ventricular outflow tract resection are comparable. For patients with moderate or greater aortic regurgitation before extended left ventricular outflow tract resection, simultaneous aortic valvuloplasty is beneficial to improve postoperative aortic valve function.

There are few studies for detecting rhythm abnormalities among healthy children and adolescents. The aim of the study was to investigate the prevalence of abnormal electrocardiographic findings in the young Iranian population and its association with blood pressure and obesity.

A total of 15084 children and adolescents were examined in a randomly selected population of Tehran city, Iran, between October 2017 and December 2018. Anthropometric values and blood pressure measurements were also assessed. A standard 12-lead electrocardiogram was recorded by a unique recorder, and those were examined by electrophysiologists.

All students mean age was 12.3 ± 3.1 years (6–18 years), and 52% were boys. A total of 2900 students (192.2/1000 persons; 95% confidence interval 186–198.6) had electrocardiographic abnormalities. The rate of electrocardiographic abnormalities was higher in boys than girls (p < 0.001). Electrocardiographic abnormalities were significantly higher in thin than obese students (p < 0.001), and there was a trend towards hypertensive individuals to have more electrocardiographic abnormalities compared to normotensive individuals (p = 0.063). Based on the multivariable analysis, individuals with electrocardiographic abnormalities were less likely to be girls (odds ratio 0.745, 95% confidence interval 0.682–0.814) and had a lower body mass index (odds ratio 0.961, 95% confidence interval 0.944–0.979).

In this large-scale study, there was a high prevalence of electrocardiographic abnormalities among young population. In addition, electrocardiographic findings were significantly influenced by increasing age, sex, obesity, and blood pressure levels. This community-based study revealed the implications of electrocardiographic screening to improve the care delivery by early detection.

This study aims to assess the surgical outcome of borderline hypoplastic left ventricle before and after the induction of the left ventricle rehabilitation strategy.

A retrospective review investigated patients with borderline hypoplastic left ventricle who underwent surgical intervention between 2012 and 2022. The patient cohort was stratified into two groups based on the initiation of left ventricle rehabilitation: an early-era group (E group, 2012–2017) and a late-era group (L group, 2018–2022). Left ventricle rehabilitation was defined as palliation combined with other procedures aimed at promoting left ventricular growth such as restriction of atrial septal defect, relief of inflow/outflow obstructive lesions, and resection of endocardial fibroelastosis.

A total of 58 patients were included. Primary diagnosis included 12 hypoplastic left heart syndromes, 11 critical aortic valve stenosis, and others. A total of 9 patients underwent left ventricle rehabilitation, 8 of whom underwent restriction of atrial septal defect. As for clinical outcomes, 9 of 23 patients achieved biventricular repair in the E group, whereas in the L group, 27 of 35 patients achieved biventricular repair (39% vs. 77%, p = 0.004). Mortality did not differ statistically between the two groups (log-rank test p = 0.182). As for the changes after left ventricle rehabilitation, left ventricular growth was observed in 8 of 9 patients. The left ventricular end-diastolic volume index (from 11.4 to 30.1 ml/m2, p = 0.017) and left ventricular apex-to-right ventricular apex ratio (from 86 to 106 %, p = 0.014) significantly increased after left ventricle rehabilitation.

The introduction of the left ventricle rehabilitation strategy resulted in an increased proportion of patients achieving biventricular repair without a concomitant increase in mortality. Left ventricle rehabilitation was associated with enhanced left ventricular growth and the formation of a well-defined left ventricle apex. Our study underscores the significance of left ventricle rehabilitation strategies facilitating successful biventricular repair. The data suggest establishing restrictive atrial communication may be a key factor in promoting left ventricular growth.

Aortic arch obstruction and/or coarctation of aorta is uncommon (5–20%) in balanced atrioventricular septal defects. Although technically challenging, prenatal diagnosis of aortic arch obstruction in atrioventricular septal defect is critical for delivery planning and improves prenatal counselling regarding the timing of cardiac surgery. We sought to identify prenatal predictors of coarctation of aorta in atrioventricular septal defect.

Retrospective review of patients prenatally diagnosed with atrioventricular septal defect at two institutions.

Ninety-five fetuses with atrioventricular septal defect were identified and sufficient outcome data and diagnostic acoustic windows were available in 62. Six patients (10%) had coarctation of aorta after birth. Among the 38 patients with Trisomy 21, four (11%) had coarctation of aorta. On multivariable analysis, the proximal transverse aortic arch z score and ratio of left:right atrioventricular valve were independent predictors of coarctation of aorta with good interobserver reproducibility. Either proximal transverse aortic arch z score < −2, or ratio of left:right atrioventricular valve <0.7, predicted aortic arch obstruction with 100% sensitivity and 89% specificity.

Proximal transverse aortic arch z score and lower ratio of left:right atrioventricular valve diameter are independent predictors of postnatal coarctation of aorta in fetal patients with atrioventricular septal defect. The next step is the prospective application of these parameters to create an algorithm directing fetal counselling in terms of delivery location, and expected timing of surgical interventions.

Poor oral feeding is a known contributor to growth challenges in neonates with complex CHD who require early surgery. Almost 60% of these infants do not achieve full oral feeding by hospital discharge. This study’s objective was to identify predictors of the inability to achieve full oral feeding by discharge in neonates with complex CHD following surgical intervention with cardiopulmonary bypass.

A retrospective analysis of a prospective study of 192 full-term neonates with complex CHD was performed. A stepwise selection logistic regression model was developed to predict oral feeding status at hospital discharge. Univariate subgroup analysis was performed with groups determined based on a CHD classification system.

58% of neonates (112/192) failed to achieve full oral feeding by hospital discharge. A logistic regression model identified duration of deep hypothermic circulatory arrest and reintubation as predictors of the inability to achieve full oral feeding. Among neonates who achieved full oral feeding by discharge (42%), only 7.5% did so after postoperative day 10. Brain maturation, brain injury, and preoperative oral feeding were not predictors of full postoperative oral feeding.

Many infants with CHD fail to achieve full oral feeding by time of hospital discharge. Longer duration of deep hypothermic circulatory arrest and increased number of intubations were predictive of poor feeding after surgery. Prolonging hospitalisation solely to achieve full oral feeding after postoperative day ten is of limited utility; earlier discharge should be promoted to avoid negative impacts on neonatal neurodevelopment as unintended consequences of lengthy hospitalisations.

The National Pediatric Cardiology Quality Improvement Collaborative (NPC-QIC) lacks a rigorous enrollment audit process, unlike other collaborative networks. Most centers require individual families to consent to participate. It is unknown whether there is variation across centers or biases in enrollment.

We used the Pediatric Cardiac Critical Care Consortium (PC4) registry to assess enrollment rates in NPC-QIC for those centers participating in both registries using indirect identifiers (date of birth, date of admission, gender, and center) to match patient records. All infants born 1/1/2018–12/31/2020 and admitted 30 days of life were eligible. In PC4, all infants with a fundamental diagnosis of hypoplastic left heart or variant or who underwent a surgical or hybrid Norwood or variant were eligible. Standard descriptive statistics were used to describe the cohort and center match rates were plotted on a funnel chart.

Of 898 eligible NPC-QIC patients, 841 were linked to 1,114 eligible PC4 patients (match rate 75.5%) in 32 centers. Match rates were lower in patients of Hispanic/Latino ethnicity (66.1%, p = 0.005), and those with any specified chromosomal abnormality (57.4%, p = 0.002), noncardiac abnormality (67.8%, p = 0.005), or any specified syndrome (66.5%, p = 0.001). Match rates were lower for patients who transferred to another hospital or died prior to discharge. Match rates varied from 0 to 100% across centers.

It is feasible to match patients between the NPC-QIC and PC4 registries. Variation in match rates suggests opportunities for improvement in NPC-QIC patient enrollment.

This study aimed to explore relationships between parental stress, coping, and outcomes for parents of infants with CHD, via observational approach reflecting domains of the Parental Stress and Resilience in CHD (PSRCHD) model.

Fifty-five parents of 45 infants with CHD completed questionnaires with measures of parental stress, Problem-Focused Coping (PFC), Emotion-Focused Coping (EFC), Avoidant Coping (AC), mental health (symptoms of anxiety and symptoms of depression), post-traumatic growth (PTG) and quality of life (QoL). Demographic and infant clinical data were obtained.

Parental stress showed significant small to medium positive correlations with MH and PTG, but no significant correlations with QoL. EFC and AC showed significant small to medium positive correlations with MH, and medium negative correlations with parental QoL. EFC and PFC had significant small to medium correlations with PTG. PFC and AC had significant small to medium correlations with infant QoL. Hierarchical multiple regression analyses indicated that parental symptoms of anxiety, PTG, parental QoL, infant QoL were significantly predicted by models comprising of parental stress, coping styles, and clinical controls (adjusted R2 = 13.0–47.9%, p range < 0.001–.048), with results for parental symptoms of depression falling marginally above significance (adjusted R2 = 12.3%, p = .056).

Parental stress, coping styles, and length of hospital stay are related to psychological outcomes in parents of infants with CHD. Future research may use the PSRCHD framework to assess mechanisms underlying CHD parents’ stress and coping experiences and investigate longitudinal relationships between parental factors and parent and child outcomes.

Cholestasis characterised by conjugated hyperbilirubinemia is a marker of hepatobiliary dysfunction following neonatal cardiac surgery. We aimed to characterise the incidence of conjugated hyperbilirubinemia following neonatal heart surgery and examine the effect of conjugated hyperbilirubinemia on post-operative morbidity and mortality.

This was a retrospective study of all neonates who underwent surgery for congenital heart disease (CHD) at our institution between 1/1/2010 and 12/31/2020. Patient- and surgery-specific data were abstracted from local registry data and review of the medical record. Conjugated hyperbilirubinemia was defined as perioperative maximum conjugated bilirubin level > 1 mg/dL. The primary outcome was in-hospital mortality. Survival analysis was conducted using the Kaplan–Meier survival function.

Conjugated hyperbilirubinemia occurred in 8.5% of patients during the study period. Neonates with conjugated hyperbilirubinemia were more likely to be of younger gestational age, lower birth weight, and non-Caucasian race (all p < 0.001). Patients with conjugated hyperbilirubinemia were more likely to have chromosomal and non-cardiac anomalies and require ECMO pre-operatively. In-hospital mortality among patients with conjugated hyperbilirubinemia was increased compared to those without (odds ratio 5.4). Post-operative complications including mechanical circulatory support, reoperation, prolonged ventilator dependence, and multi-system organ failure were more common with conjugated hyperbilirubinemia (all p < 0.04). Patients with higher levels of conjugated bilirubin had worst intermediate-term survival, with patients in the highest conjugated bilirubin group (>10 mg/dL) having a 1-year survival of only 6%.

Conjugated hyperbilirubinemia is associated with post-operative complications and worse survival following neonatal heart surgery. Cholestasis is more common in patients with chromosomal abnormalities and non-cardiac anomalies, but the underlying mechanisms have not been delineated.

Limited data exist on how trainees in paediatric cardiology are assessed among countries affiliated with the Association of European Paediatric and Congenital Cardiology.

A structured and approved questionnaire was circulated to educationalists/trainers in 95 Association for European Paediatric and Congenital Cardiology training centres.

Trainers from 46 centres responded with complete data in 41 centres. Instructional design included bedside teaching (41/41), didactic teaching (38/41), problem-based learning (28/41), cardiac catheterisation calculations (34/41), journal club (31/41), fellows presenting in the multidisciplinary meeting (41/41), fellows reporting on echocardiograms (34/41), clinical simulation (17/41), echocardiography simulation (10/41), and catheterisation simulation (3/41). Assessment included case-based discussion (n = 27), mini-clinical evaluation exercise (mini-CEX) (n = 12), directly observed procedures (n = 12), oral examination (n = 16), long cases (n = 11), written essay questions (n = 6), multiple choice questions (n = 5), and objective structured clinical examination (n = 2). Entrustable professional activities were utilised in 10 (24%) centres. Feedback was summative only in 17/41 (41%) centres, formative only in 12/41 (29%) centres and a combination of formative and summative feedback in 10/41 (24%) centres. Written feedback was provided in 10/41 (24%) centres. Verbal feedback was most common in 37/41 (90 %) centres.

There is a marked variation in instructional design and assessment across European paediatric cardiac centres. A wide mix of assessment tools are used. Feedback is provided by the majority of centres, mostly verbal summative feedback. Adopting a programmatic assessment focusing on competency/capability using multiple assessment tools with regular formative multisource feedback may promote assessment for learning of paediatric cardiology trainees.

Acute kidney injury is a common postoperative complication of paediatric cardiac surgery associated with increased morbidity and mortality. The purpose of this study is to characterise associations between haemodynamic parameters, clinical parameters, and medical interventions, on acute kidney injury.

Nine patients with univentricular physiology undergoing the Norwood procedure from a single-centre tertiary care paediatric cardiac ICU were included (September 2022 to March 2023). Patients were monitored with the T3 software. Data were analysed using a Fisher exact test, Mann–Whitney-U test, LASSO-based machine learning techniques, and receiver operator curve analyses.

Over 27,000 datapoints were included. Acute kidney injury occurred in 2 patients (22%) during this period. Net fluid balance and renal oxygen extraction were independently associated with acute kidney injury, while commonly used metrics of pressure (systolic, diastolic, or mean arterial blood pressure) were not. The resulting acute kidney injury risk score was (4.1 × fluid balance) + (1.9 × renal oxygen extraction). The risk score was significantly higher in acute kidney injury with a score of 32.9 compared to 7.9 (p < 0.01). Optimal cut-offs for fluid balance (7 mL/hr) and renal oxygen extraction (29%) were identified. Higher serum creatinine:baseline creatinine ratio was associated with a higher mean airway pressure, higher renal oxygen extraction, higher mean arterial blood pressure, higher vasoactive inotropic score, and fluid balance.

Among patients with univentricular physiology undergoing the Norwood procedure, renal oxygen extraction and a higher net fluid balance are independently associated with increased risk of acute kidney injury. Renal perfusion pressure is not significantly associated with acute kidney injury.

Haemodynamic instability is common after surgical repair of CHDs in infants and children. Monitoring cardiac output in addition to traditional circulation parameters could improve the postoperative care of these patients. Echocardiography and transpulmonary thermodilution are the two most common methods for measuring cardiac output in infants.

To compare the results of cardiac output measurements using echocardiography and a transpulmonary thermodilution setup after paediatric cardiac surgery.

Forty children, scheduled for elective repair of a ventricular septal defect or of an atrio-ventricular septal defect using cardiopulmonary bypass, were enrolled in this prospective, observational study. Cardiac output was simultaneously measured using echocardiography and a commercially available transpulmonary thermodilution method (PiCCO™) at 18 h after the end of surgery.

At 18 h after surgery, PiCCO™ gave a mean of 3.0% higher cardiac output than echocardiography. This difference was not statistically significant. 95% of the observations fell within –50.0 to 82.6%.

The methods were found to have a good agreement on average, with no statistically significant difference between them. However, the spread of the results was large. It is questionable whether the methods can be used interchangeably in clinical practice.

Physical activity is recognised as an important intervention in patients with CHD. However, more data on the actual magnitude of physical training impact on functional capacity in this group of patients are still warranted. We aim to assess effort tolerance in a contemporary cohort of patients with congenital heart disease, regularly following a training programme, in comparison with a matched control group.

Patients with CHD followed at the sports medicine department, who had undergone cardiopulmonary exercise test between 2011 and 2019, were included. Variables recorded were maximum workload, absolute and indexed maximum oxygen consumption, maximum heart rate, absolute and indexed maximum O2 pulse, ventilatory equivalent of CO2 and oxygen consumption/Work. Trend of cardiopulmonary parameters was analysed over time. Maximal workload, maximum oxygen consumption and ventilatory equivalent of CO2 were compared with a control group of patients with a more sedentary lifestyle, matched for diagnosis, gender, age, and body mass index.

Among one hundred and eleven patients, 73 males (66%) were analysed. Median age was 14 (12–17) years. Twenty-nine patients (27%) were practising sports at competitive level. Maximum oxygen consumption and oxygen consumption % of maximum predicted were not significantly different at follow-up as compared with baseline. Follow-up of maximum oxygen consumption was 38.2 ± 9 ml/kg/min versus 38.6 ± 9.2 ml/kg/min (p = NS) and follow-up of %oxygen consumption was 88 ± 20 versus 87 ± 15 (p = NS). Ventilatory equivalent of CO2 significantly improved in the last test as compared with the baseline: 30 ± 4 versus 33 ± 5 (p = 0.002). As compared with the control group, trained patients displayed a significantly higher maximum workload and oxygen consumption, while ventilatory equivalent of CO2 was not significantly different.

In our cohort, patients following a regular training programme displayed a significantly higher functional capacity as compared with not trained control group, irrespective of NYHA class. Objective functional capacity was stable over a median follow-up of 3 years.

To identify early postoperative haemodynamic and laboratory parameters predicting outcomes following total cavopulmonary connection.

Patients who underwent total cavopulmonary connection between 2012 and 2021 were evaluated. Serial values of mean pulmonary artery pressure, mean arterial pressure, peripheral oxygen saturation, and lactate levels were collected. The influence of these variables on morbidities was analyzed. Cut-off values were calculated using the receiver operating characteristic analysis.

A total of 249 patients were included. All patients had previous bidirectional cavopulmonary shunt. Median age and weight at total cavopulmonary connection were 2.2 (1.8–2.7) years and 11.7 (10.7–13.4) kg, respectively. All patients were extubated in the ICU at a median of 3 (2–5) hours after ICU admission. Postoperative pulmonary artery pressure, around 12 hours after extubation, was significantly associated with chest tube drainage (p = 0.048), chylothorax (p = 0.021), ascites (p = 0.016), and adverse events (p = 0.028). Receiver operating characteristic analysis revealed a cut-off value of 13–15 mmHg for chest tube drainage and chylothorax and 17 mmHg for ascites and adverse events. Mean arterial pressure 1 hour after extubation was associated with prolonged chest tube drainage (p = 0.015) and adverse events (p = 0.008). Peripheral oxygen saturation 6 hours after extubation (p = 0.003) was associated with chest tube duration and peripheral oxygen saturation 1 hour after extubation (p < 0.001) was associated with ascites. Lactate levels on 2nd postoperative day (p = 0.022) were associated with ascites and lactate levels on 1st postoperative day (p = 0.009) were associated with adverse events.

Higher pulmonary artery pressure, lower mean arterial pressure, lower peripheral oxygen saturation, and higher lactate in early postoperative period, around 12 hours after extubation, predicted in-hospital and post-discharge adverse events following total cavopulmonary connection.

The aim of this study is to investigate the frequency of fragmented QRS and its associations with clinical findings and prognosis in children diagnosed with dilated cardiomyopathy with or without left ventricular non-compaction.

This retrospective study was conducted between 2010 and 2020. Patients with dilated cardiomyopathy were classified into two groups according to the presence of left ventricular non-compaction: Dilated cardiomyopathy with left ventricular non-compaction and dilated cardiomyopathy without left ventricular non-compaction. Patients were also divided into two groups according to the presence of fragmented QRS (fragmented QRS group and non-fragmented QRS group).

Twenty-three of 44 patients (52.3%) were male. Among left ventricular non-compaction patients, the fragmented QRS group had more complex ventricular arrhythmias (p = 0.003). Patients with fragmented QRS had a significantly higher rate of major adverse cardiac events and/or cardiac death in both cardiomyopathy groups (p = 0.003 and p = 0.005). However, the rate of major adverse cardiac events and/or cardiac death was similar between dilated cardiomyopathy patients with and without left ventricular non-compaction. Multivariate logistic regression analysis showed that the presence of fragmented QRS strongly predicts major adverse cardiac events and/or cardiac death (odds ratio, 31.186; 95% confidence interval, 2.347–414.307). Although the survival rates between cardiomyopathy groups were similar, patients with fragmented QRS had a markedly lower survival rate during the follow-up period, as mean of 15 months (p = 0.001).

Our study showed that the presence of fragmented QRS may be an important ECG sign predicting an major adverse cardiac event and/or cardiac death in patients with dilated cardiomyopathy. We believe that recognising fragmented QRS could be valuable in forecasting patient prognosis and identifying high-risk patients who require additional support.

Accurate measurement of transcutaneous oxygen saturation is important for the assessment of cyanosis in CHD. Aim of this study was the evaluation of a supplementary transcutaneous oxygen saturation measurement with an Apple watch® in children with cyanotic heart disease.

During a six-minute walk test, measurement of transcutaneous oxygen saturation was performed simultaneously with an Oximeter (Nellcor, Medtronic, USA) and an Apple watch® Series 7 (Apple inc, USA) in 36 children with cyanotic heart disease.

Median age was 9.2 (IQR 5.7–13.8) years. Transcutaneous oxygen saturation measurement with the Apple watch® was possible in 35/36 and 34/36 subjects before and after six-minute walk test. Children, in whom Apple watch® measurement was not possible, had a transcutaneous oxygen saturation < 85% on oximeter. Before six-minute walk test, median transcutaneous oxygen saturation was 93 (IQR 91–97) % measured by oximeter and 95 (IQR 93–96) % by the Apple watch®. After a median walking distance of 437 (IQR 360–487) m, transcutaneous oxygen saturation dropped to 92 (IQR 88–95, p < 0.001) % by oximeter and to 94 (IQR 90–96, p = 0.013) % measured with the Apple watch®.

In children with mild cyanosis measurement of transcutaneous oxygen saturation with an Apple watch® showed only valid results if transcutaneous oxygen saturation was > 85%, with higher values being measured with the smart watch. In children with moderate or severe cyanosis transcutaneous oxygen saturation, measurement with the Apple watch® was not reliable and cannot be recommended to monitor oxygen saturation at home.