Prognostic value of cardiopulmonary exercise test in children with congenital heart defects.

BACKGROUND: Cardiopulmonary exercise testing (CPET) has an important prognostic value in adults with different congenital heart defects (CHDs) and is a useful tool for risk stratification and clinical decision-making. In this retrospective study, we studied the prognostic value of CPET in paediatric patients with CHD. METHODS: 411 CPET performed by paediatric patients with different CHDs were evaluated in this retrospective study. Medical records were reviewed to determine the presence of cardiac events. Participants were classified using the 2018 AHA/ACC guideline for the management of adults with CHD that combines anatomical complexity and current physiological stage. RESULTS: 411 patients with a median age at test of 12 years, 51 patients with simple CHD, 170 patients with moderate complexity CHD and 190 with high complexity CHD underwent CPET. Overall, CPET parameters were lower than the reference values (%predicted VO2peak=75% and %predicted oxygen uptake efficiency slope (OUES)=79%), showing worst exercise capacity in the most complex types of CHD (Group III: %predicted VO2peak=72% and %predicted OUES=75%). Seventy-one patients presented with cardiac events at a median time from CPET to first event of 28 months. Patients with cardiac events had lower exercise performance as compared with patients without cardiac events as determined by the submaximal variables (%predicted OUES: HR=2.6 (1.5-4.4), p<0.001 and VE/VCO2: HR=2.2 (1.4-3.5), p=0.001). CONCLUSION: Reduced exercise capacity at young age is related to a higher probability of future cardiovascular events in paediatric patients with CHD. Submaximal exercise variables can be used instead when maximal exercise cannot be achieved.

ECTOPIC trial: The efficacy of flEcainide Compared To metOprolol in reducing Premature ventrIcular contractions. A randomized open label cross-over study in pediatric patients.

BACKGROUND: Frequent premature ventricular contractions (PVCs) in children are usually considered benign. Symptoms and/or left ventricular dysfunction are indications for treatment with anti-arrhythmic drugs (AAD). OBJECTIVE: To evaluate the efficacy of flecainide versus metoprolol in reducing PVCs in children. METHODS: A randomized open label cross-over trial children with a PVC-burden of >15% on Holter; successively treated with metoprolol and flecainide or vice versa, with a drug free interval of at least two weeks. Holter measurements were repeated before and after the start of the AAD. RESULTS: Sixty patients were screened, 19 patients could be included. Median age was 13.9 years (IQR 5.5 years). Mean baseline PVC-burden was 21.7% (N=18, SD±14.0) before the start of flecainide and 21.2% (N=17, SD±11.5) before the start of metoprolol. In a mixed model analysis the estimated mean reduction in PVC-burden was 10.6 percentage-points (95%-CI 5.8-15.3) for flecainide and 2.4 percentage-points (95%-CI -2.7-7.5) for metoprolol, with a significant difference of 8.2 percentage-points (95%-CI of 0.86-15.46, P=0.031). Exploratory analysis revealed that 9/18 patients treated with flecainide and 1/17 patients treated with metoprolol, had a reduction to a PVC-burden below 5%. No discriminating factors between flecainide-responders and non-responders were found; the mean plasma level was not significantly different (0.34 mg/L versus 0.52 mg/L, P=0.277). CONCLUSIONS: In children with frequent PVCs flecainide led to a significant greater reduction of PVC-burden, compared to metoprolol. Flecainide was effective in only a subgroup of patients, which appears to be unrelated to the plasma level. (Dutch Trial Register number 26689).

Hybrid palliation to promote growth of left ventricle and left ventricular outflow tract.

OBJECTIVES: In patients with borderline left hearts or a severe left ventricular outflow tract obstruction, hybrid palliation can be used to stabilize the patient and postpone biventricular repair (BVR). In this study, we analysed growth of left-sided structures and outcomes of these patients. METHODS: We conducted a retrospective cohort study including patients who received hybrid palliation between January 2010 and September 2023. Echo measurements were collected at hybrid palliation, BVR and last follow-up. Growth of left ventricular structures were analysed. RESULTS: In 38 patients, hybrid palliation was used to promote growth of left ventricular structures. In total, 15 patients received a Ross-Konno/Yasui procedure, while 23 patients received conventional BVR. In patients with a conventional BVR, a significant increase was found in left ventricular volume indexed by body surface area, Z-score of aortic valve and left ventricular outflow tract between hybrid palliation and BVR. Mitral valve Z-score did not increase significantly. After BVR until follow-up, only increase of the aortic valve Z-scores and left ventricular volume indexed by body surface area was found significant. Of all included patients (n = 38), additional surgical procedures were necessary in 8 patients during the interstage period and 15 patients after BVR. Additional catheter interventions were needed in 14 patients in the interstage period and 15 after BVR. Six patients died, with no mortality in the conventional BVR group. CONCLUSIONS: Hybrid palliation as part of a staged BVR is a safe and effective initial step and promotes the growth of left ventricular structures in patients with small left-sided heart structures. Close follow-up is mandatory because extra catheter or surgical interventions are frequently needed.

Clinical Course of TGA After Arterial Switch Operation in the Current Era.

Background: The number of patients with an arterial switch operation (ASO) for transposition of the great arteries (TGA) is steadily growing; limited information is available regarding the clinical course in the current era. Objectives: The purpose was to describe clinical outcome late after ASO in a national cohort, including survival, rates of (re-)interventions, and clinical events. Methods: A total of 1,061 TGA-ASO patients (median age 10.7 years [IQR: 2.0-18.2 years]) from a nationwide prospective registry with a median follow-up of 8.0 years (IQR: 5.4-8.8 years) were included. Using an analysis with age as the primary time scale, cumulative incidence of survival, (re)interventions, and clinical events were determined. Results: At the age of 35 years, late survival was 93% (95% CI: 88%-98%). The cumulative re-intervention rate at the right ventricular outflow tract and pulmonary branches was 36% (95% CI: 31%-41%). Other cumulative re-intervention rates at 35 years were on the left ventricular outflow tract (neo-aortic root and valve) 16% (95% CI: 10%-22%), aortic arch 9% (95% CI: 5%-13%), and coronary arteries 3% (95% CI: 1%-6%). Furthermore, 11% (95% CI: 6%-16%) of the patients required electrophysiological interventions. Clinical events, including heart failure, endocarditis, and myocardial infarction occurred in 8% (95% CI: 5%-11%). Independent risk factors for any (re-)intervention were TGA morphological subtype (Taussig-Bing double outlet right ventricle [HR: 4.9, 95% CI: 2.9-8.1]) and previous pulmonary artery banding (HR: 1.6, 95% CI: 1.0-2.2). Conclusions: TGA-ASO patients have an excellent survival. However, their clinical course is characterized by an ongoing need for (re-)interventions, especially on the right ventricular outflow tract and the left ventricular outflow tract indicating a strict lifelong surveillance, also in adulthood.

Long-term global longitudinal strain abnormalities in paediatric patients after multisystem inflammatory syndrome in children correlate with cardiac troponin T: a single-centre cohort study.

BACKGROUND: Multisystem inflammatory syndrome in children is an inflammatory syndrome related to severe acute respiratory syndrome coronavirus 2 with a high risk of cardiovascular complications (vasoplegia, cardiac shock). We investigated the cardiac outcomes in multisystem inflammatory syndrome in children, focusing on the identification of predictors for late cardiac function impairment. METHODS: Clinical characteristics, conventional echocardiography (left ventricle ejection fraction, fractional shortening), 4-chamber left ventricular global longitudinal strain, and cardiac MRI of multisystem inflammatory syndrome in children patients (n = 48) were collected during admission, 6 weeks, 6 months, >12-≤18 months, and >18-≤24 months post-onset. Paired over-time patterns were assessed and multivariable regression analyses were performed to identify predictors for late global longitudinal strain impairment. RESULTS: In total, 81.3% of patients had acute cardiac dysfunction (left ventricle ejection fraction <50% and/or fractional shortening <28%). The left ventricle ejection fraction and fractional shortening reached a plateau level ≤6 weeks, while the global longitudinal strain continued to decrease in the first 6 months post-onset (median -17.3%, P < 0.001 [versus acute]). At 6 months, 35.7% of the patients still had an abnormal global longitudinal strain, which persisted in 5/9 patients that underwent echocardiography >12-≤18 months post-onset and in 3/3 patients >18-≤24 months post-onset. In a multivariable analysis, soluble troponin T (>62.0 ng/L [median]) was associated with reduced global longitudinal strain at 6 months. Our cardiac MRI findings indicated acute myocardial involvement (increased T1/T2 value) in 77.8% (7/9), which recovered quickly without signs of fibrosis on convalescent cardiac MRIs. CONCLUSIONS: Late global longitudinal strain impairment is seen in some multisystem inflammatory syndrome in children patients up to one-year post-onset. Careful cardiac follow-up in patients with elevated troponin in the acute phase and patients with persistent abnormal global longitudinal strain is warranted until resolution of the global longitudinal strain since the long-term implications of such abnormalities are still unclear.

CTCA in children with severe heterozygous familial hypercholesterolaemia: Screening for subclinical atherosclerosis.

Familial hypercholesterolemia (FH) is one of the most common genetically inherited disorders in the world. Children with severe heterozygous FH (HeFH), i.e. untreated low-density lipoprotein cholesterol (LDL-C) levels above the 90th percentile for age and sex among FH mutation carriers, can have LDL-C levels that overlap levels of children with homozygous FH (HoFH), but treatment regimen and cardiovascular follow-up to prevent cardiovascular disease are less intensive in children with severe HeFH. In children with HoFH, subclinical atherosclerosis can already be present using computed tomography coronary angiography (CTCA). The question remains whether this is also the case in children with severe HeFH who have a high exposure to elevated LDL-C levels from birth onwards as well. We calculated the cumulative LDL-C exposure (CEtotal [mmol]) in four children with severe HeFH and performed computed tomography coronary angiography (CTCA). These children, aged 13, 14, 15 and 18 years, had CEtotal of 71.3, 97.8, 103.6 and 136.1 mmol, respectively. None of them showed abnormalities on cardiovascular imaging, despite high LDL-C exposure. The results of this study, do not give us an indication to recommend performing CTCA routinely in children with severe HeFH.