A Novel Variant in AKAP9 Gene, a Controversial Gene, in Long QT Syndrome.

Introduction: Long QT syndrome (LQTS) is a common congenital cause of fatal cardiac arrhythmia. Characteristic clinical findings are prolonged QT interval and ventricular arrhythmia on electrocardiogram (ECG), syncope, seizure, and sudden death. It is a genetically heterogeneous disease. To date, disease-causing variant have been reported in seventeen genes. The AKAP9 is still considered controversial among those genes. Case Report: We report the case of a 10-year-old female who was born from a non-consanguineous Turkish couple. She visited pediatrics cardiology clinic presenting with dyspnea and tachycardia. Prolongation of the QT interval was detected in her ECG. Panel test associated with LQTS genes was performed. She was diagnosed with long QTS type 11 due to a heterozygous variant in AKAP9:c.11487_11489 delTACinsCGTA, p.(Thr3830ValfsTer12), that was revealed through next-generation sequencing test. The variant was also found in her mother and brother. Discussion and Conclusion: Novel heterozygous frameshift variant in the AKAP9 gene was considered as "Uncertain Significance (VUS)" in the ACMG classification. The novel variant is absent from population databases (PM2); it is a null variant (PVS1_moderate). AKAP9 gene has the lowest known rate among the causes of LQTS. Information is limited on genotype-phenotype correlation. Yet it is still among the candidate genes. Although the relationship of the AKAP9 gene with LQTS has not yet been fully indicated, individuals with a pathogenic variant in AKAP9 gene and silent carriers may be at risk for fatal cardiac events. Improvements of the genetic tests in the near future may contribute to the literature and clinical research about AKAP9 gene.

Late-term cardiac magnetic resonance imaging in multisystem inflammatory syndrome in children.

BACKGROUND: Cardiac involvement in multisystem inflammatory syndrome in children may have a spectrum ranging from mild disease to severe heart failure due to fulminant myocarditis. Cardiac involvement usually resolves after clinical recovery. However, the adverse effects of myocarditis on cardiac function after recovery are not fully known. This study aims to investigate cardiac involvement by performing cardiac magnetic resonance imaging (MRI) after the acute and recovery periods. METHODS: 21 patients with clinical and laboratory signs of myocarditis, including left ventricular systolic dysfunction, mitral regurgitation, elevated troponin T, elevated N-terminal pro-B-type natriuretic peptide and electrocardiographic changes, who had given consent for cardiac MRI, underwent cardiac MRI after completion of the acute and recovery phases. RESULTS: When compared to 16 patients with normal cardiac MRI, five patients with cardiac fibrosis on MRI were older, had greater body mass indexes, lower leucocyte counts, lower neutrophil counts, higher blood urea nitrogen levels and higher creatinine levels. Cardiac fibrosis on MRI was located in the posterior right ventricle insertion point and in mid ventricular septum. CONCLUSIONS: Adolescence and obesity appear as risk factors for the development of fibrosis as a late-term sequela of myocarditis. Furthermore, future studies reporting the follow-up data of patients with fibrosis are necessary to predict and manage adverse outcomes.

Perfusion index in newborns with CHD without clinical signs of hypoperfusion and heart failure: comparison with healthy newborns.

INTRODUCTION: Peripheral perfusion index has been proposed as a possible method for detecting circulatory impairment. We aimed to determine the normal range of peripheral perfusion index in healthy newborns and compare it with that of newborns with CHD. METHODS: Right-hand saturation and right-hand peripheral perfusion index levels were recorded, and physical examination and echocardiography were performed in newborns who were 0-28 days old and whom were evaluated in our paediatric cardiology outpatient clinic. The saturation and peripheral perfusion index levels of newborns with normal heart anatomy and function were compared with those of newborns with CHD. RESULTS: Out of 358 newborns (238 mature and 75 premature) enrolled in the study, 39 had CHD (20 mild CHD, 13 moderate CHD, and 6 severe CHD), of which 29 had CHD with left-to-right shunting, 5 had obstructive CHD, and 5 had cyanotic CHD. No newborn had clinical signs of hypoperfusion or heart failure, such as prolonged capillary refill, weakened pulses, or coldness of extremities. Peripheral perfusion index level was median (interquartile range) 1.7 (0.6) in healthy newborns, 1.8 (0.7) in newborns with mild CHD, and 1.8 (0.4) in newborns with moderate and severe CHD, and there was no significant difference between the groups regarding peripheral perfusion index level. CONCLUSION: Peripheral perfusion index remains unchanged in newborns with CHD without the clinical signs of hypoperfusion or heart failure. Larger studies with repeated peripheral perfusion index measurements can determine how valuable this method will be in the follow-up of newborns with CHD.

Does transcatheter ventricular septal defect closure affect heart rate variability in children?

BACKGROUND: Heart rate variability (HRV) is a sign of the cardiac autonomic nervous system. Its evaluation in pediatric ventricular septal defect (VSD) cases before and after transcatheter closure contributes to an understanding of cardiac autonomic control. METHODS: Nineteen children with VSDs treated with transcatheter closure and 18 healthy children were enrolled in this study. A 24-h Holter rhythm monitor was applied to all patients before VSD closure and to those in the control group. Holter rhythm monitoring was repeated at three months in the patient group. HRV parameters were measured using the Cardio Scan Premier 12® program. Frequency-domain (total power; very-low-frequency, low-frequency (LF), and high-frequency (HF) indices; and the LF/HF ratio) and time-domain (standard deviation of all RR intervals (SDNN), standard deviation of 5-min averages of RR intervals (SDANN), the SDNN index, percentage of the difference between adjacent RR intervals, and the square root of the mean of the sum of square differences between adjacent filtered RR intervals) parameters were assessed. RESULTS: Before the procedure, SDNN, SDANN, and total power values were lower in the patient group than in the control group; other parameters were similar in the two groups. No significant difference in the SDNN, SDANN, or total power was detected between the patient and control groups in the third month, indicating that autonomic control of patients' hearts became normal during the third postoperative month. No correlation was detected between any hemodynamic parameters and any time-domain or frequency-domain parameters before closure. CONCLUSION: This study showed that transcatheter closure of VSDs changed HRV parameters in pediatric patients.

Effects of azithromycin on ventricular repolarization in children with COVID-19.

Introduction: Azithromycin is used to treat pediatric COVID-19 patients. It can also prolong the QT interval in adults. This study assessed the effects of azithromycin on ventricular repolarization in children with COVID-19. Method: The study prospectively enrolled children with COVID-19 who received azithromycin between July and August 2020. An electrocardiogram was performed before, one, three, and five days post-treatment. Using ImageJ®, the following parameters were measured: QT max, QT min, Tp-e max, and Tp-e min. The parameters QTc max, QTc min, Tp-ec max, Tp-ec min, QTcd, Tp-ecd, and the QTc/Tp-ec ratio were calculated using Bazett's formula. Results: The study included 105 pediatric patients (mean age 9.8±5.3 years). The pretreatment heart rate was higher than after treatment (before 92 [79-108]/min vs. Day 1 82 [69-108)]/min vs. Day 3 80 [68-92.2]/min vs. Day 5 81 [70-92]/min; p=0.05). Conclusion: Azithromycin does not affect the ventricular repolarization parameters on ECG in pediatric COVID-19 cases.

Introdução: A azitromicina (AZ) é utilizada no tratamento da COVID-19 em pediatria. Como este fármaco pode prolongar o intervalo QT nos adultos, este estudo avaliou os efeitos da AZ na repolarização ventricular de crianças com COVID-19. Método: Este estudo prospetivo incluiu crianças com COVID-19 que foram tratadas com AZ em julho-agosto 2020. Foi efetuado um eletrocardiograma (ECG) antes e um, 3 e 5 dias após o tratamento. Utilizando ImageJ ®, foram medidos os parâmetros seguintes: QT max, QT min, Tp-e max, e Tp-e min. Os parâmetros QTc min, Tp-ec max, Tp-ec min, QTcd, Tp-ecd e QTc/Tp-ec ratio foram calculados utilizando a fórmula Bazett. Resultados: O estudo incluiu 105 doentes pediátricos (idade média 9,8±5,3 anos). A frequência cardíaca no pré-tratamento foi mais elevada do que após o tratamento (antes 92 [79­108]/min versus dia 1 82 [69­108)]/min versus dia 3 80 [68­92,2]/min versus dia 5 81 [70­92]/min; p=0,05). Conclusão: A AZ não afeta os parâmetros de repolarização ventricular no ECG nos casos pediátricos da COVID-19.

The number and activity of CD3+TCR Vα7.2+CD161+ cells are increased in children with acute rheumatic fever.

BACKGROUND: Acute rheumatic fever (ARF) is an autoimmune disease caused by group A ß-hemolytic streptococci (GAS) and may develop into rheumatic heart disease (RHD). The pathogenesis of ARF and RHD involves molecular mimicry and antibody-mediated mechanisms. T cell involvement is described in various stages of the disease. Mucosal associated invariant T (MAIT) cells are enriched at the mucosa and are present in the blood and may be activated by GAS. METHODS: In this study, we investigated the quantity and activity of CD3+TCRVα7.2+CD161+ cells in the active and recovered ARF patients and healthy controls. Twenty newly diagnosed, 20 recovered-ARF children, and 20 healthy controls were enrolled in the study. Peripheral blood (PB) mononuclear cells were isolated by Ficoll-Paque density gradient. CD4+, CD4- subsets of CD3+CD161+TCRVα7.2+ cells and IFN-γ and TNF-α production were quantified by Flow cytometry. RESULTS: Acute and recovered ARF patients had significantly elevated the number of CD3+TCRVα7.2+CD161+ cells in their PB. Both CD4+ and CD4- subsets were increased. Moreover, total CD3+TCRVα7.2+CD161+ cell numbers were significantly higher in the recovered patients' PB compared with active ARF patients. In addition, CD3+TCRVα7.2+CD161+ cells in both acute and recovered patients produced significantly more IFN-γ and TNF-α. Non-MAIT total CD3+ T cell, CD4+ and CD4- T cell subsets were also increased in active and recovered ARF patients and they also produced more IFN-γ and TNF-α. CONCLUSION: Our data reveal that CD3+TCRVα7.2+CD161+ cells are elevated and actively producing IFN-γ and TNF-α in acute and recovered ARF patients and may contribute to ARF pathology.

The immediate haemodynamic response and right and left cardiac remodelling after percutaneous transcatheter closure of secundum atrial septal defect in children: a longitudinal cohort study.

OBJECTIVE: We aimed to assess the immediate haemodynamic response and the timing of cardiac remodelling in paediatric secundum atrial septal defect patients who underwent percutaneous transcatheter closure. METHODS: In this longitudinal cohort study with 41 paediatric secundum ASD patients who underwent PTC with Amplatzer Occluder device were assessed for immediate post-interventional haemodynamic response measured by catheterisation and was evaluated for right and left cardiac remodelling during a follow-up period of 12 months by transthoracic echocardiography. SPSS 20.0 was used for statistical analyses of pre- and post-interventional invasive haemodynamic parameters of the patients, and pre- and post-interventional TTE data compared with the values of the control group consisted of 39 healthy children. RESULTS: The mean diameter of ASD was 13.9 ± 4.7 mm. PTC intervention in all patients completed with 100% success and 0% complication rates. All invasive haemodynamic data, except the ratio of pulmonary resistance to systemic resistance, significantly reduced after PTC (p < 0.05). TTE and PW Doppler revealed that right and left cardiac remodelling started as soon as the post-interventional 24th hour and completed in the 12th month. CONCLUSIONS: This study with a very high interventional success rate can be counted as the first example of research on the haemodynamic response and timing of cardiac remodelling after PTC of secundum ASD in children. We suggest that future multicentric studies with larger cohorts and a comprehensive methodology like ours with longer follow-up periods would better serve to further assess the cardiac remodelling in children after PTC of secundum ASD.

Role of kallistatin in pediatric patients with pulmonary arterial hypertension.

BACKGROUND AND OBJECTIVES: Kallistatin, a serine proteinase inhibitor, exerts its effect by vascular repair, angiogenesis inhibition, strong vasodilation, inhibition of vascular endothelial growth factor (VEGF), antiinflammation, and anti-apoptosis. We hypothesized as to whether it has a protective role in pulmonary arterial hypertension (PAH). METHODS: The study included 5 subgroups (78 patients; 44 male): Eisenmenger syndrome (n=16), PAH with left to right shunt (n=20), idiopathic PAH (n=7), patients with left to right shunt without PAH (n=19), and patients with innocent heart murmur (n=16). Physical examination, chest radiography, electrocardiography, and transthoracic echocardiography (TTE) were performed for each patient. PAH diagnosis was confirmed by catheterization. Serum kallistatin, tumor necrosis factor alpha (TNF-α), Interleukin-10 (IL-10) and N-terminal pro b-type natriuretic peptide (NT-proBNP) levels were studied for each patient. RESULTS: The lowest median kallistatin value was found in Eisenmenger syndrome: 1.19 (0.87-3.30) µg/ml. The highest value belonged to control group with innocent murmur: 2.89 (1.19-5.66) µg/ml. Serum levels of kallistatin were significantly lower in patients with PAH (p < 0.05). TNF-α values were increased and IL-10 values were decreased in pulmonary hypertension. However; no correlation was found between kallistatin levels and cytokines. CONCLUSIONS: Kallistatin may have a protective effect in pulmonary arterial hypertension by repairing vascular damage, inhibition of angiogenesis, strong vasodilator effect, inhibiting VEGF, and anti-inflammatory mechanism of action. To our knowledge, our study is the first one that shows the role of kallistatin in pulmonary hypertension. Kallistatin may represent a promising novel therapeutic approach for pulmonary hypertension in the near future.

Percutaneous ASD closure of children weighing less than 10 kg.

Background: Traditionally the procedure of percutaneous ASD closure is carried out in children weighing more than 15 kg. The aim of this study was to discuss the success, efficacy and safety of the percutaneous closure of symptomatic ASD in children weighing less than 10 kg.Material and methods: This study was performed in two centres. A total of 44 patients were included. Demographic and angiographic data of these patients were gathered retrospectively from patients' records. Main indications for ASD closure were: failure to thrive, recurrent respiratory infections, bronchopulmonary dysplasia and genetic syndromes.Results: Median weight of patients was 9.0(8.12-9.50) kg. Bodyweight of 22 patients was less than 3 percentiles. In the follow-up, this number was lowered to 9 patients at 12 months. Median age of patients was 18.0(12.0-285) months. Minimum age and weight of patients was 3 months and 4.5 kg, respectively. Median mean pulmonary pressure was 24.0(20.0-29.5). The values of median defect size were measured in Cath lab as 13.0(10.75-15.3) mm. Median device size was 13(9-15) mm. Defect size was evaluated according to body weight and body surface area. The ratio of weight per defect size was 0.65(0.54-0.84) also the ratio of body surface area per defect size was 0.032(0.028-0.04). The ratio of total septum per device diameter was 2.5(2.1-3.1). Types of devices used were Amplatzer Septal Occluder, Cera Flex Septal Occluder, Figulla Flex II Atrial Septal Occluder, Memopart Septal Occluder. All cases were closed successfully, but the device had to be retrieved in one patient after successful positioning because it was detected that device compressed the aorta. No major complications were seen.Conclusion: In the experienced centres, percutaneous ASD closure can be done effectively and safely in symptomatic children weighing less than 10 kg.

Percutaneous Ventricular Septal Defect Closure in Patients Under 1 Year of Age.

Untreated ventricular septal defect (VSD) is an important cause of congestive heart failure in early infancy. Growth is impaired in this population, and surgical closure is challenging because of congestion in the lungs, making infants prone to respiratory infection, and because of their poor nutritional status. The aim of this study is to share our experience with percutaneous VSD closure in patients under 1 year of age. Patients with hemodynamically significant left-to-right shunt, less than 1 year of age, and with VSD diameter ≤ 6 mm were retrospectively included in the study between December 2014 and January 2017. The median length of follow-up was 8.5 (4-14.2) months. Twelve patients from 2 to 12 months of age, with a median weight of 6.75 (5.4-8) kg, were included. The mean VSD diameter as measured by angiography from the left ventricle side was 4.7 ± 0.25 mm, and from the right ventricle side was 3.4 ± 1.1 mm. All were of a perimembranous type except three, which were muscular. All defects were closed with the Amplatzer Duct Occluder II (ADO II) or the ADO II-additional size. The mean fluoroscopy duration and total radiation dose were 22.6 ± 18.7 min and 1674 ± 851 cGy/min, respectively. No aortic regurgitation associated with device closure was seen in any of the patients. Complete atrioventricular block occurred in one patient 6 months after the procedure, and was treated with a permanent pacemaker. VSD closure is challenging, regardless of whether a surgical or percutaneous procedure is used. The risks are higher for children younger than 1 year with low body weight. Percutaneous closure, which carries similar risks but is less invasive than surgery, may be the preferred alternative in early infancy.

Is hypertension the fate of aortic coarctation patients treated with Cheatham Platinum (CP) stent?

AIM: The aim of this study is to address the presence of hypertension and risk for cardiovascular diseases in patients with Coarctation of the Aorta (CoA) who were treated with endovascular stent placement. METHODS: Twenty patients (mean age: 14.2 ± 3.9 years) who were treated with stent and 20 age- and sex-matched controls were included to the study. Structure and functions of left ventricle were assessed by echocardiography. Carotid intima media (CIM) thickness was measured by using sonography as a marker for detecting cardiovascular risk. As indirect marker of arterial stiffness, pulse wave velocity, and augmentation index were recorded by ambulatory blood pressure monitorization/arteriography device. RESULTS: By ambulatory blood pressure monitorization, 24 h and daytime systolic and mean arterial pressure values were found to be significantly higher in patient group. Based on percentile values, 15% and 5% of patients were pre-hypertensive and hypertensive, respectively. Pulse wave velocity and cardiac output values were found to be significantly higher than control group. CIM thickness was also found to be significantly higher in patient group when compared to controls. CONCLUSIONS: It was shown that hypertension incidence as demonstrated by ambulatory blood pressure monitorization and risk for cardiovascular diseases as indicated by CIM thickness and Pulse wave velocity were higher than those in healthy population even after CoA is corrected.

Patent Ductus Arteriosus closure in preterms less than 2kg: Surgery versus transcatheter.

BACKGROUND: As new devices come into the market, percutaneous techniques improve and interventionalists become more experienced; percutaneous closure gets more common in preterms. In this study we aimed to compare efficacy and safety of Patent Ductus Arteriosus closure surgically versus transcatheter method in preterms <2kg. Best of our knowledge this study is the first one that compares outcomes of surgery and percutaneous Patent Ductus Arteriosus closure in preterms. METHODS & RESULTS: Between the dates July 1997 to October 2014 in our center Patent Ductus Arteriosus of 26 patients <2kg were closed percutaneously (Group A) and 31 less than 2kg operated (Group B). Weight of patients in percutaneous Patent Ductus Arteriosus closure group was significantly more than the surgery group. Mean gestational age of the patients in Group A was 30±1.8weeks, in group B was 28.6±3.5weeks. In group A; all cases were closed successfully except 4 cases: device embolization in 2, cardiac tamponade and iatrogenic aortic coarctation were seen. Pneumomediastinum and chylothorax were the major complications of the surgery group. There was no statistically significance between complication and success rates between two groups. CONCLUSION: Percutaneous Patent Ductus Arteriosus closure is the candidate for taking the place of surgery in preterms. However, it is not applied routinely; can only be done in fully equipped large centers by experienced interventionalists.

Mid-term results of percutaneous ventricular septal defect closure with Amplatzer Duct Occluder-II in children.

Aim The aim of this study was to share the mid-term results of percutaneous ventricular septal defect closure using Amplatzer Duct Occluder-II in children. BACKGROUND: Nowadays, percutaneous ventricular septal defect closure is accepted as an alternative to surgery, but so far no ideal device has been developed for this procedure. METHODS: In the study centre, between April, 2011 and October, 2016, the ventricular septal defect of 49 patients was closed percutaneously using the Amplatzer Duct Occluder-II device, and seven of them were <1 year old. RESULTS: The mean age of patients was 86.8±52.6 months. The mean weight of the patients was 24.3±16 kg. The mean diameter of the defect was 3.7±1.4 mm. Mean fluoroscopy time and total procedure time were 37±19.3 and 74.1±27 minutes, respectively. The types of ventricular septal defects were muscular in six patients, and were perimembranous in the rest of them. We did not face any major complications during the procedure, but one patient was admitted with a complete atrioventricular block in the 6th month of follow-up. The total follow-up period was 66 months. CONCLUSION: To our knowledge, our study includes the largest series of paediatric patients whose ventricular septal defect was closed using Amplatzer Duct Occluder-II percutaneously. When the complications during the 66-month follow-up period are taken into consideration, we can state that Amplatzer Duct Occluder-II is a safe and effective device, even in infants aged <1 year.

Percutaneous PDA Closure in Extremely Low Birth Weight Babies.

AIM: Patent Ductus Arteriosus is an important cause of morbidity and mortality in preterms. As birth weight decrease, risks increase. Main aim of our study is to emphasize the effectiveness and safety of percutaneous PDA closure even in extremely low birth infants. MATERIALS AND METHODS: In our center between the dates June 2014-June 2016, PDA of 10 patients less than 1,000 gr were closed percutaneously. To the best of our knowledge this study includes the largest cohort of infants less than 1,000 g in the literature, that PDA of those were percutaneously closed. RESULTS: Symptomatic patients, less than 1,000 gr having PDA were included in the study. All have 3 times medical therapy for PDA closure but it did not work. PDA was decided to be contributor of this medical state of them. The mean patient age was 19.5 ± 7.2 days. The median weight was 950 (842-983) gr. Mean gestational age was: 26.3 ± 0.63 weeks. Mean PDA diameter was 1.9 ± 0.41 mm. Morphology of PDA:6 of them were conical and 4 of them were tubular. In all patients ADOII-AS device were used for PDA closure via venous route. No major complications were reported. Left pulmonary arterial stenosis was detected in 1 patient who was resolved in 6 months duration. CONCLUSION: We want to emphasize that in experienced centers percutaneous closure of PDA can be an alternative to surgery even in the extremely low birth weight babies.

Pulmonary arterial wall thickness in Eisenmenger Syndrome: Prospective, cross-sectional, controlled clinical trial.

BACKGROUND: The aim of current study is to investigate echocardiographic pulmonary artery wall thickness (PAWT) association with angiocardiography, echocardiography, and biochemical findings and to demonstrate its predictive role in morbidity of disease. METHOD: Nineteen patients with Eisenmenger Syndrome (ES) (13 females; a mean age of 12.0 ± 4.1 [min-max 4-17] years) and 24 (16 females; a mean age of 12.1 ± 4.3 [min-max 3-18 years]) healthy subjects as a control group were included in this prospective, cross-sectional, controlled clinical study between December, 2012 and December, 2013. PAWT were measured at the end of systole at the distal site of pulmonary valves at the parasternal short-axis. PAWT was compared with morbidity criteria of the disease such as functional class, pulmonary vascular resistance. RESULTS: PAWT was higher in the patient group (P = 0.005) together with pulmonary arterial diameter (Z-score, P < 0.001), vena cava inferior diameter (P = 0.002), and right ventricular wall thickness (RVWT), while TAPSE was significantly lower (P = 0.002). PAWT was strongly positively correlated to RVWT (r = 0.893, P < 0.001) and moderate negatively correlated to TAPSE (r = 0.597; P < 0.011). CONCLUSION: PAWT can be used as an additional parameter with other echocardiographic parameters in the follow-up of Eisenmenger Syndrome in children.

Efficacy of palivizumab prophylaxis among infants with congenital heart disease: A case control study.

BACKGROUND: Palivizumab prophylaxis for RSV has been consistently reported to reduce the risk of hospital admissions related to RSV infection in children with symptomatic cardiac disease. This study was designed to investigate the efficacy of palivizumab prophylaxis among infants with congenital heart disease (CHD) in Turkey. METHODS: A total of 91 infants with CHD who received palivizumab prophylaxis and 96 infants with CHD without prophylaxis (0-12 months:52; 12-24 months:44) were included in this single-center retrospective case control study. Data on patient characteristics, household environment, and LRTIs were evaluated. RESULTS: In patients without prophylaxis, the rate of overall lower respiratory tract infections (LRTIs) (P < 0.001), complicated LRTIs (P = 0.006), LRTI-related hospitalization (P < 0.001) and ICU admission (P = 0.008) were significantly higher than control patients. Weight <10th percentile (odds ratio (OR) 5.78, 95% confidence interval (CI):1.37; 24.4, P < 0.001) and concomitant chromosome abnormality (OR 4.01, 95% CI:1.01;16.45, P < 0.001) in patients with prophylaxis, while presence of a sibling <11 years of age (OR 3.38, 95% CI: 1.21; 9.46, P < 0.001) and congestive heart failure (OR 8.63, 95% CI: 2.81; 26.6, P < 0.001) in the control group were the significant correlates of LRTI-related hospitalization. CONCLUSION: Our findings revealed significantly lower rate of overall and complicated LRTIs, LRTI-related hospitalization and ICU admissions in infants with CHD via palivizumab prophylaxis.