Stent Strut Dilation in Branch Pulmonary Artery Stenosis Following Stenting of Arterial Duct in Duct-dependent Pulmonary Circulation.

To assess the feasibility and outcome of stent strut dilation after arterial duct stenting with associated branch pulmonary artery (BPA) stenosis. Stenting of arterial duct in infants with duct-dependent pulmonary circulation is technically challenging. The presence of BPA stenosis is a relative contraindication for stent implantation. Infants with duct-dependent pulmonary circulation and associated BPA stenosis were assessed either by transthoracic echocardiogram alone or additional computerized tomography angiogram when required. Following ductal stenting, the stent struts of the stenosed BPA were crossed with an additional 0.014″ coronary guide wire and dilated using coronary balloons (2.0 or 2.5 mm in diameter). Seventeen (12 male) patients were considered for the procedure. The median age and weight were 27 days (range 2-94) and 2.6 kg (range 2.2-5), respectively. Fourteen patients (82.4%) underwent stent strut dilation after arterial duct stenting. Struts to left pulmonary artery was opened in 9 (64.3%) and right pulmonary artery in 5 (35.7%). The mean systemic oxygen saturation increased from 66.23 ± 8.9% at baseline to 86 ± 2.2% immediately after the stent deployment and final saturations after stent strut dilation were 89.29 ± 4.3%. Angiographic pulmonary flow improved in all cases. Stent strut dilation could not be done in 3 patients due to unfavorable anatomy. One patient had acute stent thrombosis and died in the hospital. Two others died during follow-up, during an acute febrile illness and gastroenteritis. All survivors underwent cardiac surgery and were on regular follow-up. Strut dilation of BPA stenosis is feasible to augment pulmonary blood flow, following arterial duct stenting. This procedure may be useful in selected patients with BPA stenosis to have uniform growth of pulmonary arteries.

Patterns of Electrocardiographic Abnormalities in Children with Hypertrophic Cardiomyopathy.

Hypertrophic cardiomyopathy (HCM), a common cardiomyopathy in children, is an important cause of morbidity and mortality. Early recognition and appropriate management are important. An electrocardiogram (ECG) is often used as a screening tool in children to detect heart disease. The ECG patterns in children with HCM are not well described.ECGs collected from an international cohort of children, and adolescents (≤ 21 years) with HCM were reviewed. 482 ECGs met inclusion criteria. Age ranged from 1 day to 21 years, median 13 years. Of the 482 ECGs, 57 (12%) were normal. The most common abnormalities noted were left ventricular hypertrophy (LVH) in 108/482 (22%) and biventricular hypertrophy (BVH) in 116/482 (24%) Of the patients with LVH/BVH (n = 224), 135 (60%) also had a strain pattern (LVH in 83, BVH in 52). Isolated strain pattern (in the absence of criteria for hypertrophy) was seen in 43/482 (9%). Isolated pathologic Q waves were seen in 71/482 (15%). Pediatric HCM, 88% have an abnormal ECG. The most common ECG abnormalities were LVH or BVH with or without strain. Strain pattern without hypertrophy and a pathologic Q wave were present in a significant proportion (24%) of patients. Thus, a significant number of children with HCM have ECG abnormalities that are not typical for "hypertrophy". The presence of the ECG abnormalities described above in a child should prompt further examination with an echocardiogram to rule out HCM.

Interventional recanalisation of long segment aortic atresia.

We report the case of a long-segment aortic atresia as the cause for therapy resistant arterial hypertension in a young adult. Recanalization was achieved interventionally by wire-crossing and stent implantation with subsequent normalization of blood pressure.

Off-label use of duct occluder devices to close hemodynamically significant perimembranous ventricular septal defects: A multicenter experience.

OBJECTIVE: We sought to evaluate the feasibility, technical aspects, and outcome of transcatheter perimembranous ventricular septal defect (pmVSD) closure using duct occluder devices with a single retention disc. BACKGROUND: Use of duct occluder devices to close pmVSD seems a promising alternative therapy. However, limited data exist on this technique. METHODS: From 2010 to 2016, 222 patients (female 47.7%) were identified from databases of five participating institutions in whom pmVSD closure was attempted using an Amplatzer Duct Occluder I or Lifetech duct occluder device. RESULTS: Patients ranged in age from 0.7 to 52 years (median, 7.0 years) and in weight from 4.0 to 70 kg (median, 18.0 kg). The mean size of the VSD was 6.8 ± 2.2 mm. A large defect (> 6 mm) was present in 137 patients (61.7%). Device closure was successful in 218 patients (98.2%). The 10/8 mm device was used in most patients (n = 85, 38.3%), and the vascular approach was from the femoral vein in 169 patients (76.1%). There were 18 early complications in 17/218 patients (7.8%). Three patients (1.4%) developed complete heart block (transient n = 2; requiring permanent pacing n = 1). Median follow-up was 6 months (6 months-6 years). A mild residual shunt was seen in 10 patients at 6 months follow-up. CONCLUSIONS: The immediate results of transcatheter pmVSD closure using a duct occluder device with a single retention disc are promising. It is an effective technique with a lower rate of complications than for other currently available devices.

Subclinical myocardial disease in patients with primary hyperoxaluria and preserved left ventricular ejection fraction: a two-dimensional speckle-tracking imaging study.

BACKGROUND: Primary hyperoxaluria (PH) is characterized by progressive chronic kidney disease (CKD) and systemic oxalate deposition. Myocardial dysfunction might be present early in the course of the disease. However, this hypothesis has not yet been tested in the PH population. Therefore, we aimed to determine whether strain imaging using two-dimensional speckle tracking echocardiography (2D-STE) might detect subclinical myocardial disease in otherwise asymptomatic PH patients. METHODS: Prospective study of pediatric and adolescent PH patients with preserved LV ejection fraction (LV EF) and without renal replacement therapy. Subjects underwent conventional echocardiography and 2D-STE. Global (GLS) and segmental peak systolic LV longitudinal strain (LS) measurements were obtained. Data were compared with age- and gender-matched controls, and Z-scores were calculated as appropriate. RESULTS: Fifteen PH patients (age 14.1 ± 5.9 years; 13/15 in CKD stages 1-2) were studied. Although LV EF was preserved (63 ± 6%) in patients, GLS was significantly impaired (GLS - 17.1 ± 2.2% vs - 22.4 ± 1.9%, p < 0.001). This was mainly due to decreased LS values in the apical segments (p < 0.05). Echocardiographic indices of ventricular wall thickness were significantly increased in patients compared to controls (all p < 0.03). GLS correlated significantly with Z-scores of diastolic interventricular wall thickness (r = - 0.57, p = 0.025) and moderately with serum creatinine levels (r = 0.53, p = 0.044). No correlation was found between GLS and blood pressure measurements. CONCLUSIONS: Subclinical myocardial disease is already present early in the course of disease in PH patients with preserved LV EF and some degree of renal dysfunction, but without overt systemic oxalosis. Current recommendations to screen only PH patients with advanced CKD for cardiac disease should be revised accordingly.

Successful biventricular cardiac resynchronization therapy in a failing Fontan patient: Implications of ventriculo-ventricular interdependency in single ventricle physiology.

We describe a Fontan patient with severe heart failure who was successfully treated with biventricular cardiac resynchronization therapy (CRT). Our case shows that strain imaging might play a crucial role in guiding placement of pacing leads and in characterizing the electromechanical substrate associated with a favorable CRT response. Furthermore, we demonstrate for the first time that ventriculo-ventricular interdependency seems an important mechanical concept, which can be utilized to augment cardiac performance in failing Fontan patients with a functional hypoplastic ventricle.

Impact of Obesity on Left Ventricular Thickness in Children with Hypertrophic Cardiomyopathy.

Obesity is associated with additional left ventricular hypertrophy (LVH) in adults with hypertrophic cardiomyopathy (HCM). It is not known whether obesity can lead to further LVH in children with HCM. Echocardiographic LV dimensions were determined in 504 children with HCM. Measurements of interventricular septal thickness (IVST) and posterior wall thickness (PWT), and patients' weight and height were recorded. Obesity was defined as a body mass index (BMI) ≥ 99th percentile for age and sex. IVST data was available for 498 and PWT data for 484 patients. Patient age ranged from 2 to 20 years (mean ± SD, 12.5 ± 3.9) and 340 (68%) were males. Overall, patient BMI ranged from 7 to 50 (22.7 ± 6.1). Obesity (BMI 18-50, mean 29.1) was present in 140 children aged 2-19.6 (11.3 ± 4.1). The overall mean IVST was 20.5 ± 9.6 mm and the overall mean PWT was 11.0 ± 8.4 mm. The mean IVST in the obese patients was 21.6 ± 10.0 mm and mean PWT was 13.3 ± 14.7 mm. The mean IVST in the non-obese patients was 20.1 ± 9.5 mm and mean PWT was 10.4 ± 4.3 mm. Obesity was not significantly associated with IVST (p = 0.12), but was associated with increased PWT (0.0011). Obesity is associated with increased PWT but not IVST in children with HCM. Whether obesity and its impact on LVH influences clinical outcomes in children with HCM needs to be studied.

The electrocardiogram of the neonate and infant.

The ECG in children has a number of characteristic differences compared to the ECG of the adult. The transition of the ECG in neonates after birth represents dynamic changes of the circulatory system due to the postnatal adaptation, different physiologic properties of the fetal and neonatal myocardium, the location and orientation of the heart in the chest and influence of body mass during that period and later on in childhood. The complexity of the changes implies a broad variation of ECG changes during the first days and weeks of life, whose interpretation requires expert knowledge. The ECG is an obligatory diagnostic tool in childhood arrhythmias. The long QT syndrome is an inherited rhythm disorder with risk of sudden cardiac death in early childhood. Electrocardiographic screening in neonates for the early detection of LQTS might identify individuals with an abnormal repolarization and prevent sudden death. The potential benefits of a universal screening program, even if achievable logistically and in a cost-effective manner, are however highly debatable.

Low serum 25-hydroxyvitamin D levels and secondary hyperparathyroidism in Fontan patients.

BACKGROUND: Limited data exist on the vitamin D status in Fontan patients. We determined the prevalence and potential risk factors of vitamin D deficiency in this patient subset. Methods and results Data were collected from 27 Fontan patients (55.6% male, mean age 8.1±5.3 years). Protein-losing enteropathy was diagnosed in six patients (22.2%). Vitamin D deficiency was defined as a serum 25-hydroxyvitamin D level of <20 ng/ml. The neutrophil-to-lymphocyte ratio, a marker of systemic inflammation, was calculated. Associations between laboratory measurements and patient characteristics were explored. Mean serum 25-hydroxyvitamin D level was 14.1±10.4 ng/ml. Vitamin D deficiency was found in 19/27 patients (70.3%). Only skin type was associated with vitamin D deficiency (p=0.04). Hyperparathyroidism was present in 5/21 (23.8%) patients, and was more prevalent in patients with protein-losing enteropathy (p<0.001). Parathyroid hormone levels correlated with parameters of systemic inflammation (neutrophil-to-lymphocyte ratio: r=0.484, p=0.026; relative lymphocyte count: r=-0.635, p=0.002). Vitamin D supplementation significantly increased serum 25-hydroxyvitamin D levels (p<0.0001), and was accompanied by a reduction in parathyroid hormone concentrations (p=0.032). CONCLUSIONS: A high prevalence of vitamin D deficiency was found among Fontan patients, independent of age, time after Fontan procedure, ventricular morphology, and presence of protein-losing enteropathy. A potentially important link between parathyroid hormone levels and systemic inflammation is suggested.

Inhomogeneous Longitudinal Cardiac Rotation and Impaired Left Ventricular Longitudinal Strain in Children and Young Adults with End-Stage Renal Failure Undergoing Hemodialysis.

BACKGROUND: Cardiac dysfunction frequently complicates the clinical course of patients with end-stage renal failure (ESRF). Recently, we observed abnormal longitudinal cardiac rotation (LR) among patients with ESRF. In this study, we sought to quantify LR mechanics in patients undergoing hemodialysis (HD). METHODS: Twenty-four subjects, 12 ESRF patients (58% male; age 17.5 ± 4.4 years) receiving HD, and 12 aged-matched controls, were prospectively studied. Patients underwent echocardiographic studies before and after HD. LR mechanics were quantified with two-dimensional speckle tracking echocardiography. Peak systolic left ventricular (LV) longitudinal strain and displacement measurements were obtained in all subjects. RESULTS: LR mechanics were successfully quantified in all subjects using 5 key echocardiographic features of LR. We identified two different inhomogeneous LR motion patterns in 41.7% of ESRF patients, characterized by a delayed timing of LR or increased segmental apical rotation. Inhomogeneous LR patterns were not found in controls. Timing of early-systolic counterclockwise LR increased after HD (P = 0.006). In patients, late-systolic clockwise LR occurred earlier (P = 0.043), and showed a significant prolongation after HD (P = 0.003). Longitudinal strain was significantly impaired in patients (P = 0.015), and further decreased after HD (P < 0.0001). Strong correlations were observed between strain and displacement parameters and LR mechanics. CONCLUSIONS: Quantifying LR using speckle tracking echocardiography was feasible, easy, and reproducible. Inhomogeneous LR motion patterns were demonstrated in a large proportion of patients with ESRF. LV dysfunction seems the most important determinant of inhomogeneous LR. Further studies are required to validate these findings.

The pathophysiologic aspects and clinical implications of electrocardiographic parameters of ventricular conduction delay in repaired tetralogy of Fallot.

The 12-lead surface electrocardiogram is a valuable and feasible clinical tool in the management of patients following tetralogy of Fallot (TOF) repair. The importance of QRS duration in TOF patients has long been acknowledged. A prolonged QRS complex has been associated with increased risk for subsequent life-threatening ventricular arrhythmia and sudden cardiac death. Our current ability to risk-stratify TOF patients for malignant arrhythmogenic events primarily on the basis of QRS duration is rather limited. Nevertheless, increasing evidence suggests that QRS morphology and duration may be useful as surrogate markers of infundibular and regional right ventricular myocardial disease. The aim of this review is to provide a critical appraisal of the clinical implications of established and new electrocardiographic markers of ventricular conduction delay in TOF patients following surgical correction with a particular focus on QRS duration, lengthening, and fragmentation. In addition, the pathophysiological background of these parameters is addressed.

Fascicular and nonfascicular left ventricular tachycardias in the young: an international multicenter study.

INTRODUCTION: The aim of this study was to evaluate the clinical presentation and outcomes of pediatric patients with ventricular tachycardia (VT) originating from left heart structures. METHODS AND RESULTS: This international multicenter retrospective study including 152 patients (age 10.0 ± 5.1 years, 62% male), divided into those with fascicular VT (85%, 129/152) and nonfascicular LV VT (15%, 23/152). All patients had a normal heart structure or only a minor cardiac abnormality. Adenosine was largely ineffective in both groups (tachycardia termination in 4/74 of fascicular VT and 0/5 of nonfascicular LV VT). In fascicular VT, calcium channel blockers were effective in 80% (74/92); however, when administered orally, there was a 21% (13/62) recurrence rate. In nonfascicular LV VT, a variety of antiarrhythmic therapies were used with no one predominating. Ablation procedures were successful in 71% (72/102) of fascicular VT and 67% (12/18) of nonfascicular LV VT on an intention to treat analysis. Major complications occurred in 5 patients with fascicular VT and 1 patient with nonfascicular LV VT. After a follow-up period of 2 years (1 day to 15 years), 72% of all patients with fascicular VT were off medications with no tachycardia recurrence. One patient died of noncardiac causes. In nonfascicular LV VT, follow-up was 3.5 years (0.5-15 years), P = 0.38. A total of 65% of these patients were free from arrhythmias. Two patients died suddenly (P < 0.01). CONCLUSION: The clinical course and outcomes of pediatric patients with fascicular VT and nonfascicular LV VT are varied. Catheter ablation procedures can be curative.

Transcatheter closure of acquired left ventricle to right atrium shunts.

We describe transcatheter closure of an acquired Gerbode defect (left ventricle to right atrium shunt) in four patients, ranging in age from 8 to 75 years. All of them had undergone previous surgery (VSD closure in 3, aortic valve replacement in 1), and either had persistent symptoms of heart failure, or developed new symptoms several months or years later. The diagnosis was made by one of several imaging modalities (transthoracic or transesophageal echocardiography, or MRI), and confirmed at cardiac catheterization. Device closure using a variety of devices was successful in all, with resolution of symptoms. One patient developed complete heart block, requiring permanent pacemaker implantation. Transcatheter closure is effective, and may replace surgery in the management of these defects.

Stenting the arterial duct in neonates and infants with congenital heart disease and duct-dependent pulmonary blood flow: a multicenter experience of an evolving therapy over 18 years.

OBJECTIVES: The primary aim of this multi-institutional study was to describe our 18-year experience of ductal stenting (DS) in infants with a duct-dependent pulmonary circulation. The secondary aim sought to identify a subgroup of patients who may benefit the most using this evolving technique. BACKGROUND: No study has examined the extraordinary evolution of this promising therapy over the last two decades. METHODS: Between 1991 and 2009, 65 neonates and infants (39 male, 60%) underwent cardiac catheterization for DS in 3 participating centres. Patients were divided according to whether DS was attempted between 1991-2000 (Group 1, n = 20) or between 2001-2009 (Group 2, n = 45). RESULTS: DS was successful in 52/65 (80%) patients. DS outcome was associated with ductal morphology and cardiac diagnosis. DS failed more often in patients with univentricular physiology and tortuous duct morphology (p < 0.001). Most patients undergoing DS in Group 2 had pulmonary atresia with intact ventricular septum (PAIVS) (p < 0.001). DS was successful in 94% of these patients. Groups differed significantly in diameter and length of first implanted stent (p < 0.001), implanting additional stent (p < 0.001), and occurrence of complications (p = 0.033). Freedom from re-intervention for the 52 patients was 92.3%. No procedure-related mortality occurred. CONCLUSIONS: The technical aspects and clinical application of percutaneous DS has changed in the last two decades. DS has become a practical and safe therapy in a subgroup of neonates with ductal-dependent pulmonary blood flow.

Fast diastolic swinging motion of the mitral valve as a clinical marker of familial hypertrophic cardiomyopathy in genetically affected young children without left ventricular hypertrophy: a new role for noninvasive imaging?

Structural mitral valve (MV) abnormalities are common in patients with hypertrophic cardiomyopathy (HCM). This is the first report demonstrating MV abnormalities in very young children as the sole overt clinical feature of a known HCM-causing sarcomere protein gene mutation. Due to MV leaflet elongation, we also noticed a typical fast diastolic swinging motion of the MV in our patients. This novel echocardiographic feature may be used as a clinical marker of HCM disease in the absence of left ventricular hypertrophy.

Stent therapy for acute and chronic obstructions in extracardiac Fontan conduits.

We describe transcatheter therapy for early onset occlusion or stenoses of extracardiac conduits in three children who had undergone Fontan completion. Successful stent implantation was associated with complete resolution of symptoms.

Cardiac hydatid cyst.

We describe the clinical presentation and management of a cardiac hydatid cyst in a young girl.

Indications for and outcomes of interstage catheter interventions following the Norwood procedure: A single-institution study.

Aims: The aim of this study was to document the incidence, types, and outcome of interstage catheter interventions following the Norwood surgical palliation. Patients and Methods: A retrospective single-center study of all patients surviving the Norwood operation was performed. All data concerning interstage catheter interventions up to the completion of the superior cavopulmonary shunt were collected. Results: Catheter interventions were performed in 62 of 94 patients (66%; 38 males). These included interventions on the aortic arch (n = 44), the branch pulmonary arteries (PAs) (n = 17), and the Sano shunt (n = 14). Multiple interventions and repeat interventions were common. The minimum aortic arch diameter (pre- versus posttreatment) increased from median 3.1 (2.3-3.3) mm to 5.1 (4.2-6.2) mm (P < 0.001). The catheter pullback gradient decreased from 40 (36-46) mmHg to 9 (5-10) mmHg (P < 0.001), and the echocardiographic gradient from 54 (45-64) mmHg to 12 (10-16) mmHg (P < 0.001). The branch PA diameters increased from 2.4 (2.1-3.0) mmHg to 4.7 (4.2-5.1) mmHg (P < 0.001). The minimum Sano shunt diameters increased from 2.0 (1.5-2.1) mm to 5.9 (5.8-6.0) mm (P < 0.001); this was associated with an improvement in systemic saturation from 63% (60%-65%) to 80% (79-82%) (P < 0.001). Unexpected interstage death at home occurred in two patients who had received no interventions. The remainder received a superior cavopulmonary shunt palliation. Conclusions: Catheter interventions were common. Systematic follow-up and a low threshold for reintervention are essential to the success of staged surgical palliation for this patient cohort.

Initial Clinical Trial of a Novel Pulmonary Valved Conduit.

Valved allografts and xenografts for reconstruction of the right ventricular outflow tract (RVOT) lack durability and do not grow. We report the first clinical use of a completely bioabsorbable valved conduit (Xeltis pulmonary valve - XPV) in children. Twelve children (six male), median age five (two to twelve) years and median weight 17 (10 to 43) kg, underwent RVOT reconstruction with the XPV. Diagnoses were: pulmonary atresia with ventricular septal defect (VSD) (n = 4), tetralogy of Fallot (n = 4), common arterial trunk (n = 3), and transposition of the great arteries with VSD and pulmonary stenosis (n = 1). All had had previous surgery, including prior RVOT conduit implantation in six. Two diameters of conduit 16mm (n = 5) and 18mm (n = 7) were used. At 24 months none of the patients has required surgical re-intervention, 9 of the 12 are in NYHA functional class I and three patients in NYHA class II. None of the conduits has shown evidence of progressive stenosis, dilation or aneurysm formation. Residual peak gradient of >40 mm Hg was observed in three patients, caused by kinking of the conduit at implantation in 1 and distal stenosis in the peripheral pulmonary arteries in 2 patients. Five patients developed severe pulmonary valve insufficiency (PI); the most common mechanism was prolapse of at least one of the valve leaflets. The XPV conduit is a promising innovation for RVOT reconstruction. Progressive PI requires however an improved design (geometry, thickness) of the valve leaflets.

Multicenter study of the effectiveness of implantable cardioverter defibrillators in children and young adults with heart disease.

Implantable cardioverter defibrillators (ICDs) are being used with increasing frequency in children and young adults. Our aim was to examine the appropriateness and frequency of ICD discharges in children and young adults, to compare the effectiveness of ICDs when placed for primary or secondary prevention, and to provide time-dependent analysis of ICD discharges. Data were collected from seven institutions on 210 patients <30 years of age who underwent ICD implantation from October 1992 to January 2007. Median age at implant was 15.4 years with a follow-up average of 3.3 years. Heart disease was categorized as electrical (n = 90, 42%), cardiomyopathic (n = 62, 30%), or congenital heart disease (n = 58, 28%). ICDs are increasingly placed for primary prevention. There are increased appropriate ICD discharges for ICDs placed for secondary prevention (52%) versus primary prevention (14%) at 5 years. There is no difference in the risk of inappropriate discharges between primary and secondary prevention indications. There is an increased risk for inappropriate therapy in the congenital heart disease population. An increasing number of ICDs are being placed for primary prevention in young patients, a marked shift in practice during the last two decades. The benefits of ICDs remain greater in secondary than in primary-prevention patients. In both groups, approximately 25% of patients received inappropriate discharges within 5 years of implant. Patients with congenital heart disease are the most affected by inappropriate discharges.