Presentation of Complex Congenital Cardiac Anomalies in a Newborn Pediatric Patient: A Case Report

Tricuspid atresia, a critical congenital heart defect (CHD), accounts for approximately 1% of all cases of CHDs. When tricuspid atresia is coupled with numerous other unexpected congenital cardiac anomalies, a patient's condition becomes more serious and more complex. We present a case that demonstrates the stepwise approach to the holistic treatment of congenital tricuspid atresia in the presence of normally related great vessels, a large ventricular septal defect (VSD), atrial septal defect (ASD), and trivial patent ductus arteriosus (PDA). While expanding upon the implementation of chest X-ray imaging, serial transthoracic echocardiogram (TTE) imaging, and the balloon atrial septostomy (BAS) procedure, we also provide insight into the multidisciplinary team-based approach utilized for this patient's case. This case illustrates a rare critical CHD coupled with other, more common congenital anomalies, and suggests that with multidisciplinary management and treatment, it is possible the mortality rates associated with this diagnosis could decline.

A Female Newborn With Occipital Encephalocele and a Hypoplastic Right Ventricle Secondary to Tricuspid and Pulmonary Atresia: A Case Report

Encephaloceles and severe cardiac malformations are rare presentations in a newborn. The mechanism of these congenital abnormalities is relatively unknown, but it is hypothesized to be related to genetic, environmental, and maternal risk factors. This case report describes a newborn with an occipital encephalocele associated with severe right ventricular hypoplasia secondary to tricuspid and pulmonary atresia. The patient's maternal risk factors included obesity, type 2 diabetes mellitus, and everyday tobacco use during pregnancy. Education on preconception planning, management, and counseling is essential as a preventative measure in fetal development and is further emphasized in this case.

Francis Fontan (1929-2018): Pioneer pediatric cardiac surgeon

Up until the mid-1900s, tricuspid atresia - a birth defect of the tricuspid valve, was once categorized as a "death sentence." The challenge of achieving positive health outcomes for affected patients was compounded by a hesitancy to operate on children. The main concern was safely administering anesthesia to young patients who were going through a strenuous operation that was often poorly tolerated. Despite these assumed limitations, Francis Fontan, a pediatric cardiothoracic surgeon at the Hospital of Tondu in Bordeaux, was able to redirect blood flow from the superior and inferior vena cava to the pulmonary arteries in 1971, which elucidated the process of advancing clinical practice in medicine. With the support of mentors and a firm belief in this new technique, Fontan pioneered his eponymous procedure and ultimately paved the way for modern cardiovascular surgical techniques that helped to prolong the life of those with single functioning ventricles. The aim of this study is to examine the genesis and the evolution of the Fontan procedure to elucidate the process of advancing clinical practice in medicine by utilizing personal interviews, Fontan's works, associated primary and secondary sources in the context of 20th century cardiothoracic surgery and innovations.

Corrigendum: Comparison of cardiac function between single left ventricle and tricuspid atresia: assessment using echocardiography combined with computational fluid dynamics

[This corrects the article DOI: 10.3389/fped.2023.1159342.].

Long-Term Survival Is Superior in Patients With Pulsatile Pulmonary Flow After the Björk Procedure

Background: This study aims to evaluate clinical outcomes and hemodynamic variables late after the Björk procedure, regarding the pulmonary flow pattern. Methods: Patients who survived more than 15 years after the Björk procedure were included and then divided into two groups according to their pulmonary flow pattern by pulsed-wave Doppler assessment of echocardiography: patients with pulsatile systolic pulmonary flow (Group P) and those without (Group N). Results: A total of 43 patients were identified, of whom 13 patients were divided into Group P and 30 in Group N. Median age at the Björk procedure was 5.7 (2.1-7.3) years, and median follow-up was 32 (28-36) years. Survival after 15 years was higher in Group P, compared with Group N (100% vs 76% at 30 years, P = .045). Cardiac catheterization data demonstrated higher cardiac index in Group P patients compared with Group N patients (3.5 vs 2.8 L/m2, P = .014). Cardiac magnetic resonance imaging study revealed that Group P patients had higher right ventricular end-diastolic volume index (96 vs 57 mL/m2, P = .005), higher end-systolic volume index (49 vs 30 mL/m2, P = .013) and higher right ventricular stroke volume index (48 vs 25 mL/m2, P < .001), compared with Group N patients. Exercise capacity tests demonstrated that Group P patients showed a higher percent predicted peak oxygen consumption, compared with Group N patients (73 vs 58%, P < .001). Conclusions: Late after the Björk procedure, patients with a pulsatile systolic pulmonary flow had a larger right ventricle and better exercise capacity compared with those without pulsatile systolic pulmonary flow.

Loss of myocardial Hey2/Hrt2 function disrupts rightward shift of atrioventricular cushion tissue and causes tricuspid atresia

BACKGROUND

Endocardial cushion tissue is primordia of the valves and septa of the adult heart, and its malformation causes various congenital heart diseases (CHDs). Tricuspid atresia (TA) is defined as congenital absence or agenesis of the tricuspid valve caused by endocardial cushion defects. However, little is known about what type of endocardial cushion defect causes TA.

RESULTS

Using three-dimensional volume rendering image analysis, we demonstrated morphological changes of endocardial cushion tissue in developing Hey2/Hrt2 KO mouse embryos that showed malformation of the tricuspid valve, which resembled human TA at neonatal period. In control embryos, atrioventricular (AV) endocardial cushion tissues showed rightward shift to form a tricuspid valve. However, the rightward shift of endocardial cushion tissue was disrupted in Hey2/Hrt2 KO embryos, leading to the misalignment of AV cushions. We also found that muscular tissue filled up the space between the right atrium and ventricle, resulting in the absence of the tricuspid valve. Moreover, analysis using tissue-specific conditional KO mice showed that HEY2/HRT2-expressing myocardium may physically regulate the AV shift.

CONCLUSION

Disruption of rightward cushion movement is an initial cue of TA phenotype, and myocardial HEY2/HRT2 is necessary for the regulation of proper alignment of AV endocardial cushion tissue.

Living to Tell the Tale: A First-Person Chronicle of the Development of the Fontan-Kreutzer Procedure

The current surgical approach for patients with a single ventricle is the culmination of decades of dedicated research and groundbreaking innovation. From 1971 to the present day, a series of incremental advancements have significantly extended the life expectancy of these patients. Since the very beginning, Dr Guillermo Kreutzer and his team have pioneered different techniques with the ultimate goal of improving outcomes for these individuals. This is, narrated by him, the story of how it all began.

Postmortem magnetic resonance imaging findings of tricuspid atresia with ventricular and atrial septal defects and subvalvular pulmonic stenosis in a Japanese native Noma horse

The necropsy of a 2-day-old Noma horse that died of weakness showed an enlarged cardiac base and a narrow cardiac apex, suggesting cardiac malformation. The excised heart underwent imaging to investigate its luminal structure. On three-dimensional magnetic resonance imaging, the right atrium and right ventricle were discontinuous. The right atrium communicated with the left atrium and the left ventricle communicated with the right ventricle. The lumen narrowed near the pulmonary artery valve. Since the same findings were observed on gross examination, the foal was diagnosed with tricuspid atresia with ventricular and atrial septal defects, along with subvalvular pulmonic stenosis.

The prognostic role of liver volumetry in Fontan patients

BACKGROUND AND HYPOTHESES

High venous pressures and associated hepatic congestion are important drivers for Fontan-associated liver disease. The prognostic significance of hepatomegaly as a marker of congestion however is not well defined and is further explored in this research study.

METHODS

Fontan patients who have had liver ultrasound scans were identified from the Prince Sultan Cardiac Centre Fontan Database and had their anatomic, surgical, clinical histories abstracted from the electronic medical records following institutional ethics approval. Liver volumes were determined retrospectively from reviewing individual US images, and these, divided into tertiles, were analysed in the context of the predefined endpoints of (i) Primary - death or heart or liver transplantation, or (ii) Secondary - combined endpoint of death, transplantation, arrhythmia, or protein-losing enteropathy.

RESULTS

Mean indexed liver volumes for the entire cohort (n = 199) were 1065.1 ± 312.1 ml/m2, range 387 to 2071 ml/m2. Patients with the largest liver volumes (highest tertile) were less likely to have a functioning fenestration compared to those in the lowest tertile 44% versus 56% p = 0.016 and experienced the highest burden of mortality and heart or heart-liver transplantation, p = 0.016, and were more likely to reach the composite endpoint of death, protein-losing enteropathy, arrhythmia, or transplantation, p = 0.010. Liver volumes had an overall predictive accuracy for the combined outcome of 61% (CI 53%, 67%, p = 0.009).

CONCLUSIONS

Liver volumetry may serve as a potentially important congestion biomarker for adverse outcomes after the Fontan operation.

Combined tricuspid atresia- AV septal defect-a rare congenital cardiac abnormality

INTRODUCTION

Congenital heart diseases (CHDs) are one of the most common birth defects worldwide with a prevalence of 1%. CHDs can be classified into cyanotic and acyanotic diseases based on the presence or absence of the characteristic bluish discoloration of skin and mucus membranes. A subset of cyanotic diseases is single ventricle malformations. This group of disorders comprises 1% of all CHDs. A remarkable yet rare and underreported entity of single ventricle malformations is combined tricuspid atresia (TA) and atrioventricular (AV) septal defect which is characterized by the anatomical features of both entities. Combined TA-AV septal malformation was first anatomically described in 1953 and further explored through echocardiography and cardiac catheterization in 1987 and then 1991. Since then, no studies have been documented in the literature prompting us to share our findings.

METHODS

Herein we are describing a rare and underreported cardiac lesion based of a retrospective revision of medical charts at the American University of Beirut Medical Center (AUBMC) Children's Heart Center, a tertiary medical center in the Middle East RESULTS: Out of 200 cases with confirmed single ventricle physiology, we identified a few patients with characteristics of combined TA-AV septal defect. Our patients exhibited characteristic echocardiographic findings of primum ASD, VSD, atretic RAVV, and clefted LAVV.

CONCLUSION

In short, TA-AV septal defect is a rare, underreported congenital malformation. Tracking our patients' clinical profiles will help improve our understanding of the prognosis of this entity. Our findings may also improve treatment modalities since replacing the left-sided valve is often overlooked if the defect is inaccurately diagnosed. In addition, such findings can help shed light on the embryological development of the rarely encountered variation of AV septal malformation.

Comparing palliation strategies for single-ventricle anatomy with transposed great arteries and systemic outflow obstruction

Objective

Patients with complex single-ventricle anatomy with transposed great arteries and systemic outflow obstruction (SV-TGA-SOO) undergo varied initial palliation with ultimate goal of Fontan circulation. We examine a longitudinal experience with multiple techniques, including the largest published cohort following palliative arterial switch operation (pASO), to describe outcomes and decision-making factors.

Methods

Neonates with SV-TGA-SOO who underwent initial surgical palliation from 1995 to 2022 at a single institution were retrospectively reviewed.

Results

In total, 71 neonates with SV-TGA-SOO underwent index surgical palliation at a median age of 7 days (interquartile range, 6-10) by pASO (n = 23), pulmonary artery band (PAB) with or without arch repair (n = 25), or modified Norwood with Damus-Kaye-Stansel aortopulmonary amalgamation (n = 23). Single-ventricle pathology included double-inlet left ventricle (n = 37, 52%), tricuspid atresia (n = 27, 38%), and others (n = 7, 10%). All mortalities (n = 5, 7%) occurred in the first interstage period after PAB (n = 3) and Norwood (n = 2). Subaortic obstruction in the PAB group was addressed by operative resection (n = 10 total, 7 at index operation) and/or delayed aortopulmonary amalgamation (n = 13, 52%). Two patients with pASO (9%) had early postoperative coronary complications, 1 requiring operative revision. Median follow-up for survivors was 10.4 years (interquartile range, 4.5-16.6 years). Comparing patients by their initial palliation type, notable significant differences included size of bulboventricular foramen, weight at initial operation, operation duration, postoperative length of stay, time to second-stage palliation, multiple pulmonary artery reinterventions, and left pulmonary artery interventions. There were no significant differences in overall survival, Fontan completion, reintervention-free survival in the first interstage period, pulmonary artery reintervention-free survival, long-term systemic valve competency, or ventricular dysfunction.

Conclusions

Excellent mid- to long-term outcomes are achievable following neonatal palliation for SV-TGA-SOO via pASO, PAB, and modified Norwood, with comparable survival and Fontan completion. Initial palliation strategy should be individualized to optimize anatomy and physiology for successful Fontan by ensuring an unobstructed subaortic pathway and accessible pulmonary arteries. pASO is a reasonable strategy to consider for these heterogeneous lesions.

Endocardial pacing in a single-ventricle patient with tricuspid atresia-a case report

Key Clinical Message

The use of endocardial pacing in patients with univentricular hearts and intracardiac shunts is limited, primarily due to the increased risk of thromboembolism. However, when accompanied by proper long-term anticoagulation therapy, it may be safer than epicardial interventions in selected patients at high risk for surgery.

Abstract

We report transvenous endocardial pacing through the atrial septal defect in a patient with tricuspid atresia, transposition of the great arteries, severe pulmonary hypertension, and complete heart block. This study is among the first reported cases using this pacing method in a patient with a univentricular heart and intracardiac shunt.

Comparison of cardiac function between single left ventricle and tricuspid atresia: assessment using echocardiography combined with computational fluid dynamics

Patients with single left ventricle (SLV) and tricuspid atresia (TA) have impaired systolic and diastolic function. However, there are few comparative studies among patients with SLV, TA and children without heart disease. The current study includes 15 children in each group. The parameters measured by two-dimensional echocardiography, three-dimensional speckle tracking echocardiography (3DSTE), and vortexes calculated by computational fluid dynamics were compared among these three groups. Twist is best correlated with ejection fraction measured by 3DSTE. Twist, torsion, apical rotation, average radial strain, peak velocity of systolic wave in left lateral wall by tissue Doppler imaging (sL), and myocardial performance index are better in the TA group than those in the SLV group. sL by tissue Doppler imaging in the TA group are even higher than those in the Control group. In patients with SLV, blood flow spreads out in a fan-shaped manner and forms two small vortices. In the TA group, the main vortex is similar to the one in a normal LV chamber, but smaller. The vortex rings during diastolic phase are incomplete in the SLV and TA groups. In summary, patients with SLV or TA have impaired systolic and diastolic function. Patients with SLV had poorer cardiac function than those with TA due to less compensation and more disordered streamline. Twist may be good indicator for LV function.

Tricuspid atresia 1c accompanying neonatal encephalopathy treated with pulmonary trunk banding and therapeutic hypothermia

The influence of therapeutic hypothermia, known to improve neurodevelopmental outcomes in neonatal encephalopathy, remains unknown in newborns with severe congenital heart diseases. We report a neonate with tricuspid atresia type 1c suffering from moderate neonatal encephalopathy. A burst suppression pattern on amplitude-integrated electroencephalography recovered after inducing moderate therapeutic hypothermia, but exacerbated pulmonary overcirculation still persisted even after the rewarming. Since the medical treatment for pulmonary overcirculation had reached the limit, semi-urgent pulmonary trunk banding was performed on the 4th day of life. Postoperative brain magnetic resonance imaging showed no apparent brain injuries; the patient was discharged uneventfully. We share our perioperative management experience of a patient with tricuspid atresia type Ic who required therapeutic hypothermia for neonatal encephalopathy.

Monochorionic Twin Discordance for Horseshoe Lung and Tricuspid Atresia

Background: The horseshoe lung is a congenital malformation in which the bases of the right and the left lung are fused. Case report: We describe a monochorionic twin gestation with malformation discordance. The abnormal twin had a horseshoe lung with hypoplasia of the right lung, tricuspid atresia, cleft lip, and a pelvic right kidney. Conclusion: The discordance of anomalies in this monochorionic twin suggests that a postzygotic mutation, epigenetic change, or environmental factors may be responsible for these malformations.

Fontan operation for tricuspid atresia with absent pulmonary valve: a case series

Combined tricuspid atresia and absent pulmonary valve with dysplasia of the right ventricular myocardium is a very rare congenital heart anomaly with a poor prognosis. We present three cases of this rare disease that reached the Fontan operation without prior surgical intervention of the right ventricle or pulmonary artery; no right ventriclar dilation was detected. All patients had uneventful post-operative courses.

Common Arterial Trunk Associated with Functionally Univentricular Heart: Anatomical Study and Review of the Literature

Common arterial trunk (CAT) is a rare congenital heart disease that is commonly included into the spectrum of conotruncal heart defects. CAT is rarely associated with functionally univentricular hearts, and only few cases have been described so far. Here, we describe the anatomical characteristics of CAT associated with a univentricular heart diagnosed in children and fetuses referred to our institution, and we completed the anatomical description of this rare condition through an extensive review of the literature. The complete cohort ultimately gathered 32 cases described in the literature completed by seven cases from our unit (seven fetuses and one child). Four types of univentricular hearts associated with CAT were observed: tricuspid atresia or hypoplastic right ventricle in 16 cases, mitral atresia or hypoplastic left ventricle in 12 cases, double-inlet left ventricle in 2 cases, and unbalanced atrioventricular septal defect in 9 cases. Our study questions the diagnosis of CAT as the exclusive consequence of an anomaly of the wedging process, following the convergence between the embryonic atrioventricular canal and the common outflow tract. We confirm that some forms of CAT can be considered to be due to an arrest of cardiac development at the stages preceding the convergence.

Genetic and functional analyses detect one pathological NFATC1 mutation in a Chinese tricuspid atresia family

Background

Cardiac valvulogenesis is a highly conserved process among vertebrates and cause unidirectional flow of blood in the heart. It was precisely regulated by signal pathways such as VEGF, NOTCH, and WNT and transcriptional factors such as TWIST1, TBX20, NFATC1, and SOX9. Tricuspid atresia refers to morphological deficiency of the valve and confined right atrioventricular traffic due to tricuspid maldevelopment, and is one of the most common types of congenital valve defects.

Methods

We recruited a healthy couple with two fetuses aborted due to tricuspid atresia and identified related gene mutations using whole‐exome sequencing. We then discussed the pathogenic significance of this mutation by bioinformatic and functional analyses.

Results

PROVEAN, PolyPhen, MutationTaster, and HOPE indicated the mutation could change the protein function and cause disease; Western blotting showed the expression of NFATC1 c.964G>A mutation was lower than the wild type. What's more, dual‐luciferase reporter assay showed the transcriptional activity of NFATC1 was impact by mutation and the expression of downstream DEGS1 was influenced.

Conclusion

Taken together, the c.964G>A mutation might be pathological and related to the occurrence of disease. Our research tended to deepen the understanding of etiology of tricuspid atresia and gene function of NFATC1, and provide some references or suggestions for genetic diagnosis of tricuspid atresia.

The pulmonary vascular bed in patients with functionally univentricular physiology and a Fontan circulation

Fontan palliation represents one of the most remarkable surgical advances in the management of individuals born with functionally univentricular physiology. The operation secures adult survival for all but a few with unfavourable anatomy and/or physiology. Inherent to the physiology is passive transpulmonary blood flow, which produces a vulnerability to adequate filling of the systemic ventricle at rest and during exertion. Similarly, the upstream effects of passive flow in the lungs are venous congestion and venous hypertension, especially marked during physical activity. The pulmonary vascular bed has emerged as a defining character on the stage of Fontan circulatory behaviour and clinical outcomes. Its pharmacologic regulation and anatomic rehabilitation therefore seem important strategic therapeutic targets. This review seeks to delineate the important aspects of pulmonary artery development and maturation in functionally univentricular physiology patients, pulmonary artery biology, pulmonary vascular reserve with exercise, and pulmonary artery morphologic and pharmacologic rehabilitation.

Transition to Ductal Stenting for Single Ventricle Patients Led to Improved Survival: An Institutional Case Series

BACKGROUND

The use of systemic-to-pulmonary shunts (SPS) in neonates with single ventricle heart defects and ductal-dependent pulmonary blood flow (ddPBF) was historically associated with high morbidity and mortality at our center. As a result, we transitioned to the preferential use of ductus arteriosus stents (DS) when feasible. This report describes our initial results with this strategy.

METHODS

A single-center study of single ventricle patients that received DS or SPS from 2015 to 2019 was performed to assess whether DS was associated with decreased in-hospital morbidity and increased survival to stage II palliation.

RESULTS

A total of 34 patients were included (DS = 11; SPS = 23). Underlying cardiac anomalies were similar between groups and included pulmonary atresia, unbalanced atrioventricular septal defect, and tricuspid atresia. Procedure success was similar between groups (82% vs 83%). Two DS patients were converted to SPS, due to ductal vasospasm or pulmonary artery obstruction, and four SPS patients required surgical shunt revision. In DS patients, postprocedure mechanical ventilation duration was shorter (one vs three days, P = .009) and fewer required postprocedure extracorporeal membrane oxygenation (9% vs 39%, P = .11). A higher proportion of DS patients survived to stage II palliation (100% vs 64%, P = .035), and the probability of one-year survival was higher in DS patients (100% vs 61%, P = .02).

CONCLUSIONS

At our center, patients with single ventricle heart defects and ddPBF that received DS experienced reduced in-hospital morbidity and increased survival to stage II palliation compared to SPS.

A unique arrangement of "kissing" atrial appendages

We report a case of a 2-month-old boy with tricuspid and pulmonary atresia with a unique configuration of "kissing" atrial appendages. The case highlights the importance of computed tomography angiography in identifying such anomalies associated with complex congenital heart defects.

Single Ventricle-A Comprehensive Review

In this paper, the author enumerates cardiac defects with a functionally single ventricle, summarizes single ventricle physiology, presents a summary of management strategies to address the single ventricle defects, goes over the steps of staged total cavo-pulmonary connection, cites the prevalence of inter-stage mortality, names the causes of inter-stage mortality, discusses strategies to address the inter-stage mortality, reviews post-Fontan issues, and introduces alternative approaches to Fontan circulation.

Factors associated with mortality or transplantation versus Fontan completion after cavopulmonary shunt for patients with tricuspid atresia

OBJECTIVE

Tricuspid atresia with normally related great vessels (TA) is considered the optimal substrate for the Fontan pathway. The factors associated with death or transplantation after cavopulmonary shunt (CPS) are underappreciated. We aimed to determine factors associated with CPS-Fontan interstage death/transplantation versus transition to Fontan in TA.

METHODS

A total of 417 infants younger than 3 months of age with TA were enrolled (January 1999 to February 2020) from 40 institutions into the Congenital Heart Surgeons' Society TA cohort. Parametric competing risk methodology was used to determine factors associated with the competing end points of death/transplantation without Fontan completion, and transition to Fontan.

RESULTS

CPS was performed in 382 patients with TA; of those, 5% died or underwent transplantation without transition to Fontan and 91% transitioned to Fontan by 5 years after CPS. Prenatal diagnosis (hazard ratio [HR], 0.74; P < .001) and pulmonary artery band (PAB) at CPS (HR, 0.50; P < .001) were negatively associated with Fontan completion. Preoperative moderate or greater mitral valve regurgitation (HR, 3.0; P < .001), concomitant mitral valve repair (HR, 11.0; P < .001), PAB at CPS (HR, 3.0; P < .001), postoperative superior vena cava interventions (HR, 9.0; P < .001), and CPS takedown (HR, 40.0; P < .001) were associated with death/transplantation.

CONCLUSIONS

The mortality rate after CPS in patients with TA is notable. Those with preoperative mitral valve regurgitation remain a high-risk group. PAB at the time of CPS being associated with both increased risk of death and decreased Fontan completion may represent a deleterious effect of antegrade pulmonary blood flow in the CPS circulation.

Tricuspid Atresia Type 1B With Persistent Left Superior Vena Cava in a Four-Month-Old Child: An Unusual Combination

Tricuspid atresia (TA) is a rare cyanotic congenital heart disease. A persistent left superior vena cava (LSVC) may be associated with TA. The presence of LSVC raises important considerations for eventual repair, in that it may lead to persistent arterial desaturation even after corrective surgery, if associated with an unroofed coronary sinus. Here, we present the case of a four-month-old child who was diagnosed with TA type 1B, LSVC and a dilated coronary sinus by transthoracic echocardiography.

Exercise Intolerance, Benefits, and Prescription for People Living With a Fontan Circulation: The Fontan Fitness Intervention Trial (F-FIT)-Rationale and Design

Background: Despite developments in surgical techniques and medical care, people with a Fontan circulation still experience long-term complications; non-invasive therapies to optimize the circulation have not been established. Exercise intolerance affects the majority of the population and is associated with worse prognosis. Historically, people living with a Fontan circulation were advised to avoid physical activity, but a small number of heterogenous, predominantly uncontrolled studies have shown that exercise training is safe-and for unique reasons, may even be of heightened importance in the setting of Fontan physiology. The mechanisms underlying improvements in aerobic exercise capacity and the effects of exercise training on circulatory and end-organ function remain incompletely understood. Furthermore, the optimal methods of exercise prescription are poorly characterized. This highlights the need for large, well-designed, multi-center, randomized, controlled trials. Aims and Methods: The Fontan Fitness Intervention Trial (F-FIT)-a phase III clinical trial-aims to optimize exercise prescription and delivery in people with a Fontan circulation. In this multi-center, randomized, controlled study, eligible Fontan participants will be randomized to either a 4-month supervised aerobic and resistance exercise training program of moderate-to-vigorous intensity followed by an 8-month maintenance phase; or usual care (control group). Adolescent and adult (≥16 years) Fontan participants will be randomized to either traditional face-to-face exercise training, telehealth exercise training, or usual care in a three-arm trial with an allocation of 2:2:1 (traditional:telehealth:control). Children (<16 years) will be randomized to either a physical activity and exercise program of moderate-to-vigorous intensity or usual care in a two-arm trial with a 1:1 allocation. The primary outcome is a change in aerobic exercise capacity (peak oxygen uptake) at 4-months. Secondary outcomes include safety, and changes in cardiopulmonary exercise testing measures, peripheral venous pressure, respiratory muscle and lung function, body composition, liver stiffness, neuropsychological and neurocognitive function, physical activity levels, dietary and nutritional status, vascular function, neurohormonal activation, metabolites, cardiac function, quality of life, musculoskeletal fitness, and health care utilization. Outcome measures will be assessed at baseline, 4-months, and 12-months. This manuscript will describe the pathophysiology of exercise intolerance in the Fontan circulation and the rationale and protocol for the F-FIT.

Learning from a case of right ventricular outflow tract stenting in tricuspid atresia with critical pulmonary stenosis

Tricuspid valve atresia with severe pulmonary stenosis is one of the common cyanotic diseases in neonate. Child can succumb due to profound cyanosis and arterial hypoxaemia after closure of patent ductus arteriosus. Evolving procedure of right ventricular outflow tract stenting may be considered as a palliative procedure in such vulnerable group, destined for a later definitive management. The right ventricular outflow tract stenting is described essentially for tetralogy of Fallot physiology with a catheter course across tricuspid valve. We describe a case of successful right ventricular outflow tract stenting in a 5-day-old symptomatic neonate. We discuss the possible routes and the tips to facilitate right ventricular outflow tract stenting in such a case. This happens to be the first reported case description with successful stenting of neonate with tricuspid atresia with critical pulmonic stenosis.

Tricuspid atresia: Where are we now?

Tricuspid atresia (TA) is a complex congenital heart disease that presents with cyanosis in the neonatal period. It is invariably fatal if left untreated and requires multiple stages of palliation. Early recognition and timely surgical intervention are therefore pivotal in the management of these infants. This literature review considers the pathophysiology, presentation, investigations, and classification of TA. Moreover, it discusses the evidence upon which the latest medical and surgical treatments are based, as well as numerous recent case reports. Further work is needed to elucidate the etiology of TA, clarify the role of pharmacotherapy, and optimize the surgical management that these patients receive.

149 Fontan Conversions

Patients with a functionally univentricular heart who have had an atriopulmonary Fontan are at risk for atrial dilatation, atrial arrhythmias, and progressive circulatory failure. Between 1994 and 2018, we performed 149 Fontan conversions with arrhythmia surgery and epicardial pacemaker placement at Ann & Robert H. Lurie Children's Hospital of Chicago. This operation converts the atriopulmonary Fontan to an extracardiac Fontan that improves hemodynamics and controls the atrial arrhythmias. Operative mortality during that time was 2%, and freedom from death or heart transplant at 10 years is 84%. For properly selected patients, Fontan conversion improves both survival and quality of life. Patients with an atriopulmonary Fontan constitute an eroding population, as they face many comorbidities and have a decreased life expectancy without treatment; therefore, all patients with an atriopulmonary Fontan should be evaluated for this procedure.

Surgery of single ventricles in humanitarian practice: surgery for which patients?

OBJECTIVES

To analyse the feasibility and effectiveness in humanitarian practice of surgical management of children with single-ventricle heart condition.

METHODS

Retrospective study of children with a single ventricle, managed by the association Mécénat-Chirurgie Cardiaque since 1996, with long-term follow-up after their return home.

RESULTS

Of the 138 children in our cohort, 119 had one or more surgeries (180 procedures): palliative surgery alone (systemic-pulmonary anastomosis or banding), 41; partial cavo-pulmonary connection, 47; total cavo-pulmonary connection (mean age 8.5 years), 31. Operative mortality is 5.5%. After a mean follow-up of 5.6 years, 18 children (13%) were lost to follow-up. Survival at 10 years is 79% in children receiving surgery (palliative only, 72%; partial cavo-pulmonary connection, 77%; total cavo-pulmonary connection, 97%) versus 29% in children with no surgical intervention. The prognosis is better for tricuspid atresia and double-inlet left ventricle (86 and 83% survival at 10 years) than for double-outlet right ventricle or complete atrio-ventricular canal defect (64 and 68% at 5 years).

CONCLUSION

The surgery of the single ventricle in humanitarian medicine allows a very satisfactory survival after one or more surgeries tending towards a total cavo-pulmonary connection as soon as possible.

Management of Congenital Heart Disease: State of the Art-Part II-Cyanotic Heart Defects

In this review management of the most common cyanotic congenital heart defects (CHDs) was discussed; the management of acyanotic CHD was reviewed in Part I of this series. While the need for intervention in acyanotic CHD is by and large determined by the severity of the lesion, most cyanotic CHDs require intervention, mostly by surgery. Different types of tetralogy of Fallot require different types of total surgical corrective procedures, and some may require initial palliation, mainly by modified Blalock-Taussig shunts. Babies with transposition of the great arteries with an intact ventricular septum as well as those with ventricular septal defects (VSD) need an arterial switch (Jatene) procedure while those with both VSD and pulmonary stenosis should be addressed by Rastelli procedure. These procedures may need to be preceded by prostaglandin infusion and/or balloon atrial septostomy in some babies. Infants with tricuspid atresia require initial palliation either with a modified Blalock-Taussig shunt or banding of the pulmonary artery and subsequent staged Fontan (bidirectional Glenn and fenestrated Fontan with extra-cardiac conduit). Neonates with total anomalous pulmonary venous connection are managed by anastomosis of the common pulmonary vein with the left atrium either electively in non-obstructed types or as an emergency procedure in the obstructed types. Babies with truncus arteriosus are treated by surgical closure of VSD along with right ventricle to pulmonary artery conduit. The other defects, namely, hypoplastic left heart syndrome, pulmonary atresia with intact ventricular septum, double-outlet right ventricle, double-inlet left ventricle and univentricular hearts largely require multistage surgical correction. The currently existing medical, trans-catheter and surgical techniques to manage cyanotic CHD are safe and effective and can be performed at a relatively low risk.

Surgical and Catheter-Based Reinterventions Are Common in Long-Term Survivors of the Fontan Operation

BACKGROUND

There are limited follow-up studies examining surgical and catheter-based reinterventions in long-term survivors of the Fontan operation.

METHODS AND RESULTS

All 773 patients who underwent Fontan at our institution between 1992 and 2009 were retrospectively reviewed. Current information regarding post-Fontan intervention was available for 70%. By 20 years after Fontan, 65% of patients had experienced either surgical or transcatheter intervention. The median time to first reintervention was 9.8 years. Freedom from reoperation was 69% at 15 years and 63% at 20 years. The most common operations were pacemaker placement and Fontan revision. Risk factors for pacemaker placement included systemic left ventricle (hazard ratio [HR], 2.2; P=0.006) and lateral tunnel Fontan (HR, 4.3; P=0.001). Freedom from interventional catheterization was 53% at 15 years and 50% at 20 years. The most common procedures performed were fenestration closure and pulmonary artery intervention. Catheter intervention for anatomic indications was associated with Fontan after 2002 (HR, 2.1; P=0.007), Norwood operation (HR, 2.3; P=0.001), and longer cardiopulmonary bypass time (HR, 1.1 per 10 minutes; P=0.001). Catheter intervention for physiological indications was associated with prolonged post-Fontan pleural drainage (HR, 4.0; P<0.001) and hypoplastic left heart syndrome (HR, 2.0; P=0.01).

CONCLUSIONS

In this study of Fontan survivors, two thirds of patients required surgical or catheter-based reintervention by 20 years. Families should be counseled that the Fontan is typically not the final stage of single-ventricle palliation.

Respiratory exacerbation in a young adult with cystic fibrosis and tricuspid atresia

Tricuspid atresia (TAt) is a complex congenital heart defect (CHD) characterized by the absence of the tricuspid valve and right ventricular hypoplasia requiring surgery in childhood, the Fontan procedure. We present a case of a 21‐year‐old male with TAt and cystic fibrosis (CF), who underwent a Fontan procedure in childhood, presenting to an adult CF clinic with severe deterioration in his respiratory status and multi‐organ dysfunction associated with CF. This report describes problems associated with the management of a CF respiratory exacerbation and extrapulmonary manifestations of CF in the unique situation of a Fontan circulation, a circulation with absence of a subpulmonary ventricle and pulsatile pulmonary arterial blood flow where maintenance of systemic cardiac output is totally dependent on good respiratory function and low pulmonary artery pressures.

Evaluation of the anatomic and hemodynamic abnormalities in tricuspid atresia before and after surgery using computational fluid dynamics

Analysis of hemodynamics inside tricuspid atresia (TA) chamber is essential to the understanding of TA for optimal treatment. In this study, we introduced a combined computational fluid dynamics (CFD) to simulate blood flow in the left ventricle (LV) to study the diastolic flow changes in TA.Real-time 3-dimentional echocardiography loops (ECHO) were acquired in normal control group, in TA patients before surgery (pre-op group) and after surgery (post-op group). ECHO loops were reconstructed and simulated by CFD, the geometric, volumetric changes, and vortices in the LV were studies and compare among 3 groups.Compared with the control group, pre-op TA patients demonstrated significant LV remodeling, manifesting with smaller LV length, larger diameter, width and spherical index, as well as lager volumes; post-op TA group showed revisions in values of both geometric and volumetric measurements. CDF also demonstrated the abnormality of vortices in the pre-op TA patients and the alteration of existence and measurements of vortex in postoperation group.Echo-based CFD modeling can show the abnormality of TA in both LV geometric, volumetric measurements and intracardiac vortices; and CFD is capable to demonstrate the alterations of LV after Fontan and Glenn surgical procedure.

Cardiac haemangioma associated with a duct-dependent congenital heart disease in a newborn infant

Cardiac haemangiomas are exceedingly rare; however, they can cause significant haemodynamic impairment and disturbances in heart rhythm. Rarely, cardiac tumours may also coexist with congenital heart lesions. We present an extremely unusual case of a cardiac haemangioma in the setting of complex transposition of the great arteries that caused functional tricuspid atresia. To our knowledge, this is the first such case described in the literature.

Absent Pulmonary Valve Syndrome With Tricuspid Atresia, Ventricular Septal Defect, and Aneurysmal Dilated Pulmonary Artery: A Case Report of Successful Fontan Completion

Of the associated cardiac defects with absent pulmonary valve, the combination of tricuspid atresia, ventricular septal defect, and aneurysmal dilatation of the pulmonary arteries is very rare. We report the case of a low-birth-weight girl (2,282 g) with this anomaly, which was prenatally diagnosed. Fontan completion was successfully achieved at 16 months of age, following staged palliative procedures including banding of the main pulmonary trunk and plication of the aneurysmal dilated central pulmonary artery.

Current diagnosis and treatments for critical congenital heart defects

Congenital heart defects (CHD) affect approximately 7% of infants, and account for 3% of all infant deaths. CHD is most often caused by the defects associated with ductus arteriosus, which is a vessel that usually closes shortly after birth. The types of CHD include tetralogy of fallot, hypoplastic left heart syndrome, pulmonary atresia, total anomalous pulmonary venous return, transposition of great arteries, tricuspid atresia and truncus arteriosus. There are some risk factors that can increase the chance of a fetus developing CHD such as prematurity, an existing CHD in a first-degree relative, genetic syndromes, infections in utero, maternal drug consumptions and disorders. CHD is diagnosed is through different techniques including pulse oximetry, echocardiograms and physical exams. In this review, we examined the current incidence of CHD, the risk factors associated with CHD, the current methods of diagnosis and surgical options used to repair the defects.

Limb ischaemia and below-knee amputation following life-saving patent ductus arteriosus stent in a critically ill infant

Limb ischaemia is a rare but catastrophic complication related to cardiac catheterisation. We report an infant weighing 3 kg with unrepaired tricuspid atresia type 1b, small patent ductus arteriosus, and ventricular septal defect presenting with cardiogenic shock owing to progressively reduced pulmonary blood flow from closing ventricular septal defect and patent ductus arteriosus. An emergency palliative ductal stent was successfully placed with marked clinical improvement. However, acute limb ischaemia developed necessitating above-knee amputation, despite medical management and vascular surgery. The cause of limb loss in our patient was catheterisation-related vascular injury causing arterial dissection-arterial thrombosis in the presence of shock and coagulopathy. This report emphasises the complexity in managing limb ischaemia associated with coagulopathy and highlights the importance of early recognition of reduced pulmonary flow in a single ventricle patient. Timely elective placement of a surgical systemic to pulmonary shunt would prevent catastrophic clinical presentation of compromised pulmonary flow and avoid the need for an emergent life-saving intervention and its associated complications.

Tricuspid atresia and pulmonary atresia in a child with Rubinstein-Taybi syndrome

Rubinstein-Taybi syndrome is a well-characterized condition causing distinctive physical characteristics, intellectual disability, and multiple congenital malformations. Cardiac abnormalities are found in a third of individuals with this condition and usually consist of isolated septal defects or patent ductus arteriosus, although more complex congenital lesions have been described. We present the first reported case of tricuspid atresia and pulmonary atresia with hypoplasia of the right ventricle in the setting of Rubenstein-Taybi syndrome.

Perinatal outcome after prenatal diagnosis of single-ventricle cardiac defects

OBJECTIVES

To investigate the perinatal outcome of cases with a prenatal diagnosis of single-ventricle cardiac defects, single ventricle being defined as a dominant right ventricle (RV) or left ventricle (LV), in which biventricular circulation was not possible.

METHODS

We reviewed patients with a prenatal diagnosis of single-ventricle cardiac defects, made at one institution between 1995 and 2008. Cases diagnosed with double-inlet LV, tricuspid atresia, pulmonary atresia with intact ventricular septum and severe RV hypoplasia and those with hypoplastic left heart syndrome (HLHS) were included in the study population. Patients with HLHS were identified prenatally as being standard risk or high risk (HLHS with highly restrictive or intact atrial septum, mitral stenosis with aortic atresia and/or LV coronary artery sinusoids). Patients with an address over 200 miles from the hospital, diagnosed with heterotaxy syndrome or referred for fetal intervention, were excluded.

RESULTS

We identified 312 cases of single-ventricle cardiac defect (208 dominant RV; 104 dominant LV) that were diagnosed prenatally. Most (96%) patients with a dominant RV had HLHS. Among the total 312 cases there were 98 (31%) elective terminations of pregnancy (TOP), 12 (4%) cases of spontaneous fetal demise, 12 (4%) cases lost to prenatal follow-up and 190 (61%) live births. Among the 199 patients that underwent fetal echocardiography before 24 weeks' gestation, there were 97 (49%) cases of elective TOP. There was no difference in prenatal outcome between those with a dominant RV and those with a dominant LV (P = 0.98). Of the 190 live births, five received comfort care. With an average of 7 years' follow-up (to obtain data on the Fontan procedure), transplantation-free survival was lower in those with a dominant RV than in those with a dominant LV (standard-risk HLHS odds ratio (OR), 3.0 (P = 0.01); high-risk HLHS OR, 8.8 (P < 0.001)).

CONCLUSIONS

The prenatal outcome of cases with single-ventricle cardiac defects was similar between those with a dominant RV and those with a dominant LV, however postnatal intermediate-term survival favored those with a dominant LV. High-risk HLHS identified prenatally was associated with the lowest transplantation-free survival.

Canonical wnt signaling regulates atrioventricular junction programming and electrophysiological properties

RATIONALE

Proper patterning of the atrioventricular canal (AVC) is essential for delay of electrical impulses between atria and ventricles, and defects in AVC maturation can result in congenital heart disease.

OBJECTIVE

To determine the role of canonical Wnt signaling in the myocardium during AVC development.

METHODS AND RESULTS

We used a novel allele of β-catenin that preserves β-catenin's cell adhesive functions but disrupts canonical Wnt signaling, allowing us to probe the effects of Wnt loss of function independently. We show that the loss of canonical Wnt signaling in the myocardium results in tricuspid atresia with hypoplastic right ventricle associated with the loss of AVC myocardium. In contrast, ectopic activation of Wnt signaling was sufficient to induce formation of ectopic AV junction-like tissue as assessed by morphology, gene expression, and electrophysiological criteria. Aberrant AVC development can lead to ventricular pre-excitation, a characteristic feature of Wolff-Parkinson-White syndrome. We demonstrate that postnatal activation of Notch signaling downregulates canonical Wnt targets within the AV junction. Stabilization of β-catenin protein levels can rescue Notch-mediated ventricular pre-excitation and dysregulated ion channel gene expression.

CONCLUSIONS

Our data demonstrate that myocardial canonical Wnt signaling is an important regulator of AVC maturation and electric programming upstream of Tbx3. Our data further suggest that ventricular pre-excitation may require both morphological patterning defects, as well as myocardial lineage reprogramming, to allow robust conduction across accessory pathway tissue.

Embolic myocardial infarction in a patient with a Fontan circulation

Coronary artery embolism is an uncommon cause of acute myocardial infarction (MI). We present a patient with pulmonary atresia and severe right heart hypoplasia who underwent a lateral tunnel Fontan procedure in childhood and presented with an acute ST-segment elevation MI at 19 years of age. In addition to the known risk of thrombotic complications associated with a Fontan circulation, potential predisposing factors to thromboembolism in this patient included a right ventricle to left anterior descending coronary connection and a Fontan baffle leak. The patient was treated with device closure of the baffle leak and anticoagulation. This is one of the first reports of an embolic MI in a patient with a Fontan circulation. The optimal method of reducing thromboembolic risk in this patient, and those with a Fontan circulation in general, is complicated and no consensus exists.

The new concept of univentricular heart

The concept of univentricular heart moved from hearts with only one ventricle connected with atria [double inlet ventricle or absent atrioventricular (AV) connection] to hearts not amenable to biventricular repair, namely hearts with two ventricles unable to sustain separately pulmonary and systemic circulations in sequence. In the latter definition, even hearts with one hypoplastic ventricle are considered "functional" univentricular hearts. They include pulmonary/aortic atresia or severe stenosis with hypoplastic ventricle, and rare conditions like huge intramural cardiac tumors and Ebstein anomaly with extreme atrialization of right ventricular cavity. In this setting, the surgical repair is univentricular with "Fontan" operation, bypassing the ventricular mass. In other words, functionally univentricular heart is a condition in which, after surgery, only one ventricle sustain systemic circulation. Univentricular hearts (double inlet or absent AV connection) almost invariably show two ventricular chambers, one main and one accessory, which lacks an inlet portion. The latter is located posteriorly when morphologically left and anteriorly when morphologically right. As far as double inlet left ventricle, this is usually associated with discordant ventriculo-arterial (VA) connection (transposition of the great arteries) and all the blood flow to the aorta, which takes origin from the hypoplastic anterior right ventricle, is ventricular septal defect (bulbo-ventricular foramen) dependent. If restrictive, an aortic arch obstruction may be present. Double inlet left ventricle may be rarely associated with VA concordance (Holmes heart). As far as double inlet right ventricle with posterior hypoplastic left ventricular cavity, ventriculo-arterial connection is usually of double outlet type; thus the term double inlet-outlet right ventricle may be coined. Absent right or left AV connection may develop in the setting of both d- or l-loop, whatever the situs. In this condition, the contra-lateral patent AV valve may be either mitral or tricuspid in terms of morphology and the underlying ventricle (main chamber) either morphologically left or right. Establishing the loop, whatever right or left (also called right or left ventricular topology), is a fundamental step in the segmental-sequential analysis of congenital heart disease.

Treatment of children with protein - losing enteropathy after fontan and other complex congenital heart disease procedures in condition with limited human and technical resources

BACKGROUND

Protein-losing enteropathy (PLE) is a disorder characterized by abnormal and often profound enteric protein loss. It's relatively uncommon complication of Fontan and other complex congenital heart disease (CCHD) procedures. Because of the complexity and rarity of this disease process, the pathogenesis and pathophysiology of protein-losing enteropathy remain poorly understood, and attempts at treatment seldom yield long-term success.

AIM OF PRESENTATION

is to describe single centre experience in diagnosis, evaluation, management and treatment of children with protein-losing enteropathy after Fontan and other CCHD procedures in the current era and in centre with limited human and technical resources, follows with a comprehensive review of protein-losing enteropathy publications, and concludes with suggestions for prevention and treatment.

MATERIAL AND METHODOLOGY

Retrospectively we analyzed patients with CCHD and protein-losing enteropathy in our institution, starting from January 2000 to December 2012. The including criteria were age between two and 17 years, to have a complex congenital heart disease and available complete documentation of cardiac surgery under cardiopulmonary bypass.

RESULTS

Of all patients we evaluated 18 cases with protein-losing enteropathy, aged 6 to 19 years (mean 14±9); there were three children who had undergone screening procedure for D-transposition, one Tetralogy of Fallot, and remaining 14 patients had undergone Fontan procedures; (anatomic diagnosis are: six with tricuspid atresia, seven with d-transposition, double outlet right ventricle and pulmonary atresia and two with hypoplastic left heart syndrome). The diagnosis of protein-losing enteropathy was made at median age of 5.6 years, ranging from 13 months to 15 years. Diagnosis was made using alpha 1-antitrypsin as a gold marker in stool. By physical examination in 14 patients edema was found, in three ascites, and six patients had pleural effusion. Laboratory findings at the time of diagnosis are: abnormal enteric protein loss was documented at the time of diagnosis in all 18 patients. At the time of diagnosis all patients receiving some form of anticoagulation, 17 patients receiving other medication: 17 - diuretics and ACE inhibitors, 12 digoxin, 9 antiarrhytmics. Cross-sectional echocardiography was performed for all patients and different abnormalities were registered. In 14 patients also magnetic resonance was performed. Therapeutic approach was based on the non-specific medication (diet, diuretics, digoxin, ACE inhibitors, and anticoagulants), heparin and corticosteroids therapy. Long-term response to this type of therapy was registered in three patients. Nine patients underwent treatment with heparin and corticosteroids and no one experienced long term benefit. Despite of needs for catheter therapy or surgical intervention in our study, in the absent of technical and human resources now any one had underwent those procedures. Six patients has been transferred abroad and in five of them surgical intervention was perform.

CONCLUSION

Protein-losing enteropathy remains a devastating complication of Fontan procedure and despite in advantages in surgical and medical therapy there is no evidence that protein-losing enteropathy is less common in the current area.

Fetal heterotaxy with tricuspid atresia, pulmonary atresia, and isomerism of the right atrial appendages at 22 weeks

We report the accurate prenatal diagnosis at 22 weeks gestation of right atrial isomerism in association with tricuspid atresia. Several distinctive sonographic features of isomerism of the right atrial appendages were present in this fetus: complex cardiac abnormality, ventriculoarterial discordance, juxtaposition of the aorta and the inferior vena cava to the right side, pulmonary atresia, and anomalous pulmonary venous return to the morphological right atrium. Tricuspid atresia, which is an extremely rare lesion within heterotaxy spectrum disorders, was present. Postnatal investigations confirmed all prenatally diagnosed abnormalities, with additional findings of pulmonary atresia with discontinuous pulmonary arteries and bilateral arterial ducts, asplenia, and bilateral eparterial bronchi. To our knowledge, tricuspid atresia in the setting of isomerism of the right atrial appendages has not previously been diagnosed or reported prenatally. Because of the complexity of cardiac lesions that may be present in cases of atrial isomerism, these disorders should be considered even if sonographic findings are uncommon or atypical.

Transvenous right atrial and left ventricular pacing after the Fontan operation: long-term hemodynamic and electrophysiologic benefit of early atrioventricular resynchronization

We report a case of long-term, successful, endocardial atrioventricular pacing in a 32-year-old man who had severe heart failure and ascites after having undergone a Fontan procedure for tricuspid atresia 9 years earlier. The patient was referred to our hospital for Fontan revision. However, electroanatomic mapping of the right atrium revealed viable tissue at the interatrial septum above the os of the coronary sinus, and it appeared that the left ventricle could be paced from a coronary sinus branch. Therefore, instead of Fontan revision, an endocardial atrioventricular pacemaker was implanted transvenously. On 5-year follow-up, the patient remained in New York Heart Association functional class I and had not been readmitted to the hospital for congestive heart failure or arrhythmias. His atrial and ventricular leads continued to show excellent pacing and sensing results.

Recent modifications of the fontan procedure for complex congenital heart disease

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Pseudo-preexcitation in tricuspid atresia

Because we have observed a relatively large number of tricuspid atresia patients with a short P-R interval and slurring of the initial QRS pattern suggesting preexcitation, we conducted a retrospective study to determine the frequency of this electrocardiographic pattern and whether or not this represented the presence of a true atrioventricular bypass tract. Three pediatric cardiologists reviewed the surface electrocardiograms of 183 consecutive tricuspid atresia patients who had been evaluated at the Mayo Clinic between 1980 and 1986. The patients' ages ranged from 4 months to 21 years; the male-to-female ratio was 5:4. The criteria for preexcitation included 1) a P-R segment <0.10 sec, 2) a QRS complex >0.10 sec, and 3) slurring of the upstroke of the QRS complex ("delta wave"). Of the 183 patients, 22 (12%) had P-R segments <0.10 sec, 9 of whom fulfilled the criteria for preexcitation. Five of these had a history of supraventricular tachycardia, and 4 of the 5 had undergone invasive electrophysiologic studies: 2 had enhanced atrioventricular-nodal conduction and 1 had normal atrioventricular-nodal conduction; only 1 had an accessory pathway. Our results indicate that, although many patients with tricuspid atresia meet the surface electrocardiographic criteria for preexcitation, many of these patients may not have an atrioventricular bypass tract; this state might be termed "pseudo-preexcitation." In these instances, invasive studies probably would not be necessary; regrettably, it may be difficult to distinguish between the presence and the absence of preexcitation in such patients without invasive electrophysiologic studies.