Role and Applications of Experimental Animal Models of Fontan Circulation.

Over the last four decades, the Fontan operation has been the treatment of choice for children born with complex congenital heart diseases and a single-ventricle physiology. However, therapeutic options remain limited and despite ongoing improvements in initial surgical repair, patients still experience a multiplicity of cardiovascular complications. The causes for cardiovascular failure are multifactorial and include systemic ventricular dysfunction, pulmonary vascular resistance, atrioventricular valve regurgitation, arrhythmia, development of collaterals, protein-losing enteropathy, hepatic dysfunction, and plastic bronchitis, among others. The mechanisms leading to these late complications remain to be fully elucidated. Experimental animal models have been developed as preclinical steps that enable a better understanding of the underlying pathophysiology. They furthermore play a key role in the evaluation of the efficacy and safety of new medical devices prior to their use in human clinical studies. However, these experimental models have several limitations. In this review, we aim to provide an overview of the evolution and progress of the various types of experimental animal models used in the Fontan procedure published to date in the literature. A special focus is placed on experimental studies performed on animal models of the Fontan procedure with or without mechanical circulatory support as well as a description of their impact in the evolution of the Fontan design. We also highlight the contribution of animal models to our understanding of the pathophysiology and assess forthcoming developments that may improve the contribution of animal models for the testing of new therapeutic solutions.

Risk of infective endocarditis after hybrid melody mitral valve replacement in infants: the French experience.

OBJECTIVES: Surgical management of mitral valve disease is challenging in infants <1 year old. We aimed at reviewing the French experience with Melody mitral valve replacement in critically ill infants. METHODS: A retrospective cohort study reporting the French experience with Melody mitral valve replacement. RESULTS: Seven symptomatic infants [complete atrioventricular septal defect (n = 4, Down syndrome: n = 3), hammock valve (n = 3)] underwent Melody mitral valve replacement [age: 3 months (28 days to 8 months), weight: 4.3 kg (3.2-6.4 kg)] because of severe mitral valve regurgitation (6) or mixed valve disease (1) and 14 mm (11-16 mm) mitral valve annulus. In 2 patients whose valve was felt irreparable, Melody mitral valve replacement was performed straightaway. The others underwent 2 (1-3) previous attempts of valve repair; 3 were on extracorporeal membrane oxygenation. Melody mitral valve replacement led to competent valve and low gradient [3 mmHg, (1-4 mmHg)]. One patient died 3 days post-implant from extracorporeal membrane oxygenation-related stroke. Of the 6 discharged home patients, 3 (50%) were readmitted for a definite diagnosis (1) or high suspicion (2) of infective endocarditis, of which 2 died. Over the follow-up, 1 underwent balloon expansions of the valve at 9- and 16-months post-implant, and mechanical mitral valve replacement at 2 years; another is currently planned for transcatheter Melody valve dilation. CONCLUSIONS: Melody mitral valve replacement may be considered in selected infants with small mitral valve annulus as an alternative to mechanical mitral valve replacement. Our experience highlights a high-risk of late infective endocarditis that deserves further consideration.

The Ross Operation in Young Patients: A 15-Year Experience Focused on Right Ventricle to Pulmonary Artery Conduit Outcomes.

Background: Data on long-term outcomes of the Ross operation in children and young adult patients are limited. The best pulmonary valve substitute for the right ventricular outflow tract reconstruction remains uncertain. This study aimed to assess the outcomes of right ventricular outflow tract reconstruction in the Ross operation in young patients using various pulmonary valve substitutes at a single institution. In addition, a comparison of reintervention rates between patients younger than 18 years and those older than 18 years was performed. Methods: The study assessed all patients (N = 110) who underwent the Ross operation at the University Hospital of Bordeaux, France, between 2004 and 2020. Results: The median follow-up time was 4.2 years, and the median age at operation was 15.9 years. There was no operative mortality and 1 late noncardiac death (0.8%). The overall survival rate at 10 years was 99.2%. The need for right ventricular outflow tract reoperation was lower with the pulmonary homograft compared with the Contegra conduit and Freestyle bioprosthesis: 94.3%, 93.8%, and 80% at 5 years, respectively, and 94.3%, 72.3%, and 34.3% at 10 years, respectively (P = 0.011). The probability of reintervention was not significantly different at 10 years among children vs adults (P = 0.22). Conclusions: The Ross procedure in children and young adults was associated with a lower requirement for right ventricular outflow tract reoperation when pulmonary homografts were used instead of xenografts.

Contexte: Il existe peu de données sur les résultats à long terme de l'intervention de Ross chez les enfants et chez les jeunes adultes. Par ailleurs, des doutes persistent quant au meilleur substitut pour remplacer la valve pulmonaire lors de la reconstruction de la voie d'éjection du ventricule droit. Notre étude visait à mesurer les résultats de la reconstruction de la voie d'éjection du ventricule droit après l'intervention de Ross chez de jeunes patients d'un même établissement chez qui différents substituts valvulaires ont été utilisés. De plus, le taux de réintervention chez les patients âgés de moins de 18 ans et celui chez les patients âgés de 18 ou plus ont été comparés. Méthodologie: Notre étude portait sur tous les patients (N = 110) ayant subi une intervention de Ross au Centre Universitaire de Bordeaux (France) entre 2004 et 2020. Résultats: La durée médiane du suivi a été de 4,2 années, et l'âge médian au moment de l'intervention chirurgicale était de 15,9 ans. Aucun décès précoce n'a été constaté au terme de l'intervention, mais un décès de cause non cardiaque est survenu ultérieurement (0,8 %). Le taux global de survie à 10 ans était de 99,2 %. La réintervention chirurgicale au niveau de la voie d'éjection du ventricule droit a été nécessaire moins fréquemment chez les patients ayant reçu une homogreffe que chez les patients ayant reçu un conduit Contegra ou une bioprothèse Freestyle : les taux sans réintervention s'élevaient respectivement à 94,3 %, 93,8 % et 80 % à 5 ans, et à 94,3 %, 72,3 % et 34,3 % à 10 ans (p = 0,011). En outre, les probabilités de réintervention chirurgicale chez les enfants et chez les adultes ne différaient pas de façon significative à 10 ans (p = 0,22). Conclusions: Le recours à des homogreffes pulmonaires plutôt qu'à des xénogreffes au cours des interventions de Ross pratiquées chez les enfants et les jeunes adultes est associé à un plus faible taux de réintervention.

Development and characterization of biological sutures made of cell-assembled extracellular matrix.

Most vascular surgical repair procedures, such as vessel anastomoses, requires using suture materials that are mechanically efficient and accepted by the patient's body. These materials are essentially composed of synthetic polymers, such as polypropylene (ProleneTM) or polyglactin (VicrylTM). However, once implanted in patients, they are recognized as foreign bodies, and the patient's immune system will degrade, encapsulate, or even expel them. In this study, we developed innovative biological sutures for cardiovascular surgical repairs using Cell-Assembled extracellular Matrix (CAM)-based ribbons. After a mechanical characterization of the CAM-based ribbons, sutures were made with hydrated or twisted/dried ribbons with an initial width of 2 or 3 mm. These biological sutures were mechanically characterized and used to anastomoseex vivoanimal aortas. Data showed that our biological sutures display lower permeability and higher burst resistance than standard ProleneTMsuture material.In vivocarotid anastomoses realized in sheep demonstrated that our biological sutures are compatible with standard vascular surgery techniques. Echography confirmed the absence of thrombus and perfect homeostasis with no blood leakage was obtained within the first 10 min after closing the anastomosis. Finally, our findings confirmed the effectiveness and clinical relevance of these innovative biological sutures.

Electrophysiological study prior to planned pulmonary valve replacement in patients with repaired tetralogy of Fallot.

AIM: Ventricular arrhythmias (VAs) are the most common cause of death in patients with repaired Tetralogy of Fallot (rTOF). However, risk stratifying remains challenging. We examined outcomes following programmed ventricular stimulation (PVS) with or without subsequent ablation in patients with rTOF planned for pulmonary valve replacement (PVR). METHODS: We included all consecutive patients with rTOF referred to our institution from 2010 to 2018 aged ≥18 years for PVR. Right ventricular (RV) voltage maps were acquired and PVS was performed from two different sites at baseline, and if non-inducible under isoproterenol. Catheter and/or surgical ablation was performed when patients were inducible or when slow conduction was present in anatomical isthmuses (AIs). Postablation PVS was undertaken to guide implantable cardioverter-defibrillator (ICD) implantation. RESULTS: Seventy-seven patients (36.2 ± 14.3 years old, 71% male) were included. Eighteen were inducible. In 28 patients (17 inducible, 11 non-inducible but with slow conduction) ablation was performed. Five had catheter ablation, surgical cryoablation in 9, both techniques in 14. ICDs were implanted in five patients. During a follow-up of 74 ± 40 months, no sudden cardiac death occurred. Three patients experienced sustained VAs, all were inducible during the initial EP study. Two of them had an ICD (low ejection fraction for one and important risk factor for arrhythmia for the second). No VAs were reported in the non-inducible group (p < .001). CONCLUSION: Preoperative EPS can help identifying patients with rTOF at risk for VAs, providing an opportunity for targeted ablation and may improve decision-making regarding ICD implantation.

Correlation between three-dimensional echocardiography and cardiopulmonary fitness in patients with univentricular heart: A cross-sectional multicentre prospective study.

BACKGROUND: The prognosis of patients with a functional single ventricle has improved, with better cardiopulmonary fitness, health-related quality of life and survival. Conventional echocardiography remains the first-line technique in single ventricle follow-up. Three-dimensional (3D) echocardiography has shown recent value in congenital cardiology, but its ability to predict functional status in patients with a single ventricle remains unknown. AIM: To evaluate, in patients with a single ventricle, the association between 3D echocardiography variables and functional status determined by cardiopulmonary fitness. METHODS: Children and adults with a functional single ventricle were prospectively enrolled in this multicentre study. Cardiopulmonary fitness was assessed by cardiopulmonary exercise test, with measures of maximum oxygen uptake (VO2max) and ventilatory efficiency (VE/VCO2 slope). 3D echocardiography was performed with off-line reproducibility analyses, using TomTec Arena™ software. Health-related quality of life was assessed using the SF-36 questionnaire. RESULTS: A total of 33 patients were screened, and 3D echocardiography analyses were feasible in 22 subjects (mean age 28±9years). 3D echocardiography ejection fraction correlated with percent-predicted VO2max (r=0.64, P<0.01), VE/VCO2 slope (r=-0.41, P=0.05), two-dimensional echocardiography ejection fraction (r=0.55, P<0.01) and health-related quality of life physical functioning dimension (r=0.56, P=0.04). 3D echocardiography indexed end-systolic volume correlated with percent-predicted VO2max (r=-0.45, P=0.03) and VE/VCO2 slope (r=0.65, P<0.01). 3D echocardiography reproducibility was good. CONCLUSIONS: Single ventricle ejection fraction and volumes measured by 3D echocardiography correlated with cardiopulmonary fitness, as determined by two main prognostic cardiopulmonary exercise test variables: VO2max and VE/VCO2 slope. Despite good reproducibility, 3D echocardiography feasibility remained limited. 3D echocardiography may be of value in single ventricle follow-up, provided that the technique and analysis software are improved.

Outcomes Following Closure of Secundum Atrial Septal Defect in Children ≤ 15 kg in a French Tertiary Centre.

Secundum atrial septal defects (sASDs) are common congenital cardiac defects mostly treated using a transcatheter approach. However, small children (<15 kg) are still undergoing surgical sASD closure in many centres. Although both options have been proved to have excellent results in children, comparative data of the two techniques are missing for patients ≤ 15 kg. The medical records of children ≤ 15 kg who underwent sASD surgical (group A) and transcatheter (group B) closure between 2010 and 2023 were reviewed retrospectively. Twenty-five children in group A and twenty-two in group B were included (mean weight 8.9 kg in group A and 10.3 kg in group B). The main indications for closure were right heart enlargement and failure to thrive. Major complications occurred in two patients in group A and none in group B. Minor complications occurred in eight patients in group A and one in group B. At last follow-up, symptoms resolved completely or improved significantly for all infants, with the exception of failure to thrive in the sub-population of children with extra-cardiac comorbidities. sASD closure can be performed safely in symptomatic infants ≤ 15 kg, even in the presence of comorbidity, and should not be postponed. However, in patients with extra-cardiac comorbidities, the only indication of growth retardation must be carefully evaluated.

Berlin Heart EXCOR Paediatric Ventricular Assist Device: Does Weight Matter?

BACKGROUND: Berlin Heart EXCOR (BH) ventricular assist devices provide mechanical long-term circulatory support in children with end-stage heart failure, as a bridge to transplantation or to recovery. Most studies are from large-volume paediatric cardiac centres. AIM: The aim of this study was to analyse the experiences of three French centres and to compare these with available published data. METHOD: We performed a retrospective observational study of three paediatric cardiac intensive care units. All children supported with BH devices were included. Morbidity and mortality data were collected and risk factors analysed. RESULTS: Fifty-four (54) patients (54% male) were included. Survival rate was 73% while on a BH device. Median age at BH device implantation was 17 months (range 2-180 months). The predominant indication was dilated cardiomyopathy (61%). Bi-ventricular assist device was used in 25 (46%) cases. The total length of long-term circulatory support was 3,373 days, with a mean length per patient of 62.5 days (range 5-267 days). Thirty-two (32) patients were transplanted (59%) and seven (13%) were successfully weaned. Type and length of support did not influence morbidity. Main complications were renal dysfunction (57%), bleeding (41%), and infection (39%). In multivariate analysis, a weight <5 kg was significantly associated with higher mortality. CONCLUSIONS: The weight seems to be the most important risk factor of mortality in this precarious condition.

Anomalous left coronary artery from the pulmonary artery: modified extra-anatomic reimplantation.

The anomalous origin of the left coronary artery from the pulmonary artery in the position of a non-facing coronary sinus is extremely rare. The anatomical position of the ectopic ostia will determine which is the appropriate operative approach to create a dual-coronary supply. This report describes a technique of modified extra-anatomical rerouting using autologous pericardium patch and pulmonary artery flap to create a neo-composite coronary trunk passing anterior to the right ventricular outflow tract.

Heart rate response during exercise predicts exercise tolerance in adults with transposition of the great arteries and atrial switch operation.

BACKGROUND: To assess the relationship between heart rate response and exercise tolerance in adults with systemic right ventricle (sRV) after atrial switch repair for Transposition of the Great Artery (TGA) in addition to other physiological parameters. METHODS: All patients with a sRV after atrial switch repair for TGA followed in our institution between June 2015 and April 2018 who underwent cardiopulmonary exercise testing (CPET) were analyzed. Cardiac imaging performed within a six-month time period of the CPET were also collected. Chronotropic incompetence was defined as the inability to achieve 80% of age-predicted maximal heart rate reserve (HRR) and <62% on a beta-blocker regimen. Patient characteristics were assessed according to tertiles of the percentage of predicted pVO2 (%ppVO2). RESULTS: We studied 70 patients (mean of age 32.4 ±â€¯7.6 years old, 51 males). Mean peak oxygen uptake was 21.5 ±â€¯5.8 mL/kg/min, corresponding to a %ppVO2 of 57 ±â€¯14.1% while mean VE/VCO2 slope was 37.1 ±â€¯8.2. There was a trend toward more exaggerated hyperventilation in patient with lower pVO2. Mean age-adjusted HRR was 68.5 ±â€¯19%. Chronotropic incompetence was observed in 65.7% and was correlated with %ppVO2 (r = 0.482; p < 0.001) as physical training evaluated with Ventilatory Anaerobic threshold (r = 0.571; p < 0.001), while no difference was found based on respiratory parameters. No echocardiographic or Magnetic Resonance Imaging parameters assessing sRV systolic function at rest were correlated with %ppVO2. CONCLUSIONS: Exercise limitation is related to the inability to increase cardiac output during exercise and is notably due to the degree of chronotropic incompetence.

Animal Models of Repaired Tetralogy of Fallot: Current Applications and Future Perspectives.

Tetralogy of Fallot is the most common cyanotic congenital heart disease. Despite ongoing improvements in the initial surgical repair, there are lingering concerns regarding the long-term outcomes that may be complicated by right ventricular dysfunction, right ventricular dyssynchrony, and sudden cardiac death. The mechanisms leading to these late complications remain incompletely understood. Experimental animal models have been developed as preclinical steps to gain better insight into the pathophysiology of diseases and to develop new therapeutic strategies. This article summarizes the various types of experimental animal models of repaired tetralogy of Fallot published to date in the literature, with the aim of achieving a greater understanding of the deleterious mechanisms that may lead to these known late and sometimes lethal complications. In addition to analysing the type of animals that can be used according to a given study's objectives, needs, and constraints, the present review also evaluates the type of dysfunction that can be reproduced in our model according to the research objectives, as well as the different types of studies in which these models can be used. In view of all that, we propose a decision algorithm to create an animal model of repaired tetralogy of Fallot. This synthesis should furthermore help in the development of future studies and in the design of new experimental models, thus allowing greater insight into this disease, while not forgetting the ultimate goal of broadening future therapeutic measures to reduce the morbidity and mortality of this prevalent congenital heart disease.

Anatomic Repair of a Left Coronary Artery Main Stem Atresia.

Atresia of the main stem of the left coronary artery is the least observed congenital coronary anomaly; most patients tend to receive a coronary artery bypass graft, although some anatomical corrections have been described. A 17-year-old female patient with left coronary artery main stem atresia underwent a coronary trunk construction with an autologous pericardial patch in our department. At a 3-year follow-up, the patient was asymptomatic, with a normal cardiac stress test. The coronary computed tomography showed no stenosis between the aorta and coronary bifurcation. Long-term patency has yet to be determined.

Predictive factors for residual hypertension following aortic coarctation stenting.

Native coarctation of the aorta (CoA) and recoarctation (reCoA) after initial surgical repair are frequently associated with hypertension (HT). Most CoA cases are amenable to transcatheter balloon angioplasty with stent implantation; however, the impact of stenting on arterial blood pressure (BP) is variable. We carried out a retrospective study to identify the predictive factors for residual HT despite optimal endovascular treatment. Patients who had undergone stent implantation for native CoA or reCoA with a pressure gradient of >20 mm Hg between the upper and lower limbs, between 2007 and 2015, were included. The geometry and level of hypoplasia of the aortic arch were determined by non-invasive imaging, and BP measurements were performed pre- and post-procedure. Thirty consecutive patients (median age: 18.5 years; 76.7% male) were included. Twenty-three patients had HT before the procedure and 14 (46.7%) had post-procedural HT despite optimal endovascular treatment. Residual HT post-stenting was associated with longer stent length and gothic arch geometry. Age and body mass index (BMI) were also associated with residual HT. The pathologic association of abnormal arch geometry and aortic stent placement may lead to a loss of aortic compliance that is further increased by high BMI and older age. Determination of a patient's aortic arch anatomy and clinical profile can assist in defining those at high risk of residual HT despite optimized isthmic stent implantation.

Arrhythmogenic Remodeling of the Left Ventricle in a Porcine Model of Repaired Tetralogy of Fallot.

BACKGROUND: Ventricular arrhythmias are frequent in patients with repaired tetralogy of Fallot (rTOF), but their origin and underlying mechanisms remain unclear. In this study, the involvement of left ventricular (LV) electrical and structural remodeling was assessed in an animal model mimicking rTOF sequelae. METHODS: Piglets underwent a tetralogy of Fallot repair-like surgery (n=6) or were sham operated (Sham, n=5). Twenty-three weeks post-surgery, cardiac function was assessed in vivo by magnetic resonance imaging. Electrophysiological properties were characterized by optical mapping. LV fibrosis and connexin-43 localization were assessed on histological sections and protein expression assessed by Western Blot. RESULTS: Right ventricular dysfunction was evident, whereas LV function remained unaltered in rTOF pigs. Optical mapping showed longer action potential duration on the rTOF LV epicardium and endocardium. Epicardial conduction velocity was significantly reduced in the longitudinal direction in rTOF LVs but not in the transverse direction compared with Sham. An elevated collagen content was found in LV basal and apical sections from rTOF pigs. Moreover, a trend for connexin-43 lateralization with no change in protein expression was found in the LV of rTOFs. Finally, rTOF LVs had a lower threshold for arrhythmia induction using incremental pacing protocols. CONCLUSIONS: We found an arrhythmogenic substrate with prolonged heterogeneous action potential duration and reduced conduction velocity in the LV of rTOF pigs. This remodeling precedes LV dysfunction and is likely to contribute to ventricular arrhythmias and sudden cardiac death in patients with rTOF.

Toward the integration of global longitudinal strain analysis in the assessment of neonatal aortic coarctation? A preliminary study.

BACKGROUND: Coarctation of the aorta (CoA) is still challenging to diagnose in neonates with patent ductus arteriosus (PDA). Speckle tracking echocardiography allows reliable analysis of myocardial deformation in newborns and seems to provide important insides into regional changes in patients with left ventricular (LV) outflow tract obstruction. AIMS: To assess the interest of LV global longitudinal strain (GLS) measurement for predicting CoA in neonates with PDA and prenatal suspicion. METHODS: Prospective single-center study. Twenty-two newborns with prenatal suspicion of CoA were included. All newborns were evaluated in the first 12 hours of life. To assess the feasibility and the reproducibility of GLS, 14 healthy full-term newborns with PDA (group 3) were screened. CoA was diagnosed when DA closed, according to usual echocardiographic criteria. RESULTS: Six neonates developed CoA after DA closure (group 1) whereas 16 did not (group 2). Mean gestational age and birth weight were not different between the groups. GLS measurements were possible in 100%. Intra- and inter-observer variability of strain measurements was acceptable. GLS values were significantly lower in neonates who developed CoA (P=0.015). To predict CoA, cut-off value of -17.42% gave the best compromise for sensitivity (83%) and specificity (72%). Aortic arch dimensions were modestly correlated with strain values. The presence of a bicuspid aortic valve was not associated with significant lower GLS values. CONCLUSION: LV GLS analysis is a feasible and reproducible echocardiographic technique in newborns with PDA. Newborns who will develop CoA seem to have lower values of GLS than healthy neonates. Further studies are needed to confirm these preliminary results.

Hybrid Melody Valve Implantation in Mitral Position in a Child: Usefulness of a 3-Dimensional Printed Model for Preprocedural Planning.

We present the case of a 4-month-old child with atrioventricular canal associated with severe left atrioventricular valve dysfunction who previously underwent 3 surgical valve reconstructions without significant improvement. A Hybrid Melody valve (Medtronic, Minneapolis, MN) insertion was planned. Because of the low weight, the risk of left ventricular outflow tract obstruction was significant and therefore evaluated preprocedurally using a cardiac computed tomography-derived 3-dimensional printed model. In vitro tests showed good anchorage of the valve without subaortic obstruction and the procedure was then achieved with an excellent clinical result.

Early to mid-term results after total cavopulmonary connection performed in the second decade of life.

OBJECTIVES: Total cavopulmonary connection (TCPC) performed in the second decade of life has rarely been studied. Thus, we investigated (bicentric study) early and late morbidity and mortality following completion of TCPC in these patients. METHODS: From January 1999 to June 2014, 63 patients (14.5 ± 2.9 years) underwent TCPC (extracardiac conduit). Palliation before completion was an isolated bidirectional cavopulmonary shunt (BCPS) in 3 patients or BCPS associated with additional pulmonary blood flow (APBF) that was either antegrade (Group 1) in 38 (63%) or retrograde (Group 2) in 22 (37%). Preoperative and perioperative data were reviewed retrospectively. RESULTS: Mean pulmonary arterial and ventricular end-diastolic pressures were 12.2 and 9.2 mmHg, respectively. Mean Nakata index was 279 ± 123 and 228 ± 87 mm 2 /m 2 in Groups 1 and 2, respectively ( P = 0.01). Aortic cross-clamping was performed in 22 from Group 1 and 8 from Group 2 ( P = 0.04). Mean follow-up was 4.57 years [0.8-15]. Nine patients had prolonged stays in the intensive care unit (>6 days). There were 1 early and 2 late deaths (non-cardiac related). Actuarial survival was 96% at 4 years. At last follow-up, single-ventricle function remained normal or improved in all patients (Group 1) compared to 82% in Group 2 ( P = 0.02). New York Heart Association (NYHA) class had improved in both groups: 47 patients were NYHA class II and 16 class III preoperatively vs 50 class I and 10 class II postoperatively ( P < 0.001). CONCLUSIONS: Single-ventricle palliation with BCPS and APBF allowed completion of TCPC in the second decade of life, with encouraging mid-term results. However, BCPS with retrograde APBF was associated with single-ventricle dysfunction: thus, this technique needs to be used cautiously as long-lasting palliation.

Tricuspid valve repair and pulmonary valve replacement in adults with repaired tetralogy of Fallot.

BACKGROUND: Pulmonary valve replacement (PVR) often is performed in adults with repaired tetralogy of Fallot (TOF). For patients who have tricuspid regurgitation (TR), tricuspid valve (TV) repair associated to PVR is still debated. OBJECTIVE: We sought to evaluate perioperative factors related to TV repair when performed at the time of PVR in patients with repaired TOF. METHODS: We retrospectively reviewed 104 patients with repaired TOF (or its equivalent) who underwent PVR (2002-2014). RESULTS: Mean age at initial complete correction and at PVR was 20.1 ± 17.2 months and 26.3 ± 9.5 years, respectively. Forty-one patients had significant preoperative TR: 24 were moderate (group M) and 17 were severe (group S). A total of 16 TV repair were performed (8 for each group). Moderate and severe tricuspid regurgitation observed in the first year following the initial complete repair were significantly associated with severe TR at PVR (P < .001). In group M patients, TR was improved regardless of TV repair, whereas, in group S, residual significant TR was reported in 7 patients who did not have TV repair. No cases were observed for patients who underwent concomitant TV repair (P = .002). Among these patients with residual significant TR, 2 needed a tricuspid valve replacement. The functional status (New York Heart Association classification) of group S patients was significantly improved by concomitant TV repair. CONCLUSIONS: In adults with repaired TOF, TV repair is a safe procedure when performed at the time of PVR. If, at mid-term follow-up, there is probably no benefit of TV repair when preoperative TR is moderate, TV repair may improve both tricuspid valve function and functional status of the patients in case of severe preoperative TR.

Proarrhythmic remodelling of the right ventricle in a porcine model of repaired tetralogy of Fallot.

OBJECTIVE: The growing adult population with surgically corrected tetralogy of Fallot (TOF) is at risk of arrhythmias and sudden cardiac death. We sought to investigate the contribution of right ventricular (RV) structural and electrophysiological remodelling to arrhythmia generation in a preclinical animal model of repaired TOF (rTOF). METHODS AND RESULTS: Pigs mimicking rTOF underwent cardiac MRI functional characterisation and presented with pulmonary regurgitation, RV hypertrophy, dilatation and dysfunction compared with Sham-operated animals (Sham). Optical mapping of rTOF RV-perfused wedges revealed a significant prolongation of RV activation time with slower conduction velocities and regions of conduction slowing well beyond the surgical scar. A reduced protein expression and lateralisation of Connexin-43 were identified in rTOF RVs. A remodelling of extracellular matrix-related gene expression and an increase in collagen content that correlated with prolonged RV activation time were also found in these animals. RV action potential duration (APD) was prolonged in the epicardial anterior region at early and late repolarisation level, thus contributing to a greater APD heterogeneity and to altered transmural and anteroposterior APD gradients in rTOF RVs. APD remodelling involved changes in Kv4.3 and MiRP1 expression. Spontaneous arrhythmias were more frequent in rTOF wedges and more complex in the anterior than in the posterior RV. CONCLUSION: Significant remodelling of RV conduction and repolarisation properties was found in pigs with rTOF. This remodelling generates a proarrhythmic substrate likely to facilitate re-entries and to contribute to sudden cardiac death in patients with rTOF.