Pulmonary Valve Research Articles

Novel strategy to preserve valve morphology for 3-dimensional analysis of rat pulmonary valves

Novel strategy to preserve valve morphology for 3-dimensional analysis of rat pulmonary valves

Tetralogy of Fallot in adults.

Following surgical repair in infancy, a high proportion of children born with tetralogy of Fallot are surviving into adulthood, and it is important that these patients are monitored by an adult congenital heart disease specialist for problems and complications that can occur in the adult patient. To provide an overview on the management of adult patients with repaired tetralogy of Fallot and emphasise the need for specialist follow-up. Following surgical repair of tetralogy of Fallot, it is important to have lifelong surveillance in adulthood for complications such as pulmonary valve dysfunction. Modern imaging modalities have helped with monitoring and the early detection of problems. Cardiac surgery has been refined over the years, leading to improved longevity. Over the past 23 years, percutaneous interventions have been developed to deal with valve complications and the results have been promising. Healthy behaviour, such as regular exercise, and behaviours to minimise the risk of endocarditis should be encouraged. Regular follow-up with an adult congenital heart disease specialist is important. Patients wishing to undertake a pregnancy should be supervised through a high-risk pregnancy clinic.

An Incidental Finding of Asymptomatic Quadricuspid Pulmonary Valve at Autopsy: A Case Report and Comprehensive Literature Review

An Incidental Finding of Asymptomatic Quadricuspid Pulmonary Valve at Autopsy: A Case Report and Comprehensive Literature Review

Absent Pulmonary Valve Syndrome with Non-Confluent Branches: Case Report and Literature Review

Absent pulmonary valve syndrome (APVS) is a rare form of congenital heart defect. Among the various variations of this rare anomaly are non-confluent branches of the pulmonary artery (PA) with anomalous origin of one of the PA branches from the patent ductus arteriosus (PDA). Constriction of the PDA in early neonatal age may result in cessation of blood supply to one of the pulmonary artery branches, leading to exclusion of one lung from circulation and gas exchange processes. PDA stenting creates a reliable source of blood flow, and as a first step, an endovascular approach was chosen for treatment. Case report. A newborn (3 kg) with a prenatal diagnosis of APVS and a non-confluent left PA branch filling through PDA was chosen for PDA stenting. Considering the complex anatomy of the heart defect, it was decided to perform PDA stenting to delay total repair until the patient reaches optimal age and weight. Our patient successfully underwent PDA stenting as the first stage, which provided conditions for blood supply to one lung. The second stage involved total repair with good long-term results. Conclusion. APVS treatment may have several options of surgical correction, differing from each other depending on the anatomical features of the defect and the patient’s age. Palliative treatment options help the child transition from the neonatal period and gain optimal weight for total repair.. Analyzing the data from the presented literature, it is noted that prenatal diagnosis is an important stage in determining the urgency and choice of treatment tactics for this defect.

Changes in blood biomarkers correlate with changes in cardiac size and function in patients with tetralogy of Fallot

IntroductionPatients after surgical correction of Tetralogy of Fallot (ToF) often show adverse cardiac remodeling. To better understand the underlying biological processes, we studied the relation between changes in blood biomarkers and changes in biventricular size and function as assessed by cardiac magnetic resonance imaging (CMR). MethodsThis study included 50 ToF patients, who underwent blood biomarker and CMR analysis at least twice between 2002 and 2018.34 (68 %) of these patients were male. Patients had an average age of 16.1 at first visit. Biomarkers were chosen based on earlier research by our group and included: NT-proBNP, ST2, GDF-15, DLK-1, IGFBP-1/7, and FABP-4. Pearson correlations coefficients (rpearson) were determined to quantify the relationship between changes in biomarkers and CMR measurements. ResultsFor changes in parameters of right ventricular (RV) size significant correlations were observed with changes in NT-proBNP, ST-2, GDF-15, IGFBP7 and FABP-4 (rpearson between 0.28 and 0.51). Correlations with NT-proBNP were driven by changes in RV size induced by pulmonary valve replacement (n = 9). For LV serial size changes, significant correlations were noted with changes in NT-pro-BNP, ST-2, GDF-15 and FABP-4 (rpearson between 0.32 and 0.52). ConclusionIn clinically stable ToF patients changes in right and left ventricular size and function correlated with alterations in blood biomarkers of inflammation and immune response to stress.

Gross morphology and morphometry of native and decellularized heart valves of caprine: A comparative study.

The gross morphological examination of native caprine heart valves revealed distinctive structural characteristics of the caprine's cardiac anatomy. Four primary orifices were identified, each protected by thin, valve-like structures. Atrioventricular orifices featured tricuspid and bicuspid valves, while the aorta and pulmonary arteries were guarded by semilunar valves. Within the atrioventricular apparatus, distinct features were observed including the tricuspid valve's three leaflets and the bicuspid valve's anterior and posterior leaflets. Ultrasonography provided insights into valve thickness and chordae tendineae lengths. Morphometric studies compared leaflets/cusps within individual native valves, showcasing significant variations in dimensions. Comparative analysis between native and decellularized valves highlighted the effects of decellularization on leaflet thickness and chordae tendineae lengths. Decellularized valves exhibited reduced dimensions compared to native valves, indicating successful removal of cellular components. While some dimensions remained unchanged post-decellularization, significant reductions were observed in leaflet thicknesses and chordae tendineae lengths. Notably, semilunar valve cusps displayed varying responses to decellularization, with significant reductions in cusp lengths observed in the aortic valve, while the pulmonary valve exhibited more subtle changes. These findings underscore the importance of understanding structural alterations in heart valves post-decellularization, providing valuable insights for tissue engineering applications and regenerative medicine.

Melody transcatheter pulmonary valve replacement: a single-center case series in Southeast Asia

BackgroundStudies of transcatheter pulmonary valve replacement (TPVR) with the Melody valve have demonstrated good clinical and hemodynamic outcomes. Our study analyzes the midterm clinical and hemodynamic outcomes for patients who underwent Melody valve implantation in Southeast Asia.MethodsPatients with circumferential conduits or bioprosthetic valves and experiencing post-operative right ventricular outflow tract (RVOT) dysfunction were recruited for Melody TPVR.ResultsOur cohort (n = 14) was evenly divided between pediatric and adult patients. The median age was 19 years (8–38 years), a male-to-female ratio of 6:1 with a median follow-up period of 48 months (16–79 months), and the smallest patient was an 8-year-old boy weighing 18 kg. All TPVR procedures were uneventful and successful with no immediate mortality or conduit rupture. The primary implant indication was combined stenosis and regurgitation. The average conduit diameter was 21 ± 2.3 mm. Concomitant pre-stenting was done in 71.4% of the patients without Melody valve stent fractures (MSFs). Implanted valve size included 22-mm (64.3%), 20-mm (14.3%), and 18-mm (21.4%). After TPVR, the mean gradient across the RVOT was significantly reduced from 41 mmHg (10–48 mmHg) to 16 mmHg (6–35 mmHg) at discharge, p < 0.01. Late follow-up infective endocarditis (IE) was diagnosed in 2 patients (14.3%). Overall freedom from IE was 86% at 79 months follow-up. Three patients (21.4%) developed progressive RVOT gradients.ConclusionFor patients in Southeast Asia with RVOT dysfunction, Melody TPVR outcomes are similar to those reported for patients in the US in terms of hemodynamic and clinical improvements. A pre-stenting strategy was adopted and no MSFs were observed. Post-implantation residual stenosis and progressive stenosis of the RVOT require long term monitoring and reintervention. Lastly, IE remained a concern despite vigorous prevention and peri-procedural bacterial endocarditis prophylaxis.

One-Year Outcome of an Ongoing Pre-Clinical Growing Animal Model for a Tissue-Engineered Valved Pulmonary Conduit.

Objectives: A self-constructed valved pulmonary conduit made out of a de-cellularized porcine small intestinal submucosal extracellular matrix biological scaffold was tested in a chronic growing lamb model. Methods: The conduit was implanted in pulmonary valve position in 19 lambs. We monitored clinical, laboratory, and echocardiographic findings until 12 months after surgery. In two animals, euthanasia was planned at nine and twelve months. Pre-mortem chest computed tomography and post-mortem pathologic work up were performed. Data are presented as frequency and percentage, median and range, or mean and standard deviation. Results: Twelve (63.2%) animals survived the perioperative period. Three unexpected deaths occurred during the follow-up period: one due to aspiration pneumonia at 23 days after surgery, and two due to early and late infective endocarditis of the conduit at 18 and 256 days. In the two animals with planned scarification, the pre-mortem CT scan revealed mild or no calcification within the conduit or valve leaflets. In the echocardiographic examination at 12 months, peak and mean systolic pressure gradients across the conduit valve were 6.5 (3-21) mmHg and 3 (2-12) mmHg, while valve regurgitation was none (n = 2), trivial (n = 5), moderate (n = 1), or severe (n = 1). No clinical or laboratory signs of hemolysis were seen. After 12 months of follow-up, the animals' body weights had increased from 33 (27-38) kg to 53 (38-66) kg (p = 0.010). Conclusions: Implantation of a valved pulmonary conduit in our growing lamb model was feasible. Infective endocarditis of the implanted valved conduit remained a significant complication.

Precision Medicine Approach Using Triple Combination Antifungal Therapy for Fusarium Brain Abscesses and Endocarditis in an Adult Burn Patient.

We report a management strategy for disseminated Fusarium solani fungal infection in an adult 35% total body surface area burn patient with brain abscesses and concomitant pulmonic valve endocarditis resulting in the longest survival reported in a burn patient. Early in his hospital course, the patient was diagnosed with a Fusarium burn wound infection with concomitant fungemia and was treated with a prolonged course of intravenous (IV) antifungal monotherapy. Shortly thereafter, he developed focal neurologic deficits and was found to have brain abscesses on MRI. He underwent emergent craniotomy with debridement, and triple antifungal therapy was initiated. Transesophageal echocardiography demonstrated pulmonic valve vegetations, which resolved with triple antifungal therapy. Disseminated Fusarium solani infection is quite rare with mortality approaching 100%. Given the rarity of this disease process, there are no established antifungal treatment guidelines. However, this patient survived for approximately 1 year after diagnosis with treatment including source control via craniotomy and debridement coupled with prolonged courses of combination antifungal therapy (given the near pan-resistance of his fungal infection). Pharmacogenomic testing was utilized to establish the patient's metabolism of voriconazole and dosing adjusted accordingly to improve the efficacy of the combination therapy. To our knowledge, an adult burn patient surviving this length of time after Fusarium brain abscesses with disseminated infection has not been previously described.

Long-Term Effects of Pulmonary Valve Implantation and Prosthesis Evolution in Patients with Repaired Tetralogy of Fallot.

Pulmonary valve regurgitation is a significant long-term complication in patients with tetralogy of Fallot (TOF). This study aims to investigate the effects of pulmonary valve implantation (PVI) on the anatomy and function of the right ventricle (RV) and the long-term evolution of the implanted prosthesis in the pulmonary position. A single-center retrospective cohort analysis was performed in 56 consecutive patients with TOF who underwent PVI. The study included patients of both sexes, aged ≥ 12 years, and involved assessing clinical and surgical data, pre- and post-operative cardiovascular magnetic resonance imaging, and echocardiogram data more than 1 year after PVI. After PVI, there was a significant decrease in RV end-systolic volume indexed by body surface area (BSA), from 89 mL/BSA to 69 mL/BSA (p < 0.001) and indexed RV end-diastolic volume, from 157 mL/BSA to 116 mL/BSA (p < 0.001). Moreover, there was an increase in corrected RV ejection fraction [ RVEFC = net pulmonary flow (pulmonary forward flow - regurgitant flow) / R V end-diastolic volume ] from 23% to 35% (p < 0.001) and left ventricular ejection fraction from 58% to 60% (p = 0.008). However, a progressive increase in the peak pulmonary valve gradient was observed over time, with 25% of patients experiencing a gradient exceeding 60 mmHg. Smaller prostheses (sizes 19 to 23) were associated with a 4.3-fold higher risk of a gradient > 60 mmHg compared to larger prostheses (sizes 25 to 27; p = 0.029; confidence interval: 1.18 to 17.8). As expected, PVI demonstrated improvements in RV volumes and function. Long-term follow-up and surveillance are crucial for assessing the durability of the prosthesis and detecting potential complications. Proper sizing of prostheses is essential for improved prosthesis longevity.

Outcomes After Pediatric Pulmonary Valve Replacement in Patients With Tetralogy of Fallot

BackgroundPeople with tetralogy of Fallot might require a transannular patch during primary repair, which leads to pulmonary valve regurgitation. Pulmonary valve replacement (PVR) is performed to prevent complications of chronic pulmonary regurgitation, but the optimal timing of PVR remains a matter of debate. In this study we aimed to assess the association of PVR performed in children younger than 18 years of age with the rate of hospitalizations, interventions, and mortality. MethodsThis was a retrospective observational cohort of people with tetralogy of Fallot born in Québec between 1982 and 2015, using a combination of clinical and administrative data. Marginal means and rates models and survival curves were used to compare outcomes of patients with pediatric PVR (younger than 18 years) and those without. Outcomes of interest were rates of cardiac hospitalizations, all-cause hospitalizations, cardiac interventions, and mortality. Groups were balanced using models weighed on the inverse probability of receiving pediatric PVR. ResultsOf the 316 eligible patients, 58 (18.4%) received a pediatric PVR. Compared with patients who did not receive pediatric PVR, they were at increased risk of cardiac hospitalizations, although the rates of cardiac hospitalization were low: 0.50 vs 0.09 hospitalizations per 20 years (hazard ratio [HR] = 4.71 [95% confidence interval (CI), 2.22-9.96]). Patients who received a pediatric PVR had a comparable risk of all-cause hospitalizations (HR = 0.95 [95% CI, 0.71-1.26]) and of cardiac interventions (HR = 1.13 [95% CI, 0.72-1.77]). ConclusionsPatients who underwent pediatric PVR had higher rates of cardiac hospitalizations, but similar rates of all-cause hospitalizations, cardiac procedures, and mortality. In this observational cohort, pediatric PVR was not associated with an improved outcome.

Cell signaling and tissue remodeling in the pulmonary autograft after the Ross procedure: A computational study

In the Ross procedure, a patient’s pulmonary valve is transplanted in the aortic position. Despite advantages of this surgery, reoperation is still needed in many cases due to excessive dilatation of the pulmonary autograft. To further understand the failure mechanisms, we propose a multiscale model predicting adaptive processes in the autograft at the cell and tissue scale. The cell-scale model consists of a network model, that includes important signaling pathways and relations between relevant transcription factors and their target genes. The resulting gene activity leads to changes in the mechanical properties of the tissue, modeled as a constrained mixture of collagen, elastin and smooth muscle. The multiscale model is calibrated with findings from experiments in which seven sheep underwent the Ross procedure. The model is then validated against a different set of sheep experiments, for which a qualitative agreement between model and experiment is found. Model outcomes at the cell scale, including the activity of genes and transcription factors, also match experimentally obtained transcriptomics data.

Assessing the correlation between the degree of tricuspid regurgitation and pulmonary hypertension: A comprehensive study.

To evaluate the relationship between severity of tricuspid regurgitation (TR) and pulmonary hypertension. Cross-sectional study of 118 patients with pulmonary hypertension was carried out at a single center in Jeddah, Saudi Arabia, between 2018-2021. Patients who had pulmonary or tricuspid valves organic diseases, previously undergone tricuspid or pulmonary valve surgeries, had permanent pacemakers or critically ill were excluded. A high proportion of patients were women (n=100, 85%) and obese (n=57, 48%). Patients with more than mild TR had higher systolic pulmonary artery pressure (sPAP) than those with trivial or mild regurgitation (p<0.001). There was a significant association between severity of TR (p<0.001) and right chambers size (p=0.001). Furthermore, pulmonary artery pressure (PAP) was significantly higher in patients with mild right ventricular impairment (p=0.001). Increase in degree of TR and right atrial size were predictors of elevated sPAP. Our findings highlight the interplay among TR, right heart size, ventricular function, and PAP. Understanding these associations can aid in risk stratification, monitoring disease progression, and potentially guiding treatment in those patients.

Progression of valve heart disease in a cohort of patients undergoing renal replacement therapy.

Cardiovascular disease is an important cause of death among patients with chronic kidney disease (CKD). Valve calcification is a predictor of cardiovascular mortality and coronary artery disease. To assess heart valve disease frequency, associated factors, and progression in CKD patients. We conducted a retrospective study on 291 CKD patients at Hospital das Clínicas de Pernambuco. Inclusion criteria were age ≥ 18 with CKD and valve disease, while those on conservative management or with missing data were excluded. Clinical and laboratory variables were compared, and patients were categorized by dialysis duration (<5 years; 5-10 years; >10 years). Statistical tests, including chi-square, Fisher's exact, ANOVA, and Kruskal-Wallis, were employed as needed. Simple and multivariate binary regression models were used to analyze valve disease associations with dialysis duration. Significance was defined as p < 0.05. Mitral valve disease was present in 82.5% (240) of patients, followed by aortic valve disease (65.6%; 86). Over time, 106 (36.4%) patients developed valve disease. No significant association was found between aortic, pulmonary, mitral, or tricuspid valve disease and dialysis duration. Secondary hyperparathyroidism was the sole statistically significant factor for mitral valve disease in the regression model (OR 2.59 [95% CI: 1.09-6.18]; p = 0.031). CKD patients on renal replacement therapy exhibit a high frequency of valve disease, particularly mitral and aortic valve disease. However, no link was established between dialysis duration and valve disease occurrence or progression.

A Case of Antenatal Diagnosis of Absent Pulmonary Valve Syndrome with Intact Ventricular Septum, Large Patent Ductus Arteriosus, and Ascending Aorta Dilatation

A Case of Antenatal Diagnosis of Absent Pulmonary Valve Syndrome with Intact Ventricular Septum, Large Patent Ductus Arteriosus, and Ascending Aorta Dilatation

3D transesophageal echocardiographic visualization of the pulmonary artery catheter through the tricuspid valve and their position relative to the tricuspid valve leaflets

BackgroundThe tricuspid valve is an atrioventricular valve consisting of three lobes. We used the 3D transesophageal echocardiography to visualize position of the pulmonary artery catheter at the tricuspid valve annulus and examined where the catheter passed through at the level of the tricuspid annulus.MethodsIn this prospective and observational study, we monitored the pressure wave on patients undergoing cardiac surgery with the catheter placement by monitoring the pressure waveform for 8 months. We measured the time required for the catheter to pass through the tricuspid and pulmonary valves, respectively. We acquired the 3D image of the tricuspid valve by transesophageal echocardiography and determined the position of the pulmonary artery catheter at the level of the tricuspid annulus. The data were analyzed by Kruskal-Wallis test followed by Mann-Whitney test with Holm multiple comparisons. P < 0.05 was considered significant.ResultsOf the 116 cases, the pulmonary artery catheter passed through the tricuspid valve between antero-posterior leaflets in 78 cases (67.2 %), between septal-posterior leaflets in 25 cases (21.6 %), and between antero-septal leaflets in 2 cases (1.7 %) and the center in 11 cases (9.5 %), respectively. The time required for the catheter to pass through the pulmonary valves was significantly different among the catheter positions at the level of the tricuspid annulus.ConclusionThe pulmonary artery catheter location at the level of the tricuspid annulus can be identified using 3D transesophageal echocardiography. The location of the catheter significantly affects the pulmonary artery catheter placement time.

Survival after partial heart transplantation in a piglet model

Partial heart transplantation (PHT) is a novel surgical approach that involves transplantation of only the part of the heart containing a valve. The rationale for this approach is to deliver growing heart valve implants that reduce the need for future re-operations in children. However, prior to clinical application of this approach, it was important to assess it in a preclinical model. To investigate PHT short-term outcomes and safety, we performed PHT in a piglet model. Yorkshire piglets (n = 14) were used for PHT of the pulmonary valve. Donor and recipient pairs were matched based on blood types. The piglets underwent PHT at an average age of 44 days (range 34–53). Post-operatively, the piglets were monitored for a period of two months. Of the 7 recipient piglets, one mortality occurred secondary to anesthesia complications while undergoing a routine echocardiogram on post-operative day 19. All piglets had appropriate weight gain and laboratory findings throughout the post-operative period indicating a general state of good health and rehabilitation after undergoing PHT. We conclude that PHT has good short-term survival in the swine model. PHT appears to be safe for clinical application.

Enhancing diagnostic performance and image quality in coronary CT angiography: Impact of SnapShot Freeze 2 algorithm across varied heart rates in stent patients.

To investigate the enhancement of image quality achieved through the utilization of SnapShot Freeze 2 (SSF2), a comparison was made against the results obtained from the original SnapShot Freeze algorithm (SSF) and standard motion correction (STND) in stent patients undergoing coronary CT angiography (CCTA) across the entire range of heart rates. A total of 118 patients who underwent CCTA, were retrospectively included in this study. Images of these patients were reconstructed using three different algorithms: SSF2, SSF, and STND. Objective assessments include signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), diameters of stents and artifact index (AI). The image quality was subjectively evaluated by two readers. Compared with SSF and STND, SSF2 had similar or even higher quality in the parameters (AI, SNR, CNR, inner diameters) of coronary artery, stent, myocardium, MV (mitral valve), TV (tricuspid valve), AV (aorta valve), and PV (pulmonary valve), and aortic root (AO). Besides the above structures, SSF2 also demonstrated comparable or even higher subjective scores in atrial septum (AS), ventricular septum (VS), and pulmonary artery root (PA). Furthermore, the enhancement in image quality with SSF2 was significantly greater in the high heart rate group compared to the low heart rate group. Moreover, the improvement in both high and low heart rate groups was better in the SSF2 group compared to the SSF and STND group. Besides, when using the three algorithms, an effect of heart rate variability on stent image quality was not detected. Compared to SSF and STND, SSF2 can enhance the image quality of whole-heart structures and mitigate artifacts of coronary stents. Furthermore, SSF2 has demonstrated a significant improvement in the image quality for patients with a heart rate equal to or higher than 85bpm.

Outcomes of Neonates Born with Symptomatic Tetralogy of Fallot and Absent Ductus Arteriosus

ObjectiveTo test the hypothesis that neonates with symptomatic tetralogy of Fallot (TOF) and absent ductus arteriosus (ADA) have worse clinical outcomes compared with those with a ductus arteriosus (DA), and that this difference is driven by those born with ADA and with critically deficient pulmonary blood flow (CDPBF). Study designWe performed a retrospective, multicenter cohort study of neonates who underwent intervention for symptomatic TOF comparing death and reintervention between subjects with and without a DA identified on fetal echocardiogram or on echocardiogram performed in the first postnatal day. Exclusion criteria were: inability to define DA status, collaterals supplying pulmonary blood flow, atrioventricular septal defect, and absent pulmonary valve. We defined CDPBF as undergoing a procedure to augment pulmonary blood flow on the date of birth or extracorporeal membrane oxygenation prior to such a procedure. ResultsThe study cohort included 519 patients, among whom 11% had ADA. Patients with ADA were more likely to have a genetic syndrome and had smaller branch pulmonary artery size. In analyses adjusting for center, interventional treatment strategy, genetic syndrome, and minimum branch pulmonary artery size, ADA was associated with higher mortality risk (adjusted hazard ratio of 2.37 (95% CI:1.07,5.27; p=0.034). Seven patients had CDPBF (1.3% of the entire cohort and 12% of patients with ADA). ConclusionsA minority of symptomatic TOF neonates have ADA, which is associated with higher adjusted mortality risk compared with those with a DA. CDPBF appears to be a rare but important entity in this population.

Systematic right ventricular electrophysiologic evaluation in patients with repaired tetralogy of Fallot before pulmonary valve replacement

Abstract Introduction Adults with repaired tetralogy of Fallot (rToF) are prone to develop ventricular tachycardia (VT) in adulthood, due to reentry related to slowly conducting anatomical isthmuses (SCAI). Pulmonary valve replacement (PVR) in patients without history of VT, may lead to obliteration of unrecognized SCAI with subsequent catheter ablation failure; electrophysiologic study is thus recommended before PVR. A systematic evaluation of the topology of SCAI in this population is, however, scant. Methods Consecutive rToF patients undergoing PVR with native right ventricular outflow tract were studied with pre-PVR EPS. Electroanatomical mapping with systematic evaluation of all possible anatomical isthmuses (AI) with pacemapping, activation mapping in sinus/paced rhythm and bipolar voltage mapping was performed (AI1: anterior scar/patch to tricuspid annulus; AI2: anterior scar to pulmonary annulus; AI3: pulmonary annulus to ventricular septal defect – VSD- patch; AI4: VSD to tricuspid annulus). Conduction velocity (CV) across all documented AI was calculated (ratio between the distance among the nearest point with bipolar voltage &amp;gt;1.5 mV and their difference in activation timing). Ventricular programmed stimulation was performed at 2 sites (apex and outflow tract) with drive train ad 600/400 ms, up to three extrastimuli until refractoriness or induction, during baseline and isoproterenol infusion. Radiofrequency catheter ablation (RFCA) was performed in all patients with inducible VT and/or SCAI, aiming at conduction block across the SCAI validated with differential pacing. Results Between May 2023 and November 2023, 10 patients with rToF and 1 double outlet right ventricle were studied (73% males, age 46±10 years; 54% with a previous shunt, 46% with a previous transannular patch, 27% pulmonary valvotomy and infundibular boring; median age at surgery 4 years, interquartile range 3-6). EPS was positive for inducible VT in 4 patients (mean cycle length 297 ms, 3 with left bundle branch morphology and 1 right bundle branch morphology, all inferior axis) and polymorphic VT in 1. AI1 was present in 5 patients, AI2 in 5, AI3 in 7, AI 4 in 2. At least 1 SCAI was present in 7 patients (64%), 2 SCAI in 3 patients (43% of patients with SCAI; in every patient SCAI3+SCAI2 in 2 and SCAI 4 in 1 patient). There were no SCAI1; there were 3 SCAI 2 (mean CV 0.43 m/s), 4 SCAI 3 (mean CV 0.3 m/s), 1 SCAI 4 (CV 0.4 m/s). RFCA was performed in 8 patients; acute success was achieved in all patients, achieving bidirectional conduction block across treated SCAI and non-inducibility of VT. Conclusions SCAI are often present in rToF candidate to PVR and without clinical history of spontaneous VT, involving prevalently SCAI3 and SCAI2. Inducible VT is not sufficient as a marker of arrhythmic risk and SCAI should be better sought for. RFCA of SCAI with bidirectional conduction block is acutely highly efficacious.