Coronary artery anomalies: what are they? when to suspect? how to treat?-a narrative review.

Background and Objective: In the literature have been widely discussed different classification criteria for coronary artery anomalies (CAAs), some authors have tried to categorize them only as "major" or "hemodynamically significant" anomalies versus "minor" or "not hemodynamically significant" ones. However, the most recent literature has concluded that all possible coronary anatomy should be taken into consideration in a comprehensive classification of CAAs. The aim of the article is to review the most recent literature regarding CAAs to provide a comprehensive overview of this challenging topic. Methods: We propose a narrative overview of the most impactful and recent literature, synthetizing and re-elaborating the most important articles concerning CAAs. Key Content and Findings: The important gap of knowledge on the specific characteristics of CAAs has led to a progressively increased interest of the current research in this field. Albeit their nature is still unclear, an increased awareness of their fatality is spreading among clinicians and the general population, mostly associated with their clinical relevance among young patients and athletes. On the other side, we do believe that clinical and hemodynamic repercussions are of crucial importance and should always be integrated to understand the true nature of this important pathology. Conclusions: In the field of pediatric cardiology, CAAs are one of the most fascinating and studied subject. We propose a state-of-the art review to provide a comprehensive and systematic description and subsequently an approach to the epidemiological, pathophysiological, and clinical aspects of the most important CAAs in the pediatric population.

Holography-guided procedural planning for modifying Venus P-valve implantation technique in patients with left pulmonary artery stents: a case-series.

Background: Venus P-valve™ (Venus Medtech, Hangzhou, China) is a self-expandable bioprosthetic valve that can be transcatheter-implanted in native right ventricular outflow tract (RVOT) patients. Valve implantation is technically challenging. Due to the implantation technique, left pulmonary artery (LPA) stents represent a relative contraindication to Venus P-valve. In this case series, we describe our experience in implanting Venus P-valve in patients with previous LPA stents and the use of holographic models to facilitate procedural planning. Methods and results: From January to October 2023, 17 patients were scheduled for Venus P-Valve implantation. 16/17 (94%) patients were successfully implanted. 3/16 (18.7%) patients underwent Venus P-valve implantation with LPA stents. All patients underwent pre-operative CT scan. CT data set were employed to create three-dimensional (3D) holographic models (Artiness, Milan, Italy) of the entire heart, which were useful to plan valve implantation with a modified technique. Procedural success rate was 100%. No procedural complications occurred. All three patients presented good haemodynamic and angiographic results at discharge and follow-up visits. Conclusion: This case-series underscores the feasibility of Venus P-valve implantation in patients with previous LPA stents. The use of holographic models facilitated procedural planning in these challenging anatomical scenarios.

Right disc thrombosis of the new Gore Cardioform ASD Occluder.

BACKGROUND: The GCA is a well performing device in terms of efficacy despite complex anatomies (aortic rim <5 mm and ASD diameter >17 mm) with a good safety profile. AIMS: To evaluate atrial septal defect (ASD) features impacting on right disc device thrombosis in patients who underwent Gore Cardioform ASD Occluder (GCA) implantation. METHODS: A total of 44 consecutive patients undergoing percutaneous ASD with GCA device from January 2020 to September 2022 at our tertiary care Center were evaluated. The minimum follow-up was 6 months. RESULTS: The patients were stratified in two groups according to a cut-off value of ASD diameter equal to 20 mm at sizing balloon, derived from ROC analysis (AUC = 0.894; p = 0.024). Baseline characteristics were comparable between groups in terms of age, sex, weight, height, and interatrial septum dimensions. Patients with ASD > 20 mm (n = 9) had a higher ASD/device dimension ratio, both at echocardiography (p = 0.009) and at sizing balloon (p = 0.001), longer fluoroscopic time (p = 0.022), and higher incidence of device thrombosis (0.006). Right disc thrombosis was observed in three patients of the ASD > 20 mm group, always in the inferior portion of the right disc. On univariate analysis, ASD diameter at sizing balloon (OR 1.360; p = 0.036) was the only positive predictor of device thrombosis. CONCLUSIONS: Right disc thrombosis of the GCA device may be under-recognized at follow-up, hence deserving clinical attention, especially in those patients with larger ASD diameters.

Overview of Long-Term Outcome in Adults with Systemic Right Ventricle and Transposition of the Great Arteries: A Review.

The population of patients with a systemic right ventricle (sRV) in biventricular circulation includes those who have undergone an atrial switch operation for destro-transposition of the great arteries (d-TGA) and those with congenitally corrected transposition of the great arteries (ccTGA). Despite the life expectancy of these patients is significantly increased, the long-term prognosis remains suboptimal due to late complications such as heart failure, arrhythmias, and premature death. These patients, therefore, need a close follow-up to early identify predictive factors of adverse outcomes and to implement all preventive therapeutic strategies. This review analyzes the late complications of adult patients with an sRV and TGA and clarifies which are risk factors for adverse prognosis and which are the therapeutic strategies that improve the long-term outcomes. For prognostic purposes, it is necessary to monitor sRV size and function, the tricuspid valve regurgitation, the functional class, the occurrence of syncope, the QRS duration, N-terminal pro B-type natriuretic peptide levels, and the development of arrhythmias. Furthermore, pregnancy should be discouraged in women with risk factors. Tricuspid valve replacement/repair, biventricular pacing, and implantable cardioverter defibrillator are the most important therapeutic strategies that have been shown, when used correctly, to improve long-term outcomes.

Ross Operation in Pediatric Population: Impact of the Surgical Timing and the Native Pulmonary Diameter on the Outcome.

Aortic valve replacement early in life may be inevitable. Ross operation, until present day, remains the favorite surgical option in pediatrics with irreparable aortic valve disease. Nonetheless, the necessity for re-operation was always its principal limitation due to aortic valve failure or homograft degeneration. We present our 25 years of experience in the pediatric population. From August 1994 until June 2018, 157 children below 18 years underwent the Ross operation. This retrospective review aims at assessing the long-term outcomes, as well as the risk factors for re-operation after Ross procedure. Median age was 10.9 years, of which seven patients were infants, 79 children, and 71 adolescents. The median follow-up time was 14 years. Hospital mortality was 0.6%. Freedom from autograft re-operation for children was 96.7% and 94.1% at 10 and 20 years, respectively; whereas for adolescents, it was 92.6% and 74.9% at 10 and 20 years. For children, freedom from homograft re-operation was 92.5%, 83.5%, and 56.2% at 10, 15, and 20 years; while for adolescents, it was 96.8%, 91.8%, and 86.7% at 10, 15, and 20 years. Homograft size (p = 0.008) and childhood (p = 0.05) were risk factors for homograft re-operation. Pulmonary valve diameter > 24 mm (p = 0.044) and adolescence (p = 0.032) were risk factors for autograft re-operation. Our experience demonstrated excellent early and late survival. While children have preferential outcomes concerning autograft re-operation, those who received a smaller homograft had a higher right-sided re-intervention incidence than adolescents. Pulmonary diameter > 24 mm at surgery was an indicator of future autograft failure.

Holographic Techniques as a Novel Method for Intervention Planning: A Tertiary Centres Experience.

Advanced holographic visualization techniques are becoming increasingly important in clinical practice, not only for diagnostic purposes but also in the planning of interventional or surgical procedures. The traditional approach for visualizing anatomic structures is based on standard imaging modalities such as echocardiography, cardiac magnetic resonance (CMR) and cardiac CT scan (CCT) which, however, can only provide two-dimensional (2D) images thus limiting 3D perception. Many recent studies have shown that the use of 3D imaging modalities such as augmented reality, virtual reality, mixed reality and holography improve the short and long-term outcome of percutaneous or surgical procedures. In this article, we report our experience on the use of the hologram in different clinical scenarios and in the field of university education.

Lombardy regional urgent reorganization for congenital cardiac patients following the Covid-19 pandemic.

OBJECTIVE: By the end of February 2020, the COVID-19 pandemic infection had spread in Northern Italy, with thousands of patients infected. In Lombardy, the most affected area, the majority of public and private hospitals were dedicated to caring for COVID-19 patients and were organized following the 'Hub-and-Spoke' model for other medical specialties, like cardiac surgery and interventional procedures for congenital cardiac disease (CHD). Here, we report how the congenital cardiac care system was modified in Lombardy and the first results of this organization. METHODS: We describe a modified 'Hub-and-Spoke' model - that involves 59 birthplaces and three specialized Congenital Cardiac Centers -- and how the hub center organized his activity. We also reported the data of the consecutive cases hospitalized during this period. RESULTS: From 9 March to 15 April, we performed: a total of 21 cardiac surgeries, 4 diagnostic catheterizations, 3 CT scans, and 2 CMR. In three cases with prenatal diagnosis, the birth was scheduled. The spoke centers referred to our center six congenital cardiac cases. The postop ExtraCorporeal Membrane Oxygenation support was required in two cases; one case died. None of these patients nor their parents or accompanying person was found to be COVID-19-positive; 2 pediatric intensivists were found to be COVID-19-positive, and needed hospitalization without mechanical ventilation; 13 nurses had positive COVID swabs (4 with symptoms), and were managed and isolated at home. CONCLUSION: Our preliminary data suggest that the model adopted met the immediate needs with a good outcome without increased mortality, nor COVID-19 exposure for the patients who underwent procedures.

Results for tricuspid valve surgery in adults with congenital heart disease other than Ebstein's anomaly†.

OBJECTIVES: Tricuspid valve (TV) surgery in the adult with congenital heart disease (ACHD) is a frequently performed procedure. The aim of this study was to analyse postoperative and medium-term outcomes. METHODS: We conducted a single-centre retrospective study of patients with ACHD who underwent TV surgery (January 2000-December 2016); patients with Ebstein's anomalies were excluded. Operative and clinical records were reviewed. Outcomes considered were survival, grade of insufficiency/stenosis and TV reoperation at follow-up. RESULTS: A total of 128 patients with ACHD had TV surgery for functional regurgitation (n = 95), dysplasia (n = 23) and systemic TV (n = 10). Median age was 40.8 years [interquartile range (IQR) 25.3]; 55.5% were men. Preoperative regurgitation was classified as mild (n = 8), moderate (n = 47) and severe (n = 70). The TV was repaired in 109 as follows: ring annuloplasty (n = 43), de Vega annuloplasty (n = 29), Wooler annuloplasty (n = 13), commissural plasty (n = 9), Kay annuloplasty (n = 7) and others (n = 8). The TV was replaced in 19 patients with biological (n = 10) and mechanical (n = 9) prostheses. The median hospital stay was 12 days (IQR 10). The overall mortality rate was 8.6% (n = 11): 2 hospital deaths (1.6%) and 9 late deaths. Survival was 93% [95% confidence interval (CI) 85-97%] at 5 years and 83% (95% CI 70-91%) at 10 years. The median follow-up period was 4.95 years (IQR 7.7) with 1 TV reoperation. Echocardiographic assessment showed ≥moderate regurgitation in 34 (34.3%) patients. Suture plasty had a significantly higher incidence of TV regurgitation ≥moderate compared to ring annuloplasty (48.9% vs 26.3%; P = 0.033). CONCLUSIONS: TV surgery in the ACHD is frequently associated with other main procedures. Stabilizing the TV annulus with a prosthetic ring guarantees lower recurrence of moderate to severe regurgitation compared to suture plasty repair.

Improving health perception through a transition care model for adolescents with congenital heart disease.

AIMS: The aim of this study was to assess the impact of a transition clinic model on adolescent congenital heart disease (CHD) patients' health perception outcomes. The transition clinic model consists of multidisciplinary standardized interventions to educate and support CHD patients and represents a key element in the adequate delivery of care to these individuals during their transition from childhood to adulthood. Currently, empirical data regarding the impact of transition clinic models on the improvement of health perceptions in CHD adolescent patients are lacking. METHODS: A quasi-experimental design was employed. Quality of life, satisfaction, health perceptions and knowledge were assessed at the time of enrolment (T0) and a year after enrolment (T1), respectively. During the follow-up period, the patients enrolled (aged 11-18 years) were involved in the CHD-specific transition clinic model (CHD-TC). RESULTS: A sample of 224 CHD adolescents was enrolled (60.7% boys; mean age: 14.84 ±â€Š1.78 years). According to Warnes' classification, 22% of patients had simple heart defect, 56% showed moderate complexity and 22% demonstrated severe complexity. The overall results suggested a good impact of the CHD-TC on adolescents' outcomes, detailing in T1 the occurrence of a reduction of pain (P < 0.001) and anxiety (P < 0.001) and an improvement of knowledge (P < 0.001), life satisfaction (P < 0.001), perception of health status (P < 0.001) and quality of life (P < 0.001). CONCLUSION: The CHD-TC seems to provide high-quality care to the patient by way of a multidisciplinary team. The results of the present study are encouraging and confirm the need to create multidisciplinary standardized interventions in order to educate and support the delivery of care for CHD adolescents and their families.

Surgical ablation of ventricular tachycardia in patients with repaired tetralogy of Fallot†.

OBJECTIVES: Life expectancy of patients with repaired tetralogy of Fallot is normal until adulthood, when it becomes burdened by major complications such as cardiac arrhythmias and heart failure. Ventricular tachycardia (VT), associated with electrical conduction abnormalities in anatomical isthmuses, is the most common complication and is refractory to medical therapy. The arrhythmogenic sources can be surgically ablated during reoperations for pulmonary valve incompetence. The purpose of our study is to evaluate the safety and effectiveness of surgical radiofrequency ablation during PVR and its long-term impact on the occurrence of cardiac events. METHODS: A total of 118 patients with repaired tetralogy of Fallot underwent reoperation for pulmonary valve regurgitation in IRCCS-Policlinico San Donato between January 2002 and February 2016. Twenty patients with risk factors for ventricular arrhythmia underwent EP testing and were found positive. The mean QRS duration was 178 ms. Right ventricular dysfunction was present in all the patients, and 20% had associated tricuspid regurgitation. The cohort (N = 20), with positive EP study, underwent pulmonary valve replacement and concomitant intraoperative ventricular surgical radiofrequency ablation, targeting the slow conducting isthmuses identified during preoperative electroanatomical mapping. All patients were reviewed at 1 month, 3 months and 6 months with clinical evaluation, echocardiography, ECG and implantable cardioverter-defibrillator interrogation. At 6 months, a postoperative electrophysiological study was performed in all patients, and a cardioverter defibrillator was implanted as primary preventive measure in patients with residual inducible VT. RESULTS: Pulmonary valve replacement and surgical ventricular radiofrequency ablation were performed in all cases. One patient died while on V-V extracorporeal membrane oxygenation (ECMO) due to respiratory failure. There was no late mortality. Follow-up was complete with a median of 6.5 years. During the postoperative EPS study, inducible VT was found in 15.7% of patients who received an implantable cardioverter-defibrillator, whereas VT could no longer be induced in the remaining patients. No procedure-related complication was observed, and freedom from ventricular arrhythmia was 94% and 89.5% at 1 year and 5 years, respectively. CONCLUSIONS: Pulmonary regurgitation and right ventricular dysfunction correlate with VT and SCD, but valve replacement alone does not reduce the risk of ventricular tachyarrhythmias. Intraoperative ventricular ablation during reoperation for pulmonary regurgitation prevents the occurrence of ventricular arrhythmias in the early and medium term. Accordingly, this technique may be proposed as a safe associated procedure in selected patients.

The Challenging Pathway Toward Heart Transplant Listing for Adult Congenital Heart Disease Patients.

Adult congenital heart disease (ACHD) patients are at risk for end-stage heart failure; heart transplantation (Htx) represents the only definitive therapy available although not easily achievable for all patients. The study aims to assess the pathway difficulties and outcomes of ACHD patients with end-stage heart failure referred for Htx evaluation. This is a single center retrospective study on ACHD patients with end-stage heart failure referred to Htx evaluation from 2004 to 2015. Demographic data, medical history, failure modality, and follow-up were obtained from patient charts. End-points were Htx list enrollment, transplant, and survival. Statistical analysis was performed comparing patients listed and not listed. There were 21 ACHD patients with end-stage heart failure referred to Htx evaluation. Transplant listing was declined for 12 (57%) meanwhile 9 patients were listed. Htx was successfully achieved in 3 patients after 24 and 36 months, respectively. Three patients are still on the wait list and three died while waiting, with a listed group mortality of 33.3% (3/9). Mortality occurred in first 18 months after Htx list enrollment. Not listed group mortality was 50% (6/12) and occurred after a median time of 17.5 months (IQR: 9-23 months). There was no difference in survival (P = 0.574) between listed and not listed (89, 63, and 63% vs. 83, 56, and 47% at 12-24-48 months). Follow-up median duration was 27 months (IQR: 14-56 months). Heart transplant listing for ACHD patients with end-stage heart failure is hard to obtain. Almost 2/3 of the patients were declined. Survival for these patients is reduced severely either in waiting list for transplant or excluded indicating the potential need of mechanical circulatory support as bridge to transplant or as destination therapy to improve survival likelihood.

[The effect of the transition care model on health perception among adolescents with congenital heart disease: a quasi-experimental study]. / Gli effetti di un set standardizzato di interventi educazionali sulla percezione della salute di adolescenti con cardiopatia congenita (modello Transition): risultati preliminari di uno studio quasi-sperimentale.

BACKGROUND: The multidisciplinary standardized interventions to educate and support patients with congenital heart disease (CHD) are described as "Transition Clinic" (TC). TC represents a key element to deliver care for patients during the transition from childhood to adulthood. So far, there is a lack of empirical evidence regarding the impact of TC models on the improvement of health perception in adolescent patients with CHD (CHD-specific TC model). For this reason, the aim of this study is assess the impact of the TC model on CHD adolescent patients' health perception outcomes. METHODS: This study has a quasi-experimental design. Quality of life, satisfaction and health perception were assessed in T0 and after 1 year from enrollment (T1). During the follow-up period, the patients enrolled (aged 14 to 21 years) were involved in the CHD-specific TC model. RESULTS: The results are referred to the first 100 patients enrolled (mean age 14.79 ± 1.85 years; 60% male), as they have already completed the follow-up. The overall study is currently ongoing. According to Warnes' classification, 29% of patients had simple heart defects, 46% showed moderate complexity, and 25% showed severe complexity. The comparison between T0 and T1 showed statistically significant improvement in T1 regarding pain/discomfort, anxiety/depression and perception of health status (EQ-5D), general satisfaction and quality of life (LAS QoL). CONCLUSIONS: The preliminary results showed in this study are encouraging, and confirm the need to create a multidisciplinary standardized intervention of education and support to deliver care for adolescent patients with CHD.

Heart failure in grown-up congenital heart disease.

The increasing survival to adulthood of patients with congenital heart disease (CHD) has changed the epidemiology of adult CHD (ACHD) patients and has led to an increment in hospitalization rates due to heart failure (HF). ACHD patients hospitalized for HF have a five-fold higher risk of death than those compensated. HF occurs predominantly in patients with tetralogy of Fallot, single ventricles, and after the Mustard operation for transposition of the great arteries. Diagnostic strategies applied in acquired HF patients are usually used to evaluate ACHD patients, but sometimes this can postpone the identification of HF that can become manifest with unusual and peculiar signs or symptoms. In the same way, therapeutic management resembles the acquired HF one, even if no large randomized clinical trials have been conducted in ACHD patients. Therefore, a close monitoring in dedicated units is mandatory in order to identify in time HF manifestations and manage them adequately.

Percutaneous management of failed bioprosthetic pulmonary valves in patients with congenital heart defects.

AIMS: We reviewed our center experience in the field of transcatheter pulmonary valve-in-valve implantation (TPViV), that is emerging as a treatment option for patients with pulmonary bioprosthetic valve (BPV) dysfunction. METHODS: Between April 2008 and September 2015, a total of six patients with congenital heart disease (four men) underwent TPViV due to stenosis of preexisting BPV. Four patients received a Melody Medtronic Transcatheter Pulmonary Valve and two an Edward Sapien Valve. RESULTS: No procedural-related complications occurred. After valve implantation, right ventricular systolic pressure (RVSP, 80.5 ±â€Š25.3-41.2 ±â€Š8.35 mmHg, P < 0.05), right ventricular outflow tract (RVOT) gradient (55.3 ±â€Š23.4-10.6 ±â€Š3.8 mmHg, P < 0.05), and RVSP-to-aortic pressure (0.75 ±â€Š0.21-0.38 ±â€Š0.21, P = 0.01) fell significantly. Echocardiograms at follow-up revealed a significant reduction in estimated RVSP (88.7 ±â€Š22-21.7 ±â€Š4.7 mmHg, P < 0.05), in RVOT (76.2 ±â€Š17.9-25.7 ±â€Š6.1 mmHg, P = 0.005), and in mean RVOT (40.7 ±â€Š9.9-15.5 ±â€Š4.8 mmHg, P < 0.05) gradients. Cardiac magnetic resonance showed no significant change in biventricular dimensions and function. Symptomatic patients reported improvement of symptoms, although cardiopulmonary exercise did not show any significant differences. CONCLUSION: TPViV is an effective and well tolerated treatment for BPV dysfunction, improving freedom from surgical reintervention. Long-term studies will redefine the management of dysfunctional RVOT, either native or surrogate.

The care for adults with congenital heart disease: organization and function of a grown-up congenital heart disease unit.

Thanks to the improvement of surgical and interventional cardiac procedures, the majority of children with congenital heart defects (CHD) can now be expected to reach adulthood. The number of adults with congenital heart disease (ACHD) will inevitably increase, and recent data affirm that in Europe, we are actually faced with an estimated patient population of 2.3 million. These patients, particularly the adults with moderate and highly complex CHD, can be very difficult to manage, and should be treated in few experienced and specialized 'grown-up congenital heart disease' (GUCH) units, concentrating resources, patients, funding, and professional experiences. On 2000, we created a GUCH unit in our hospital that rapidly became a referral centre in Italy for number and complexity of patients treated. The present study is a presentation of how is organized our GUCH unit and a brief overview of our more recent experience with ACHD patients.

Treatment of right ventricular outflow tract dysfunction: a multimodality approach.

The right timing to replace the pulmonary valve in a patient with dysfunction of the right ventricular outflow tract is unknown. Both percutaneous pulmonary valve and surgical prosthesis are suitable options. In every patient, the right ventricle (RV) remodels and recovers differently after pulmonary replacement. Therefore, it is difficult to identify the best treatment option and to predict the long-term results. In the last few years, we focused our research on optimizing the characterization of these patients through advanced cardiovascular imaging in order to find possible variables, parameters, and reproducible measurements that can help us in the decision-making process. The aim of the present article is to present our ongoing research lines that focus on the characterization and optimal treatment approach to the dysfunction of the RVOT.

Percutaneous pulmonary valve implantation in a single artery branch: A preliminary experience.

To describe preliminary experience of percutaneous pulmonary valve implantation, in a single pulmonary branch position. Two procedures in 2 patients from a single center are described, where implantation of percutaneous valves within a single pulmonary artery branch was technically successful. The procedural indication was pulmonary valve regurgitation and/or residual stenosis. The 2 patients were symptomatic. An Edwards Sapien™ valve (Patient 1), and a Medtronic Melody™ valve (Patient 2) were implanted. Both pts were discharged with an excellent valve function. In this report it is underlined that this modality is technically feasible and may be considered an option in patients with congenital heart defect under special circumstances.

Hemodynamic, not ventilatory, inefficiency is associated with high VE/VCO2 slope in repaired, noncyanotic congenital heart disease.

BACKGROUND: A high slope of the ventilation vs. carbon dioxide relationship (VE/VCO2 slope) during incremental exercise has been reported in several congenital heart disease (CHD) types, but it is not clear whether the main cause of high VE/VCO2 slope is excessive ventilation or reduced perfusion. METHODS: We studied 169 adolescent and adult patients with repaired, noncyanotic CHD, divided into 2 groups according to VE/VCO2 slope %predicted values (≤120 and >120), and 15 age- and sex-matched normals. VCO2/VE max and VO2/VE max were considered proxies of the perfusion/ventilation relationship, with VCO2 and VO2 as indirect descriptors of cardiac output. RESULTS: VCO2/VE max was significantly and inversely related to VE/VCO2 slope (r=-0.73, p<0.0001), and higher in normals and ≤120 than in >120 (39.6 ± 7.7, 36.1 ± 5.3 and 28.5 ± 4.1, respectively, p<0.0001). Similarly, VCO2 at VCO2/VE max was higher in normals and ≤120 than in >120 (1701 ± 474, 1480 ± 492 and 1169 ± 388 ml/min, respectively, p<0.0001), whereas ventilation at VCO2/VE max showed no changes (43 ± 8, 41 ± 12, 41 ± 11 and 41 ± 9l/min, respectively, p=0.82) between groups. Thus, differences in VCO2/VE max and VE/VCO2 slope between groups were due mostly to changes in VCO2, i.e. in cardiac output, rather than ventilation. The same behavior was observed for VO2/VE max. CONCLUSIONS: A high VE/VCO2 slope observed in patients with repaired, noncyanotic CHD seems not to depend on excessive ventilation but on hypoperfusion due to impaired cardiac output response to incremental exercise. This finding should focus researchers' attention mainly on the heart when addressing exercise pathophysiology of this patient population.