Exercise Pathophysiology and Testing in Individuals With a Fontan Circulation.

The Fontan circulation, a surgical palliation for single-ventricle congenital heart disease, profoundly impacts the cardiopulmonary response to exercise. Reliant on passive pulmonary blood flow, the Fontan circulation has limited capacity to augment cardiac output as necessary to supply working muscles during exercise. Cardiopulmonary exercise testing (CPET) objectively assesses cardiorespiratory fitness and provides insight into the etiology of exercise intolerance. Furthermore, CPET variables, such as peak oxygen consumption and submaximal variables, have prognostic value and may be used as meaningful endpoints in research studies. CPET is also useful in clinical research applications to assess the effect of pharmacologic or other interventions. Medical therapies to improve exercise tolerance in individuals with a Fontan circulation, such as pulmonary vasodilators, may modestly improve peak oxygen consumption. Exercise training focused on aerobic fitness and lower extremity strength may have a more consistent and larger impact on these measures of aerobic fitness. CPET is a valuable diagnostic and prognostic tool for those with a Fontan circulation. Newer ancillary assessments, such as noninvasive peripheral venous pressure monitoring and cardiac output measurements, hold promise to provide a more nuanced insight into the underlying pathophysiology.

La circulation de Fontan, une solution chirurgicale palliative aux cardiopathies congénitales univentriculaires, a de profondes répercussions sur la réponse cardiorespiratoire à l'exercice physique. Puisqu'elle repose sur un flux sanguin pulmonaire passif, la circulation de Fontan présente une capacité limitée à accroître le débit cardiaque au besoin pour assurer l'approvisionnement des muscles durant l'effort physique. L'épreuve d'effort cardiorespiratoire (EECR) permet de mesurer la capacité cardiorespiratoire de manière objective et de mieux comprendre les causes de l'intolérance à l'effort. En outre, les variables mesurées lors de l'EECR, comme la consommation maximale d'oxygène (VO2) et les variables sous-maximales, ont une valeur pronostique et pourraient constituer des critères d'évaluation pertinents dans les travaux de recherche.L'EECR possède également des applications utiles en recherche clinique pour évaluer les effets des interventions pharmacologiques ou d'autre nature. Les traitements médicaux qui visent à améliorer la tolérance à l'effort chez les personnes ayant une circulation de Fontan, comme les vasodilatateurs pulmonaires, pourraient entraîner une modeste augmentation de la valeur maximale de VO2. L'entraînement physique axé sur la capacité aérobique et sur la force des membres inférieurs pourrait avoir un effet plus constant et important sur ces mesures de la capacité aérobique. L'EECR est un précieux outil diagnostique et pronostique pour l'évaluation des patients ayant une circulation de Fontan. Des méthodes d'évaluation complémentaires plus récentes, comme la surveillance non invasive de la pression veineuse périphérique et les mesures du débit cardiaque, sont des avenues prometteuses vers une compréhension plus nuancée des mécanismes physiopathologiques sous-jacents.

Associations Between Characteristics of Individuals With Fontan Circulation With Blood and Urine Biomarkers of Kidney Injury and Dysfunction.

Background Fontan circulation is associated with kidney injury and dysfunction, often unappreciated until Fontan circulatory failure. We hypothesized that cystatin C-estimated glomerular filtration rate (eGFR) would identify chronic kidney disease more frequently and that urine kidney injury biomarkers would be higher with declining Fontan physiological features. Methods and Results We enrolled 100 ambulatory individuals. Blood and urinary laboratory measurements were compared with demographics and clinically obtained data. Different eGFR equations were used for individuals aged ≥19 years and <19 years. Chronic kidney disease was defined as eGFR <90 mL/min per 1.73 m2. Median (25th-75th percentile) age was 19 (14-26) years, and 43% were female patients. Cystatin C eGFR detected chronic kidney disease (37%) in more patients than creatinine eGFR (11%). Cystatin C eGFR was positively associated, and skeletal muscle mass was negatively associated, with creatinine eGFR in both univariate (cystatin C eGFR ß=0.44±0.12, P=0.0006; skeletal muscle mass ß=-0.72±0.32, P=0.03) and multivariable analysis (cystatin C eGFR ß=0.43±0.12, P=0.0005; skeletal muscle mass ß=-0.69±0.29, P=0.02). Urine neutrophil gelatinase-associated lipocalin concentration correlated with Fontan pressure (r=0.28; P=0.04), ventricular end-diastolic pressure (r=0.28; P=0.04), and body fat mass (r=0.26; P=0.03). Conclusions Cystatin C eGFR identified more kidney dysfunction, likely attributable to creatinine eGFR being confounded by skeletal muscle mass. Elevated urine neutrophil gelatinase-associated lipocalin was associated with worse Fontan hemodynamics and higher percentage body fat, suggesting that higher venous pressure and higher adiposity are associated with ongoing kidney injury.

The impact of the COVID-19 pandemic on individuals with Fontan circulation: Focus on gaps in care.

Background: Gaps in subspecialty cardiology care could potentially delay identification and care for multi-organ complications common in patients with Fontan circulation. This study analyzed the frequency of gaps in care for individuals with Fontan circulation during the COVID-19 pandemic and associated demographic and clinical factors. Methods: This retrospective study evaluated individuals with Fontan circulation followed at our center since 2010. A gap in care was defined as an absence of any formal cardiology provider-patient contact (clinic visit or telehealth) for >15 months. Results: Over a third of 308 patients with Fontan circulation experienced at least one gap in care between 2010 and 2022, and 77 experienced a gap in care during the COVID-19 pandemic. Of this latter group, 27 (35%) had never experienced a prior gap in cardiology care until the pandemic. Those who experienced gaps in care during the pandemic were on average older (18.0 [IQR 9.6-25.6] vs. 14.2 [7.2-21.2] years, p = 0.01), more likely to be of Black/African American race (23.4% vs 7.4%, p = 0.001), and less likely to have a diagnosis of protein-losing enteropathy or plastic bronchitis (0% vs. 8.6%, p = 0.005). Those without a gap in care during the pandemic were more likely to have utilized telehealth visits (13% vs 3%, p = 0.02). Conclusion: Gaps in care are common and appear to have been exacerbated by the COVID-19 pandemic in those with a Fontan circulation. Such gaps are particularly common among African American and adult patients, and may potentially be mitigated by expanding telehealth access.

Fluoroscopy-free ablation in congenital heart disease of moderate or great complexity.

BACKGROUND: Fluoroscopy-free (FF) ablation has been demonstrated to be safe and successful in patients with structurally normal hearts, but has not been systematically evaluated in patients with congenital heart disease (CHD) of moderate or great (M/G) complexity. This study aimed to evaluate and compare feasibility, safety, and outcomes of FF ablation in patients with or without M/G-CHD. METHODS: Consecutive patients undergoing electrophysiologic study and intended catheter ablation over a 24-month period were included. Subgroups were created based on presence and complexity of CHD-M/G-CHD or simple complexity/no CHD (S/N-CHD). Cases with total radiation dose of zero qualified as FF. Demographic and peri-procedural variables and outcome data were analyzed. RESULTS: A total of 89 procedures were included with 62 comprising the S/N-CHD group and 27 comprising the M/G-CHD group. Of the M/G-CHD patients, 13 had CHD of great complexity (including 6 single ventricle/Fontan and 2 atrial switch patients). Patients with M/G-CHD were older, had higher BMI, had higher incidence of ventricular dysfunction, and greater incidence of complex arrhythmias. Fluoroscopy-free ablation was achieved in 59% of M/G-CHD and 69% of S/N-CHD patients. Both groups had similar rates of acute procedural success, recurrence, and complications. Fluoroscopy was primarily used to visualize pre-existing transvenous leads and peripheral venous anomalies or to guide transbaffle/transseptal puncture. CONCLUSIONS: A fluoroscopy-free ablation approach is feasible, safe, and successful even in patients with M/G-CHD with comparable outcomes to those with S/N-CHD.

Health Care Policy and Congenital Heart Disease: 2020 Focus on Our 2030 Future.

The congenital heart care community faces a myriad of public health issues that act as barriers toward optimum patient outcomes. In this article, we attempt to define advocacy and policy initiatives meant to spotlight and potentially address these challenges. Issues are organized into the following 3 key facets of our community: patient population, health care delivery, and workforce. We discuss the social determinants of health and health care disparities that affect patients in the community that require the attention of policy makers. Furthermore, we highlight the many needs of the growing adults with congenital heart disease and those with comorbidities, highlighting concerns regarding the inequities in access to cardiac care and the need for multidisciplinary care. We also recognize the problems of transparency in outcomes reporting and the promising application of telehealth. Finally, we highlight the training of providers, measures of productivity, diversity in the workforce, and the importance of patient-family centered organizations in advocating for patients. Although all of these issues remain relevant to many subspecialties in medicine, this article attempts to illustrate the unique needs of this population and highlight ways in which to work together to address important opportunities for change in the cardiac care community and beyond. This article provides a framework for policy and advocacy efforts for the next decade.

Cardiac MRI Detection of Left Ventricular Aneurysm in Children After Ventricular Assist Device Explantation.

Consensus is lacking regarding screening for complications such as ventricular aneurysms after ventricular assist device explant. We report two pediatric patients, status-post explantation, who developed true left ventricular apical aneurysms diagnosed by cardiac magnetic resonance imaging. Imaging also suggested laminated thrombus versus postoperative changes which were treated with antiplatelet therapy.

Retro-aortic brachiocephalic vein with azygous vein continuation: a rare vascular variant.

We present an infant with incidentally found retro-aortic left brachiocephalic vein draining directly into azygous vein. This rare vascular variant is asymptomatic but does have clinical implications with surgical and interventional procedures.

Electrocardiographic interference: know your patient well.

Two cases of paediatric patients with gastric pacemakers causing distinct electrocardiographic artefact. Recognition of extracardiac artefact is essential for proper ECG interpretation in patients.

Leadless Pacemaker Implantation in a Four-year-old, 16-kg Child.

Leadless pacemakers have an accepted role with demonstrable benefits in adults. In contrast, implant experience and follow-up data in pediatric patients are more limited. Clinical indications and patient candidacy for leadless pacing in pediatrics continue to evolve. We present our experience implanting a leadless pacemaker in a four-year-old for the treatment of high-grade atrioventricular block. Implant considerations in small patients, short-term patient and device follow-up data, and follow-up assessment of the vessel used for implantation are discussed.

Myocardial Ischemia with Cannabinoid Use in an Adolescent.

A 16-year-old male presented to the emergency department with chest pain after smoking a synthetic cannabinoid from a vape pen. He had rising troponin I levels, and his exercise stress echocardiogram showed distal apical and septal hypokinesis that resolved at six-month follow-up. This case report raises concern about cardiac ischemia related to synthetic cannabinoid abuse in the pediatric population in the current era of cannabis legalization.