Impact of Age-Related Change in Caval Flow Ratio on Hepatic Flow Distribution in the Fontan Circulation.

BACKGROUND: The Fontan operation is a palliative technique for patients born with single ventricle heart disease. The superior vena cava (SVC), inferior vena cava (IVC), and hepatic veins are connected to the pulmonary arteries in a total cavopulmonary connection by an extracardiac conduit or a lateral tunnel connection. A balanced hepatic flow distribution (HFD) to both lungs is essential to prevent pulmonary arteriovenous malformations and cyanosis. HFD is highly dependent on the local hemodynamics. The effect of age-related changes in caval inflows on HFD was evaluated using cardiac magnetic resonance data and patient-specific computational fluid dynamics modeling. METHODS: SVC and IVC flow from 414 patients with Fontan were collected to establish a relationship between SVC:IVC flow ratio and age. Computational fluid dynamics modeling was performed in 60 (30 extracardiac and 30 lateral tunnel) patient models to quantify the HFD that corresponded to patient ages of 3, 8, and 15 years, respectively. RESULTS: SVC:IVC flow ratio inverted at ≈8 years of age, indicating a clear shift to lower body flow predominance. Our data showed that variation of HFD in response to age-related changes in caval inflows (SVC:IVC, 2, 1, and 0.5 corresponded to ages, 3, 8, and 15+, respectively) was not significant for extracardiac but statistically significant for lateral tunnel cohorts. For all 3 caval inflow ratios, a positive correlation existed between the IVC flow distribution to both the lungs and the HFD. However, as the SVC:IVC ratio changed from 2 to 0.5 (age, 3-15+) years, the correlation's strength decreased from 0.87 to 0.64, due to potential flow perturbation as IVC flow momentum increased. CONCLUSIONS: Our analysis provided quantitative insights into the impact of the changing caval inflows on Fontan's long-term HFD, highlighting the importance of SVC:IVC variations over time on Fontan's long-term hemodynamics. These findings broaden our understanding of Fontan hemodynamics and patient outcomes.

Design and implementation of multicenter pediatric and congenital studies with cardiovascular magnetic resonance: Big data in smaller bodies.

Cardiovascular magnetic resonance (CMR) has become the reference standard for quantitative and qualitative assessment of ventricular function, blood flow, and myocardial tissue characterization. There is a preponderance of large CMR studies and registries in adults; However, similarly powered studies are lacking for the pediatric and congenital heart disease (PCHD) population. To date, most CMR studies in children are limited to small single or multicenter studies, thereby limiting the conclusions that can be drawn. Within the PCHD CMR community, a collaborative effort has been successfully employed to recognize knowledge gaps with the aim to embolden the development and initiation of high-quality, large-scale multicenter research. In this publication, we highlight the underlying challenges and provide a practical guide toward the development of larger, multicenter initiatives focusing on PCHD populations, which can serve as a model for future multicenter efforts.

A Deep Learning Pipeline for Assessing Ventricular Volumes from a Cardiac MRI Registry of Patients with Single Ventricle Physiology.

Purpose To develop an end-to-end deep learning (DL) pipeline for automated ventricular segmentation of cardiac MRI data from a multicenter registry of patients with Fontan circulation (Fontan Outcomes Registry Using CMR Examinations [FORCE]). Materials and Methods This retrospective study used 250 cardiac MRI examinations (November 2007-December 2022) from 13 institutions for training, validation, and testing. The pipeline contained three DL models: a classifier to identify short-axis cine stacks and two U-Net 3+ models for image cropping and segmentation. The automated segmentations were evaluated on the test set (n = 50) by using the Dice score. Volumetric and functional metrics derived from DL and ground truth manual segmentations were compared using Bland-Altman and intraclass correlation analysis. The pipeline was further qualitatively evaluated on 475 unseen examinations. Results There were acceptable limits of agreement (LOA) and minimal biases between the ground truth and DL end-diastolic volume (EDV) (bias: -0.6 mL/m2, LOA: -20.6 to 19.5 mL/m2) and end-systolic volume (ESV) (bias: -1.1 mL/m2, LOA: -18.1 to 15.9 mL/m2), with high intraclass correlation coefficients (ICCs > 0.97) and Dice scores (EDV, 0.91 and ESV, 0.86). There was moderate agreement for ventricular mass (bias: -1.9 g/m2, LOA: -17.3 to 13.5 g/m2) and an ICC of 0.94. There was also acceptable agreement for stroke volume (bias: 0.6 mL/m2, LOA: -17.2 to 18.3 mL/m2) and ejection fraction (bias: 0.6%, LOA: -12.2% to 13.4%), with high ICCs (>0.81). The pipeline achieved satisfactory segmentation in 68% of the 475 unseen examinations, while 26% needed minor adjustments, 5% needed major adjustments, and in 0.4%, the cropping model failed. Conclusion The DL pipeline can provide fast standardized segmentation for patients with single ventricle physiology across multiple centers. This pipeline can be applied to all cardiac MRI examinations in the FORCE registry. Keywords: Cardiac, Adults and Pediatrics, MR Imaging, Congenital, Volume Analysis, Segmentation, Quantification Supplemental material is available for this article. © RSNA, 2023.

Ventricular dyssynchrony late after the Fontan operation is associated with decreased survival.

BACKGROUND: Ventricular dyssynchrony and its relationship to clinical outcomes is not well characterized in patients following Fontan palliation. METHODS: Single-center retrospective analysis of cardiac magnetic resonance (CMR) imaging of patients with a Fontan circulation and an age-matched healthy comparison cohort as controls. Feature tracking was performed on all slices of a ventricular short-axis cine stack. Circumferential and radial strain, strain rate, and displacement were measured; and multiple dyssynchrony metrics were calculated based on timing of these measurements (including standard deviation of time-to-peak, maximum opposing wall delay, and maximum base-to-apex delay). Primary endpoint was a composite measure including time to death, heart transplant or heart transplant listing (D/HTx). RESULTS: A total of 503 cases (15 y; IQR 10, 21) and 42 controls (16 y; IQR 11, 20) were analyzed. Compared to controls, Fontan patients had increased dyssynchrony metrics, longer QRS duration, larger ventricular volumes, and worse systolic function. Dyssynchrony metrics were higher in patients with right ventricular (RV) or mixed morphology compared to those with LV morphology. At median follow-up of 4.3 years, 11% had D/HTx. Multiple risk factors for D/HTx were identified, including RV morphology, ventricular dilation, dysfunction, QRS prolongation, and dyssynchrony. Ventricular dilation and RV morphology were independently associated with D/HTx. CONCLUSIONS: Compared to control LVs, single right and mixed morphology ventricles in the Fontan circulation exhibit a higher degree of mechanical dyssynchrony as evaluated by CMR-FT. Dyssynchrony indices correlate with ventricular size and function and are associated with death or need for heart transplantation. These data add to the growing understanding regarding factors that can be used to risk-stratify patients with the Fontan circulation.

Cardiac Magnetic Resonance Imaging to Determine Single Ventricle Function in a Pediatric Population is Feasible in a Large Trial Setting: Experience from the Single Ventricle Reconstruction Trial Longitudinal Follow up.

The Single Ventricle Reconstruction (SVR) Trial was a randomized prospective trial designed to determine survival advantage of the modified Blalock-Taussig-Thomas shunt (BTTS) vs the right ventricle to pulmonary artery conduit (RVPAS) for patients with hypoplastic left heart syndrome. The primary aim of the long-term follow-up (SVRIII) was to determine the impact of shunt type on RV function. In this work, we describe the use of CMR in a large cohort follow up from the SVR Trial as a focused study of single ventricle function. The SVRIII protocol included short axis steady-state free precession imaging to assess single ventricle systolic function and flow quantification. There were 313 eligible SVRIII participants and 237 enrolled, ages ranging from 10 to 12.5 years. 177/237 (75%) participants underwent CMR. The most common reasons for not undergoing CMR exam were requirement for anesthesia (n = 14) or ICD/pacemaker (n = 11). A total of 168/177 (94%) CMR studies were diagnostic for RVEF. Median exam time was 54 [IQR 40-74] minutes, cine function exam time 20 [IQR 14-27] minutes, and flow quantification time 18 [IQR 12-25] minutes. There were 69/177 (39%) studies noted to have intra-thoracic artifacts, most common being susceptibility artifact from intra-thoracic metal. Not all artifacts resulted in non-diagnostic exams. These data describe the use and limitations of CMR for the assessment of cardiac function in a prospective trial setting in a grade-school-aged pediatric population with congenital heart disease. Many of the limitations are expected to decrease with the continued advancement of CMR technology.

Magnetic resonance three-dimensional steady-state free precession imaging of the thoracic duct in patients with Fontan circulation and its relationship to outcomes.

BACKGROUND: Lymphatic complications are common in patients with Fontan circulation. Three-dimensional balanced steady-state free precession (3D bSSFP) angiography by cardiovascular magnetic resonance (CMR) is widely used for cardiovascular anatomical assessment. We sought to determine the frequency of thoracic duct (TD) visualization using 3D bSSFP images and assess whether TD characteristics are associated with clinical outcomes. METHODS: This was a retrospective, single-center study of patients with Fontan circulation who underwent CMR. Frequency matching of age at CMR was used to construct a comparison group of patients with repaired tetralogy of Fallot (rTOF). TD characteristics included maximum diameter and a qualitative assessment of tortuosity. Clinical outcomes included protein-losing enteropathy (PLE), plastic bronchitis, listing for heart transplantation, and death. A composite outcome was defined as presence of any of these events. RESULTS: The study included 189 Fontan patients (median age 16.1 years, IQR 11.0-23.2 years) and 36 rTOF patients (median age 15.7 years, IQR 11.1-23.7 years). The TD diameter was larger (median 2.50 vs. 1.95 mm, p = 0.002) and more often well visualized (65% vs. 22%, p < 0.001) in Fontan patients vs. rTOF patients. TD dimension increased mildly with age in Fontan patients, R = 0.19, p = 0.01. In Fontan patients, the TD diameter was larger in those with PLE vs. without PLE (age-adjusted mean 4.11 vs. 2.72, p = 0.005), and was more tortuous in those with NYHA class ≥ II vs. class I (moderate or greater tortuosity 75% vs. 28.5%, p = 0.02). Larger TD diameter was associated with a lower ventricular ejection fraction that was independent of age (partial correlation = - 0.22, p = 0.02). More tortuous TDs had a higher end-systolic volume (mean 70.0 mL/m2 vs. 57.3 mL/m2, p = 0.03), lower creatinine (mean 0.61 mg/dL vs. 0.70 mg/dL, p = 0.04), and a higher absolute lymphocyte count (mean 1.80 K cells/µL vs. 0.76 K cells/µL, p = 0.003). The composite outcome was present in 6% of Fontan patients and was not associated with TD diameter (p = 0.50) or tortuosity (p = 0.09). CONCLUSIONS: The TD is well visualized in two-thirds of patients with Fontan circulation on 3D-bSSFP images. Larger TD diameter is associated with PLE and increased TD tortuosity is associated with an NYHA class ≥ II.

The Fontan Udenafil Exercise Longitudinal Trial: Subgroup Analysis.

The Pediatric Heart Network's Fontan Udenafil Exercise Longitudinal (FUEL) Trial (Mezzion Pharma Co. Ltd., NCT02741115) demonstrated improvements in some measures of exercise capacity and in the myocardial performance index following 6 months of treatment with udenafil (87.5 mg twice daily). In this post hoc analysis, we evaluate whether subgroups within the population experienced a differential effect on exercise performance in response to treatment. The effect of udenafil on exercise was evaluated within subgroups defined by baseline characteristics, including peak oxygen consumption (VO2), serum brain-type natriuretic peptide level, weight, race, gender, and ventricular morphology. Differences among subgroups were evaluated using ANCOVA modeling with fixed factors for treatment arm and subgroup and the interaction between treatment arm and subgroup. Within-subgroup analyses demonstrated trends toward quantitative improvements in peak VO2, work rate at the ventilatory anaerobic threshold (VAT), VO2 at VAT, and ventilatory efficiency (VE/VCO2) for those randomized to udenafil compared to placebo in nearly all subgroups. There was no identified differential response to udenafil based on baseline peak VO2, baseline BNP level, weight, race and ethnicity, gender, or ventricular morphology, although participants in the lowest tertile of baseline peak VO2 trended toward larger improvements. The absence of a differential response across subgroups in response to treatment with udenafil suggests that the treatment benefit may not be restricted to specific sub-populations. Further work is warranted to confirm the potential benefit of udenafil and to evaluate the long-term tolerability and safety of treatment and to determine the impact of udenafil on the development of other morbidities related to the Fontan circulation.Trial Registration NCT0274115.

Thromboprophylaxis in Patients With Fontan Circulation.

BACKGROUND: The optimal strategy for thromboprophylaxis in patients with a Fontan circulation is unknown. OBJECTIVES: The aim of this study was to compare the efficacy and safety of aspirin, warfarin, and nonvitamin K oral anticoagulants (NOACs) in a network meta-analysis. METHODS: Relevant studies published by February 2022 were included. The primary efficacy outcome was thromboembolic events; major bleeding was a secondary safety outcome. Frequentist network meta-analyses were conducted to estimate the incidence rate ratios (IRRs) of both outcomes. Ranking of treatments was performed based on probability (P) score. RESULTS: A total of 21 studies were included (26,546 patient-years). When compared with no thromboprophylaxis, NOAC (IRR: 0.11; 95% CI: 0.03-0.40), warfarin (IRR: 0.23; 95% CI: 0.14-0.37), and aspirin (IRR: 0.24; 95% CI: 0.15-0.39) were all associated with significantly lower rates of thromboembolic events. However, the network meta-analysis revealed no significant differences in the rates of major bleeding (NOAC: IRR: 1.45 [95% CI: 0.28-7.43]; warfarin: IRR: 1.38 [95% CI: 0.41-4.69]; and aspirin: IRR: 0.72 [95% CI: 0.20-2.58]). Rankings, which simultaneously analyze competing interventions, suggested that NOACs have the highest P score to prevent thromboembolic events (P score 0.921), followed by warfarin (P score 0.582), aspirin (P score 0.498), and no thromboprophylaxis (P score 0.001). Aspirin tended to have the most favorable overall profile. CONCLUSIONS: Aspirin, warfarin, and NOAC are associated with lower risk of thromboembolic events. Recognizing the limited number of patients and heterogeneity of studies using NOACs, the results support the safety and efficacy of NOACs in patients with a Fontan circulation.

Longitudinal changes in ventricular size and function are associated with death and transplantation late after the Fontan operation.

BACKGROUND: Cross-sectional studies have reported that ventricular dilation and dysfunction are associated with adverse clinical outcome in Fontan patients; however, longitudinal changes and their relationship with outcome are not known. METHODS: This was a single-center retrospective analysis of Fontan patients with at least 2 cardiovascular magnetic resonance (CMR) scans without intervening interventions. Serial measures of end-diastolic volume index (EDVI), end-systolic volume index (ESVI), ejection fraction (EF), indexed mass (massi), mass-to-volume ratio, and end-systolic wall stress (ESWS) were used to estimate within-patient change over time. Changes were compared for those with and without a composite outcome (death, heart transplant, or transplant listing) as well as between patients with left (LV) and right ventricular (RV) dominance. RESULTS: Data from 156 patients were analyzed with a mean age at 1st CMR of 17.8 ± 9.6 years. 490 CMRs were included with median of 3 CMRs/patient (range 2-9). On regression analysis with mixed effects models, volumes and ESWS increased, while mass, mass-to-volume ratio, and EF decreased over time. With a median follow-up of 10.2 years, 14% met the composite outcome. Those with the composite outcome had a greater increase in EDVI compared to those without (4.7 vs. 0.8 ml/BSA1.3/year). Compared with LV dominance, RV dominance was associated with a greater increase in ESVI (1.4 vs. 0.5 ml/BSA1.3/year), a greater decrease in EF (- 0.61%/year vs. - 0.24%/year), and a higher rate of the composite outcome (21% vs. 8%). CONCLUSIONS: Ventricles in the Fontan circulation exhibit a steady decline in performance with an increase in EDVI, ESVI, and ESWS, and decrease in EF, mass index, and mass-to-volume ratio. Those with death or need for heart transplantation have a faster increase in EDVI. Patients with rapid increase in EDVI (> 5 ml/BSA1.3/year) may be at a higher risk of adverse outcomes and may benefit from closer surveillance. RV dominance is associated with worse clinical outcomes and remodeling compared to LV dominance.

Isolated Coarctation of the Aorta: Current Concepts and Perspectives.

Current management of isolated CoA, localized narrowing of the aortic arch in the absence of other congenital heart disease, is a success story with improved prenatal diagnosis, high survival and improved understanding of long-term complication. Isolated CoA has heterogenous presentations, complex etiologic mechanisms, and progressive pathophysiologic changes that influence outcome. End-to-end or extended end-to-end anastomosis are the favored surgical approaches for isolated CoA in infants and transcatheter intervention is favored for children and adults. Primary stent placement is the procedure of choice in larger children and adults. Most adults with treated isolated CoA thrive, have normal daily activities, and undergo successful childbirth. Fetal echocardiography is the cornerstone of prenatal counseling and genetic testing is recommended. Advanced 3D imaging identifies aortic complications and myocardial dysfunction and guides individualized therapies including re-intervention. Adult CHD program enrollment is recommended. Longer follow-up data are needed to determine the frequency and severity of aneurysm formation, myocardial dysfunction, and whether childhood lifestyle modifications reduce late-onset complications.

Characterization of Circulating and Urinary Biomarkers in the Fontan Circulation and Their Correlation With Cardiac Imaging.

Several circulating biomarkers have been found to play a role in the surveillance and risk stratification of heart failure without congenital heart disease, but these have not been widely studied in patients with single ventricles palliated with a Fontan operation. Imaging predictors of worse outcomes in this population include ventricular dilation and dysfunction. Patients who weighed >30 kg with a Fontan circulation referred for cardiac magnetic resonance imaging were invited to participate in the study. Blood and urine samples were obtained at the time of imaging and multiple conventional and novel biomarkers were measured. A total of 82 patients with a median age of 18 years were enrolled. Among the novel biomarkers, N-terminal pro-B-type natriuretic peptide (NT-proBNP) and high-sensitivity troponin T had the strongest correlation with ventricular dilation and dysfunction. NT-ProBNP >100 pg/ml has a sensitivity of 91% for the detection of significant ventricular dilation (end-diastolic volume >120 ml/body surface area1.3) and 82% for detection of ejection fraction <50%. The urinary neutrophil gelatinase-associated lipocalin-2 to creatinine ratio correlated with ejection fraction and estimated glomerular filteration rate. In conclusion, abnormalities in biomarkers of heart failure are common in ambulatory, largely asymptomatic patients with Fontan circulation. NT-ProBNP may serve as a sensitive marker for the identification of patients with significant ventricular dilation or dysfunction. Further work is needed to understand how these easily measured circulating biomarkers may be integrated into clinical care.

Reaching consensus for unified medical language in Fontan care.

AIMS: The Fontan operation has resulted in improved survival in patients with single-ventricle congenital heart disease. As a result, there is a growing population of teenagers and adults with a Fontan circulation. Many co-morbidities have been increasingly recognized in this population due to the unique features of the Fontan circulation. Standardization of how Fontan co-morbid conditions are defined will help facilitate understanding, consistency and interpretability of research and clinical experience. Unifying common language usage in Fontan is a critical precursor step for data comparison of research findings and clinical outcomes and ultimately accelerating improvements in management for this growing group of patients. This manuscript aimed to create unified definitions for morbidities seen after the Fontan palliation. METHODS: In association of many congenital heart disease organizations, this work used Delphi methodology to reach a broad consensus among recognized experts regarding commonly used terms in Fontan care and research. Each definition underwent at least three rounds of revisions to reach a final definition through surveys sent to experts in the field of single-ventricle care. RESULTS: The process of reaching a consensus on multiple morbidities associated with the Fontan procedure is summarized in this manuscript. The different versions that preceded reaching the consensus are also presented in the Supporting Information. Table 1 represents the final definitions according to the consensus. CONCLUSIONS: We propose the use of these definitions for clinical care, future research studies, registry development and clinical trials.

A Novel Pulmonary Valve Replacement Surgery Strategy Using Contracting Band for Patients With Repaired Tetralogy of Fallot: An MRI-Based Multipatient Modeling Study.

Patients with repaired Tetralogy of Fallot (ToF), a congenital heart defect which includes a ventricular septal defect and severe right ventricular outflow obstruction, account for the majority of cases with late-onset right ventricle (RV) failure. Current surgery procedures, including pulmonary valve replacement (PVR) with right ventricle remodeling, yield mixed results. PVR with active band insertion was hypothesized to be of clinical usage on improving RV function measured by ejection fraction (EF). In lieu of risky open-heart surgeries and experiments on animal and human, computational biomechanical models were adapted to study the impact of PVR with five band insertion options. Cardiac magnetic resonance (CMR) images were acquired from seven TOF patients before PVR surgery for model construction. For each patient, five different surgery plans combined with passive and active contraction band with contraction ratio of 20, 15, and 10% were studied. Those five plans include three single-band plans with different band locations; one plan with two bands, and one plan with three bands. Including the seven no-band models, 147 computational bi-ventricle models were constructed to simulate RV cardiac functions and identify optimal band plans. Patient variations with different band plans were investigated. Surgery plan with three active contraction bands and band active contraction ratio of 20% had the best performance on improving RV function. The mean ± SD RV ejection fraction value from the seven patients was 42.90 ± 5.68%, presenting a 4.19% absolute improvement or a 10.82% relative improvement, when compared with the baseline models (38.71 ± 5.73%, p = 0.016). The EF improvements from the seven patients varied from 2.87 to 6.01%. Surgical procedures using active contraction bands have great potential to improve RV function measured by ejection fraction for patients with repaired ToF. It is possible to have higher right ventricle ejection fraction improvement with more bands and higher band active contraction ratio. Our findings with computational models need to be further validated by animal experiments before clinical trial could become possible.

Atrial pacing in Fontan patients: The effect of transvenous lead on clot burden.

BACKGROUND: Transvenous permanent pacemaker (PPM) implantation is an available option for Fontan patients with sinus node dysfunction. However, the thrombogenic potential of leads within the Fontan baffle is unknown. OBJECTIVE: The purpose of this study was to compare the clot burden in Fontan patients with a transvenous atrial PPM to those without a PPM and those with an epicardial PPM. METHODS: This was a retrospective cohort study of all transvenous PPM implantations in Fontan patients followed at our institution (2000-2018). We performed frequency matching on Fontan type and age group. Primary outcome was identification of intracardiac clot, pulmonary embolus, or embolic stroke. RESULTS: Of 1920 Fontan patients, 58 patients (median age 23 years; interquartile range [25th-75th percentiles] 14-33) at the time of transvenous PPM implantation and 174 matched subjects formed our cohort. The type of Fontan performed in case subjects was right atrium-pulmonary artery or right atrium-right ventricle conduit (54%), lateral tunnel (43%), and extracardiac (3%). The cumulative incidence of clot was highest in patients with transvenous PPM, followed by patients with epicardial PPM and no PPM (1.2 vs 0.87 vs 0.67 per 100 person-years of follow-up, respectively). In multivariable analysis, anticoagulation and/or antiplatelet therapy were protective against clot and resulted in reduction of clot risk by 3-fold (incidence rate ratio 0.33; 95% confidence interval 0.21-0.53; P <.001). CONCLUSION: In a large cohort of Fontan patients matched for age and Fontan type, patients with transvenous PPM had a higher but not statistically significant incidence of clot compared to those with no PPM and epicardial PPM. Patients treated with warfarin/aspirin had lower clot risk.

Atrial function in the Fontan circulation: comparison with invasively assessed systemic ventricular filling pressure.

Abnormal atrial mechanics in biventricular circulations have been associated with elevated left heart filling pressures. Similar associations in the Fontan circulation are unknown. The aim of this study was to examine the relationship between atrial mechanics and invasively assessed hemodynamic parameters late after the Fontan operation. Thirty-nine Fontan patients with echocardiographic and invasive hemodynamic studies done within 48 h were included and were compared to 40 age-matched healthy controls. Atrial and ventricular strain measurements were measured offline using 2-dimensional speckle-tracking. Mean age was 10.2 ± 6.7 years and 24 (62%) were male. Atrial strain measures were lower in Fontan patients compared to healthy controls. There was no significant association between atrial strain measurements and Fontan systemic ventricular filling pressures (SVFP) as indicated by pulmonary artery occlusion pressures, direct left atrial pressure or systemic ventricular end-diastolic pressure. Global atrial strain was not correlated with segmental atrial strain in the pulmonary venous atrium. Global atrial reservoir strain was positively correlated with pulmonary vascular resistance (r = 0.508, p = 0.045). Global atrial conduit strain was positively correlated with E/A ratio of the AV valve inflow (r = 0.555, p = 0.002). Atrial and ventricular strain measurements were not significantly correlated. In patients with a Fontan, global atrial function is significantly depressed, and is uncoupled from segmental left lateral atrial function. Global as well as segmental atrial mechanics are not significantly associated with SVFPs in Fontan patients. Instead, global atrial reservoir function appears to parallel pulmonary vascular resistance.

Integrated Clinical and Magnetic Resonance Imaging Assessments Late After Fontan Operation.

BACKGROUND: Several clinical and cardiac magnetic resonance (CMR)-derived parameters have been shown to be associated with death or heart transplant late after the Fontan operation. OBJECTIVES: The objective of this study was to identify the relative importance and interactions of clinical and CMR-based parameters for risk stratification after the Fontan operation. METHODS: Fontan patients were retrospectively reviewed. Clinical and CMR parameters were analyzed using univariable Cox regression. The primary endpoint was time to death or (listing for) heart transplant. To identify the patients at highest risk for the endpoint, classification and regression tree survival analysis was performed, including all significant variables from Cox regression. RESULTS: The cohort consisted of 416 patients (62% male) with a median age of 16 years (25th, 75th percentiles: 11, 23 years). Over a median follow-up of 5.4 years (25th, 75th percentiles: 2.4, 10.0 years) after CMR, 57 patients (14%) reached the endpoint (46 deaths, 7 heart transplants, 4 heart transplant listings). Lower total indexed end-diastolic volume (EDVi) was the strongest predictor of transplant-free survival. Among patients with dilated ventricles (EDVi ≥156 ml/BSA1.3), worse global circumferential strain (GCS) was the next most important predictor (73% vs. 44%). In patients with smaller ventricles (EDVi <156 ml/BSA1.3), New York Heart Association functional class ≥II was the next most important predictor (30% vs. 4%). CONCLUSIONS: In this cohort of patients late after Fontan operation, increased ventricular dilation was the strongest independent predictor of death or transplant (listing). Patients with both ventricular dilation and worse GCS were at highest risk. These data highlight the value of integrating CMR and clinical parameters for risk stratification in this population.

Resynchronizing Right and Left Ventricles With Right Bundle Branch Block in the Congenital Heart Disease Population.

OBJECTIVES: This study describes a single center experience with the use of cardiac resynchronization therapy (CRT) in a difficult patient population, including single systemic right ventricles (RVs), subpulmonary RVs, and left ventricles (LVs) with right bundle branch block (RBBB). BACKGROUND: CRT remains challenging in the congenital heart disease population. METHODS: Consecutive patients undergoing resynchronization of single RVs, subpulmonary RVs, or LVs in the setting of RBBB were identified between 2016 and 2019. Patients who had CRT performed for complete heart block or had <3 months of follow-up were excluded. Patients underwent pre-procedural advanced imaging by echocardiogram, computed tomography, or cardiac magnetic resonance to assess ventricular function and synchrony; intraoperative mapping was performed to identify optimal lead placement. RESULTS: All patients undergoing resynchronization presented with at least moderate systolic ventricular dysfunction in the setting of intrinsic atrioventricular nodal conduction and RBBB. Seven patients were identified. Two patients underwent CRT of a single RV, 3 with subpulmonary RVs and 2 with systemic LVs. The median age at CRT was 5 years (range 0.6 to 48 years). The median follow-up was 9 months (range 3 to 18 months). The median baseline QRS duration was 180 ms (range 115 to 260ms). Post-CRT, the QRS duration decreased by a median of 34% (range 19% to 38%). All patients had improvement in their systolic ventricular function. CONCLUSIONS: Targeted resynchronization in systemic and subpulmonary RVs can be used to improve ventricular function and heart failure in the congenital heart disease population. Similar techniques can be applied to successfully treat patients with LV dysfunction and RBBB and improve their long-term outcomes.