Results From the Big Ten COVID-19 Cardiac Registry: Impact of SARS-COV-2 on Myocardial Involvement.

OBJECTIVE: COVID-19 has been associated with myocardial involvement in collegiate athletes. The first report from the Big Ten COVID-19 Cardiac Registry (Registry) was an ecological study that reported myocarditis in 37 of 1597 athletes (2.3%) based on local clinical diagnosis. Our objective was to assess the relationship between athlete and clinical characteristics and myocardial involvement. DESIGN: Cross-sectional study. SETTING: We analyzed data from 1218 COVID-19 positive Big Ten collegiate athletes who provided informed consent to participate in the Registry. PARTICIPANTS: 1218 athletes with a COVID-19-positive PCR test before June 1, 2021. ASSESSMENT OF INDEPENDENT VARIABLES: Demographic and clinical characteristics of athletes were obtained from the medical record. MAIN OUTCOME MEASURES: Myocardial involvement was diagnosed based on local clinical, cardiac magnetic resonance (CMR), electrocardiography, troponin assay, and echocardiography. We assessed the association of clinical factors with myocardial involvement using logistic regression and estimated the area under the receiver operating characteristic (ROC) curve. RESULTS: 25 of 1218 (2.0%) athletes met criteria for myocardial involvement. The logistic regression model used to predict myocardial involvement contained indicator variables for chest pain, new exercise intolerance, abnormal echocardiogram (echo), and abnormal troponin. The area under the ROC curve for these indicators was 0.714. The presence of any of these 4 factors in a collegiate athlete who tested positive for COVID-19 would capture 55.6% of cases. Among noncases without missing data, 86.9% would not be flagged for possible myocardial involvement. CONCLUSION: Myocardial involvement was infrequent. We predicted case status with good specificity but deficient sensitivity. A diagnostic approach for myocardial involvement based exclusively on symptoms would be less sensitive than one based on symptoms, echo, and troponin level evaluations. Abnormality of any of these evaluations would be an indication for CMR.

The Role of Multimodality Imaging in the Evaluation of Heart Failure and Surgical Transplant Planning of Patients with Adult Congenital Heart Disease.

Cardiac imaging is pivotal in evaluating ventricular function, residual lesions, and long-term complications in patients with adult congenital heart disease (ACHD). Longitudinal imaging in ACHD is key for the timely identification of patients requiring evaluation for advanced therapies. The guidelines recommend routine imaging surveillance. In all patients undergoing evaluation with cardiac imaging, it is critical that studies are performed at centers with expertise and that the imaging protocols are tailored to the specific condition. The authors briefly highlight the utility and diagnostic yield of different modalities, review pertinent considerations for special populations, and focus on imaging for transplant planning.

Patient Experience with Telemedicine in Adults with Congenital Heart Disease.

Introduction: The COVID-19 pandemic has resulted in increased use of telemedicine. There are limited data on patient experience with telemedicine in adults with congenital heart disease (ACHD). We hypothesized that due to their complex medical history, ACHD would prefer in-person clinic visits over telemedicine. Methods: We conducted a nurse-administered telephone survey based on Agency for Healthcare Research and Quality recommendations to assess patient experience after ACHD telemedicine visits in the early part of the pandemic from March 2020 to June 2020. Results: Of 216 ACHD who had telemedicine visits, 136 (63%) agreed to participate in the survey. Mean age was 45 ± 18 years, majority (65%) being video encounters. Most (98%) patients expressed that the telemedicine visit was successful in addressing their health care needs. Only 21 (15%) patients reported technical issues. Most patients (76%) preferred telemedicine given testing was provided separately, 25 (18%) preferred in-person clinic visits, and 8 (6%) had no preference. Of the 25 patients over 65 years, 19 (76%) would choose telemedicine over the in-person clinic, and only 1 patient reported technical difficulties. Conclusion: ACHD reported a positive experience with telemedicine. Technical limitations were infrequent even among the elderly. The majority of patients felt that their health care needs were addressed and would consider telemedicine over clinic visits. These data are important as payors move away from supporting telemedicine and hospitals restructure, with and without ongoing COVID-19 concerns.

Fully self-gated whole-heart 4D flow imaging from a 5-minute scan.

PURPOSE: To develop and validate an acquisition and processing technique that enables fully self-gated 4D flow imaging with whole-heart coverage in a fixed 5-minute scan. THEORY AND METHODS: The data are acquired continuously using Cartesian sampling and sorted into respiratory and cardiac bins using the self-gating signal. The reconstruction is performed using a recently proposed Bayesian method called ReVEAL4D. ReVEAL4D is validated using data from 8 healthy volunteers and 2 patients and compared with compressed sensing technique, L1-SENSE. RESULTS: Healthy subjects-Compared with 2D phase-contrast MRI (2D-PC), flow quantification from ReVEAL4D shows no significant bias. In contrast, the peak velocity and peak flow rate for L1-SENSE are significantly underestimated. Compared with traditional parallel MRI-based 4D flow imaging, ReVEAL4D demonstrates small but significant biases in net flow and peak flow rate, with no significant bias in peak velocity. All 3 indices are significantly and more markedly underestimated by L1-SENSE. Patients-Flow quantification from ReVEAL4D agrees well with the 2D-PC reference. In contrast, L1-SENSE markedly underestimated peak velocity. CONCLUSIONS: The combination of highly accelerated 5-minute Cartesian acquisition, self-gating, and ReVEAL4D enables whole-heart 4D flow imaging with accurate flow quantification.

Correlation of echocardiographic probability of pulmonary hypertension with maternal outcomes in pregnant women with elevated right ventricular systolic pressure.

INTRODUCTION: The use of echocardiography to evaluate the probability for pulmonary hypertension (PH) in pregnant women has not been reported or correlated with outcomes. We hypothesized that in women with elevated right ventricular systolic pressure (RVSP) on echocardiography first identified during pregnancy, those with low probability for PH would have fewer major adverse cardiac events (MACE). METHODS: We performed a retrospective cohort study of pregnant women with RVSP >35 mm Hg on echocardiogram first identified during pregnancy. Women were classified as intermediate-high probability for PH (HP) or low probability for PH (LP) based on simplified European Society of Cardiology echocardiographic criteria. Maternal cardiac, obstetric, and fetal outcomes were assessed. RESULTS: A total of 77 women met inclusion criteria (mean age 30 ± 5 years), with 45 (58%) classified as HP and 32 (42%) as LP. There were 21 (27%) women who experienced MACE, more commonly in the HP cohort (HP 18 (40%) women vs. LP 3 (9%) women, P = .01). The echocardiographic criteria for intermediate-high probability of PH identified women at risk for MACE with 85% sensitivity and 52% specificity. The negative predictive value for MACE in women meeting low echocardiographic probability for PH criteria was 91%. CONCLUSIONS: In women with elevated RVSP on echocardiography first identified during pregnancy, those with low echocardiographic PH probability are at significantly lower risk for MACE during pregnancy, though the risk is not eliminated. This may be useful to risk stratify pregnant women with suspected PH, guiding tertiary care referral and invasive catheterization.

Troponin Elevation in Sickle Cell Disease.

OBJECTIVE: Sickle cell disease is associated with cardiovascular abnormalities. Troponin is not typically measured in this population, and thus the significance of abnormal levels of troponin is unknown. We wanted to evaluate the use of troponin and factors that predispose troponin elevation in patients admitted with sickle cell pain crisis (SCPC). METHODS: We reviewed data of consecutive patients admitted to a tertiary care hospital between 2006 and 2011 with a diagnosis of SCPC. Subjects with elevated troponin (ET) (troponin I >0.04 ng/mL) were compared with those with normal troponin (NT) for demographics, risk factors, presence of echocardiography-derived tricuspid regurgitant jet velocity (TRV) ≥3 m/s suggesting pulmonary hypertension, and laboratory tests. The Mann-Whitney U test was used to compare groups. RESULTS: Two hundred eighty-three of 724 patients admitted with SCPC had chest pain. Troponin I was measured in 63 patients: 51 had NT and 12 had ET ranging from 0.06 to 3.42 ng/ml. ET was associated lower hemoglobin (p = 0.02), lower hematocrit (p = 0.02), lower platelet number (p < 0.001), higher LDH (p = 0.012), higher AST levels (p = 0.004), higher bilirubin levels (p = 0.006), and TRV ≥3 m/s (p = 0.028). CONCLUSIONS: Troponin was measured in <10% of patients with SCPC, and 1 out of 5 of them had ET. Troponin elevation was not associated with traditional cardiovascular risk factors but was associated with lower hematocrit, elevated LDH, bilirubin levels, and TRV ≥3 m/s.

Patient-Adaptive Magnetic Resonance Oximetry: Comparison With Invasive Catheter Measurement of Blood Oxygen Saturation in Patients With Cardiovascular Disease.

BACKGROUND: The current standard method to measure intracardiac oxygen (O2 ) saturation is by invasive catheterization. Accurate noninvasive blood O2 saturation by MRI could potentially reduce the duration and risk of invasive diagnostic procedures. PURPOSE: To noninvasively determine blood oxygen saturation in the heart with MRI and compare the accuracy with catheter measurements. STUDY TYPE: Prospective. SUBJECTS: Thirty-two patients referred for right heart catheterization (RHC) and five healthy subjects. FIELD STRENGTH/SEQUENCE: T2-prepared single-shot balanced steady-state free-precession at 1.5T. ASSESSMENT: MR signals in venous and arterial blood, hematocrit, and arterial O2 saturation from a pulse oximeter were jointly processed to fit the Luz-Meiboom model and estimate blood O2 saturation in the right heart. Interstudy reproducibility was evaluated in volunteers and patients. Interobserver reproducibility among three readers was assessed using data from volunteers and 10 patients. Accuracy of MR oximetry was compared to RHC in all patients. STATISTICAL TESTS: Coefficient of variation, intraclass correlation coefficient, Bland-Altman analysis, Pearson's correlation. RESULTS: The coefficient of variation for interstudy reproducibility of O2 saturation was 2.6% on average in volunteers and 3.2% in patients. Interobserver reproducibility among three observers yielded intraclass correlation coefficients of 0.81 and 0.87 respectively for RV and MPA O2 saturation. O2 saturation (y = 0.85x + 0.13, R = 0.78) and (a-v)O2 difference (y = 0.71x + 0.90, R = 0.69) by MR and RHC were significantly correlated (N = 32, P < 0.05 in both cases) in patients. MR slightly overestimated O2 saturation compared to RHC with 2% ± 5% bias and limits of agreement between -7% and 12%. DATA CONCLUSION: MR oximetry is repeatable and reproducible. Good agreement was shown between MR and catheter venous O2 saturation and (a-v)O2 difference in a cohort whose venous O2 ranged from abnormally low to high levels, with most values in the normal physiological range. LEVEL OF EVIDENCE: 2. TECHNICAL EFFICACY STAGE: 2.

Creatinine versus cystatin C to estimate glomerular filtration rate in adults with congenital heart disease: Results of the Boston Adult Congenital Heart Disease Biobank.

BACKGROUND: Glomerular filtration rate is a key physiologic variable with a central role in clinical decision making and a strong association with prognosis in diverse populations. Reduced estimated glomerular filtration rate (eGFR) is common among adults with congenital heart disease (ACHD). METHODS: We conducted a prospective cohort study of outpatient ACHD ≥18 years old seen in 2012-2017. Creatinine and cystatin C were measured; eGFR was calculated using either the creatinine or cystatin C Chronic Kidney Disease-Epidemiology Collaboration equation (CKD-EPICr and CKD-EPICysC, respectively). Survival analysis was performed to define the relationship between eGFR and both all-cause mortality and a composite outcome of death or nonelective cardiovascular hospitalization. RESULTS: Our cohort included 911 ACHD (39 ±â€¯14 years old, 49% female). Mean CKD-EPICr and CKD-EPICysC were similar (101 ±â€¯20 vs 100 ±â€¯23 mL/min/1.73 m2), but CKD-EPICr estimates were higher for patients with a Fontan circulation (n = 131, +10 ±â€¯19 mL/min/1.73 m2). After mean follow-up of 659 days, 128 patients (14.1%) experienced the composite outcome and 31 (3.4%) died. CKD-EPICysC more strongly predicted all-cause mortality (eGFR <60 vs >90 mL/min/1.73 m2: CKD-EPICysC unadjusted HR = 20.2 [95% CI 7.6-53.1], C-statistic = 0.797; CKD-EPICr unadjusted HR = 4.6 [1.7-12.7], C-statistic = 0.620). CKD-EPICysC independently predicted the composite outcome, whereas CKD-EPICr did not (CKD-EPICysC adjusted HR = 3.0 [1.7-5.3]; CKD-EPICr adjusted HR = 1.5 [0.8-3.1]). Patients reclassified to a lower eGFR category by CKD-EPICysC, compared with CKD-EPICr, were at increased risk for the composite outcome (HR = 2.9 [2.0-4.3], P < .0001); those reclassified to a higher eGFR class were at lower risk (HR = 0.5 [0.3-0.9], P = .03). CONCLUSIONS: Cystatin C-based eGFR more strongly predicts clinical events than creatinine-based eGFR in ACHD. Creatinine-based methods appear particularly questionable in the Fontan circulation.

Current Role of Blood and Urine Biomarkers in the Clinical Care of Adults with Congenital Heart Disease.

PURPOSE OF REVIEW: There is an increasing number of adult patients with congenital heart disease (CHD). While several biomarkers have been validated and integrated into general cardiology clinical practice, these tests are often applied to adults with CHD in the absence of disease-specific validation. Although these patients are often grouped into a single population, there is heterogeneous pathophysiology, variable disease chronicity, extensive multisystem involvement, and a low event rate relative to acquired heart disease. These stand as challenges to systematic investigation and clinical application of biomarkers for adults with CHD. This paper reviews recent studies investigating the use of biomarkers in this population, with emphasis on biomarkers applied in clinical adult CHD care. RECENT FINDINGS: A handful of biomarkers have been integrated into adult CHD practice, such as iron studies in cyanotic heart disease and stool alpha-1 antitrypsin for diagnosis of protein losing enteropathy in the Fontan circulation. Use of kidney and liver tests has been studied in prognostication of adult CHD patients. A few other biomarkers like natriuretic peptides and troponins seem likely to provide useful information in other ACHD situations based on limited disease-specific data and extrapolation from acquired heart disease. More research is needed to support the robust validity of most existing clinical biomarkers in adult congenital cardiology practice. Until data from larger, prospectively enrolled cohorts are available, clinical use of biomarkers in these patients will require careful interpretation with attention to underlying pathophysiology, as well as detailed understanding of potential pitfalls of specific assays and clinical contexts.

High-Risk Congenital Heart Disease in Pregnancy.

High-risk congenital heart disease (CHD) in pregnancy presents a complex clinical challenge. With improved medical care and increased survival rates, a growing population of adults with complex CHD are surviving to adulthood, including women of reproductive age. This chapter focuses on risk stratification and management of pregnant women with high-risk CHD, emphasizing the importance of considering both anatomical and physiological complexity. Maternal physiological changes, such as blood volume increase, cardiac output changes, and alterations in vascular resistance, can significantly impact high-risk CHD patients. Management of high-risk CHD in pregnancy necessitates a multidisciplinary approach and individualized care.

Invasive Implanted Hemodynamic Monitoring in Patients With Complex Congenital Heart Disease: State-of-the-Art Review.

As the number of patients with congenital heart disease (CHD) continues to increase, the burden of heart failure (HF) in this population requires innovative strategies to individualize management. Given the success of implanted invasive hemodynamic monitoring (IHM) with the CardioMEMSTM HF system in adults with acquired HF, this is often suggested for use in patients with CHD, though published data are limited to case reports and case series. Therefore, this review summarizes the available published reports on the use of IHM in patients with complex CHD, describes novel applications, and highlights future directions for study. In patients with CHD, IHM has been used across the lifespan, from age 3 years to adulthood, with minimal device-related complications reported. IHM uses include (1) prevention of HF hospitalizations; (2) reassessment of hemodynamics after titration of medical therapy without repeated cardiac catheterization; (3) serial monitoring of at-risk patients for pulmonary hypertension to optimize timing of heart transplant referral; (4) and hemodynamic assessment with exercise (5) or after ventricular assist device placement. IHM has the potential to reduce the number of cardiac catheterizations in anatomically complex patients and, in patients with Fontan circulation, IHM pressures may have prognostic implications. In conclusion, though further studies are needed, as patients with CHD age and HF is more prevalent, this tool may assist CHD physicians in caring for this complex patient population.

The impact of severe obesity on image quality and ventricular function assessment in echocardiography and cardiac MRI.

This study sought to evaluate the impact of severe obesity on image quality and ventricular function assessment in cardiovascular magnetic resonance (MRI) and trans-thoracic echocardiography (TTE). We studied 100 consecutive patients who underwent clinically indicated cardiac MRI and TTE studies within 12 months between July 2017 and December 2020; 50 (28 females and 22 males; 54.5 ± 18.7 years) with normal body mass index (BMI) (18.5-25 kg/m2) and 50 (21 females and 29 males; 47.2 ± 13.3 years) with severe obesity (BMI ≥ 40 kg/m2). MRI and TTE image quality scores were compared within and across cohorts using a linear mixed model. Categorical left (LVF) and right (RVF) ventricular function were compared using Cohens Kappa statistic. Mean BMI for normal weight and obese cohorts were 22.2 ± 1.7 kg/m2 and 50.3 ± 5.9 kg/m2, respectively. Out of a possible 93 points, mean MRI image quality score was 91.5 ± 2.5 for patients with normal BMI, and 88.4 ± 5.5 for patients with severe obesity; least square (LS) mean difference 3.1, p = 0.460. TTE scores were 64.2 ± 13.6 for patients with normal BMI and 46.0 ± 12.9 for patients with severe obesity, LS mean difference 18.2, p < 0.001. Ventricular function agreement between modalities was worse in the obese cohort for both LVF (72% vs 80% agreement; kappa 0.53 vs 0.70, obese vs. normal BMI), and RVF (58% vs 72% agreement, kappa 0.18 vs 0.34, obese vs. normal BMI). Severe obesity had limited impact on cardiac MRI image quality, while obesity significantly degraded TTE image quality and ventricular function agreement with MRI.

Sudden death in adults with repaired coarctation of the aorta: A case for sex-based risk factors.

Background: Sudden cardiac death (SCD) is an important risk for adults with repaired coarctation of the aorta (rCoA). We aimed determine if there are clinical risk factors for SCD in adults with rCoA. Methods and results: SCD events and clinical data from all adults with rCoA at a tertiary care center (2007-2017) were evaluated. In 167 adults with rCoA (39 ± 11 years old, 75 (45%) female) SCD occurred in 8 (5%) (vs. age-matched adults 0.9%). Those with SCD demonstrated significant QTc prolongation (QTc: 479 ± 16 vs. 434 ± 30 msec, p < 0.001). Overall, adults with rCoA and a prolonged sex-normative QTc interval had a 12-fold increased risk of SCD (x2 (1) = 12.3, p < 0.001), with men sustaining SCD at younger ages (42 ± 13 years vs. women 60 ± 10 years, p < 0.05). Multiple logistic regression modeling demonstrated that prolonged QTc selectively advanced risk for SCD in men only (x2 QTc prolongation 8.46, p < 0.005 and x2 age 0.29, p = 0.587), whereas in women, age was associated with SCD risk (x2 QTc prolongation 2.84, p = 0.092 and x2 age 7.81, p = 0.005). Non-sustained ventricular tachycardia, ventricular dysfunction, and myocardial fibrosis did not significantly impact SCD risk. Conclusions: There is an unanticipated high burden of SCD in adults with rCoA, occurring in men at younger age than women, suspicious for primary electrophysiologic dysfunction. Future investigation of sex-specific SCD risk in rCoA is important to better understand this disease and its late phenotype.

Novel uses for implanted haemodynamic monitoring in adults with subaortic right ventricles.

BACKGROUND: Pulmonary hypertension (PH) is a common complication in patients with complete dextro-transposition of the great arteries (TGA) after atrial switch (D-TGA/AS) and congenitally corrected TGA (ccTGA). In this population with subaortic right ventricles (sRVs), echocardiography is a poor screening tool for PH; implantable invasive haemodynamic monitoring (IHM) could be used for this purpose, but data are limited. The aim of this study is to report on novel uses of IHM in patients with sRV. METHODS: This retrospective study describes the uses of IHM, impact of IHM on heart failure hospitalisation (HFH) and device-related complications in adults with sRV from a single centre (2015-2022). RESULTS: IHM was placed in 18 patients with sRV (median age 43 (range 30-54) years, 8 female, 16 with D-TGA/AS, 2 with ccTGA); 16 had moderate or severe sRV systolic dysfunction, 13 had PH on catheterisation. IHM was used for (1) Medical therapy titration, (2) Medical management after ventricular assist device in patients with transplant-limiting PH and (3) Serial monitoring of pulmonary artery pressures without repeat catheterisations to help identify the optimal time for heart transplant referral. In follow-up (median 23 months), HFHs/year were similar to the year prior to IHM (median 0 (IQR 0-1.0) before vs 0 (0-0.8) after, p=0.984). Device migration occurred in one, without long-term sequelae. CONCLUSIONS: Uses of IHM in patients with sRV are described which may minimise the need for serial catheterisations in a population where PH is prevalent. HFHs were low overall but not impacted by IHM. One device-related complication occurred without long-term consequence.

Treatment of methadone-induced torsades de pointes with lidocaine.

Methadone maintenance treatment (MMT) is commonly used for chronic pain control and for substitution in heroin addicts undergoing rehabilitation. Methadone is known to prolong QT interval and sometimes cause torsade de pointes (TdP) and ventricular fibrillation (VF). Treatment of TdP by antiarrhythmic drugs that prolong QT interval may worsen TdP. To our knowledge, worsening of methadone-induced TdP by amiodarone has not been reported before. We describe here a case of methadone-induced TdP that deteriorated into ventricular fibrillation upon treatment with intravenous (IV) amiodarone and resolved after discontinuation of amiodarone and treatment with IV magnesium, potassium, and lidocaine.

Parametric mapping by cardiovascular magnetic resonance imaging in sudden cardiac arrest survivors.

Etiology of sudden cardiac arrest (SCA) is identified in less than 30% of survivors without coronary artery disease. We sought to assess the diagnostic role of myocardial parametric mapping using cardiovascular magnetic resonance (CMR) in identifying SCA etiology. Consecutive SCA survivors undergoing CMR with myocardial parametric mapping were included in the study. The determination if CMR was decisive or contributory in identifying SCA etiology was made if the diagnosis was unclear prior to CMR, and the discharge diagnosis was consistent with the CMR result. Parametric mapping was considered essential for establishing probable SCA etiology by CMR if the SCA cause could not have been determined without its utilization. If the CMR diagnosis could have been potentially based on the combination of cine and LGE imaging, parametric mapping was considered contributory. Of the 35 patients (mean age 46.9 ± 14.1 years; 57% males) included, SCA diagnosis was based on CMR in 23 (66%) patients. Of those, parametric mapping was essential for the diagnosis of myocarditis and tako-tsubo cardiomyopathy (11/48%) and contributed to the diagnosis in 10 (43%) additional cases. Inclusion of quantitative T1 and T2 parametric mapping in the SCA CMR protocol has the potential to increase diagnostic yield of CMR and further specify SCA etiology, especially myocarditis.

Early Experience and Lessons Learned Using Implanted Hemodynamic Monitoring in Patients With Fontan Circulation.

BACKGROUND: Data on the use of implanted hemodynamic monitoring (IHM) in patients with Fontan circulation are limited. This study reports our experience using the CardioMEMS HF system in adults with Fontan circulation. METHODS AND RESULTS: This single-center, retrospective study evaluated heart failure hospitalizations, procedural complications, and device-related complications in patients with Fontan circulation referred for IHM placement (2015-2022). The association of pulmonary artery pressure (by most recent catheterization and median IHM pressure within 30 days of placement) with both death and follow-up Model for End-Stage Liver Disease Excluding International Normalized Ratio score were evaluated. Of 18 patients referred for IHM placement, 17 were successful (median age, 30 [range 21-48] years, 6 women). Procedural complications (access site hematomas, pulmonary artery staining) occurred in 3 patients, without device-related procedural complications. In follow-up (median, 35 [range, 6-83] months), 1 patient developed a pulmonary embolism (possibly device-related). Heart failure hospitalizations/year were similar before and after IHM (median, 1 [interquartile range, 0-1.0] versus 0.6 [0-2.3]; P=0.268), though only 46% of heart failure hospitalizations had associated IHM transmissions. IHM pressures were associated with Model for End-Stage Liver Disease Excluding International Normalized Ratio scores (R2=0.588, P<0.001), though catheterization pressures were not (R2=0.140, P=0.139). The long-term mortality rate was 53% in this cohort. On unadjusted survival analysis, IHM pressures ≥18 mm Hg were associated with mortality (log rank P=0.041), which was not reproduced with catheterization pressures (log rank P=0.764). CONCLUSIONS: In patients with Fontan circulation, IHM did not reduce heart failure hospitalizations, though patient adherence to transmission was low. Device-related complications were low. IHM pressures may better represent real-life conditions compared with catheterization given associations with mortality and Model for End-Stage Liver Disease Excluding International Normalized Ratio score.