Quantification of diffuse myocardial fibrosis and its association with myocardial dysfunction in congenital heart disease

Preoperative right ventricular longitudinal strain as a prognosticator of postoperative residual or recurrent tricuspid regurgitation in Ebstein anomaly: a cardiovascular magnetic resonance study

Background

The preoperative predictors of residual or recurrent tricuspid regurgitation (TR) after cone reconstruction (CR) remains unclear in patients with Ebstein anomaly (EA). We aimed to determine the predictive value of right ventricular longitudinal strain, assessed using cardiac magnetic resonance (CMR) imaging, for residual or recurrent TR after CR in patients with EA.

Methods

This single-centre, retrospective study analysed data from 48 patients with EA [mean ± standard deviation (SD), age, 35.0±13.6 years; 13 males] who underwent CMR before CR between January 2017 and February 2023. Two-dimensional colour Doppler echocardiography was performed before CR and mid-term (>6 months) after CR to evaluate the degree of TR in patients with EA. Thirty healthy volunteers served as controls. Univariate and multivariate logistic regression analyses were performed to identify CMR predictors of moderate or severe TR >6 months after CR.

Results

Mid-term postoperative results revealed severe, moderate, and mild TR in 8 (17%), 7 (15%), and 33 (69%) patients, respectively. For patients with EA and moderate or severe TR after CR, left ventricular global longitudinal strain (GLS), left ventricular ejection fraction, right ventricular global longitudinal strain (RVGLS), and right ventricular ejection fraction (RVEF) were significantly worse compared to patients with mild TR (all P<0.05). Multivariate logistic regression analyses revealed that RVGLS was independently associated with moderate or severe TR >6 months after CR [odds ratio (OR) 1.193, 95% confidence interval (CI): 1.025-1.388; P=0.02].

Conclusions

RVGLS was a significant predictor of moderate or severe TR >6 months after CR. This finding emphasizes that early and accurate measurement of RV function may help to identify patients at high risk for severe residual or recurrent TR.

Left ventricular structural integrity on tetralogy of Fallot patients: approach using longitudinal relaxation time mapping

Purpose

Tetralogy of Fallot (TOF) is a congenital heart disease, and patients undergo surgical repair early in their lives. The evaluation of TOF patients is continuous through their adulthood. The use of cardiac magnetic resonance imaging (CMR) is vital for the evaluation of TOF patients. We aim to correlate advanced MRI sequences [parametric longitudinal relaxation time (T1), extracellular volume (ECV) mapping] with cardiac functionality to provide biomarkers for the evaluation of these patients.

Methods

A complete CMR examination with the same imaging protocol was conducted in a total of 11 TOF patients and a control group of 25 healthy individuals. A Modified Look-Locker Inversion recovery (MOLLI) sequence was included to acquire the global T1 myocardial relaxation times of the left ventricular (LV) pre and post-contrast administration. Appropriate software (Circle cmr42) was used for the CMR analysis and the calculation of native, post-contrast T1, and ECV maps. A regression analysis was conducted for the correlation between global LV T1 values and right ventricular (RV) functional indices.

Results

Statistically significant results were obtained for RV cardiac index [RV_CI= -32.765 + 0.029 × T1 native; p = 0.003 ], RV end diastolic volume [RV_EDV/BSA = -1023.872 + 0.902 × T1 native; p = 0.001 ], and RV end systolic volume [RV_ESV/BSA = -536.704 + 0.472 × T1 native; p = 0.011 ].

Conclusions

We further support the diagnostic importance of T1 mapping as a structural imaging tool in CMR. In addition to the well-known affected RV function in TOF patients, the LV structure is also impaired as there is a strong correlation between LV T1 mapping and RV function, evoking that the heart operates as an entity.

Multiparametric Cardiovascular MRI Assessment of Post-COVID Syndrome in Children in Comparison to Matched Healthy Individuals

BACKGROUND

Post-COVID syndrome (PCS) can adversely affect the quality of life of patients and their families. In particular, the degree of cardiac impairment in children with PCS is unknown.

OBJECTIVE

The aim of this study was to identify potential cardiac inflammatory sequelae in children with PCS compared with healthy controls.

METHODS

This single-center, prospective, intraindividual, observational study assesses cardiac function, global and segment-based strains, and tissue characterization in 29 age- and sex-matched children with PCS and healthy children using a 3 T magnetic resonance imaging (MRI).

RESULTS

Cardiac MRI was carried out over 36.4 ± 24.9 weeks post-COVID infection. The study cohort has an average age of 14.0 ± 2.8 years, for which the majority of individuals experience from fatigue, concentration disorders, dyspnea, dizziness, and muscle ache. Children with PSC in contrast to the control group exhibited elevated heart rate (83.7 ± 18.1 beats per minute vs 75.2 ± 11.2 beats per minute, P = 0.019), increased indexed right ventricular end-diastolic volume (95.2 ± 19.2 mlm -2 vs 82.0 ± 21.5 mlm -2 , P = 0.018) and end-systolic volume (40.3 ± 7.9 mlm -2 vs 34.8 ± 6.2 mlm -2 , P = 0.005), and elevated basal and midventricular T1 and T2 relaxation times ( P < 0.001 to P = 0.013). Based on the updated Lake Louise Criteria, myocardial inflammation is present in 20 (69%) children with PCS. No statistically significant difference was observed for global strains.

CONCLUSIONS

Cardiac MRI revealed altered right ventricular volumetrics and elevated T1 and T2 mapping values in children with PCS, suggestive for a diffuse myocardial inflammation, which may be useful for the diagnostic workup of PCS in children.

Right ventricular fibrosis in adults with uncorrected secundum atrial septal defect and pulmonary hypertension: a cardiovascular magnetic resonance study with late gadolinium enhancement, native T1 and extracellular volume

Introduction

Right ventricular (RV) fibrosis represents both adaptive and maladaptive responses to the overloaded RV condition. Its role in pulmonary hypertension (PH) associated with secundum atrial septal defect (ASD), which is the most common adult congenital heart disease (CHD), remains poorly understood.

Methods

We enrolled 65 participants aged ≥18 years old with uncorrected secundum ASD who had undergone clinically indicated right heart catheterization (RHC), divided into the non-PH group (n = 7), PH group (n = 42), and Eisenmenger syndrome (ES) group (n = 16). We conducted cardiovascular magnetic resonance (CMR) studies with late gadolinium enhancement (LGE) imaging, native T1 mapping, and extracellular volume (ECV) measurement to evaluate the extent and clinical correlates of RV fibrosis.

Results

LGE was present in 94% of the population and 86% of the non-PH group, mostly located at the right ventricular insertion point (RVIP) regions. LGE in the septal and inferior RV region was predominantly observed in the ES group compared to the other groups (p = 0.031 and p < 0.001, respectively). The mean LGE scores in the ES and PH groups were significantly higher than those in the non-PH group (3.38 ± 0.96 vs. 2.74 ± 1.04 vs. 1.57 ± 0.79; p = 0.001). The ES and PH groups had significantly higher degrees of interstitial RV fibrosis compared to those in the non-PH group, indicated by native T1 (1,199.9 ± 68.9 ms vs. 1,131.4 ± 47.8 ms vs. 1,105.4 ± 44.0 ms; p < 0.001) and ECV (43.6 ± 6.6% vs. 39.5 ± 4.9% vs. 39.4 ± 5.8%; p = 0.037). Additionally, native T1 significantly correlated with pulmonary vascular resistance (r = 0.708, p < 0.001), RV ejection fraction (r = -0.468, p < 0.001) and peripheral oxygen saturation (r = -0.410, p = 0.001).

Conclusion

In patients with uncorrected secundum ASD, RV fibrosis may occur before the development of PH and progressively intensify alongside the progression of PH severity. A higher degree of RV fibrosis, derived from CMR imaging, correlates with worse hemodynamics, RV dysfunction, and poorer clinical conditions.

Right ventricular myocardial fibrosis evaluated by extracellular volume fraction by magnetic resonance imaging in patients with repaired tetralogy of Fallot: a meta-analysis

OBJECTIVE

The objective of this meta-analysis was to assess the clinical utility of anomalous discoveries on cardiac magnetic resonance, particularly the right ventricular extracellular volume (RV-ECV), among individuals who underwent surgical repair for Tetralogy of Fallot (rTOF).

METHODS

We conducted a systematic search of electronic databases including PubMed, Web of Science Core Collection, Cochrane advanced search, and EMBASE. Our analysis involved a comparison of ECV levels between rTOF patients and controls, as well as an evaluation of the predictive value of ECV for future adverse events.

RESULTS

We identified 16 eligible studies that encompassed 856 rTOF patients and 283 controls. Our meta-analysis showed a significant increase in LV-ECV among rTOF patients compared to control subjects (MD = 2.63, 95%CI: 1.35 to 3.90, p < 0.0001, I2 = 86%, p for heterogeneity < 0.00001). Moreover, RV-ECV was found to be substantially higher in patients compared to LV-ECV. Our meta-analysis also revealed a significant association between RV-ECV and adverse events (HR = 1.15, 95% CI: 1.04 to 1.27, p = 0.005, I2 = 0%, p for heterogeneity = 0.62), while LV-ECV did not show any significant association with adverse events (HR = 1.12, 95% CI: 0.92 to 1.36, p = 0.16, I2 = 0%, p for heterogeneity = 0.46).

CONCLUSION

The results of this meta-analysis on RV-ECV confirmed the presence of RV fibrosis as one of the prognostic factors in rTOF patients.

Novel Techniques in Imaging Congenital Heart Disease: JACC Scientific Statement

Recent years have witnessed exponential growth in cardiac imaging technologies, allowing better visualization of complex cardiac anatomy and improved assessment of physiology. These advances have become increasingly important as more complex surgical and catheter-based procedures are evolving to address the needs of a growing congenital heart disease population. This state-of-the-art review presents advances in echocardiography, cardiac magnetic resonance, cardiac computed tomography, invasive angiography, 3-dimensional modeling, and digital twin technology. The paper also highlights the integration of artificial intelligence with imaging technology. While some techniques are in their infancy and need further refinement, others have found their way into clinical workflow at well-resourced centers. Studies to evaluate the clinical value and cost-effectiveness of these techniques are needed. For techniques that enhance the value of care for congenital heart disease patients, resources will need to be allocated for education and training to promote widespread implementation.

ISE/ISHNE expert consensus statement on the ECG diagnosis of left ventricular hypertrophy: The change of the paradigm

The ECG diagnosis of LVH is predominantly based on the QRS voltage criteria. The classical paradigm postulates that the increased left ventricular mass generates a stronger electrical field, increasing the leftward and posterior QRS forces, reflected in the augmented QRS amplitude. However, the low sensitivity of voltage criteria has been repeatedly documented. We discuss possible reasons for this shortcoming and proposal of a new paradigm. The theoretical background for voltage measured at the body surface is defined by the solid angle theorem, which relates the measured voltage to spatial and non-spatial determinants. The spatial determinants are represented by the extent of the activation front and the distance of the recording electrodes. The non-spatial determinants comprise electrical characteristics of the myocardium, which are comparatively neglected in the interpretation of the QRS patterns. Various clinical conditions are associated with LVH. These conditions produce considerable diversity of electrical properties alterations thereby modifying the resultant QRS patterns. The spectrum of QRS patterns observed in LVH patients is quite broad, including also left axis deviation, left anterior fascicular block, incomplete and complete left bundle branch blocks, Q waves, and fragmented QRS. Importantly, the QRS complex can be within normal limits. The new paradigm stresses the electrophysiological background in interpreting QRS changes, i.e., the effect of the non-spatial determinants. This postulates that the role of ECG is not to estimate LV size in LVH, but to understand and decode the underlying electrical processes, which are crucial in relation to cardiovascular risk assessment.

Exercise as Medicine: Evaluation and Prescription for Adults with Congenital Heart Disease

PURPOSE OF REVIEW

Understanding exercise physiology as it relates to adult congenital heart disease (ACHD) can be complex. Here we review fundamental physiologic principles and provide a framework for application to the unique ACHD patient population.

RECENT FINDINGS

ACHD exercise participation has changed dramatically in the last 50 years. A modern approach focuses on exercise principles and individual anatomic and physiologic considerations. With an evolving better understanding of ACHD exercise physiology, we can strategize plans for patients to participate in dynamic and static exercises. Newly developed technologies including wearable devices provide additive information for ACHD providers for further assessment and monitoring. Preparation and assessment for ACHD patients prior to exercise require a thoughtful, personalized approach. Exercise prescriptions can be formulated to adequately meet the needs of our patients.

ISE/ISHNE Expert Consensus Statement on ECG Diagnosis of Left Ventricular Hypertrophy: The Change of the Paradigm. The joint paper of the International Society of Electrocardiology and the International Society for Holter Monitoring and Noninvasive Electrocardiology

The ECG diagnosis of LVH is predominantly based on the QRS voltage criteria, i.e. the increased QRS complex amplitude in defined leads. The classical ECG diagnostic paradigm postulates that the increased left ventricular mass generates a stronger electrical field, increasing the leftward and posterior QRS forces. These increased forces are reflected in the augmented QRS amplitude in the corresponding leads. However, the clinical observations document increased QRS amplitude only in the minority of patients with LVH. The low sensitivity of voltage criteria has been repeatedly documented. We discuss possible reasons for this shortcoming and proposal of a new paradigm.

Myocardial Fibrosis in Congenital Heart Disease and the Role of MRI

Progress in the field of congenital heart surgery over the last century can only be described as revolutionary. Recent improvements in patient outcomes have been achieved through refinements in perioperative care. In the current and future eras, the preservation and restoration of myocardial health, beginning with the monitoring of tissue remodeling, will be central to improving cardiac outcomes. Visualization and quantification of fibrotic myocardial remodeling is one of the greatest assets that cardiac MRI brings to the field of cardiology, and its clinical use within the field of congenital heart disease (CHD) has been an area of particular interest in the last few decades. This review summarizes the physical underpinnings of myocardial tissue characterization in CHD, with an emphasis on T1 parametric mapping and late gadolinium enhancement. It describes methods and suggestions for obtaining images, extracting quantitative and qualitative data, and interpreting the results for children and adults with CHD. The tissue characterization observed in different lesions is used to examine the causes and pathomechanisms of fibrotic remodeling in this population. Similarly, the clinical consequences of elevated imaging biomarkers of fibrosis on patient health and outcomes are explored. Keywords: Pediatrics, MR Imaging, Cardiac, Heart, Congenital, Tissue Characterization, Congenital Heart Disease, Cardiac MRI, Parametric Mapping, Fibrosis, Late Gadolinium Enhancement © RSNA, 2023.

Biopsy-detected myocardial fibrosis predicts adverse cardiac events after pulmonary valve replacement in patients with repaired tetralogy of Fallot

OBJECTIVES

Risk factors associated with adverse cardiac events (cardiac AEs) after pulmonary valve replacement (PVR) in patients with repaired tetralogy of Fallot are incompletely understood. In this study, we aimed to determine the relationship between histological myocardial fibrosis and cardiac AEs after PVR in patients with rTOF.

METHODS

We consecutively collected clinical, cardiac magnetic resonance, echocardiography and electrocardiogram data of 51 patients with rTOF who underwent surgical PVR. The right ventricular outflow tract tissue was collected during the PVR and the degree of histological myocardial fibrosis was determined by a tailor-made automated image analysis method of picrosirius red staining.

RESULTS

The median follow-up time was 4.9 years, and 14 patients had cardiac AEs (a composite of heart failure admission and arrhythmia) during follow-up. The total analysis area of myocardial samples was 5782.18 mm2, and the median percentage of myocardial fibrosis was 20.6% (interquartile range 16.7-27.0%), which were significantly elevated in patients with cardiac AEs compared with patients without cardiac AEs (24.1% vs 19.7%, P = 0.007). Right ventricular ejection fraction and left ventricular end-systolic volume index were significantly associated with myocardial fibrosis in multivariable stepwise linear regression analysis (R2 = 0.238). Cox proportional hazards regression identified degree of myocardial fibrosis [hazard ratio 1.127; 95% confidence interval (CI) 1.047-1.213; P = 0.001] and age at PVR (hazard ratio 1.062; 95% CI 1.010-1.116; P = 0.019) were associated with increased risk of cardiac AEs. The incidence of adverse cardiac events was significantly increased when myocardial fibrosis >20.1% and age at PVR >18.2 years.

CONCLUSIONS

Histological myocardial fibrosis was associated with biventricular systolic functions in rTOF. Higher myocardial fibrosis and older age at PVR are independent risk factors for the adverse cardiac events after PVR in patients with rTOF.

Comparison of electrocardiographic versus echocardiographic detection of left ventricular mass changes over time and evaluation of new onset left ventricular hypertrophy

We assessed the value of 3 electrocardiographic (EKG) voltage criteria in detecting variations of left ventricular mass (LVM) over time, taking echocardiographic (ECHO) LVM as reference, in the Pressioni Arteriose Monitorate E Loro Associazioni study. In 927 subjects (age 47 ± 13 years on entry, 49.9% men) an ECHO evaluation of LVM and EKG suitable for measurement of EKG-LVH criteria (Sokolow-Lyon voltage, Cornell voltage and R-wave voltage in aVL) were available at baseline and at a 2^nd evaluation performed 10 years later. Δ (delta) LVM, Δ LVMI, and Δ EKG parameters values were calculated from 2^nd evaluation to baseline. The sensitivity of the EKG criteria in the diagnosis of LVH, poor at baseline, becomes even worse after 10 years, reaching very low values. Only the sensitivity of R-wave amplitude exhibited slight increase over time but with unsatisfactory absolute values. Despite the prevalence of ECHO-LVH at the 2^nd evaluation was threefold increased compared to baseline (29.3% and 33.7% for LVM indexed to BSA and height^2.7 , respectively), the prevalence of EKG-LVH was unchanged when evaluated by Sokolow-Lyon criteria, significantly reduced when assessed by Cornell voltage index, while significantly increased using R-wave voltage in aVL criteria. Despite an ECHO-LVM increase over the time, mean EKG changes were of opposite sign, except for R-wave amplitude in aVL. Our study highlights the discrepancy between ECHO and EKG in monitoring LVM changes over the time, especially for Sokolow-Lyon and Cornell voltage. Thus, EKG is an unsuitable method for the longitudinal evaluation of LVM variations.

Heart failure in systemic right ventricle: Mechanisms and therapeutic options

d-loop transposition of the great arteries (d-TGA) and congenitally corrected transposition of the great arteries (cc-TGA) feature a right ventricle attempting to sustain the systemic circulation. A systemic right ventricle (sRV) cannot support cardiac output in the long run, eventually decompensating and causing heart failure. The burden of d-TGA patients with previous atrial switch repair and cc-TGA patients with heart failure will only increase in the coming years due to the aging adult congenital heart disease population and improvements in the management of advanced heart failure. Clinical data still lags behind in developing evidence-based guidelines for risk stratification and management of sRV patients, and clinical trials for heart failure in these patients are underrepresented. Recent studies have provided foundational data for the commencement of robust clinical trials in d-TGA and cc-TGA patients. Further insights into the multifactorial nature of sRV failure can only be provided by the results of such studies. This review discusses the mechanisms of heart failure in sRV patients with biventricular circulation and how these mediators may be targeted clinically to alleviate sRV failure.

Detection and evaluation of myocardial fibrosis in Eisenmenger syndrome using cardiovascular magnetic resonance late gadolinium enhancement and T1 mapping

BACKGROUND

Myocardial fibrosis is a common pathophysiological process involved in many cardiovascular diseases. However, limited prior studies suggested no association between focal myocardial fibrosis detected by cardiovascular magnetic resonance (CMR) late gadolinium enhancement (LGE) and disease severity in Eisenmenger syndrome (ES). This study aimed to explore potential associations between myocardial fibrosis evaluated by the CMR LGE and T1 mapping and risk stratification profiles including exercise tolerance, serum biomarkers, hemodynamics, and right ventricular (RV) function in these patients.

METHODS

Forty-five adults with ES and 30 healthy subjects were included. All subjects underwent a contrast-enhanced 3T CMR. Focal replacement fibrosis was visualized on LGE images. The locations of LGE were recorded. After excluding LGE in ventricular insertion point (VIP), ES patients were divided into myocardial LGE-positive (LGE+) and LGE-negative (LGE-) subgroups. Regions of interest in the septal myocardium were manually contoured in the T1 mapping images to determine the diffuse myocardial fibrosis. The relationships between myocardial fibrosis and 6-min walk test (6MWT), N-terminal pro-brain natriuretic peptide (NT-pro BNP), hematocrit, mean pulmonary arterial pressure (mPAP), pulmonary vascular resistance index (PVRI), RV/left ventricular end-systolic volume (RV/LV ESV), RV ejection fraction (RVEF), and risk stratification were analyzed.

RESULTS

Myocardial LGE (excluding VIP) was common in ES (16/45, 35.6%), and often located in the septum (12/45, 26.7%). The clinical characteristics, hemodynamics, CMR morphology and function, and extracellular volume fraction (ECV) were similar in the LGE+ and LGE- groups (all P > 0.05). ECV was significantly higher in ES patients (28.6 ± 5.9% vs. 25.6 ± 2.2%, P < 0.05) and those with LGE- ES (28.3 ± 5.9% vs. 25.6 ± 2.2%, P < 0.05) than healthy controls. We found significant correlations between ECV and log NT-pro BNP, hematocrit, mPAP, PVRI, RV/LV ESV, and RVEF (all P < 0.05), and correlations trends between ECV and 6MWT (P = 0.06) in ES patients. An ECV threshold of 29.0% performed well in differentiating patients with high-risk ES from those with intermediate or low risk (area under curve 0.857, P < 0.001).

CONCLUSIONS

Myocardial fibrosis is a common feature of ES. ECV may serve as an important imaging marker for ES disease severity.

An electrocardiography score predicts heart failure hospitalization or death beyond that of cardiovascular magnetic resonance imaging

The electrocardiogram (ECG) and cardiovascular magnetic resonance imaging (CMR) provide powerful prognostic information. The aim was to determine their relative prognostic value. Patients (n = 783) undergoing CMR and 12-lead ECG with a QRS duration < 120 ms were included. Prognosis scores for one-year event-free survival from hospitalization for heart failure or death were derived using continuous ECG or CMR measures, and multivariable logistic regression, and compared. Patients (median [interquartile range] age 55 [43-64] years, 44% female) had 155 events during 5.7 [4.4-6.6] years. The ECG prognosis score included (1) frontal plane QRS-T angle, and (2) heart rate corrected QT duration (QTc) (log-rank 55). The CMR prognosis score included (1) global longitudinal strain, and (2) extracellular volume fraction (log-rank 85). The combination of positive scores for both ECG and CMR yielded the highest prognostic value (log-rank 105). Multivariable analysis showed an association with outcomes for both the ECG prognosis score (log-rank 8.4, hazard ratio [95% confidence interval] 1.29 [1.09-1.54]) and the CMR prognosis score (log-rank 47, hazard ratio 1.90 [1.58-2.28]). An ECG prognosis score predicted outcomes independently of CMR. Combining the results of ECG and CMR using both prognosis scores improved the overall prognostic performance.

OTUD7B (Cezanne) ameliorates fibrosis after myocardial infarction via FAK-ERK/P38 MAPK signaling pathway

Fibrosis is one of the crucial reasons for cardiac dysfunction after myocardial infarction (MI). Understanding the underlying molecular mechanism that causes fibrosis is crucial to developing effective therapy. Recently, OUT domain-containing 7B (OTUD7B), also called Cezanne, a multifunctional deubiquitylate, has been found to play various roles in cancer and vascular diseases and control many important signaling pathways, including inflammation, proliferation, and so on. However, whether OTUD7B plays a role in fibrosis caused by MI remains unclear. Our study aimed to explore the function of OTUD7B in cardiac fibrosis and investigate the underlying mechanism. We found that the expression of OTUD7B was downregulated in the MI rat model and cultured cardiac fibroblasts (CFs) in hypoxic conditions and after TGF-β1 treatment. In vitro, silencing OTUD7B using small interfering RNA (siRNA) increased α-SMA (smooth muscle actin α) and collagen Ⅰ levels in CFs, whereas the overexpression of OTUD7B using adenovirus decreased their expression. Mechanistically, OTUD7B could regulate the phosphorylation of focal adhesion kinase (FAK), a non-receptor tyrosine kinase that has been proved to act as a potential mediator of fibrosis, and ERK/P38 MAPK was involved in this regulation process. In vitro, overexpression of OTUD7B downregulated the phosphorylation level of FAK and then inhibited ERK/P38 phosphorylation, thus leading to decreased α-SMA and collagen Ⅰ expressions, while OTUD7B knockdown showed an opposite result. These findings suggest that OTUD7B could become a potentially effective therapeutic strategy against fibrosis after MI.

Left, but not right, ventricular status determines heart failure in adults with Ebstein anomaly - A case-control study based on magnetic resonance

BACKGROUND

Ebstein anomaly (EA) is a congenital heart defect affecting the right heart. Heart failure (HF) is a significant complication in adults with EA. It may result not only from the right ventricle (RV), but also from the left ventricle (LV) abnormalities. We evaluate the size and function of both ventricles in patients with EA in cardiac magnetic resonance (CMR); to assess their association with the clinical markers of HF.

METHODS

Study group: 37 unoperated adults with EA (mean age 43.0 ± 14.4y, 21[56.8%] males).

CONTROLS

25 volunteers (mean age 39.9 ± 10.9y, 15[60%] males). Study protocol included: CMR [ejection fraction (EF), end-diastolic (EDVind) and stroke volumes (SVind) indexed by body surface area]; cardiopulmonary test (peak VO2, %peak VO2, VE/VCO2 slope).

RESULTS

Size and systolic function of LV were reduced comparing to the controls [LVEDVind (ml/m2): 63.7(range 38.7-94.2) vs. 79.3(48.7-105.1), p < 0.001; LV SVind (ml/m2): 35.8(22.9-55.1) vs. 49.2(37.8-71.7), p < 0.0001; LVEF(%): 58.3(34-70.5) vs. 62.0(52.0-77.0), p = 0.009]. RV was enlarged comparing to the controls [RVEDVind (ml/m2): 124.3(52.8-378.9) vs. 83.0(64.0-102.0), p < 0.0001) with impaired systolic function (RV SVind (ml/m2): 22.7(11.1-74.1) vs. 48.0(37.8-71.7), p < 0.0001; RVEF(%): 38.0(21.0-66.1) vs. 59.0(49.0-69.0), p < 0.0001). A significant correlation was found between LVEDVind vs. peakVO2 (r = 0.52, p = 0.001); LV SVind vs. peakVO2 (r = 0.47,p = 0.005). There was no correlation between the right ventricular status and exercise capacity.

CONCLUSIONS

In adults with Ebstein anomaly the size of left ventricle is reduced, right ventricle is enlarged; the function of both is impaired. Abnormal exercise capacity is associated with left ventricular status. Ventricular interdependence probably plays a role in heart failure pathomechanism.

Myocardial fibrosis in congenital heart disease

Myocardial fibrosis resulting from the excessive deposition of collagen fibers through the myocardium is a common histopathologic finding in a wide range of cardiovascular diseases, including congenital anomalies. Interstitial fibrosis has been identified as a major cause of myocardial dysfunction since it distorts the normal architecture of the myocardium and impairs the biological function and properties of the interstitium. This review summarizes current knowledge on the mechanisms and detrimental consequences of myocardial fibrosis in heart failure and arrhythmias, discusses the usefulness of available imaging techniques and circulating biomarkers to assess this entity and reviews the current body of evidence regarding myocardial fibrosis in the different subsets of congenital heart diseases with implications in research and treatment.

Myocardial Parametric Mapping by Cardiac Magnetic Resonance Imaging in Pediatric Cardiology and Congenital Heart Disease

Parametric mapping, that is, a pixel-wise map of magnetic relaxation parameters, expands the diagnostic potential of cardiac magnetic resonance by enabling quantification of myocardial tissue-specific magnetic relaxation on an absolute scale. Parametric mapping includes T₁ mapping (native and postcontrast), T₂ and T₂* mapping, and extracellular volume measurements. The myocardial composition is altered in various disease states affecting its inherent magnetic properties and thus the myocardial relaxation times that can be directly quantified using parametric mapping. Parametric mapping helps in the diagnosis of nonfocal disease states and allows for longitudinal disease monitoring, evaluating therapeutic response (as in Thalassemia patients with iron overload undergoing chelation), and risk-stratification of certain diseases. In this review article, we describe various mapping techniques and their clinical utility in congenital heart disease. We will also review the available literature on normative values in children, the strengths, and weaknesses of these techniques. This review provides a starting point for pediatric cardiologists to understand and implement parametric mapping in their practice.

Is experienced pregnancy in women with repaired tetralogy of Fallot related to diffuse myocardial fibrosis?

OBJECTIVES

To assess the impact of pregnancy on cardiac function and fibrosis by cardiovascular magnetic resonance (CMR) in patients with repaired Tetralogy of Fallot (rToF).

BACKGROUND

CMR T1 mapping can assess diffuse myocardial fibrosis which is associated to adverse clinical outcomes. Right ventricular (RV) accelerated remodeling is reported in rToF women with experienced pregnancy.

METHODS

We included rToF women from the national registry of congenital heart disease to perform CMR, assessing functional data, T1 mapping/ extracellular volume fraction (ECV). The results including clinical data were compared between women with experienced pregnancy vs non-experienced pregnancy and healthy individuals.

RESULTS

Fifty rToF women performed CMR, median age 36 (range 21-67) years. Fifteen were nulliparous. T1 mapping was compared to 30 controls, (14 women) median age 42 (24-64) years. In the left ventricle (LV), T1 times and ECV in all rToF women vs female controls were 1248 ± 61 ms/ 25.8 ± 2.9% vs 1255 ± 40 ms/ 26.8 ± 3.1%, p = 0.7 and p = 0.3, respectively. In rToF, RV T1 times was 1385 ± 124 ms and ECV 37.7 ± 5.4%. There was no association to parity or age in rToF LV T1/ ECV, p = 0.9 for both, or RV T1/ECV, p = 0.4 and p = 0.6, respectively. Indexed LV mass was higher in the rToF pregnancy group, 43 ± 10 vs 38 ± 6 g/m², p = 0.03 while RV ejection fraction was lower, 49 ± 7% vs 53 ± 6%, p = 0.04.

CONCLUSION

Women with rTOF showed evidence of increased RV CMR markers suggestive of diffuse fibrosis while LV CMR markers were within normal values. Having experienced pregnancy might affect RV function, however without association to CMR biomarkers.

Narrative review of Ebstein's anomaly beyond childhood: Imaging, surgery, and future perspectives

Ebstein's anomaly is a rare congenital heart disease with malformation of the tricuspid valve and myopathy of the right ventricle. The septal and inferior leaflets adhere to the endocardium due to failure of delamination. This leads to apical displacement of their hinge points with a shift of the functional tricuspid valve annulus towards the right ventricular outflow tract with a possibly restrictive orifice. Frequently, a coaptation gap yields tricuspid valve regurgitation and over time the "atrialized" portion of the right ventricle may dilate. The highly variable anatomy determines the clinical presentation ranging from asymptomatic to very severe with need for early operation. Echocardiography and magnetic resonance imaging are the most important diagnostic modalities to assess the tricuspid valve as well as ventricular morphology and function. While medical management of asymptomatic patients can be effective for many years, surgical intervention is indicated before development of significant right ventricular dilatation or dysfunction. Onset of symptoms and arrhythmias are further indications for surgery. Modified cone reconstruction of the tricuspid valve is the state-of-the-art approach yielding the best results for most patients. Alternative procedures for select cases include tricuspid valve replacement and bidirectional cavopulmonary shunt depending on patient age and other individual characteristics. Long-term survival after surgery is favorable but rehospitalization and reoperation remain significant issues. Further studies are warranted to identify the optimal surgical strategy and timing before adverse right ventricular remodeling occurs. It is this article's objective to provide a comprehensive review of current literature and an overview on the management of Ebstein's Anomaly. It focuses on imaging, cardiac surgery, and outcome. Additionally, a brief insight into arrhythmias and their management is given. The "future perspectives" summarize open questions and fields of future research.

Myocardial Perfusion in Hypoplastic Left Heart Syndrome

BACKGROUND

The status of the systemic right ventricular coronary microcirculation in hypoplastic left heart syndrome (HLHS) is largely unknown. It is presumed that the systemic right ventricle's coronary microcirculation exhibits unique pathophysiological characteristics of HLHS in Fontan circulation. The present study sought to quantify myocardial blood flow by cardiac magnetic resonance imaging and evaluate the determinants of microvascular coronary dysfunction and myocardial ischemia in HLHS.

METHODS

One hundred nineteen HLHS patients (median age, 4.80 years) and 34 healthy volunteers (median age, 5.50 years) underwent follow-up cardiac magnetic resonance imaging ≈1.8 years after total cavopulmonary connection. Right ventricle volumes and function, myocardial perfusion, diffuse fibrosis, and late gadolinium enhancement were assessed in 4 anatomic HLHS subtypes. Myocardial blood flow (MBF) was quantified at rest and during adenosine-induced hyperemia. Coronary conductance was estimated from MBF at rest and catheter-based measurements of mean aortic pressure (n=99).

RESULTS

Hyperemic MBF in the systemic ventricle was lower in HLHS compared with controls (1.89±0.57 versus 2.70±0.84 mL/g per min; P<0.001), while MBF at rest normalized by the rate-pressure product, was similar (1.25±0.36 versus 1.19±0.33; P=0.446). Independent risk factors for a reduced hyperemic MBF were an HLHS subtype with mitral stenosis and aortic atresia (P=0.017), late gadolinium enhancement (P=0.042), right ventricular diastolic dysfunction (P=0.005), and increasing age at total cavopulmonary connection (P=0.022). The coronary conductance correlated negatively with systemic blood oxygen saturation (r, -0.29; P=0.02). The frequency of late gadolinium enhancement increased with age at total cavopulmonary connection (P=0.014).

CONCLUSIONS

The coronary microcirculation of the systemic ventricle in young HLHS patients shows significant differences compared with controls. These hypothesis-generating findings on HLHS-specific risk factors for microvascular dysfunction suggest a potential benefit from early relief of frank cyanosis by total cavopulmonary connection.

A dual adaptive explicit time integration algorithm for efficiently solving the cardiac monodomain equation

The monodomain model is widely used in in-silico cardiology to describe excitation propagation in the myocardium. Frequently, operator splitting is used to decouple the stiff reaction term and the diffusion term in the monodomain model so that they can be solved separately. Commonly, the diffusion term is solved implicitly with a large time step while the reaction term is solved by using an explicit method with adaptive time stepping. In this work, we propose a fully explicit method for the solution of the decoupled monodomain model. In contrast to semi-implicit methods, fully explicit methods present lower memory footprint and higher scalability. However, such methods are only conditionally stable. We overcome the conditional stability limitation by proposing a dual adaptive explicit method in which adaptive time integration is applied for the solution of both the reaction and diffusion terms. We perform a set of numerical examples where cardiac propagation is simulated under physiological and pathophysiological conditions. Results show that the proposed method presents preserved accuracy and improved computational efficiency as compared to standard operator splitting-based methods.

Lifespan Perspective on Congenital Heart Disease Research: JACC State-of-the-Art Review

More than 90% of patients with congenital heart disease (CHD) are nowadays surviving to adulthood and adults account for over two-thirds of the contemporary CHD population in Western countries. Although outcomes are improved, surgery does not cure CHD. Decades of longitudinal observational data are currently motivating a paradigm shift toward a lifespan perspective and proactive approach to CHD care. The aim of this review is to operationalize these emerging concepts by presenting new constructs in CHD research. These concepts include long-term trajectories and a life course epidemiology framework. Focusing on a precision health, we propose to integrate our current knowledge on the genome, phenome, and environome across the CHD lifespan. We also summarize the potential of technology, especially machine learning, to facilitate longitudinal research by embracing big data and multicenter lifelong data collection.

Myocardial Fibrosis in Pediatric Patients With Ebstein's Anomaly

BACKGROUND

Left ventricular dysfunction in Ebstein's anomaly (EA) is associated with higher mortality. The health of the left ventricular myocardium in children and adolescents with EA has not been investigated in detail.

METHODS

Patients with unrepaired EA who had undergone cardiac magnetic resonance imaging including T1 mapping were retrospectively reviewed. Patients were compared with age- and sex-matched controls. EA severity index was calculated using volumetric measurements at end diastole ([right atrial+atrialized right ventricular volumes]/[functional right ventricular+left atrial+left ventricular volumes]). Global circumferential and radial strain and as well as strain rate were examined using cardiac magnetic resonance feature tracking.

RESULTS

Twelve EA patients and an equal number of controls were included. Functional and atrialized right ventricular end-diastolic volumes were 84±15 and 21±13 mL/m², respectively. Late gadolinium enhancement, confined to the right ventricle, was found in 2 patients (16%). Left ventricular native T1 values and extracellular volume fractions were higher in patients compared with controls (1026±47 versus 956±40 ms, P=0.0004 and 28.5±3.4% versus 22.5±2.6%, P<0.001, respectively). Native T1 times correlated inversely with patients' age, body surface area, and O₂ saturations (r=-0.63, -0.62, and -0.91, respectively; P=0.02, P=0.02, and P<0.0001, respectively). EA severity index ranged between 0.15 and 0.94 and correlated with T1 values (r=0.76, P=0.003). Native T1 correlated with global circumferential strain (r=0.58, P=0.04) but not ejection fraction (EF). EA patients had reduced maximum oxygen uptake (Vo₂max). Vo₂max correlated inversely with T1 values (r=-0.79, P=0.01).

CONCLUSIONS

Children and adolescents with EA experience an abnormal degree of diffuse myocardial fibrosis. Its association with O₂ saturation points toward a role of hypoxemia in the pathogenesis of fibrosis. Larger and prospective studies are needed to evaluate the value of T1 mapping for risk stratification and monitoring in EA.

Myocardial fibrosis in patients with a history of Kawasaki disease

Objectives

Cardiac magnetic resonance (CMR) measurements of myocardial extracellular volume fraction (ECV) and late gadolinium enhancement (LGE) in patients with a history of Kawasaki disease (KD) were analyzed to determine whether fibrosis was increased compared to controls.

Methods

In this single center retrospective study, patients with KD who had a CMR with ECV measurement and LGE assessment were included. The ECV was calculated in the mid-left ventricle by measuring T1 values for blood pool and myocardium before and after gadolinium administration with a Look-Locker technique. CMR findings were compared to 20 control subjects.

Results

KD patients (n = 13) had a median age at CMR of 14.9 years (range, 7.5-36.0). Control subjects (n = 20) had a median age at CMR of 16 years (range, 11.0-36.0). Twelve KD patients had coronary aneurysms. The KD patients had a significantly lower indexed LV mass (p = 0.03) and LV mass/volume ratio (p = 0.01). ECV was not significantly different in KD patients and controls (0.26 (range, 0.20-0.30) vs. 0.25 (range, 0.18-0.28), p = 0.28). One KD patient (8%) had an increased (>0.28) ECV. LGE indicating focal fibrosis was found in 5 of 13 (38%) of KD patients. Patients with LGE tended to have a higher maximum coronary dimension z-score (p = 0.09).

Conclusions

In this study of KD patients, most of whom had aneurysms, ECV did not differ significantly from that in normal controls. Focal fibrosis based on LGE was common. Future larger studies should compare ECV in KD patients with and without aneurysms to define the risk of myocardial fibrosis after KD.

Measuring myocardial extracellular volume of the right ventricle in patients with congenital heart disease

The right ventricle´s (RV) characteristics—thin walls and trabeculation—make it challenging to evaluate extracellular volume (ECV). We aimed to assess the feasibility of RV ECV measurements in congenital heart disease (CHD), and to introduce a novel ECV analysis tool. Patients (n = 39) and healthy controls (n = 17) underwent cardiovascular magnetic resonance T1 mapping in midventricular short axis (SAX) and transverse orientation (TRANS). Regions of interest (ROIs) were evaluated with regard to image quality and maximum RV wall thickness per ROI in pixels. ECV from plane ROIs was compared with values obtained with a custom-made tool that derives the mean T1 values from a “line of interest” (LOI) centered in the RV wall. In CHD, average image quality was good (no artifacts in the RV, good contrast between blood/myocardium), and RV wall thickness was 1–2 pixels. RV ECV was not quantifiable in 4/39 patients due to insufficient contrast or wall thickness < 1 pixel. RV myocardium tended to be more clearly delineated in SAX than TRANS. ECV from ROIs and corresponding LOIs correlated strongly in both directions (SAX/TRANS: r = 0.97/0.87, p < 0.001, respectively). In conclusion, RV ECV can be assessed if image quality allows sufficient distinction between myocardium and blood, and RV wall thickness per ROI is ≥ 1 pixel. T1 maps in SAX are recommended for RV ECV analysis. LOI application simplifies RV ECV measurements.

Late gadolinium enhancement in patients with Tetralogy of Fallot: A systematic review

PURPOSE

The aim of this study is to review the literature concerning myocardial late gadolinium enhancement (LGE) with cardiac magnetic resonance in patients with Tetralogy of Fallot (ToF), with regards to its prevalence, characteristics and clinical relevance.

METHODS

We performed a systematic search, aiming to retrieve original articles that evaluated LGE in ToF, running a search string on MEDLINE and EMBASE in November 2019 and November 2020. Papers were then selected by two independent, blinded readers based on title and abstract, and then on full-text reading, and articles which did not include LGE evaluation were excluded. From each included paper two readers extracted descriptive data concerning technical parameters of LGE acquisition, LGE description and clinical significance.

RESULTS

18 articles were eventually included in our review. The included studies observed that a higher amount of right ventricular LGE relates with higher right ventricular volumes, lower ejection fraction and a higher pulmonary regurgitant fraction, thus acting as a marker of progressive impairment of myocardial function. Moreover, LGE in ToF patients correlated with the onset of arrhythmias, and with serum biomarkers indicative of myocardial stress and fibrosis.

CONCLUSIONS

LGE could be used in the follow-up repaired ToF patients as its appraisal can provide information concerning cardiac dysfunction. Moreover, it may be ideal to aim towards a common framework for standardizing assessment and quantification of LGE in ToF patients.

Cardiac MRI Assessment of Mouse Myocardial Infarction and Regeneration

Small animal models are indispensable for cardiac regeneration research. Studies in mouse and rat models have provided important insights into the etiology and mechanisms of cardiovascular diseases and accelerated the development of therapeutic strategies. It is vitally important to be able to evaluate the therapeutic efficacy and have reliable surrogate markers for therapeutic development for cardiac regeneration research. Magnetic resonance imaging (MRI), a versatile and noninvasive imaging modality with excellent penetration depth, tissue coverage, and soft-tissue contrast, is becoming a more important tool in both clinical settings and research arenas. Cardiac MRI (CMR) is versatile, noninvasive, and capable of measuring many different aspects of cardiac functions, and, thus, is ideally suited to evaluate therapeutic efficacy for cardiac regeneration. CMR applications include assessment of cardiac anatomy, regional wall motion, myocardial perfusion, myocardial viability, cardiac function assessment, assessment of myocardial infarction, and myocardial injury. Myocardial infarction models in mice are commonly used model systems for cardiac regeneration research. In this chapter, we discuss various CMR applications to evaluate cardiac functions and inflammation after myocardial infarction.

Can T1 mapping be an alternative of post-contrast magnetic resonance sequences in patients with surgically corrected tetralogy of Fallot?

Objective:

The objective of this study is to investigate the ability of native T1 mapping in the determination of myocardial fibrosis in patients with surgically corrected tetralogy of Fallot (TOF).

Methods:

We included 35 patients with surgically corrected TOF who underwent cardiac magnetic resonance imaging in this study. Additionally, we added pre- and post-contrast T1 mapping sequences at the right ventricular outflow tract (RVOT) and short-axis planes to the routine protocol. We visually evaluated the pre-contrast native T1 mapping images to determine the presence of areas with higher T1 times that indicate focal fibrosis. We compared the findings with the findings of post-contrast images.

Results:

In 22 of the 35 cases, RVOT enhancement was observed in the delayed enhancement images; however, none of these cases could be distinguished on the native T1 maps. When compared to post-contrast imaging, 28 of the 30 contrast enhancements at right ventricle insertion points and 14 of the 17 contrast enhancements at the remaining left ventricle walls were visually observed on the color-coded native T1 maps. The sensitivity, specificity, positive and negative predictive values of native T1 mapping for the detection of focal fibrosis at the right ventricle insertion points were found to be 93.3%, 100%, 100%, and 71.4%, respectively, whereas these values were found to be 82.4%, 100%, 100%, and 85.8% in the detection of fibrosis in the remaining left ventricle walls.

Conclusion:

Native T1 mapping is valuable in the detection of focal fibrosis at the right ventricle insertion points and the remaining left ventricle walls; however, it was not possible to visually detect RVOT fibrosis by native T1 mapping. Hence, T1 mapping may not replace the contrast-enhanced imaging in patients with surgically corrected TOF. (Anatol J Cardiol 2020; 24: 377-81)

CMR-derived ECVs vary with myocardial region and associate with the regional wall thickness

This study was designed to identify whether the position and size of the region of interest (ROI) influence extracellular volume fraction (ECV) measurements. Patients with localized (n = 203) or infiltrative (n = 215) cardiomyopathies and 36 normal controls were enrolled in this study. ECV measurements at 4 different regions, including the anterior, septal, posterior and lateral wall regions, were measured, and all groups were compared. Regional ECV was correlated with the corresponding regional wall thickness. The diagnostic power to differentiate the myocardial abnormalities was evaluated for each myocardial region. ECVs measured using five different ROI sizes within each myocardial region were compared. Our results showed that ECVs varied among the myocardial regions, and this variation was significantly associated with regional wall thicknesses. For the detection of myocardial abnormalities, regional ECV revealed similar results as ECV derived from the whole region except for the anterior region. No significant difference was found in the ECVs measured using the five different ROI sizes. In conclusion, CMR-derived ECVs vary with myocardial region, and this variation is significantly associated with the regional wall thickness. In contrast, the measured size of the ROI has less of an effect on the ECV.

Focal scar and diffuse myocardial fibrosis are independent imaging markers in repaired tetralogy of Fallot

Aims

To identify the correlates of focal scar and diffuse fibrosis in patients with history of tetralogy of Fallot (TOF) repair.

Methods and results

Consecutive patients with prior TOF repair underwent electrocardiogram, 24-h Holter, transthoracic echocardiography, exercise testing, and cardiac magnetic resonance (CMR) including cine imaging to assess ventricular volumes and ejection fraction, T1 mapping to assess left ventricular (LV) and right ventricular (RV) diffuse fibrosis, and free-breathing late gadolinium-enhanced imaging to quantify scar area at high spatial resolution. Structural imaging data were related to clinical characteristics and functional imaging markers. Cine and T1 mapping results were compared with 40 age- and sex-matched controls. One hundred and three patients were enrolled (age 28 ± 15 years, 36% women), including 36 with prior pulmonary valve replacement (PVR). Compared with controls, TOF showed lower LV ejection fraction (LVEF) and RV ejection fraction (RVEF), and higher RV volume, RV wall thickness, and native T1 and extracellular volume values on both ventricles. In TOF, scar area related to LVEF and RVEF, while LV and RV native T1 related to RV dilatation. On multivariable analysis, scar area and LV native T1 were independent correlates of ventricular arrhythmia, while RVEF was not. Patients with history of PVR showed larger scars on RV outflow tract but shorter LV and RV native T1.

Conclusion

Focal scar and biventricular diffuse fibrosis can be characterized on CMR after TOF repair. Scar size relates to systolic dysfunction, and diffuse fibrosis to RV dilatation. Both independently relate to ventricular arrhythmias. The finding of shorter T1 after PVR suggests that diffuse fibrosis may reverse with therapy.

Predictors of low exercise cardiac output in patients with severe pulmonic regurgitation

BACKGROUND AND OBJECTIVES

Chronic pulmonic regurgitation (PR) following repair of congenital heart disease (CHD) impairs right ventricular function that impacts peak exercise cardiac index (pCI). We aimed to estimate in a non-invasive way pCI and peak oxygen consumption (pVO₂) and to evaluate predictors of low pCI in patients with significant residual pulmonic regurgitation after CHD repair.

METHOD

We included 82 patients (median age 19 years (range 10-54 years)) with residual pulmonic regurgitation fraction >40%. All underwent cardiac MRI and cardiopulmonary testing with measurement of pCI by thoracic impedancemetry. Low pCI was defined <7 L/min/m².

RESULTS

Low pCI was found in 18/82 patients. Peak indexed stroke volume (pSVi) tended to compensate chronotropic insufficiency only in patients with normal pCI (r=-0.31, p=0.01). Below 20 years of age, only 5/45 patients had low pCI but near-normal (≥6.5 L/min/m²). pVO₂ (mL/kg/min) was correlated with pCI (r=0.58, p=0.0002) only in patients aged >20 years. Left ventricular stroke volume in MRI correlated with pSVi only in the group of patients with low pCI (r=0.54, p=0.02). No MRI measurements predicted low pCI. In multivariable analysis, only age predicted a low pCI (OR=1.082, 95% CI 1.035 to 1.131, p=0.001) with continuous increase of risk with age.

CONCLUSIONS

In patients with severe PR, pVO₂ is a partial reflection of pCI. Risk of low pCI increases with age. No resting MRI measurement predicts low haemodynamic response to exercise. Probably more suitable to detect ventricular dysfunction, pCI measurement could be an additional parameter to take into account when considering pulmonic valve replacement.

Pattern Analysis of Left Ventricular Remodeling Using Cardiac Computed Tomography in Children with Congenital Heart Disease: Preliminary Results

OBJECTIVE

To assess left ventricular remodeling patterns using cardiac computed tomography (CT) in children with congenital heart disease and correlate these patterns with their clinical course.

MATERIALS AND METHODS

Left ventricular volume and myocardial mass were quantified in 17 children with congenital heart disease who underwent initial and follow-up end-systolic cardiac CT studies with a mean follow-up duration of 8.4 ± 9.7 months. Based on changes in the indexed left ventricular myocardial mass (LVMi) and left ventricular mass-volume ratio (LVMVR), left ventricular remodeling between the two serial cardiac CT examinations was categorized into one of four patterns: pattern 1, increased LVMi and increased LVMVR; pattern 2, decreased LVMi and decreased LVMVR; pattern 3, increased LVMi and decreased LVMVR; and pattern 4, decreased LVMi and increased LVMVR. Left ventricular remodeling patterns were correlated with unfavorable clinical courses.

RESULTS

Baseline LVMi and LVMVR were 65.1 ± 37.9 g/m² and 4.0 ± 3.2 g/mL, respectively. LVMi increased in 10 patients and decreased in seven patients. LVMVR increased in seven patients and decreased in 10 patients. Pattern 1 was observed in seven patients, pattern 2 in seven, and pattern 3 in three patients. Unfavorable events were observed in 29% (2/7) of patients with pattern 1 and 67% (2/3) of patients with pattern 3, but no such events occurred in pattern 2 during the follow-up period (4.4 ± 2.7 years).

CONCLUSION

Left ventricular remodeling patterns can be characterized using cardiac CT in children with congenital heart disease and may be used to predict their clinical course.

The Extent of Late Gadolinium Enhancement Can Predict Adverse Cardiac Outcomes in Patients with Non-Ischemic Cardiomyopathy with Reduced Left Ventricular Ejection Fraction: A Prospective Observational Study

OBJECTIVE

The clinical course of an individual patient with heart failure is unpredictable with left ventricle ejection fraction (LVEF) only. We aimed to evaluate the prognostic value of cardiac magnetic resonance (CMR)-derived myocardial fibrosis extent and to determine the cutoff value for event-free survival in patients with non-ischemic cardiomyopathy (NICM) who had severely reduced LVEF.

MATERIALS AND METHODS

Our prospective cohort study included 78 NICM patients with significantly reduced LV systolic function (LVEF < 35%). CMR images were analyzed for the presence and extent of late gadolinium enhancement (LGE). The primary outcome was major adverse cardiac events (MACEs), defined as a composite of cardiac death, heart transplantation, implantable cardioverter-defibrillator discharge for major arrhythmia, and hospitalization for congestive heart failure within 5 years after enrollment.

RESULTS

A total of 80.8% (n = 63) of enrolled patients had LGE, with the median LVEF of 25.4% (19.8-32.4%). The extent of myocardial scarring was significantly higher in patients who experienced MACE than in those without any cardiac events (22.0 [5.5-46.1] %LV vs. 6.7 [0-17.1] %LV, respectively, p = 0.008). During follow-up, 51.4% of patients with LGE ≥ 12.0 %LV experienced MACE, along with 20.9% of those with LGE ≤ 12.0 %LV (log-rank p = 0.001). According to multivariate analysis, LGE extent more than 12.0 %LV was independently associated with MACE (adjusted hazard ratio, 6.71; 95% confidence interval, 2.54-17.74; p < 0.001).

CONCLUSION

In NICM patients with significantly reduced LV systolic function, the extent of LGE is a strong predictor for long-term adverse cardiac outcomes. Event-free survival was well discriminated with an LGE cutoff value of 12.0 %LV in these patients.

Differential myocardial fibrosis of the systemic right ventricle and subpulmonary left ventricle after atrial switch operation for complete transposition of the great arteries

Background

This study aimed to assess diffuse myocardial fibrosis of the systemic right ventricle and subpulmonary left ventricle in patients after Senning or Mustard operation for complete transposition of the great artery (TGA) using cardiac magnetic resonance (CMR) T1 mapping.

Methods

Thirty-one adult TGA patients after Senning (n = 24) or Mustard (n = 7) operation were studied at the age of 33.3 ± 4.0 years. Systemic right ventricular (RV) and subpulmonary left ventricular (LV) volumes, ejection fraction, and myocardial T1 values and extracellular volume fraction (ECV) were determined using CMR.

Results

The RV and LV ejection fractions were 47.0 ± 10.9% and 61.3 ± 7.4%, respectively. Compared to published normative values, patients had significantly greater RV and LV native T1 and ECV values (all p < 0.001). For each of the basal, mid, and apical segments, the LV native T1 and ECV values were significantly greater in the left than the right ventricle (all p < 0.05). There is a significant trend on progressive increase in ECV value from the basal towards the apical segments in both the right (p = 0.002) and the left (p < 0.001) ventricle. Modestly strong correlations were found between RV and LV native T1 (r = 0.60, p < 0.001) and ECV (r = 0.49, p = 0.005) values but not with ejection fractions of the respective ventricles.

Conclusions

Differential myocardial fibrosis, with greater involvement of the subpulmonary left ventricle than the systemic right ventricle, is present in patients with TGA after atrial switch operation. Associations between the magnitude of RV and LV fibrosis suggests adverse ventricular-ventricular interaction at the cardiac extracellular matrix level.

Duchenne and Becker muscular dystrophy carriers: Evidence of cardiomyopathy by exercise and cardiac MRI testing

BACKGROUND

Varied detection methods have resulted in conflicting reports on the prevalence of cardiac disease in Duchenne and Becker muscular dystrophy carriers (MDC).

METHODS

We performed a prospective cohort study of 77 genetically-confirmed MDC mothers, 22 non-carrier mothers, and 25 controls. All participants underwent Cardiopulmonary Exercise Testing (CPET) and Cardiac Magnetic Resonance imaging (CMR).

RESULTS

25% of carriers had ventricular ectopy in recovery of exercise (RecVE) as compared to 1 non-carrier and no controls (p = .003). No difference in age or maximal oxygen consumption was noted. 11 carriers had abnormal (<55%) left ventricular ejection fraction by CMR. Evidence of late gadolinium enhancement (LGE) was noted in 48% of MDC, 1 non-carrier patient and no control subjects (p < .0001). Subset analysis of LGE+ and LGE- subjects revealed differences in age (44.1 v 38.6 yrs.; p = .005), presence of RecVE, (38.9% v 10.5%, p = .004), and high serum creatine kinase (CK) (> 289 U/l; 52.8% v 31.6%, p = .065).

CONCLUSION

We describe the prevalence of disease using CPET and CMR in genetically-proven MDC. 49% of carriers had fibrosis, opposed to 5% of non-carriers, highlighting the importance of genetic testing in this population. Despite cardiomyopathy, functional assessment by treadmill was normal, illustrating the discrepancy in cardiac and skeletal muscle impacts. Age, RecVE and serum CK appear to have an important role in predicting cardiomyopathy. Serum CK levels suggest that a systemic higher global disease severity and not tissue heterogeneity may be the etiology for greater cardiac disease and relatively spared skeletal muscle disease in this population. Clinical Trial Registration https://clinicaltrials.gov/ct2/show/NCT02972580?term=mendell&cond=Duchenne+Muscular+Dystrophy&rank=5; ClinicalTrials.gov Identifier: NCT02972580.

Heart failure in single right ventricle congenital heart disease: physiological and molecular considerations

Because of remarkable surgical and medical advances over the past several decades, there are growing numbers of infants and children living with single ventricle congenital heart disease (SV), where there is only one functional cardiac pumping chamber. Nevertheless, cardiac dysfunction (and ultimately heart failure) is a common complication in the SV population, and pharmacological heart failure therapies have largely been ineffective in mitigating the need for heart transplantation. Given that there are several inherent risk factors for ventricular dysfunction in the setting of SV in addition to probable differences in molecular adaptations to heart failure between children and adults, it is perhaps not surprising that extrapolated adult heart failure medications have had limited benefit in children with SV heart failure. Further investigations into the molecular mechanisms involved in pediatric SV heart failure may assist with risk stratification as well as development of targeted, efficacious therapies specific to this patient population. In this review, we present a brief overview of SV anatomy and physiology, with a focus on patients with a single morphological right ventricle requiring staged surgical palliation. Additionally, we discuss outcomes in the current era, risk factors associated with the progression to heart failure, present state of knowledge regarding molecular alterations in end-stage SV heart failure, and current therapeutic interventions. Potential avenues for improving SV outcomes, including identification of biomarkers of heart failure progression, implications of personalized medicine and stem cell-derived therapies, and applications of novel models of SV disease, are proposed as future directions.

Potential Value of Native T1 Mapping in Symptomatic Adults with Congenital Heart Disease: A Preliminary Study of 3.0 Tesla Cardiac Magnetic Resonance Imaging

The native T1 value at 3.0 Tesla is a sensitive marker of diffuse myocardial damage. We evaluated the clinical usefulness of native T1 mapping in symptomatic adults with congenital heart disease (CHD), particularly in the systemic right ventricle (RV). Prospectively, 45 consecutive symptomatic adults with CHD were enrolled: 20 with systemic RV and 25 with tetralogy of Fallot underwent cardiac magnetic resonance (CMR) imaging at 3.0 Tesla. The Modified Look-Locker Inversion recovery sequence was used for T1 mapping. Cardiovascular events in the systemic RV were defined as heart failure and tachyarrhythmia. Brain natriuretic peptide (BNP) and indexed systemic ventricular end-diastolic volume were significantly higher in the systemic RV group. The native T1 value and extracellular volume (ECV) of the septal and lateral walls were higher in the systemic RV group, suggesting high impairment of the myocardium in the systemic RV group. There was a strong correlation between the native T1 value and ECV of the septum (r = 0.58, P = 0.03) and lateral wall (r = 0.56, P = 0.046) in the systemic RV group. Seven patients with systemic RV had cardiovascular events. In univariate logistic regression analysis, BNP and native T1 values of the insertion point were important for predicting cardiovascular events. The native T1 value at 3.0 Tesla may be a sensitive, contrast-free, and non-invasive adjunct marker of myocardial damage in CHD and predictive of cardiovascular events in the systemic RV.

Percutaneous Pulmonary Valve Implantation: Current Status and Future Perspectives

Patients with congenital heart disease (CHD) with right ventricle outflow tract (RVOT) dysfunction need sequential pulmonary valve replacements throughout their life in the majority of cases. Since their introduction in 2000, the number of percutaneous pulmonary valve implantations (PPVI) has grown and reached over 10,000 procedures worldwide. Overall, PPVI has been proven safe and effective, but some anatomical variations can limit procedural success. This review discusses the current status and future perspectives of the procedure.

Advanced Imaging to Phenotype Patients With a Systemic Right Ventricle

Background

Reduced ventricular function and decreased exercise capacity are widespread in adults with complete transposition of the great arteries after atrial switch (TGA‐Mustard/Senning) and congenitally corrected TGA (ccTGA). Advanced imaging techniques may help to better phenotype these patients and evaluate exercise cardiac response.

Methods and Results

Thirty‐three adults with a systemic right ventricle (70% TGA‐Mustard/Senning, 37±9 years of age, 24% female, 94% New York Heart Association class I‐II) underwent echocardiogram, cardiopulmonary exercise testing, and cardiovascular magnetic resonance imaging at rest and during a 4‐stage free‐breathing bicycle test. They were compared with 12 healthy controls (39±10 years of age, 25% female, all New York Heart Association class I). TGA‐Mustard/Senning patients had a higher global circumferential strain (−15.8±3.6 versus −11.2±5.2%, P=0.008) when compared with ccTGA, whereas global longitudinal strain and systemic right ventricle contractility during exercise were similar in both groups. Septal extracellular volume (ECV) in ccTGA was significantly higher than in TGA‐Mustard/Senning (30.2±2.0 versus 27.1±2.7%, P=0.005). During exercise, TGA‐Mustard/Senning had a fall in end‐diastolic volume and stroke volume (11% and 8%, respectively; both P≤0.002), whereas ccTGA could increase their stroke volume in the same way as healthy controls. Because of a greater heart rate reserve in TGA‐Mustard/Senning (P for interaction=0.010), cardiac index and peak oxygen uptake were similar between both patient groups.

Conclusions

Caution should be exercised when evaluating pooled analyses of systemic right ventricle patients, given the differences in myocardial contraction pattern, septal extracellular volume, and the exercise response of TGA‐Mustard/Senning versus ccTGA patients. Longitudinal follow‐up will determine whether abnormal exercise cardiac response is a marker of earlier failure.

Noninvasive imaging assessment of rehabilitation therapy in heart failure with preserved and reduced left ventricular ejection fraction (IMAGING-REHAB-HF): design and rationale

Background:

Studies have shown significant benefits of exercise therapy in heart failure (HF) with a reduced ejection fraction (HFrEF) and HF with a preserved ejection fraction (HFpEF). The mechanisms responsible for the beneficial effect of exercise in HFrEF and HFpEF are still unclear. We hypothesized that the effect of exercise on myocardial remodeling may explain its beneficial effect.

Methods:

IMAGING-REHAB-HF is a single-center, randomized, controlled clinical trial using cardiac magnetic resonance imaging, vasomotor endothelial function, cardiac sympathetic activity imaging and serum biomarkers to compare the effect of exercise therapy in HFpEF (LVEF ≥ 45%) and HFrEF (LVEF < 45%). Subjects will be assessed at baseline and after 4 months. The exercise program will consist of three 60-min exercise sessions/week. The primary endpoints are the effect of exercise on myocardial extracellular volume (ECV), left ventricular (LV) systolic function, LV mass, LV mass-to-volume and LV cardiomyocyte volume. Secondary endpoints include the effect of exercise on vasomotor endothelial function, cardiac sympathetic activity and plasmatic biomarkers. Patients will be allocated in a 2:1 fashion to supervised exercise program or usual care. A total sample size of 90 patients, divided into two groups according to LVEF:HFpEF group (45 patients:30 in the intervention arm and 15 in the control arm) and HFrEF group (45 patients:30 in the intervention arm and 15 in the control arm) – will be necessary to achieve adequate power.

Conclusion:

This will be the first study to evaluate the benefits of a rehabilitation program on cardiac remodeling in HF patients. The unique design of our study may provide unique data to further elucidate the mechanisms involved in reverse cardiac remodeling after exercise in HFpEF and HFrEF patients.

Determinants of Left Ventricular Dysfunction and Remodeling in Patients With Corrected Tetralogy of Fallot

Background

The aim of this study was to identify in asymptomatic patients with repaired tetralogy of Fallot the prevalence and determinants of impaired left‐sided cardiac function and adverse ventricular remodeling and the relation of left ventricular (LV) dysfunction and remodeling with cardiopulmonary exercise capacity.

Methods and Results

In a cross‐sectional study, 103 patients with tetralogy of Fallot (median age, 16.3 years) in New York Heart Association class 1, with surgical repair at a median age of 1.1 years, and 63 age‐matched controls were studied. LV, right ventricular function and geometry, LV myocardial extracellular volume (n=57), and left atrial function were quantified with cardiac magnetic resonance. Peak oxygen consumption was measured by a standardized cardiopulmonary exercise test (n=70). Patients with tetralogy of Fallot had lower LV ejection fraction (P=0.001; 49% below age‐adjusted fifth percentile for controls), lower LV mass index (P=0.003), lower LV mass/volume ratio (P<0.01), and impaired left atrial function. Right ventricular mass/volume ratio was the best predictor for LV systolic dysfunction and for a lower LV mass/volume ratio. Compared with controls, LV extracellular volume was higher (P<0.001), particularly in female patients, and associated with subnormal peak oxygen consumption (P=0.037). A peak oxygen consumption below the third percentile reference level was more likely with decreasing LV ejection fraction (P=0.008), and lower LV mass index (P=0.024), but independent of right ventricular ejection fraction.

Conclusions

In New York Heart Association class 1 patients with tetralogy of Fallot, frequent impaired systolic and diastolic LV function, LV adverse remodeling with LV atrophy, a decreased mass/volume ratio, and extracellular matrix expansion suggest cardiomyopathic changes. The best predictor for LV systolic dysfunction was the right ventricular mass/volume ratio. The subnormal peak oxygen consumption indicates that monitoring of LV status may be important for long‐term prognosis.

MRI of Cardiotoxicity

Cardiovascular magnetic resonance (CMR) imaging is useful to identify systolic dysfunction, particularly when echocardiographic imaging is not acceptable because of poor acoustic windows or when left ventricular ejection fraction (LVEF) is inconclusive by other modalities and an accurate LVEF measurement is needed. Of particular advantage in cardio-oncology is CMR's capability to perform tissue characterization to noninvasively identify changes in pathologic conditions related to cancer therapy or to discriminate causes of disease that may confound presentation in cardio-oncology patients. For these reasons, there is an increasing use of CMR in the screening and surveillance of cardio-oncology patients.

Mapping versus source methods for quantifying myocardial T1 in controls and in repaired tetralogy of Fallot: interchangeability and reproducibility in children

BACKGROUND

Myocardial T1 relaxometry can be performed by contouring on individual T1-weighted source images (source method) or on a single T1 map (mapping method).

OBJECTIVE

This study compares (a) agreement between native T1 and extracellular volume results of the two methods and (b) interobserver reproducibility of the two methods in children without heart disease and those with tetralogy of Fallot (TOF).

MATERIALS AND METHODS

We retrospectively analyzed pediatric patients (controls and those with repaired TOF) with cardiac magnetic resonance examinations including extracellular volume quantification using the modified Look-Locker inversion recovery (MOLLI) sequence. We compared native T1 and extracellular volume of the entire left ventricle and interventricular septum derived using the source and the mapping approaches.

RESULTS

In the control group (n=25, median age 14.0 years, interquartile range [IQR] 11.5-16.5 years), the mapping method produced lower native T1 values than the source method in the interventricular septum (mean difference ± standard deviation [SD] = 12±15 ms, P<0.001). In the TOF group (n=50, median age 13.3 years, IQR 9.9-15.0 years), the mapping method produced lower values for native T1 and extracellular volume in the interventricular septum (mean difference 9±14 ms and 0.6±1.1%, P<0.001). In 6-12% of the children, differences were >3 standard deviations from the mean difference. Interobserver reproducibility between the two methods by intraclass correlation coefficients were clinically equivalent.

CONCLUSION

T1 and extracellular volume values generated by the source and mapping methods show systematic differences and can vary significantly in an individual child, and thus cannot be used interchangeably in clinical practice. The source method might allow for easier detection and, in some cases, mitigation of artifacts that are not infrequent in children and can be difficult to appreciate on the T1 map.