Relation of right ventricular mechanics to exercise tolerance in children after tetralogy of Fallot repair

The mechanics of congenital heart disease: from a morphological trait to the functional echocardiographic evaluation

Advances in pediatric cardiac surgery have resulted in a recent growing epidemic of children and young adults with congenital heart diseases (CHDs). In these patients, congenital defects themselves, surgical operations and remaining lesions may alter cardiac anatomy and impact the mechanical performance of both ventricles. Cardiac function significantly influences outcomes in CHDs, necessitating regular patient follow-up to detect clinical changes and relevant risk factors. Echocardiography remains the primary imaging method for CHDs, but clinicians must understand patients' unique anatomies as different CHDs exhibit distinct anatomical characteristics affecting cardiac mechanics. Additionally, the use of myocardial deformation imaging and 3D echocardiography has gained popularity for enhanced assessment of cardiac function and anatomy. This paper discusses the role of echocardiography in evaluating cardiac mechanics in most significant CHDs, particularly its ability to accommodate and interpret the inherent anatomical substrate in these conditions.

Adverse remodelling in tetralogy of Fallot: From risk factors to imaging analysis and future perspectives

Although contemporary outcomes of initial surgical repair of tetralogy of Fallot (TOF) are excellent, the survival of adult patients remains significantly lower than that of the normal population due to the high incidence of heart failure, ventricular arrhythmias, and sudden cardiac death. The underlying mechanisms are only partially understood but involve an adverse biventricular response, so-called remodelling, to key stressors such as right ventricular (RV) pressure-and/or volume-overload, myocardial fibrosis, and electro-mechanical dyssynchrony. In this review, we explore risk factors and mechanisms of biventricular remodelling, from histological to electro-mechanical aspects, and the role of imaging in their assessment. We discuss unsolved challenges and future directions to better understand and treat the long-term sequelae of this complex congenital heart disease.

Tetralogy of Fallot Across the Lifespan: A Focus on the Right Ventricle

Tetralogy of Fallot is a cyanotic congenital heart disease, for which various surgical techniques allow patients to survive to adulthood. Currently, the natural history of corrected tetralogy of Fallot is underlined by progressive right ventricular (RV) failure due to pulmonic regurgitation and other residual lesions. The underlying cellular mechanisms that lead to RV failure from chronic volume overload are characterized by microvascular and mitochondrial dysfunction through various regulatory molecules. On a clinical level, these cardiac alterations are commonly manifested as exercise intolerance. The degree of exercise intolerance can be objectified and aid in prognostication through cardiopulmonary exercise testing. The timing for reintervention on residual lesions contributing to RV volume overload remains controversial; however, interval assessment of cardiac function and volumes by echocardiography and magnetic resonance imaging may be helpful. In patients who develop clinically important RV failure, clinicians should aim to maintain a euvolemic state through the use of diuretics while paying particular attention to preload and kidney function. In patients who develop signs of cardiogenic shock from right heart failure, stabilization through the use of inotropes and pressor is indicated. In special circumstances, the use of mechanical support may be appropriate. However, cardiologists should pay particular attention to residual lesions that may impact the efficacy of the selected device.

Electromechanical Dyssynchrony Is Associated With Right Ventricular Remodeling and Dysfunction Independently of Pulmonary Regurgitation Late After Tetralogy of Fallot Repair

BACKGROUND

The aim of this study was to investigate the relationship among right ventricular (RV) dilatation, dysfunction, and electromechanical dyssynchrony (EMD) in patients with repaired tetralogy of Fallot (rTOF).

METHODS

Data from a prospective rTOF registry of subjects with moderate or greater pulmonary regurgitation (PR) and contemporary imaging were analyzed. Electrocardiograms and echocardiograms were analyzed for EMD (prolonged QRS duration [QRSd], echocardiographic septal flash, and mechanical delay) and mechanical dispersion. The relationship among these, RV measurements on cardiac magnetic resonance, exercise capacity, and incident arrhythmia or death was analyzed with adjustment for PR.

RESULTS

In total, 271 patients with rTOF (42% women; median age, 32 years; interquartile range [IQR], 23-34 years) were included. Patients had moderate to severe PR (median PR fraction, 38%; IQR, 30%-47%), moderate to severe RV enlargement (median RV end-diastolic volume index, 161 mL/m2; IQR, 138-186 mL/m2) and mild RV systolic dysfunction (median RV ejection fraction [RVEF], 44%; IQR, 38%-48%). Eleven patients (4%) experienced ventricular arrhythmia or death. Presence of EMD was associated with larger RV size (RV end-diastolic volume index and RV end-systolic volume index, P = .006 and P < .001, respectively) and lower RVEF (P < .001). A sharp inflection in the relation among QRSd, RV size, and RVEF was observed when QRSd exceeded 150 msec (3.1% decrease in RVEF for every 20-msec increase in QRSd between 160 and 200 msec). Similar inflection points were observed for the mechanical delay between the RV basal-lateral and midseptal segments. The mechanical delay was higher in patients with vs without incident atrial arrhythmia (371 vs 276 msec, P = .014).

CONCLUSIONS

In adults with rTOF, EMD is independently associated with larger RV size, lower RVEF, and incident atrial arrhythmias.

Physical Activity Promotion Among Individuals With Tetralogy of Fallot

In the general population, the most cited barriers to physical activity (PA) are time, energy, and motivation. Consequently, despite the significant contribution of PA to health and well-being, many individuals are insufficiently active. Physical inactivity and sedentary lifestyles increase the risk of acquired cardiometabolic disease, a risk that may complicate and is compounded by the anatomic and physiologic features inherent in the patient with repaired tetralogy of Fallot (ToF). Individuals with ToF commonly present with reduced exercise capacity and PA levels. In light of historically PA restrictive management of their heart disease, known reductions in exercise capacity among individuals with ToF are combined with psychosocial barriers to their participation, potentially establishing a cycle of further detraining, inactivity, and disease progression/health decline. To this end, children and young adults with ToF are known to have reduced self-efficacy towards PA, defined as their confidence in their ability to participate. In this review, we apply self-efficacy as an overarching mediator of PA participation and explore trends and determinants of PA participation among individuals with ToF and its subsequent impact on exercise capacity, disease risk, and health-related quality of life. We outline the rationale and strategies aimed at improving PA in children and adults with ToF and highlight current knowledge gaps and future directions in the promotion of PA in the population with ToF.

Biventricular shape modes discriminate pulmonary valve replacement in tetralogy of Fallot better than imaging indices

Current indications for pulmonary valve replacement (PVR) in repaired tetralogy of Fallot (rTOF) rely on cardiovascular magnetic resonance (CMR) image-based indices but are inconsistently applied, lead to mixed outcomes, and remain debated. This study aimed to test the hypothesis that specific markers of biventricular shape may discriminate differences between rTOF patients who did and did not require subsequent PVR better than standard imaging indices. In this cross-sectional retrospective study, biventricular shape models were customized to CMR images from 84 rTOF patients. A statistical atlas of end-diastolic shape was constructed using principal component analysis. Multivariate regression was used to quantify shape mode and imaging index associations with subsequent intervention status (PVR, n = 48 vs. No-PVR, n = 36), while accounting for confounders. Clustering analysis was used to test the ability of the most significant shape modes and imaging indices to discriminate PVR status as evaluated by a Matthews correlation coefficient (MCC). Geometric strain analysis was also conducted to assess shape mode associations with systolic function. PVR status correlated significantly with shape modes associated with right ventricular (RV) apical dilation and left ventricular (LV) dilation (p < 0.01), RV basal bulging and LV conicity (p < 0.05), and pulmonary valve dilation (p < 0.01). PVR status also correlated significantly with RV ejection fraction (p < 0.05) and correlated marginally with LV end-systolic volume index (p < 0.07). Shape modes discriminated subsequent PVR better than standard imaging indices (MCC = 0.49 and MCC = 0.28, respectively) and were significantly associated with RV and LV radial systolic strain. Biventricular shape modes discriminated differences between patients who did and did not require subsequent PVR better than standard imaging indices in current use. These regional features of cardiac morphology may provide insight into adaptive vs. maladaptive types of structural remodeling and point toward an improved quantitative, patient-specific assessment tool for clinical use.

The value of myocardial strain imaging in the evaluation of patients with repaired Tetralogy of Fallot: a review of the literature

Tetralogy of Fallot (ToF) is considered to be the most common, complex, cyanotic congenital heart disease (CHD) representing 7-10% of all congenital heart defects, whereas the patients with ToF are the most frequently operated in their early infancy or childhood. Cardiac magnetic resonance (CMR) consists a valuable imaging technique for the diagnosis and serial follow-up of CHD patients. Furthermore, in recent years, advanced echocardiography imaging techniques have come to the fore, aiming to achieve a complete and more accurate evaluation of cardiac function using speckle tracking imaging modalities. We conducted a review of the literature in order to assess the myocardial deformation of patients with repaired ToF (rToF) using echocardiographic and CMR parameters. Patients with rToF have impaired myocardial strain parameters, that are well standardized either with the use of speckle tracking echocardiography or with the use of CMR imaging. Subclinical left ventricular dysfunction (low GLS) and myocardial dyssynchrony are commonly identified in rToF patients. Impaired left atrium (LA) and right atrium (RA) mechanics are, also, a common finding in this study population, but the studies using atrial strain are a lot fewer than those with LV and RV strain. No studies using myocardial work were identified in the literature, as far as rToF patients are concerned, which makes it an ideal field for further investigation.

Evaluation of right ventricle systolic function after tetralogy of Fallot repair: A systematic review comparing cardiac magnetic resonance and global longitudinal strain

BACKGROUND

Most patients who undergo tetralogy of Fallot (TOF) repair experience late right ventricle (RV) dysfunction due to pulmonary valve regurgitation (PVR). Cardiac magnetic resonance (CMR) is the gold standard method for evaluating RV during follow-up. Global longitudinal strain (GLS) has been introduced as a novel method for the assessment of RV dysfunction. We aimed to compare the feasibility of GLS and CMR for assessing RV function after TOF repair.

METHODS

We systematically reviewed the English literature using PubMed, SciELO and Google Scholar for articles published between January 1, 2015, and December 31, 2020. Articles evaluating RV function comparing by GLS and CMR after TOF repair were included.

RESULTS

Nine studies including 465 patients were analyzed. Most patients were men (280; 60%), the male:female ratio was 1.5:1, and the age range was .8 to 57.7 years. The mean follow-up time was 6 to 32 months. The correlation between RV GLS and RV ejection fraction (EF) by CMR was negative for the articles and varied from moderate to strong (r = -.45, r = -.60, r = -.76).

CONCLUSION

Right ventricle GLS can be considered for routine follow-up of TOF repair patients, even though CMR remains the noninvasive gold standard method. Using a single parameter may not allow comparison of the accuracy of 3D RV EF by using CMR and GLS. Further studies with a larger number of patients undergoing TOF repair are required to evaluate the correlation between these examinations.

Superior prognostic value of right ventricular free wall compared to global longitudinal strain in patients with repaired tetralogy of Fallot

Objectives

Both right ventricular free wall longitudinal strain (RVFWLS) and right ventricular global longitudinal strain (RVGLS) using two-dimensional speckle tracking echocardiography (2D-STE) has been demonstrated to predict adverse outcomes in patients with repaired tetralogy of Fallot (r-TOF). However, RVGLS may be affected by left ventricular (LV) function owing to the fact that the interventricular septum is also a part of the left ventricle. Therefore, the aim of our study was to compare the predictive value of RVFWLS with that of RVGLS in patients with r-TOF.

Materials and methods

A total of 179 patients with r-TOF were included in this study. RVFWLS, RVGLS, and left ventricle global longitudinal strain (LVGLS) were evaluated by 2D-STE. The adverse clinical events were death or r-TOF-related rehospitalization. Prognostic performance was evaluated by C-statistic and Akaike information criterion (AIC).

Results

Thirty-one patients developed poor outcomes during a median follow-up period of 2.8 years. Compared with patients without end-point events, those with end-point events had higher incidence of moderate/severe pulmonary regurgitation, larger right heart sizes, and lower RV fractional area change (RVFAC), RVFWLS, RVGLS, and LVGLS than those without. Multivariate Cox regression analysis revealed that RVFAC, RVFWLS, RVGLS, and LVGLS were predictive of poor outcomes in patients with r-TOF after adjustment for transannular patch and QRS duration. A Cox model using RVFWLS (C index = 0.876, AIC = 228) was found to predict unfavorable outcomes more accurately than a model with RVGLS (C index = 0.856, AIC = 243), RVFAC (C index = 0.811, AIC = 248), and LVGLS (C index = 0.830, AIC = 248).

Conclusion

Although both RVGLS and RVFWLS are associated with adverse events, RVFWLS provides superior prognostic value than that of RVGLS in patients with r-TOF.

Right Ventricular-Pulmonary Arterial Coupling in Repaired Tetralogy of Fallot

We assessed right ventricular (RV)-pulmonary arterial (PA) coupling in patients with repaired tetralogy of Fallot (TOF). Sixty patients (34 males) aged 18.6 ± 8.3 years at 14.8 ± 7.4 years after repair and 60 controls were studied. Two-dimensional, tissue Doppler and speckle tracking echocardiography and colour flow mapping were performed to assess RV end-systolic (ESA) and -diastolic areas, tricuspid valve Doppler and myocardial velocities, left ventricular (LV) and RV deformation and pulmonary (PR), tricuspid regurgitation (TR), respectively. The ratios of RV area change to ESA and peak tricuspid annular systolic (s) velocity to RV ESA indexed to body surface area reflected RV-PA coupling. Patients had greater RV areas and reduced tricuspid annular and myocardial velocities, LV and RV myocardial mechanics compared to controls (all p < 0.05). Both RV area change/ESA ratio and peak tricuspid annular s velocity/indexed RV ESA ratio were reduced in patients (all p < 0.001). Sixty-one and 100% of patients had, respectively, RV area change/ESA ratio and peak tricuspid annular s velocity/indexed RV ESA ratio < -2SD of controls. Indices of RV-PA coupling correlated positively with tricuspid myocardial velocities, LV and RV deformation and inversely with PR and TR (all p < 0.05). Multivariate analysis showed RV systolic strain rate, PR and TR as independent predictors of both RV-PA coupling indices, whilst age, gender and LV systolic strain were also predictors of peak tricuspid annular s velocity/indexed RV ESA ratio (all p < 0.05). In conclusion, RV-PA coupling is impaired and is associated with RV and LV mechanics and severity of PR and TR in patients with repaired TOF.

Cardiac MRI-Derived Myocardial Deformation Parameters Correlate with Pulmonary Valve Replacement Indications in Repaired Tetralogy of Fallot

Right ventricular (RV) volumetric cardiac magnetic resonance (CMR) criteria serve as indicators for pulmonary valve replacement (PVR) in repaired tetralogy of Fallot (rTOF). Myocardial deformation and tricuspid valve displacement parameters may be more sensitive measures of RV dysfunction. This study's aim was to describe rTOF RV deformation and tricuspid displacement patterns using novel CMR semi-automated software and determine associations with standard CMR measures. Retrospective study of 78 pediatric rTOF patients was compared to 44 normal controls. Global RV longitudinal and circumferential strain and strain rate (SR) and tricuspid valve (TV) displacement were measured. Correlation analysis between strain, SR, TV displacement, and volumes was performed between and within subgroups. The sensitivity and specificity of strain parameters in predicting CMR criteria for PVR was determined. Deformation variables were reduced in rTOF compared to controls. Decreased RV strain and TV shortening were associated with increased RV volumes and decreased RVEF. Longitudinal and circumferential parameters were predictive of RVESVi (> 80 ml/m2) and RVEF (< 47%), with circumferential strain (> - 15.88%) and SR (> - 0.62) being most sensitive. Longitudinal strain was unchanged between rTOF subgroups, while circumferential strain trended abnormal in those meeting PVR criteria compared to controls. RV deformation and TV displacement are abnormal in rTOF, and RV circumferential strain variation may reflect an adaptive response to chronic volume or pressure load. This coupled with associations of ventricular deformation with traditional PVR indications suggest importance of this analysis in the evolution of rTOF RV assessment.

The challenges of an aging tetralogy of Fallot population

Introduction: Advancements in surgery and management have resulted in a growing population of aging adults with tetralogy of Fallot (TOF). As a result, there has been a parallel growth in late complications associated with the sequelae from the underlying cardiac anomalies as well as the surgical and other interventional treatments.Areas covered: Here, we review challenges related to an aging population of patients with TOF, particularly late complications, and highlight advances in management and key areas for future research. Pulmonary regurgitation, heart failure, arrhythmias, and aortic complications are some of these late complications. There is also a growing incidence of acquired cardiovascular disease, obesity, and diabetes associated with aging. Management of these late complications and acquired comorbidities continues to evolve as research provides insights into long-term outcomes from medical therapies and surgical interventions.Expert opinion: The management of an aging TOF population will continue to transform with advances in imaging technologies to identify subclinical disease and valve replacement technologies that will prevent and mitigate disease progression. In the coming years, we speculate that there will be more data to support the use of novel heart failure therapies in TOF and consensus guidelines on the management of refractory arrhythmias and aortic complications.

Exercise capacity in patients with repaired Tetralogy of Fallot aged 6 to 63 years

OBJECTIVES

This study aimed to provide a perspective for the interpretation of exercise capacity (peakVO₂) in patients with repaired Tetralogy of Fallot (patients with rTOF) by describing the course of peakVO₂ from patients aged 6-63 years.

METHODS

A retrospective study was performed between September 2001 and December 2016 in the German Heart Centre Munich, Germany, and in the University Medical Centre Groningen, the Netherlands. A total of 1175 cardiopulmonary exercise tests (CPETs) were collected from 586 patients with rTOF, 46% female. Maximal exertion was verified using a respiratory exchange ratio ≥1.00. PeakVO₂ was modelled using time-dependent multilevel models for repeated measurements (n=889 in 300 patients), and compared with subject-specific reference values calculated by the models of Bongers et al and Mylius et al. RESULTS: The peakVO₂ of patients with rTOF was reduced at all ages. At the age of 6, the peakVO₂ was 614 mL/min (70% of predicted (95% CI 67 to 73)). The reduced increase in peakVO₂ during adolescence resulted in a significant lower maximum peakVO₂ of 1209 mL/min at 25 years (65% predicted, p<0.001). A linear decline after 25 years was observed in patients and references, although patients showed an accelerated decline, with a -0.24% point of predicted (95% CI 0.11 to 0.38) per year without differences between sexes (p=0.263).

CONCLUSIONS

This study provides a context for peakVO₂ across ages in patients with rTOF under contemporary treatment strategies. It showed that the reduction in peakVO₂ originates from childhood and declines over time. Sex differences in patients with rTOF were similar to natural existing sex differences.

Outcomes of pulmonary valve leaflet augmentation for transannular repair of tetralogy of Fallot

OBJECTIVE

To evaluate the midterm results of pulmonary valve leaflet augmentation in transannular repair of tetralogy of Fallot (TOF).

METHODS

From 2007 to 2019, 131 patients underwent a transannular repair with pulmonary leaflet augmentation for TOF (n = 120) and double outlet right ventricle with pulmonary stenosis (n = 11). Patch material was expanded polytetrafluoroethylene (n = 76), glutaraldehyde-treated autologous pericardium (n = 47) and bovine pericardium (n = 8).

RESULTS

Median age at repair was 8.9 months (interquartile range, 5.4-14.8). There was no operative mortality. Median follow-up was 6.25 years (interquartile range, 2.77-7.75). Freedom from severe pulmonary regurgitation (PR) was 85% (95% confidence interval [CI], 77%-90%) and 76% (95% CI, 66%-83%) at 1 and 5 years, respectively. Freedom from moderate or greater PR was 69% (95% CI, 60%-76%) and 30% (95% CI, 21%-39%) at 5 and 10 years, respectively. Three patients required pulmonary valve replacement for PR. Nine patients required pulmonary balloon valvuloplasty. Freedom from intervention for pulmonary valve stenosis was 98% (95% CI, 93%-99%) and 94% (95% CI, 87%-97%) at 1 and 5 years, respectively. One patient with severe PR had an indexed right ventricular volume >160 mL/m². Use of expanded polytetrafluoroethylene resulted in a greater freedom from moderate or greater PR (log-rank test P < .001; Cox regression hazard ratio, 0.40; 95% CI, 0.25-0.63; P < .001).

CONCLUSIONS

At midterm follow-up of transannular repair with pulmonary valve leaflet augmentation, severe PR occurs in less than 50% of patients. The expanded polytetrafluoroethylene patch performs better than pericardium.

Three-dimensional right ventricular shape and strain in congenital heart disease patients with right ventricular chronic volume loading

AIMS

Right ventricular (RV) function assessment is crucial in congenital heart disease patients, especially in atrial septal defect (ASD) and repaired Tetralogy of Fallot (TOF) patients with pulmonary regurgitation (PR). In this study, we aimed to analyse both 3D RV shape and deformation to better characterize RV function in ASD and TOF-PR.

METHODS AND RESULTS

We prospectively included 110 patients (≥16 years old) into this case-control study: 27 ASD patients, 28 with TOF, and 55 sex- and age-matched healthy controls. Endocardial tracking was performed on 3D transthoracic RV echocardiographic sequences and output RV meshes were post-processed to extract local curvature and deformation. Differences in shape and deformation patterns between subgroups were quantified both globally and locally. Curvature highlights differences in RV shape between controls and patients while ASD and TOF-PR patients are similar. Conversely, strain highlights differences between controls and TOF-PR patients while ASD and controls are similar [global area strain: -31.5 ± 5.8% (controls), -34.1 ± 7.9% (ASD), -24.8 ± 5.7% (TOF-PR), P < 0.001, similar significance for longitudinal and circumferential strains]. The regional and local analysis highlighted differences in particular in the RV free wall and the apical septum.

CONCLUSION

Chronic RV volume loading results in similar RV shape remodelling in both ASD and TOF patients while strain analysis demonstrated that RV strain is only reduced in the TOF group. This suggests a fundamentally different RV remodelling process between both conditions.

Ventricular Myocardial Deformation Imaging of Patients with Repaired Tetralogy of Fallot

In patients with repaired tetralogy of Fallot (TOF), dysfunction of the right and left ventricles remains an important issue. Adverse right ventricular (RV) remodeling has been related to RV dilation secondary to pulmonary regurgitation, electromechanical dyssynchrony, and myocardial fibrosis. Left ventricular (LV) dysfunction is attributed among other factors to altered ventricular-ventricular interaction. Advancements in echocardiography and cardiac magnetic resonance imaging have enabled direct interrogation of myocardial deformation of both ventricles in terms of myocardial strain and strain rate. Emerging evidence suggests that myocardial deformation imaging may provide incremental information for clinical use. In children and adults with repaired TOF, there is a growing body of literature on the use of myocardial deformation imaging in the assessment of ventricular mechanics and its clinical and prognostic values. The present review aims to provide an overview of impairment in RV and LV mechanics, associations between RV and LV deformation, changes in ventricular deformation after pulmonary valve replacement, and associations between measures of RV and LV deformation and outcomes and to highlight the clinical translational potential of myocardial deformation imaging in patients with repaired TOF.

The right ventricular myocardial systolic-to-diastolic duration ratio in children after surgical repair of Tetralogy of Fallot

Right ventricular (RV) function impacts clinical outcomes after surgical repair of Tetralogy of Fallot (rTOF). However, assessment of RV function remains difficult. We investigated the RV myocardial systolic-to-diastolic (S/D) duration ratio derived from strain imaging time intervals to characterize RV myocardial performance, exploring its relation with peak oxygen consumption during exercise (V̇o₂) and cardiac magnetic resonance-derived RV dilation and function in rTOF. We retrospectively analyzed 76 children with rTOF and 42 normal controls. The RV myocardial S/D duration ratio was measured from RV global and regional 2D speckle tracking longitudinal strain. Time from QRS onset to peak systolic strain was defined as the systolic duration. The S/D duration ratio was calculated and corrected for heart rate (HR). Postsystolic shortening (PSS) duration was defined as shortening time after cessation of pulmonary systolic antegrade flow. The RV myocardial S/D duration ratio, corrected or uncorrected for HR, was significantly higher in rTOF vs. controls (1 ± 0.3 vs. 0.8 ± 0.2, P = 0.004) in relation to prolonged PSS. The HR-corrected myocardial S/D duration ratio correlated weakly with RV ejection fraction (EF, r = -0.37, P = 0.001) and V̇o₂ (r = -0.32, P = 0.042). In multiregression analysis, RV EF was independently associated with the myocardial S/D duration ratio. The RV myocardial S/D duration ratio is a parameter of RV myocardial performance and efficiency, incorporating elements of systolic and diastolic performance, mechanical dyssynchrony, and PSS. The S/D duration ratio is associated with exercise capacity and RV dysfunction in rTOF.NEW & NOTEWORTHY This is the first study to assess right ventricular myocardial performance using the systolic-to-diastolic duration ratio derived from 2D strain. Seventy-six children with repaired Tetralogy of Fallot were evaluated. Echocardiographic data were correlated with cardiac magnetic resonance and peak oxygen consumption during exercise. The results show the right ventricular myocardial systolic-to-diastolic duration ratio incorporates systolic and diastolic performance, electromechanical dyssynchrony, and postsystolic shortening and is associated with exercise capacity in repaired Tetralogy of Fallot.

Exercise echocardiography demonstrates potential myocardial damage in patients with repaired tetralogy of Fallot using layer-specific strain analysis

INTRODUCTION

Exercise stress echocardiography and layer-specific strains are emerging as important tools for cardiac assessment. This study was aimed to evaluate layer-specific strains and torsion parameters during exercise in order to investigate the characteristics of cardiac dysfunction in patients with repaired tetralogy of Fallot and to detect subclinical left ventricular dysfunction.

MATERIALS AND METHODS

Thirteen patients with repaired tetralogy of Fallot (median age, 17.3 [interquartile range, 14.5-22.9] years; 6 males) and 13 controls (median age, 28.5 [interquartile range, 27.6-31.6] years; 13 males) underwent echocardiography at rest and during supine exercise. Layer-specific longitudinal strain and circumferential strain of three myocardial layers (endocardium, midmyocardium, and epicardium), torsion, and untwisting rate were measured using two-dimensional speckle-tracking echocardiography.

RESULTS

Peak endocardial papillary circumferential strain (-21.1 ± 2.6% vs. -25.8 ± 3.8%, p = 0.007), midmyocardial apical circumferential strain (-11.1 ± 4.0% vs. -15.6 ± 3.2%, p = 0.001), epicardial apical circumferential strain (-11.1 ± 4.0% vs. -15.6 ± 3.2%, p = 0.021), and torsion (8.9 ± 6.0 vs. 14.9 ± 4.8 degree, p = 0.021) were significantly lower in the repaired tetralogy of Fallot group than in the control group during exercise, though no significant difference was found between patients and controls at rest.

CONCLUSIONS

Analysis of layer-specific strains and torsion parameters during exercise could detect subclinical left ventricular dysfunction in patients with repaired tetralogy of Fallot, which might reflect potential myocardial damage, at a stage where these parameters have normal values at rest. This finding provides new insight into the mechanisms of cardiac dysfunction in patients with repaired tetralogy of Fallot.

Relative Impact of Right Ventricular Electromechanical Dyssynchrony Versus Pulmonary Regurgitation on Right Ventricular Dysfunction and Exercise Intolerance in Patients After Repair of Tetralogy of Fallot

Background The relative impact of right ventricular ( RV ) electromechanical dyssynchrony versus pulmonary regurgitation ( PR ) on exercise capacity and RV function after tetralogy of Fallot repair is unknown. We aimed to delineate the relative effects of these factors on RV function and exercise capacity. Methods and Results We retrospectively analyzed 81 children with tetralogy of Fallot repair using multivariable regression. Predictor parameters were electrocardiographic QRS duration reflecting electromechanical dyssynchrony and PR severity by cardiac magnetic resonance. The outcome parameters were exercise capacity (percentage predicted peak oxygen consumption) and cardiac magnetic resonance ejection fraction (RV ejection fraction). To understand the relative effects of RV dyssynchrony versus PR on exercise capacity and RV function, virtual patient simulations were performed using a closed-loop cardiovascular system model (CircAdapt), covering a wide spectrum of disease severity. Eighty-one patients with tetralogy of Fallot repair (median [interquartile range { IQR} ] age, 14.48 [11.55-15.91] years) were analyzed. All had prolonged QRS duration (median [IQR], 144 [123-152] ms), at least moderate PR (median [IQR], 40% [29%-48%]), reduced exercise capacity (median [IQR], 79% [68%-92%] predicted peak oxygen consumption), and reduced RV ejection fraction (median [IQR], 48% [44%-52%]). Longer QRS duration, more than PR , was associated with lower oxygen consumption and lower RV ejection fraction. In a multivariable regression analysis, oxygen consumption decreased with both increasing QRS duration and PR severity. CircAdapt modeling showed that RV dyssynchrony exerts a stronger limiting effect on exercise capacity and on RV ejection fraction than does PR , regardless of contractile function. Conclusions In both patient data and computer simulations, RV dyssynchrony, more than PR , appears to be associated with reduced exercise capacity and RV systolic dysfunction in patients after TOF repair.

The evaluation of right ventricular systolic function in patients with repaired Tetralogy of Fallot by conventional echocardiographic methods and speckle tracking echocardiography: Compared with the gold standard cardiac mangenetic resonance

BACKGROUND

Right ventricular (RV) function is one of the important prognostic factors in patients with repaired Tetralogy of Fallot (TOF). We aimed to assess RV function by conventional echocardiography and two-dimensional speckle tracking echocardiography (2D-STE) in patients with repaired TOF.

METHODS

Twenty-seven (male 17) adolescents and young adult patients (mean age 22.7 ± 6.7 years) operated on for TOF and age- and gender-matched healthy controls were included. RV systolic function in both groups were evaluated by fractional area change (FAC), tricuspid annular plane systolic excursion (TAPSE), RV myocardial performance index (RVMPI) and tricuspid annular peak systolic velocity by pulsed tissue Doppler (tricuspid S'), and also RV global longitudinal strain (RV GLS) obtained from STE. These results were compared with RV ejection fraction (RVEF) measured by cardiac magnetic resonance imaging (CMRI) performed within 3 months in patient group.

RESULTS

Systolic RVGLS values were significantly lower in patients compared to controls (-17.4 ± 3.1% vs -25.6 ± 3%). Among the echocardiographic parameters, RVGLS had the best correlation with RV EF derived from CMRI (r: -.6). By receiver operating characteristics analysis (ROC), an RV GLS cutoff value of -17.4% had 75% sensitivity and 68.4% specificity in identifying RVEF <45% with an area under curve 0.743 (P < .05). The intra- and inter-observer agreement for RV GLS was excellent.

CONCLUSION

RVGLS is an easy, effective, feasible, and reproducible tool in the evaluation of RV systolic function. So, RVGLS measurement by STE may be one of the routine echocardiographic parameters in the evaluation of RV systolic function in patients with repaired TOF.

Quantification of Right Ventricular Electromechanical Dyssynchrony in Relation to Right Ventricular Function and Clinical Outcomes in Children with Repaired Tetralogy of Fallot

BACKGROUND

Electromechanical dyssynchrony occurs ubiquitously following tetralogy of Fallot (TOF) repair, manifesting electrically as a wide QRS duration and mechanically as a right-sided septal/apical flash. Early septal activation and prestretch of the right ventricular (RV) basal lateral wall followed by its postsystolic shortening contributes to inefficient RV mechanics. However, a right-sided septal flash is a dichotomous finding, and the severity of RV dyssynchrony as a continuous spectrum in relationship to RV dysfunction and clinical outcomes in patients with repaired TOF has not been studied. The aim of this study was to quantify the severity of electromechanical dyssynchrony in relation to RV remodeling and clinical outcomes in a pediatric cohort following TOF repair.

METHODS

A retrospective analysis was performed in 81 children with RV volume loading after TOF repair, aged 13.6 ± 2.9 years, and compared with 50 matched control subjects.

RESULTS

Patients had higher RV basal-lateral prestretch and postsystolic strain amplitude and duration, RV mechanical dispersion, and basal lateral-septal wall delay compared with control subjects (P < .001 for all). All intra-RV dyssynchrony timing parameters were associated with reduced cardiac magnetic resonance-derived RV ejection fraction and/or echocardiography-derived RV longitudinal strain. Prestretch duration as a percentage of total shortening time and RV basal lateral-to-midseptal delay were independently associated with RV dysfunction. Postsystolic strain amplitude was higher in patients with ventricular arrhythmias compared with arrhythmia-free patients (7.8% [4.2%-13%] vs 2.0% [0%-12.5%], P = .03).

CONCLUSION

RV prestretch duration, postsystolic strain, and RV lateral-septal delay quantify RV electromechanical dyssynchrony severity and reflect the underlying pathophysiology. The prestretch duration percentage and RV basal lateral-to-midseptal delay were independently associated with RV dysfunction, potentially providing a clinical tool to quantify RV electromechanical dyssynchrony.

Functional Capacity Is Affected by Younger Age of Repair in Tetralogy of Fallot Patients But Not by Era of Repair

Background:

Cardiopulmonary exercise testing is widely used to assess functional capacity in patients with tetralogy of Fallot after surgical repair. Little is known regarding the impact of age at the time of primary complete repair and surgical era effect on exercise capacity.

Methods:

A retrospective, single-center chart review was done from 1976 to 2016 on pediatric patients with tetralogy of Fallot who underwent cardiopulmonary exercise testing with cycle ergometry utilizing the James protocol and were then sorted by repair before/after 1990 and by age of complete repair before/after one year. Exclusion criteria included submaximal tests, incomplete data, previous pulmonary valve replacement, and surgery prior to complete repair (ie, Blalock-Taussig shunt placement).

Results:

When comparing the groups who underwent primary complete repair before (N = 39) and after (N = 26) one year of age, the younger group demonstrated a higher percentage of predicted peak oxygen consumption ([Formula: see text] o2peak; 83.1% ± 11.8% vs 73.1% ± 16.1%; P = .005) despite having worse pulmonary insufficiency at the time of exercise testing. There were no differences in heart rate and blood pressure response. Age of repair was independently associated with [Formula: see text] o2peak. Data were statistically similar to the study eras (repair before 1990, N = 23; repair after 1990, N = 65): percentage of predicted [Formula: see text] o2peak (81.4% ± 13.6% vs 79.1% ± 14.4%, P = .5), maximal systolic blood pressure (155.1 ± 22.4 mm Hg vs 153.9 ± 17 mm Hg, P = .8), and percentage of predicted maximal heart rate (89.8% ± 9% vs 92% ± 7.1%, P = .3).

Conclusions:

Older age at primary repair appears to negatively impact [Formula: see text] o2peak; however, era effect does not appear to influence cardiopulmonary exercise testing outcomes.

Atrial Strain Imaging after Repair of Tetralogy of Fallot: A Systematic Review

We performed a systematic review of the literature on assessment of right atrial (RA) and left atrial (LA) deformation by myocardial strain imaging in patients with repaired tetralogy of Fallot. Ten studies with a total of 536 adolescent and adult patients were included, of which 5 evaluated RA deformation, 2 studied LA deformation and 3 assessed deformation of both atria. Seven studies used speckle tracking echocardiography, 2 employed tissue Doppler imaging and 1 applied cardiac magnetic resonance feature tracking. Main findings were (i) reduced regional and/or global RA and LA strain and strain rate consistent with reduced conduit, reservoir and contractile function of the two atria in patients; (ii) associations between RA and LA deformation indices suggestive of atrial-atrial interaction; and (iii) relationships between RA deformation and indices of right ventricular systolic and diastolic function. The lack of data on prognostic value of atrial strain is an important knowledge gap.

A prospective 5-year study of exercise performance following Melody valve implant

BACKGROUND

The long-term benefits of Melody valve implant for right ventricular outflow tract conduit obstruction or insufficiency on exercise capacity are undefined.

METHODS

As part of the Melody valve clinical trial, 136 patients with congenital heart disease underwent serial cardiopulmonary exercise testing prior to, 6 months after, and annually for up to 5 years postimplant.

RESULTS

Mean age at Melody valve implantation was 22.4 ± 0.9 years (range 7-53 years). The 95 patients who completed the study protocol provide the basis of this report. An initial improvement in % predicted workload was present at 6 months postimplant; however, at the final (5 year) follow-up, sustained or further improvements in workload were not demonstrated for the entire cohort compared to baseline. By subgroup analysis, age <17 years at implant and pulmonary regurgitation as the primary lesion were variables associated with sustained improvement in exercise performance. There were sustained improvements in the ventilatory equivalents for O₂ (minute ventilation/O₂ intake, P = .01) and CO₂ (minute ventilation/CO₂ output, P < .01) at the ventilatory anaerobic threshold at the study conclusion. Improvements in forced vital capacity were also observed during the study but not sustained at the final follow-up.

CONCLUSIONS

A cautious appraisal of the cardiovascular benefits of Melody valve implant on sustained improvements in exercise performance appears warranted. Although the observed changes in pulmonary function suggest improved restrictive lung physiology and more efficient gas exchange, after an initial increase in % predicted performance, neither sustained nor further improvements in exercise performance were observed, except in specific patient subgroups.

Impact of age and cardiac disease on regional left and right ventricular myocardial motion in healthy controls and patients with repaired tetralogy of fallot

The assessment of both left (LV) and right ventricular (RV) motion is important to understand the impact of heart disease on cardiac function. The MRI technique of tissue phase mapping (TPM) allows for the quantification of regional biventricular three-directional myocardial velocities. The goal of this study was to establish normal LV and RV velocity parameters across a wide range of pediatric to adult ages and to investigate the feasibility of TPM for detecting impaired regional biventricular function in patients with repaired tetralogy of Fallot (TOF). Thirty-six healthy controls (age = 1-75 years) and 12 TOF patients (age = 5-23 years) underwent cardiac MRI including TPM in short-axis locations (base, mid, apex). For ten adults, a second TPM scan was used to assess test-retest reproducibility. Data analysis included the calculation of biventricular radial, circumferential, and long-axis velocity components, quantification of systolic and diastolic peak velocities in an extended 16 + 10 LV + RV segment model, and assessment of inter-ventricular dyssynchrony. Biventricular velocities showed good test-retest reproducibility (mean bias ≤ 0.23 cm/s). Diastolic radial and long-axis peak velocities for LV and RV were significantly reduced in adults compared to children (19-61%, p < 0.001-0.02). In TOF patients, TPM identified significantly reduced systolic and diastolic LV and RV long-axis peak velocities (20-50%, p < 0.001-0.05) compared to age-matched controls. In conclusion, tissue phase mapping enables comprehensive analysis of global and regional biventricular myocardial motion. Changes in myocardial velocities associated with age underline the importance of age-matched controls. This pilot study in TOF patients shows the feasibility to detect regionally abnormal LV and RV motion.

Right Ventricular Contractile Reserve Is Impaired in Children and Adolescents With Repaired Tetralogy of Fallot: An Exercise Strain Imaging Study

BACKGROUND

Pulmonary insufficiency (PI) and right ventricular (RV) dysfunction are long-term complications in patients with repaired tetralogy of Fallot (rTOF). The aim of this study was to investigate RV contractile reserve and changes in PI that occur during exercise in patients with rTOF and the associations of these changes with exercise performance using stress echocardiography.

METHODS

Subjects with rTOF (n = 32) and healthy control subjects (n = 10) were prospectively enrolled and underwent rest and peak exercise echocardiography during standard cardiopulmonary exercise test protocol on a cycle ergometer or treadmill. RV contractile reserve was defined as the change in RV global longitudinal strain from rest to peak exercise. PI was assessed with the diastolic-to-systolic time-velocity integral ratio and diastolic/systolic velocity ratio from pulmonary artery Doppler interrogation. Exercise measures included heart rate reserve, percentage predicted maximum oxygen consumption, percentage predicted maximum work, and oxygen pulse.

RESULTS

RV contractile reserve was impaired in patients with rTOF compared with control subjects, with a significant drop in the absolute value of RV global longitudinal strain from 17% (range, 8%-27%) at rest to 13% (range, 5%-28%) at peak exercise. Similarly, PI decreased at peak exercise, with decreases in diastolic-to-systolic time-velocity integral and diastolic/systolic velocity ratios. Reduction in PI was directly associated with percentage predicted maximum oxygen consumption, percentage predicted maximum work, and greater oxygen pulse. Heart rate reserve was directly associated with percentage predicted maximum oxygen consumption and percentage predicted maximum work. RV contractile reserve was not associated with any exercise parameters.

CONCLUSIONS

Patients with rTOF have an abnormal myocardial response to exercise with impaired RV contractile reserve compared with control subjects. Heart rate reserve and reduction in PI at peak exercise are associated with better exercise performance and appear to be significant contributors to exercise performance in rTOF. Measures to improve chronotropic health in rTOF should be explored.

Impact of surgical pulmonary valve replacement on ventricular strain and synchrony in patients with repaired tetralogy of Fallot: a cardiovascular magnetic resonance feature tracking study

BACKGROUND

In patients with repaired tetralogy of Fallot (TOF), a better understanding of the impact of surgical pulmonary valve replacement (PVR) on ventricular mechanics may lead to improved indications and outcomes. Therefore, we used cardiovascular magnetic resonance (CMR) feature tracking analysis to quantify ventricular strain and synchrony in repaired TOF patients before and after PVR.

METHODS

Thirty-six repaired TOF patients (median age 22.4 years) prospectively underwent CMR a mean of 4.5 ± 3.8 months before PVR surgery and 7.3 ± 2.1 months after PVR surgery. Feature tracking analysis on cine steady-state free precession images was used to measure right ventricular (RV) and left ventricular (LV) circumferential strain from short-axis views at basal, mid-ventricular, and apical levels; and longitudinal strain from 4-chamber views. Intraventricular synchrony was quantified using the maximum difference in time-to-peak strain, the standard deviation of the time-to-peak, and cross correlation delay (CCD) metrics; interventricular synchrony was assessed using the CCD metric.

RESULTS

Following PVR, RV end-diastolic volume, end-systolic volume, and ejection fraction declined, and LV end-diastolic volume and end-systolic volume both increased with no significant change in the LV ejection fraction. LV global basal and apical circumferential strains, and basal synchrony improved. RV global circumferential and longitudinal strains were unchanged, and there was a varied impact on synchrony across the locations. Interventricular synchrony worsened at the midventricular level but was unchanged at the base and apex, and on 4-chamber views.

CONCLUSIONS

Surgical PVR in repaired TOF patients led to improved LV global strain and no change in RV global strain. LV and RV synchrony parameters improved or were unchanged, and interventricular synchrony worsened at the midventricular level.

The continuing challenge of evaluating diastolic function by echocardiography in children: developing concepts and newer modalities

PURPOSE OF REVIEW

Assessment of diastolic function by echocardiography is challenging but important. Left ventricular filling has been more extensively studied than the right ventricle, and predominantly in adult populations. Although multiple parameters exist to assess diastolic function, they all have limitations, including load and heart rate dependency, which make assessment of diastolic function particularly challenging. The purpose of this article is to review evolving concepts and modalities for echo assessment of diastolic function in children.

RECENT FINDINGS

The paradigm whereby diastolic dysfunction severity progresses in a staged fashion from impaired relaxation to increasing ventricular stiffness, may not apply in children. In addition, previous adult guidelines are not readily applicable to children with cardiomyopathy and the applicability of the newly revised adult guidelines needs to be evaluated in children. It is unlikely that any one single echocardiographic diastolic parameter will adequately reflect diastolic function. Hence, parameters derived from atrioventricular valve inflow, pulmonary venous, and tissue Doppler need to be integrated. Newer modalities such as diastolic strain rate and rotation mechanics may be useful as more sensitive markers of early ventricular dysfunction but have important limitations and require more evaluation before routine use in practice. Assessment of systolic-diastolic coupling may enhance assessment of diastolic function.

SUMMARY

Diastolic function impacts outcomes and should be part of routine echocardiographic assessment of function. An integrative approach combining different parameters, possibly with contribution of newer modalities in the future, is required.

Exercise gas exchange in continuous-flow left ventricular assist device recipients

Exercise ventilation/perfusion matching in continuous-flow left ventricular assist device recipients (LVAD) has not been studied systematically. Twenty-five LVAD and two groups of 15 reduced ejection fraction chronic heart failure (HFrEF) patients with peak VO₂ matched to that of LVAD (HFrEF-matched) and ≥14 ml/kg/min (HFrEF≥14), respectively, underwent cardiopulmonary exercise testing with arterial blood gas analysis, echocardiogram and venous blood sampling for renal function evaluation. Arterial-end-tidal PCO₂ difference (P(a-ET)CO₂) and physiological dead space-tidal volume ratio (VD/VT) were used as descriptors of alveolar and total wasted ventilation, respectively. Tricuspid annular plane systolic excursion/pulmonary artery systolic pressure ratio (TAPSE/PASP) and blood urea nitrogen/creatinine ratio were calculated in all patients and used as surrogates of right ventriculo-arterial coupling and circulating effective volume, respectively. LVAD and HFrEF-matched showed no rest-to-peak change of P(a-ET)CO₂ (4.5±2.4 vs. 4.3±2.2 mm Hg and 4.1±1.4 vs. 3.8±2.5 mm Hg, respectively, both p >0.40), whereas a decrease was observed in HFrEF≥14 (6.5±3.6 vs. 2.8±2.0 mm Hg, p <0.0001). Rest-to-peak changes of P(a-ET)CO₂ correlated to those of VD/VT (r = 0.70, p <0.0001). Multiple regression indicated TAPSE/PASP and blood urea nitrogen/creatinine ratio as independent predictors of peak P(a-ET)CO₂. LVAD exercise gas exchange is characterized by alveolar wasted ventilation, i.e. hypoperfusion of ventilated alveoli, similar to that of advanced HFrEF patients and related to surrogates of right ventriculo-arterial coupling and circulating effective volume.

Normative Data for Left and Right Ventricular Systolic Strain in Healthy Caucasian Italian Children by Two-Dimensional Speckle-Tracking Echocardiography

BACKGROUND

There is an increasing interest in echocardiographic strain (ε) measurements for the assessment of ventricular myocardial function in children; however, pediatric nomograms remain limited. Our aim was to establish pediatric nomograms for the left ventricular (LV) and the right ventricular (RV) ε measured by two-dimensional speckle-tracking echocardiography (2D-STE) in a large cohort of healthy children prospectively enrolled.

METHODS

Echocardiographic measurements included STE LV longitudinal and circumferential and RV longitudinal global end-systolic ε. Age, weight, height, heart rate (HR), and body surface area (BSA) were used as independent variables in different analyses to predict the mean values of each measurement. Echocardiograms were performed by Philips-iE33 systems (Philips, Bothell, WA) and offline measurements on Philips-Q-Lab-9.

RESULTS

In all, 721 subjects (age 31 days to 17 years; 48% female) were studied. Low coefficients of determination (R²) were noted among all of the ε parameters evaluated and adjusted for age, weight, height, BSA, and HR (i.e., R² all ≤ 0.10; range, 0.01-0.088). This hampered the possibility of performing z-scores with a sufficient reliability. Thus, we are limited to presenting data as mean values (±SD) stratified for age groups and divided by gender. LV longitudinal ε values decreased with age (P < .001), while no significant age-related variations were noted for RV longitudinal ε. A significant base-to-apex (lowest to highest) gradient in circumferential LV ε values was noted at all ages (P < .001).

CONCLUSIONS

We report pediatric echocardiographic normative data for 2D-STE for the LV and RV ε by using vendor-specific software. Our results confirm previous observations, showing only little variations of strain parameters with age and gender.

Pulmonary Right Ventricular Resynchronization in Congenital Heart Disease

Background—

Electromechanical discoordination may contribute to long-term pulmonary right ventricular (RV) dysfunction in patients after surgery for congenital heart disease. We sought to evaluate changes in RV function after temporary RV cardiac resynchronization therapy.

Methods and Results—

Twenty-five patients aged median 12.0 years after repair of tetralogy of Fallot and similar lesions were studied echocardiographically (n=23) and by cardiac catheterization (n=5) after primary repair (n=4) or after surgical RV revalvulation for significant pulmonary regurgitation (n=21). Temporary RV cardiac resynchronization therapy was applied in the presence of complete right bundle branch block by atrial-synchronized RV free wall pacing in complete fusion with spontaneous ventricular depolarization using temporary electrodes. The q-RV interval at the RV free wall pacing site (mean 77.2% of baseline QRS duration) confirmed pacing from a late activated RV area. RV cardiac resynchronization therapy carried significant decrease in QRS duration ( P <0.001) along with elimination of the right bundle branch block QRS morphology, increase in RV filling time ( P =0.002), pulmonary artery velocity time integral ( P =0.006), and RV maximum +dP/dt ( P <0.001), and decrease in RV index of myocardial performance ( P =0.006). RV mechanical synchrony improved: septal-to-lateral RV mechanical delay decreased ( P <0.001) and signs of RV dyssynchrony pattern were significantly abolished. RV systolic stretch fraction reflecting the ratio of myocardial stretching and contraction during systole diminished ( P =0.001).

Conclusions—

In patients with congenital heart disease and right bundle branch block, RV cardiac resynchronization therapy carried multiple positive effects on RV mechanics, synchrony, and contraction efficiency.

[Pulmonary revalvulation and rhythmologenic risks in patients with repaired tetralogy of Fallot]

Tetralogy of Fallot is a frequent congenital heart disease that has been repaired since the mid-1950s. The follow-up after repair is good despite a persistent risk of sudden death. The risk factors in long-term follow-up are advanced age at repair, hemodynamic status of the right ventricle, QRS duration≥180ms, left ventricular dysfunction, and existence of sustained or not ventricular tachycardia. In the presence of significant pulmonary regurgitation, it is necessary to perform revalvulation either by classic surgery or cardiac catheterization. To correct the risk of ventricular arrhythmia, some have proposed radiofrequency ablation of critical isthmus, or cryo-application during surgery. However, the use of implantable cardioverter defibrillator is another therapeutic option that is more and more employed as secondary or primary prevention in patients at risk of sudden death.

The value of right ventricular longitudinal strain in the evaluation of adult patients with repaired tetralogy of Fallot: a new tool for a contemporary challenge

OBJECTIVE

The role of right ventricular longitudinal strain for assessing patients with repaired tetralogy of Fallot is not fully understood. In this study, we aimed to evaluate its relation with other structural and functional parameters in these patients.

METHODS

Patients followed-up in a grown-up CHD unit, assessed by transthoracic echocardiography, cardiac MRI, and treadmill exercise testing, were retrospectively evaluated. Right ventricular size and function and pulmonary regurgitation severity were assessed by echocardiography and MRI. Right ventricular longitudinal strain was evaluated in the four-chamber view using the standard semiautomatic method.

RESULTS

In total, 42 patients were included (61% male, 32±8 years). The mean right ventricular longitudinal strain was -16.2±3.7%, and the right ventricular ejection fraction, measured by MRI, was 42.9±7.2%. Longitudinal strain showed linear correlation with tricuspid annular systolic excursion (r=-0.40) and right ventricular ejection fraction (r=-0.45) (all p<0.05), which in turn showed linear correlation with right ventricular fractional area change (r=0.50), pulmonary regurgitation colour length (r=0.35), right ventricular end-systolic volume (r=-0.60), and left ventricular ejection fraction (r=0.36) (all p<0.05). Longitudinal strain (β=-0.72, 95% confidence interval -1.41, -0.15) and left ventricular ejection fraction (β=0.39, 95% confidence interval 0.11, 0.67) were independently associated with right ventricular ejection fraction. The best threshold of longitudinal strain for predicting a right ventricular ejection fraction of <40% was -17.0%.

CONCLUSIONS

Right ventricular longitudinal strain is a powerful method for evaluating patients with tetralogy of Fallot. It correlated with echocardiographic right ventricular function parameters and was independently associated with right ventricular ejection fraction derived by MRI.

The association between right ventricular free wall strain and exercise capacity for health check-up subjects

BACKGROUND

Right ventricular (RV) function has been found to be a major factor of exercise capacity in patients with heart failure. However, the role of RV function in exercise capacity in healthy subjects has not been well studied. This study aims to validate the role of RV strain derived from speckle tracking echocardiography for exercise capacity for health check-up subjects.

METHODS

This study prospectively recruited subjects from a routine health examination. All of them were symptom free. RV function represented by RV strain was derived from speckle tracking echocardiography in addition to traditional echocardiography parameters. Functional capacity was determined by a symptom limited treadmill exercise test with the Bruce protocol.

RESULTS

Among 164 recruited subjects (age 52.2 ±9.2 years, 66.4% male), 32 subjects represented impaired functional capacity (MET<8), which was significantly correlated with age, left ventricular mass index, left ventricular filling pressure (E/e'), global longitudinal strain of the left ventricle (LVGLS) (-16.0±2.5% vs. -18.9±3.8%, p < 0.001) and RV free wall strain (RVLS_FW) (-17.0±4.9% vs. -21.9±3.2%, p <0.001). After multivariate logistic regression, RVS_FW was an independent predictor for impaired functional capacity (OR 1.62, CI 1.32-1.98; p <0.001).

CONCLUSIONS

In conclusion, RV strain is independently associated with exercise capacity for health check-up subjects. RV function is an important factor for functional capacity.

The impact of pulmonary insufficiency on the right ventricle: a comparison of isolated valvar pulmonary stenosis and tetralogy of fallot

Pulmonary insufficiency (PI) is associated with right ventricular (RV) dilation, dysfunction, and exercise intolerance in patients with tetralogy of fallot (TOF). We sought to compare RV function and exercise performance in patients with valvar pulmonary stenosis (VPS) following pulmonary balloon valvuloplasty to those with repaired TOF with similar degrees of PI. We performed a cross-sectional study of patients with VPS and TOF. Cardiac magnetic resonance (CMR) and exercise stress test were performed. Subjects were matched by time from initial procedure and severity of PI using propensity scores. After matching, there were 16 patients with VPS and 16 with TOF for comparison, with similar demographics. Time from initial procedure was 14 years (12-16), p = 0.92, and pulmonary regurgitant fraction was 19 % (6-31), p = 0.94, Patients with TOF had lower ejection fraction [58 % (53-66) vs. 65 % (60-69), p = 0.04] and more RV hypertrophy [69 g/m(2) (52-86) vs. 44 g/m(2) (32-66), p = 0.04] compared to those with VPS. Aerobic capacity was worse in patients with TOF [68 ± 19 % mVO2 (56-84) vs. 82 ± 9.2 % (74-89) in VPS, p = 0.01], with a trend for less habitual physical activity [0.9 (0-12) vs. 8 h/week (4-12), p = 0.056], respectively. With similar degrees of PI, patients with TOF demonstrate worse RV function and aerobic capacity as compared to patients with just VPS. Habitual exercise may in part explain differences in exercise performance and should be further explored.

Functional assessment for congenital heart disease

Significant improvement in survival of children with congenital cardiac malformations has resulted in an increasing population of adolescent and adult patients with congenital heart disease. Of the long-term cardiac problems, ventricular dysfunction remains an important issue of concern. Despite corrective or palliative repair of congenital heart lesions, the right ventricle, which may be the subpulmonary or systemic ventricular chamber, and the functional single ventricle are particularly vulnerable to functional impairment. Regular assessment of cardiac function constitutes an important aspect in the long-term follow up of patients with congenital heart disease. Echocardiography remains the most useful imaging modality for longitudinal monitoring of cardiac function. Conventional echocardiographic assessment has focused primarily on quantification of changes in ventricular size and blood flow velocities during the cardiac cycles. Advances in echocardiographic technologies including tissue Doppler imaging and speckle tracking echocardiography have enabled direct interrogation of myocardial deformation. In this review, the issues of ventricular dysfunction in congenital heart disease, conventional echocardiographic and novel myocardial deformation imaging techniques, and clinical applications of these techniques in the functional assessment of congenital heart disease are discussed.

Normal ranges of right ventricular systolic and diastolic strain measures in children: a systematic review and meta-analysis

BACKGROUND

Establishment of the range of normal values and associated variations of two-dimensional (2D) speckle-tracking echocardiography (STE)-derived right ventricular (RV) strain is a prerequisite for its routine clinical application in children. The objectives of this study were to perform a meta-analysis of normal ranges of RV longitudinal strain measurements derived by 2D STE in children and to identify confounders that may contribute to differences in reported measures.

METHODS

A systematic review was conducted in PubMed, Embase, Scopus, the Cochrane Central Register of Controlled Trials, and ClinicalTrials.gov. Search hedges were created to cover the concepts of pediatrics, STE, and the right heart ventricle. Two investigators independently identified and included studies if they reported the 2D STE-derived RV strain measure RV peak global longitudinal strain, peak global longitudinal systolic strain rate, peak global longitudinal early diastolic strain rate, peak global longitudinal late diastolic strain rate, or segmental longitudinal strain at the apical, middle, and basal ventricular levels in healthy children. Quality and reporting of the studies were assessed. The weighted mean was estimated using random effects with 95% confidence intervals (CIs), heterogeneity was assessed using Cochran's Q statistic and the inconsistency index (I(2)), and publication bias was evaluated using funnel plots and Egger's test. Effects of demographic, clinical, equipment, and software variables were assessed in a metaregression.

RESULTS

The search identified 226 children from 10 studies. The reported normal mean values of peak global longitudinal strain among the studies varied from -20.80% to -34.10% (mean, -29.03%; 95% CI, -31.52% to -26.54%), peak global longitudinal systolic strain rate varied from -1.30 to -2.40 sec(-1) (mean, -1.88 sec(-1); 95% CI, -2.10 to -1.59 sec(-1)), peak global longitudinal early diastolic strain rate ranged from 1.7 to 2.69 sec(-1) (mean, 2.34 sec(-1); 95% CI, 2.00 to 2.67 sec(-1)), and peak global longitudinal late diastolic strain rate ranged from 1.00 to 1.30 sec(-1) (mean, 1.18 sec(-1); 95% CI, 1.04 to 1.33 sec(-1)). A significant base-to-apex segmental strain gradient (P < .05) was observed in the RV free wall. There was significant between-study heterogeneity and inconsistency (I(2) > 88% and P < .01 for each strain measure), which was not explained by age, gender, body surface area, heart rate, frame rate, tissue-tracking methodology, equipment, or software. The metaregression showed that these effects were not significant determinants of variations among normal ranges of strain values. There was no evidence of publication bias (P = .59).

CONCLUSIONS

This study is the first to define normal values of 2D STE-derived RV strain in children on the basis of a meta-analysis. The normal mean value in children for RV global strain is -29.03% (95% CI, -31.52% to -26.54%). The normal mean value for RV global systolic strain rate is -1.88 sec(-1) (95% CI, -2.10 to -1.59 sec(-1)). RV segmental strain has a stable base-to-apex gradient that highlights the dominance of deep longitudinal layers of the right ventricle that are aligned base to apex. Variations among different normal ranges did not appear to be dependent on differences in demographic, clinical, or equipment parameters in this meta-analysis. All of the eligible studies used equipment and software from one manufacturer (GE Healthcare).

Factors influencing adaptation and performance at physical exercise in complex congenital heart diseases after surgical repair

In the last thirty years, steady progress in the diagnostic tools and care of subjects affected by congenital heart diseases (CHD) has resulted in a significant increase in their survival to adulthood, even for those affected by complex CHD. Based on these premises, a number of teenagers and adults affected by corrected (surgically or through interventional techniques) CHD ask to be allowed to undertake sporting activities, both at a recreational and competitive level. The purpose of this review is to examine the mechanisms influencing the adaption at physical exercise of patients suffering from complex CHD. The conclusion is that even if there are some modest risks with exercise, they should be seen in perspective, and the life-long benefits of regular exercise on general health, mood, and well-being should be emphasized.