Impaired Left Ventricular Myocardial Mechanics and Their Relation to Pulmonary Regurgitation, Right Ventricular Enlargement and Exercise Capacity in Asymptomatic Children after Repair of Tetralogy of Fallot

Multimodality Imaging Assessment of Tetralogy of Fallot: From Diagnosis to Long-Term Follow-Up

Tetralogy of Fallot (TOF) is the most common complex congenital heart disease with long-term survivors, demanding serial monitoring of the possible complications that can be encountered from the diagnosis to long-term follow-up. Cardiovascular imaging is key in the diagnosis and serial assessment of TOF patients, guiding patients' management and providing prognostic information. Thorough knowledge of the pathophysiology and expected sequalae in TOF, as well as the advantages and limitations of different non-invasive imaging modalities that can be used for diagnosis and follow-up, is the key to ensuring optimal management of patients with TOF. The aim of this manuscript is to provide a comprehensive overview of the role of each modality and common protocols used in clinical practice in the assessment of TOF patients.

Abnormal developmental trajectory and vulnerability to cardiac arrhythmias in tetralogy of Fallot with DiGeorge syndrome

Tetralogy of Fallot (TOF) is the most common cyanotic congenital heart disease. Ventricular dysfunction and cardiac arrhythmias are well-documented complications in patients with repaired TOF. Whether intrinsic abnormalities exist in TOF cardiomyocytes is unknown. We establish human induced pluripotent stem cells (hiPSCs) from TOF patients with and without DiGeorge (DG) syndrome, the latter being the most commonly associated syndromal association of TOF. TOF-DG hiPSC-derived cardiomyocytes (hiPSC-CMs) show impaired ventricular specification, downregulated cardiac gene expression and upregulated neural gene expression. Transcriptomic profiling of the in vitro cardiac progenitors reveals early bifurcation, as marked by ectopic RGS13 expression, in the trajectory of TOF-DG-hiPSC cardiac differentiation. Functional assessments further reveal increased arrhythmogenicity in TOF-DG-hiPSC-CMs. These findings are found only in the TOF-DG but not TOF-with no DG (ND) patient-derived hiPSC-CMs and cardiac progenitors (CPs), which have implications on the worse clinical outcomes of TOF-DG patients.

When do patients with Tetralogy of Fallot need a transannular patch

OBJECTIVES

The objective of this study was to evaluate the predictive value of main pulmonary artery (MPA) Z score, pulmonary valve annulus (PVA) prop, great aortic valve annulus (GA) ratio, PVA index (PAI), and PVA area index (PAAI) indicators in patients with Tetralogy of Fallot (TOF) and whether or not to undergo transannular patch (TAP).

METHODS

A retrospective analysis was performed on the clinical data of 263 patients with TOF who underwent radical operations from 2010 to 2021 at Beijing Children's Hospital. Sixteen cases were excluded, and 247 cases (male/female = 155/92) were included in this study. Based on whether TAP was selected intraoperatively, the patients were divided into the TAP group (82/247) and the non-TAP group (165/247). The diameter of the PVA, the aortic valve annulus, and the MPA were measured by echocardiography, and the PVA Z score, MPA Z score, PVA prop, GA ratio, PAI, and PAAI indexes were calculated, and statistical analysis was carried out.

RESULTS

The PVA Z score, MPA Z score, PVA prop, GA ratio, PAI, and PAAI of the TAP group were lower than those of the non-TAP group (p < .0001, p < .0001, p < .0001, p < .0001, p < .0001, and p < .0001). Receiver-operating curve analysis showed that the cut-off value of PVA Z score was -1.96 (area under the curve [AUC]: 0.822; 95% confidence interval [CI]: 0.769-0.874); the cut-off value of MPA Z score was -1.04 (AUC: 0.778; 95% CI: 0.711-0.845); the cut-off value of PVA prop was 0.37 (AUC: 0.812; 95% CI: 0.751-0.874); the cut-off value of GA ratio was 0.64 (AUC: 0.812; 95% CI: 0.750-0.874); the cut-off value of PAI is 0.78 (AUC: 0.812; 95% CI: 0.750-0.874); and the cut-off value of PAAI is 0.4 (AUC: 0.812; 95% CI: 0.750-0.874). Pulmonary valve bicuspid malformation is one reason why predictive models fail to predict the possible avoidance of TAP. Pearson's correlation and linear regression analysis showed that PAI had the strongest correlation with PVA Z score, followed by that between PVA prop and PVA Z score, and the weakest correlation between PAAI and PVA Z score.

CONCLUSIONS

PVA prop, GA ratio, PAI, and PAAI can well predict TAP selection, and the measurement is simple and convenient. Compared with PVA Z score, they are not hindered by other confounding factors, and can well replace the application value of PVA Z score in TAP prediction. The predictive efficacy of PAI and PVA prop is numerically better than the GA ratio, and PAAI, PAI, and PVA prop combined with MPA Z score can improve the predictive value of PAI and PVA prop, respectively. Although various echocardiographic parameters can be used as indicators to predict surgical approach in patients with TOF, PV morphology and tissue characteristics should also be considered.

Right-left ventricular shape variations in tetralogy of Fallot: associations with pulmonary regurgitation

BACKGROUND

Relationships between right ventricular (RV) and left ventricular (LV) shape and function may be useful in determining optimal timing for pulmonary valve replacement in patients with repaired tetralogy of Fallot (rTOF). However, these are multivariate and difficult to quantify. We aimed to quantify variations in biventricular shape associated with pulmonary regurgitant volume (PRV) in rTOF using a biventricular atlas.

METHODS

In this cross-sectional retrospective study, a biventricular shape model was customized to cardiovascular magnetic resonance (CMR) images from 88 rTOF patients (median age 16, inter-quartile range 11.8-24.3 years). Morphometric scores quantifying biventricular shape at end-diastole and end-systole were computed using principal component analysis. Multivariate linear regression was used to quantify biventricular shape associations with PRV, corrected for age, sex, height, and weight. Regional associations were confirmed by univariate correlations with distances and angles computed from the models, as well as global systolic strains computed from changes in arc length from end-diastole to end-systole.

RESULTS

PRV was significantly associated with 5 biventricular morphometric scores, independent of covariates, and accounted for 12.3% of total shape variation (p < 0.05). Increasing PRV was associated with RV dilation and basal bulging, in conjunction with decreased LV septal-lateral dimension (LV flattening) and systolic septal motion towards the RV (all p < 0.05). Increased global RV radial, longitudinal, circumferential and LV radial systolic strains were significantly associated with increased PRV (all p < 0.05).

CONCLUSION

A biventricular atlas of rTOF patients quantified multivariate relationships between left-right ventricular morphometry and wall motion with pulmonary regurgitation. Regional RV dilation, LV reduction, LV septal-lateral flattening and increased RV strain were all associated with increased pulmonary regurgitant volume. Morphometric scores provide simple metrics linking mechanisms for structural and functional alteration with important clinical indices.

Left Ventricular Torsion Obtained Using Equilibrated Warping in Patients with Repaired Tetralogy of Fallot

Patients after surgical repair of Tetralogy of Fallot (rTOF) may suffer a decrease in left ventricular (LV) function. The aim of our study is to evaluate a novel method of assessing LV torsion in patients with rTOF, as an early indicator of systolic LV dysfunction. Motion tracking based on image registration regularized by the equilibrium gap principle, known as equilibrated warping, was employed to assess LV torsion. Seventy-six cases of rTOF and ten normal controls were included. The group of controls was assessed for reproducibility using both equilibrated warping and standard clinical tissue tracking software (CVI42, version 5.10.1, Calgary, Canada). Patients were dichotomized into two groups: normal vs. loss of torsion. Torsion by equilibrated warping was successfully obtained in 68 of 76 (89%) patients and 9 of 10 (90%) controls. For equilibrated warping, the intra- and interobserver coefficients of variation were 0.095 and 0.117, respectively, compared to 0.260 and 0.831 for tissue tracking by standard clinical software. The intra- and inter-observer intraclass correlation coefficients for equilibrated warping were 0.862 and 0.831, respectively, compared to 0.992 and 0.648 for tissue tracking. Loss of torsion was noted in 32 of the 68 (47%) patients with rTOF. There was no difference in LV or RV volumes or ejection fraction between these groups. The assessment of LV torsion by equilibrated warping is feasible and shows good reliability. Loss of torsion is common in patients with rTOF and its robust assessment might contribute into uncovering heart failure in an earlier stage.

Influence of right ventricular pressure and volume overload on right and left ventricular diastolic function

BACKGROUND

Ventricular interdependence may account for altered ventricular mechanics in congenital heart disease. The present study aimed to identify differences in load-dependent right ventricular (RV)-left ventricular (LV) interactions in porcine models of pulmonary stenosis (PS) and pulmonary insufficiency (PI) by invasive admittance-derived hemodynamics in conjunction with noninvasive cardiovascular magnetic resonance (CMR).

METHODS

Seventeen pigs were used in the study (7 with PS, 7 with PI, and 3 controls). Progressive PS was created by tightening a Teflon tape around the pulmonary artery, and PI was created by excising 2 leaflets of the pulmonary valve. Admittance catheterization data were obtained for the RV and LV at 10 to 12 weeks after model creation, with the animal ventilated under temporary diaphragm paralysis. CMR was performed in all animals immediately prior to pressure-volume catheterization.

RESULTS

In the PS group, RV contractility was increased, manifested by increased end-systolic elastance (mean difference, 1.29 mm Hg/mL; 95% confidence interval [CI], 0.57-2.00 mm Hg/mL). However, in the PI group, no significant changes were observed in RV systolic function despite significant changes in RV diastolic function. In the PS group, LV end-systolic volume was significantly lower compared with controls (mean difference, 25.1 mL; 95% CI, -40.5 to -90.7 mL), whereas in the PI group, the LV showed diastolic dysfunction, demonstrated by an elevated isovolumic relaxation constant and ventricular stiffness (mean difference, 0.03 mL^-1; 95% CI, -0.02 to 0.09 mL^-1).

CONCLUSIONS

The LV exhibits systolic dysfunction and noncompliance with PI. PS is associated with preserved LV systolic function and evidence of some LV diastolic dysfunction. Interventricular interactions influence LV filling and likely account for differential effects of RV pressure and volume overload on LV function.

Value of pulmonary annulus index in predicting transannular patch in tetralogy of Fallot repair

OBJECTIVE

It is very important to accurately assess the transannular patch (TAP) in the surgical treatment of tetralogy of Fallot (TOF). The pulmonary annulus index (PAI; the actual pulmonary annulus diameter divided by the expected pulmonary annulus diameter), GA ratio (the ratio of pulmonary annulus and aortic annulus), PAAI (the ratio of pulmonary annulus cross-section and aortic annulus cross-section), and pulmonary annulus Z score (PA Z score) were compared. This study aimed to analyze and explore the application value of PAI in predicting the need for TAP in children undergoing TOF repair.

METHODS

In total, 130 patients who were diagnosed with TOF and underwent TOF repair in Beijing Anzhen Hospital affiliated to Capital Medical University from December 2018 to December 2019 were retrospectively studied. In total, 112 cases were included in this study and 18 cases were excluded, of which 16 cases were aged above 18 years and 2 cases suffered from Down syndrome. They were divided into TAP group and no TAP group; the values of the pulmonary annulus and aortic annulus were measured. GA ratio, PAI, PAAI, the pulmonary annulus Z score, and main pulmonary artery (MPA) Z score were calculated to perform statistical analysis.

RESULTS

A total of 112 patients were included in the study, aged 4-177 months, with an average of 22.87 ± 30.21 months; 66 males and 46 females; weighing 5.3-29 kg, with an average of 9.94 ± 4.08 kg; three cases died, one case died of sepsis caused by pulmonary infection, one case died of low cardiac output syndrome, and one case died of multiple organ failure. In total, 62 cases (55.8%) did not undergo TAP and 50 cases (44.2%) underwent TAP. The pulmonary annulus Z score, main pulmonary artery Z score, and PAI in the TAP group were smaller than those in the no TAP group (p < .05). Receiver operating curve (ROC) analysis showed that when the cut-off value of pulmonary annulus was -1.98, the area under the curve (AUC) was 0.88, the sensitivity was 80%, and the specificity was 71%; when the cut-off value of PAI was 0.53, AUC was 0.85, the sensitivity was 75%, and the specificity was 80%; when the cut-off value of GA ratio was 0.55, AUC was 0.85, the sensitivity was 76%, and the specificity was 80%. The area under the PAAI curve was 0.85, the sensitivity was 76%, and the specificity was 79%. When the pulmonary valve Z score, PAI, GA ratio, PAAI, and MPA Z score were all greater than the dividing value, TAP was avoided in more than 90% of children with TOF. When the pulmonary valve Z score, PAI, GA ratio, PAAI, and the main pulmonary artery Z score were all below the dividing value, more than 90% of children with TOF needed TAP.

CONCLUSION

The predictive effect of PAI as a simple and effective predictor of TAP in TOF radical operation is the same as that of pulmonary annulus Z score, and combining it with the main pulmonary artery Z score was the most accurate method of prediction.

The reduced left ventricular stroke volume does not fully recover after pulmonary valve replacement in patients with repaired tetralogy of Fallot

 

OBJECTIVES

The present study was conducted to investigate the decrease in left ventricular stroke volume index (LVSVI) that is caused by pulmonary regurgitation-induced right heart dysfunction and its clinical implications before and after pulmonary valve replacement (PVR).

METHODS

Between January 2010 and December 2019, 30 adults who underwent surgical PVR for chronic pulmonary regurgitation with right ventricular dilation late after tetralogy of Fallot (TOF) repair were included. All patients were evaluated using cardiac magnetic resonance before PVR. The median interval from TOF repair to PVR was 29 [25th, 75th percentile: 25, 37] years. The median pulmonary regurgitation fraction and right ventricular end-diastolic volume index were 56 [48, 66] % and 203 [187, 239] ml/m2. Twenty-three patients (76.7%) were re-evaluated 1 year after PVR.

RESULTS

Before PVR, the median LVSVI was 40 [35, 46] ml/beat/m2. A lower LVSVI was associated with a longer interval from TOF repair to PVR (r = -0.40, P = 0.029) and a lower right ventricular ejection fraction (r = 0.52, P = 0.004). A lower LVSVI was not associated with a higher right ventricular end-diastolic volume index. LVSVI remained unchanged after PVR. The patients were subdivided into Normal-stroke volume index (SVI) and Subnormal-SVI groups using the preoperative LVSVI cut-off value of 35 mL/beat/m2. Compared with the Normal-SVI group, the Subnormal-SVI group had a higher incidence of ablation therapy before PVR (4.7 vs 2.3 patient-years, P = 0.044). After PVR, LVSVI in the Subnormal-SVI group was still lower (40 [34, 42] vs 44 [42, 47] ml/beat/m2, P = 0.038) despite the right ventricular end-diastolic volume index normalization. There was no difference in the clinical event incidence between the 2 groups during the follow-up period. Brain natriuretic peptide level in the Subnormal-SVI group was higher within 3 years after PVR (P = 0.046).

CONCLUSIONS

Reduced left ventricular stroke volume did not fully recover after PVR. PVR for patients with repaired TOF should be performed before the left ventricular stroke volume begins to decrease.

Neo-aortic Root Dilatation, Aortic Stiffness, and Ventricular interactions in Long-Term Follow-Up After the Ross Procedure in Childhood

Patients after the Ross procedure are at risk for right (RV) and left ventricular (LV) dysfunction due to neo-aortic and pulmonary dysfunction. While neo-aortic root dilatation has been related to LV dysfunction, the potential contributions of aortic stiffness and ventricular interactions have not been evaluated. Patients status post Ross procedure up to age 18 years with cardiac magnetic resonance (CMR) exam from 2007 to 2018 were retrospectively reviewed. Aortic pulse wave velocity (PWV) was calculated from phase contrast and angiogram images. RV and LV peak global longitudinal (GLS) and circumferential strain (GCS) were measured using tissue tracking software. Multivariable regression was performed for variables associated with parameters of LV function. In 58 patients (median age 20.5 years at CMR exam), male gender, longer time since Ross procedure, aortic root dilatation, and lower RV ejection fraction (EF) were associated with decreased LV EF. There was no association with LV late gadolinium enhancement or neo-aortic or conduit regurgitation. LV GCS and GLS also correlated with RV GCS, RV GLS and PWV. In multivariable analysis, the relation of RV and LV systolic function, but not aortic measurements, remained significant. In conclusion, in long-term follow-up after pediatric Ross procedure, RV function rather than aortic root size or aortic stiffness most closely relates to LV function. Ventricular interactions may impact decision-making on timing of conduit intervention, which could differ from established criteria in populations with only aortic or pulmonary valve disease. Further study is warranted to evaluate possible association with clinical outcome.

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.

Transcatheter pulmonary valve replacement in pediatric patients

INTRODUCTION

Right ventricular outflow tract (RVOT) dysfunction is common among individuals with congenital heart disease (CHD). Surgical intervention often carries prohibitive risks due to the need for sequential pulmonary valve (PV) replacements throughout their life in the majority of cases. Transcatheter pulmonary valve replacement (tPVR) is one of the most exciting recent developments in the treatment of CHD and has evolved to become an attractive alternative to surgery in patients with RVOT dysfunction.

AREAS COVERED

In this review, we examine the pathophysiology of RVOT dysfunction, indications for tPVR, and the procedural aspect. Advancements in clinical application and valve technology will also be covered.

EXPERT OPINION

tPVR is widely accepted as an alternative to surgery to address RVOT dysfunction, but still significant numbers of patients with complex RVOT morphology deemed not suitable for tPVR. As the technology continues to evolve, new percutaneous valves will allow such complex RVOT patient to benefit from tPVR.

Value of pulmonary annulus area index in predicting transannular patch placement in tetralogy of Fallot repair

BACKGROUND

Precisely evaluating the need for transannular patch (TAP) placement is very important in the surgical treatment of tetralogy of Fallot. We hypothesized that the pulmonary annulus area index (PAAI, the pulmonary-to-aortic valve annulus cross-sectional area ratio) could be a useful and accessible predictor for TAP placement.

METHODS

The medical records of patients who underwent tetralogy of Fallot repair between 1 January 2016 and 31 December 2017 were reviewed retrospectively. A total of 255 patients were included and categorized into two groups: patients who needed TAP placement and patients who did not. Various candidate predictors for TAP placement (PAAI, pulmonary annulus z-score, and velocity across the pulmonary annulus) were compared using receiver operating characteristic curves. The optimal cutoff for each predictor was assessed.

RESULTS

Among the 255 patients included, 156 needed TAP placement (156/237, 65.8%). Both the PAAI (0.28 [0.20/0.34] vs 0.14 [0.09/0.19]; P < .0001) and z-score (-1.5 [-2.9, -0.4] vs -3.6 [-5.3/-2.6]; P < .0001) were smaller in the TAP group. The PAAI is a useful predictor of the pulmonary annulus z-score (AUC 0.830 vs 0.811, P = .19). Combination analysis of the PAAI and velocity across the pulmonary annulus (PV v_max ) showed better predictive value than the PAAI and z-score (AUC 0.860, sensitivity 89.7%, specificity 61.7%, P < .0001).

CONCLUSIONS

Our results suggest that the PAAI is a useful and accessible predictor for TAP placement and can be applied readily and simply in clinical practice. A combination with the velocity across the pulmonary annulus could promote the accuracy of prediction.

Biventricular tissue tracking demonstrating associations between left ventricular myocardial extracellular volume, pulmonary artery pressure, and reduced right ventricular ejection fraction in patients with systemic lupus erythematosus using cardiovascular MRI

AIM

To investigate the feasibility and prognostic value of biventricular strain analysis for patients with systemic lupus erythematosus (SLE) and relationship to left ventricular (LV) myocardial fibrosis, pulmonary hypertension (PAH), and right ventricular (RV) ejection fraction (RVEF).

MATERIALS AND METHODS

A total of 50 SLE patients (47 women; 34.4±12 years) and 15 controls (13 women; 32.9±8.6 years) were imaged via echocardiography and a 3 T magnetic resonance imaging (MRI). Pulmonary artery systolic pressure (sPAP) was assessed using echocardiography. Biventricular global circumferential strain (GCS), global longitudinal strain (GLS), global circumferential strain rate (GCSR), and global longitudinal strain rate (GLSR) as well as LV myocardial extracellular volume (ECV) were derived for each subject.

RESULTS

Elevated LV ECV was significantly associated with LV GCS (beta -0.428, p=0.000), GLS (beta 0.404, p=0.000), GCSR (beta -0.350, p=0.006), GLSR (beta -0.445, p=0.000) and RV GCS (beta -0.373, p=0.000), and the presence of reduced RVEF was significantly associated with LV GCS (beta -0.338, p=0.002), GLS (beta -0.465, p=0.000) and RV GCS (beta -0.465, p=0.000). Raised sPAP was significantly associated with RV GLS (beta 0.445, p=0.000) and GCSR (beta -0.387, p=0.001). Moreover, there were significantly correlations between LV and RV strain and strain rate.

CONCLUSIONS

Biventricular strain analysis may be a better prognostic tool for patients with SLE as it allows greater comprehensive analysis and more definitive treatment planning compared to separate assessment of LV or RV contractility.

Arrhythmogenic Remodeling of the Left Ventricle in a Porcine Model of Repaired Tetralogy of Fallot

Supplemental Digital Content is available in the text.

Background

Ventricular arrhythmias are frequent in patients with repaired tetralogy of Fallot (rTOF), but their origin and underlying mechanisms remain unclear. In this study, the involvement of left ventricular (LV) electrical and structural remodeling was assessed in an animal model mimicking rTOF sequelae.

Methods

Piglets underwent a tetralogy of Fallot repair–like surgery (n=6) or were sham operated (Sham, n=5). Twenty-three weeks post-surgery, cardiac function was assessed in vivo by magnetic resonance imaging. Electrophysiological properties were characterized by optical mapping. LV fibrosis and connexin-43 localization were assessed on histological sections and protein expression assessed by Western Blot.

Results

Right ventricular dysfunction was evident, whereas LV function remained unaltered in rTOF pigs. Optical mapping showed longer action potential duration on the rTOF LV epicardium and endocardium. Epicardial conduction velocity was significantly reduced in the longitudinal direction in rTOF LVs but not in the transverse direction compared with Sham. An elevated collagen content was found in LV basal and apical sections from rTOF pigs. Moreover, a trend for connexin-43 lateralization with no change in protein expression was found in the LV of rTOFs. Finally, rTOF LVs had a lower threshold for arrhythmia induction using incremental pacing protocols.

Conclusions

We found an arrhythmogenic substrate with prolonged heterogeneous action potential duration and reduced conduction velocity in the LV of rTOF pigs. This remodeling precedes LV dysfunction and is likely to contribute to ventricular arrhythmias and sudden cardiac death in patients with rTOF.

Accuracy of a New Echocardiographic Index to Predict Need for Trans-annular Patch in Tetralogy of Fallot

The long-term outcome after repair of tetralogy of Fallot (TOF) is critically dependent pulmonary valve competence that is compromised by trans-annular patch (TAP). We compared a new echocardiographic index [pulmonary annulus index (PAI)] to conventional methods of predicting need for TAP in infants undergoing TOF repair. Consecutive infants undergoing TOF repair were prospectively studied. Pre-operative aortic and pulmonary annuli and main pulmonary artery (MPA) diameters were measured and z scores determined. PAI was a ratio of observed to expected pulmonary annulus (PA) diameter. TAP was based on intra-operative sizing by surgeons blinded to PAI values. Receiver operator curves (ROC) were generated for all PAI, MPA z scores and pulmonary annulus z scores. Of 84 infants (8.6 ± 2.6 months; 7.5 ± 1.3 kg), 36 needed TAP (43%). All the three indices viz. PAI, Pulmonary annulus and MPA z scores performed similarly in predicting need for TAP (ROC curves ~ 80%). Combining cut-offs of MPA z scores (> - 3.83) with either PAI (> 0.73) or PA z score (> - 1.83) predicted avoidance of TAP with ~ 90% accuracy. When both PAI and MPA z scores were below the cut-offs there was an 80% likelihood of TAP. Failure to predict TAP was associated with unicommisural pulmonary valves. PAI was equal to PA z scores in predicting need for TAP during repair of TOF. Combining either with MPA z scores was the most accurate method of prediction. Failure of prediction was mainly due to presence of a unicommissural pulmonary valve.

Use of Speckle Tracking Echocardiography to Assess Left Ventricular Systolic Function in Patients with Surgically Repaired Tetralogy of Fallot: Global and Segmental Assessment

Patients with repaired Tetralogy of Fallot (rToF) can have significant right and left ventricular dysfunction which can impact clinical outcome. Conventional echocardiographic evaluation using ejection fraction can be limited in detecting early stages of deteriorating left ventricular (LV) systolic function. Speckle-tracking echocardiography (STE) provides a promising emerging tool for early detection of LV systolic dysfunction. The aim of this cross-sectional study is to evaluate the left ventricular global and regional function using STE in rToF patients with preserved left ventricular ejection fraction to detect early signs of LV dysfunction. The study is a retrospective review of the medical records and transthoracic echocardiograms of rTOF patients who were seen in the pediatric cardiology clinic at our institution from August 2016 till May 2018. The rTOF group was compared with a matched healthy control group. Offline strain analysis of TTE studies was completed in each subject according to mode set by the American Society of Echocardiography. Twenty-two patients with rTOF and 22 age-matched controls (rTOF 18.7 ± 6 years and control 14.6 ± 9.6 years, P value 0.19) were included during the study period. The rTOF group consisted of 12 males and 10 females, whereas the control group consisted of 15 males and 7 females. There was no significant difference in terms of LV ejection fraction using both 2-chamber as well as 4-chamber views. Global LV longitudinal strain was significantly lower in the rTOF group compared with the control group (rTOF - 15.92 ± 3.16 vs control - 22.79 ± 2.45, P value 0.00). All 17 segments showed significantly lower longitudinal strains in rTOF group compared with the control group. Global circumferential left ventricle strain was significantly lower in the rTOF patients compared with the control group (- 17.24 ± 5.86 vs - 22.74 ± 3.99, P value 0.001). 13 out of 16 segments had lower circumferential strains in the rTOF patients compared with controls. Asymptomatic surgically repaired TOF patients exhibited abnormal segmental and global left ventricle longitudinal and circumferential strains despite having normal left ventricle ejection fraction. Our findings suggest subclinical damage to the left ventricle systolic function post-surgical repair of TOF. 2-D speckle-tracking echocardiography may be used as a valuable method in the early recognition of left myocardial systolic function impairment in patients after TOF repair. The application of this method to guide clinical decision and management of rTOF patients such as earlier pulmonary valve replacement or risk stratification for sudden cardiac death needs further investigation.

Abnormalities in Left Ventricular Rotation Are Inherent in Young Children with Repaired Tetralogy of Fallot and Are Independent of Right Ventricular Dilation

Left ventricular (LV) dysfunction is a risk factor for adverse outcomes in older children and adults with repaired Tetralogy of Fallot (rToF). Pulmonary regurgitation (PR), right ventricular (RV) dilation, and dysfunction have been shown to result in abnormal LV myocardial mechanics and dysfunction. The aim of our study was to evaluate LV rotational mechanics, especially apical rotation in young children with rToF with and without RV dilation. This is a retrospective, single center study in 28 asymptomatic young children with rToF (16 with RV dilation; 12 without RV dilation); 29 age-matched normal controls. RV and LV systolic and diastolic function was studied using conventional two-dimensional echocardiography (2DE) and speckle tracking echocardiography (STE). Rotational mechanics studied included basal and apical rotation (BR, AR), peak twist (calculated by difference between the apical and basal rotation), twist rate (TR), and untwist rate (UnTR). The mean age of the cohort was 4.7 years (± 2.3). Abnormal AR, BR, TR, and UnTR were noted in patients with rToF. The abnormalities were significant in magnitude as well as the direction of rotation; more pronounced in the absence of RV dilation. LV systolic and diastolic dysfunction as evidenced by abnormal AR and degree of untwist is inherent in rToF and not associated with RV dilation in rToF children. Abnormal BR may reflect a lack of maturation to adult type of rotational mechanics. Further longitudinal studies are required to study the progression of these abnormalities and their correlation with clinical outcomes.

Three-dimensional analysis of regional right ventricular shape and function in repaired tetralogy of Fallot using cardiovascular magnetic resonance

BACKGROUND

Patients with surgically repaired tetralogy of Fallot (rTOF) often have residual pulmonic valve regurgitation, leading to abnormal remodeling and dysfunction of the right ventricle often requiring pulmonic valve replacement. We tested the hypothesis that 3D analysis of right ventricular (RV) shape and function may reveal differences in regional adaptive remodeling that occurs in patients with rTOF, depending on whether a transannular patch (TAP) was utilized.

METHODS

Forty patients with rTOF who underwent cardiac magnetic resonance imaging (1.5 T), including 20 with and 20 without TAP, and 10 normal controls were studied. Images were analyzed to measure RV endocardial curvature and global and regional volume and function.

RESULTS

RV ejection fraction (EF) was 42 ± 11% in TAP and 38 ± 9% in no-TAP (p = 0.19), both lower than 54 ± 3% in controls (p < 0.01). Left ventricular (LV) EF was 54 ± 9% in TAP, 54 ± 8% in no-TAP (p = 0.87) and 61 ± 16% in controls (both p < 0.01). Indexed LV end-diastolic volumes were higher in no-TAP than in TAP subgroup (p = 0.02). With TAP, mid RV septum showed lower curvature during diastole (less convex), than the mid and apical free walls and free wall adjacent to the RV outflow tract (RVOT; more convex). There were no differences in curvature during systole between rTOF subgroups but mid and RVOT free walls showed higher curvature versus controls.

CONCLUSIONS

This is the first study to comprehensively describe the influence of TAP on changes in regional RV shape in patients with rTOF. Understanding these differences may help guide therapeutic options for residual pulmonary valve regurgitation in rTOF patients.

Transcatheter Pulmonary Valve Replacement: Current State of Art

PURPOSE OF REVIEW

The past couple of decades have brought tremendous advances to the field of pediatric and adult congenital heart disease (CHD). Percutaneous valve interventions are now a cornerstone of not just the congenital cardiologist treating patients with congenital heart disease, but also-and numerically more importantly-for adult interventional cardiologists treating patients with acquired heart valve disease. Transcatheter pulmonary valve replacement (tPVR) is one of the most exciting recent developments in the treatment of CHD and has evolved to become an attractive alternative to surgery in patients with right ventricular outflow tract (RVOT) dysfunction. This review aims to summarize (1) the current state of the art for tPVR, (2) the expanding indications, and (3) the technological obstacles to optimizing tPVR.

RECENT FINDINGS

Since its introduction in 2000, more than ten thousands tPVR procedures have been performed worldwide. Although the indications for tPVR have been adapted earlier from those accepted for surgical intervention, they remain incompletely defined. The new imaging modalities give better assessment of cardiac anatomy and function and determine candidacy for the procedure. The procedure has been shown to be feasible and safe when performed in patients who received pulmonary conduit and or bioprosthetic valves between the right ventricle and the pulmonary artery. Fewer selected patients post trans-annular patch repair for tetralogy of Fallot may also be candidates for this technology. Size restrictions of the currently available valves limit deployment in the majority of patients post trans-annular patch repair. Newer valves and techniques are being developed that may help such patients. Refinements and further developments of this procedure hold promise for the extension of this technology to other patient populations.

Association between left ventricular mechanics and diffuse myocardial fibrosis in patients with repaired Tetralogy of Fallot: a cross-sectional study

BACKGROUND

Patients with repaired tetralogy of Fallot (TOF) have progressive, adverse biventricular remodeling, leading to abnormal contractile mechanics. Defining the mechanisms underlying this dysfunction, such as diffuse myocardial fibrosis, may provide insights into poor long-term outcomes. We hypothesized that left ventricular (LV) diffuse fibrosis is related to impaired LV mechanics.

METHODS

Patients with TOF were evaluated with cardiac magnetic resonance in which modified Look-Locker (MOLLI) T1-mapping and spiral cine Displacement encoding (DENSE) sequences were acquired at three LV short-axis positions. Linear mixed modeling was used to define the association between regional LV mechanics from DENSE based on regional T1-derived diffuse fibrosis measures, such as extracellular volume fraction (ECV).

RESULTS

Forty patients (26 ± 11 years) were included. LV ECV was generally within normal range (0.24 ± 0.05). For LV mechanics, peak circumferential strains (-15 ± 3%) and dyssynchrony indices (16 ± 8 ms) were moderately impaired, while peak radial strains (29 ± 8%) were generally normal. After adjusting for patient age, sex, and regional LV differences, ECV was associated with log-adjusted LV dyssynchrony index (β = 0.67) and peak LV radial strain (β = -0.36), but not LV circumferential strain. Moreover, post-contrast T1 was associated with log-adjusted LV diastolic circumferential strain rate (β = 0.37).

CONCLUSIONS

We observed several moderate associations between measures of fibrosis and impaired mechanics, particularly the LV dyssynchrony index and peak radial strain. Diffuse fibrosis may therefore be a causal factor in some ventricular dysfunction in TOF.

Abnormal right atrial performance in repaired tetralogy of Fallot: A CMR feature tracking analysis

BACKGROUND

We hypothesized that right atrial (RA) performance is abnormal in repaired tetralogy of Fallot (TOF).

METHODS

TOF patients were prospectively enrolled for cardiovascular magnetic resonance (CMR), echocardiography and exercise stress following a standardized 14-center protocol. Peak RA longitudinal strain (RALS) and right ventricular longitudinal strain (RVLS) were measured using CMR feature tracking (FT) and correlated to RA and RV end diastolic volumes (EDVi) and ejection fraction (EF).

RESULTS

The cohort had 311 subjects: 171 TOF (94 male, age 18.2±8years) and 140 healthy controls (69 male, 16.4±11years). RAEDVi, RALS, RVEDVi, RVLS, RAEF, and RVEF in TOF were 60.8±17.1ml/m², 13.6±5.7%, 120.3±30.3ml/m², 12.3±4.2%, 32.5±9.9% and 51.2±8.4% and differed from respective indices in controls: 51.7±15.7ml/m², 27±10.1%, 74±19.0ml/m², 18.5±5.3%, 54±8% and 62.5±5.5% (p<0.001). RAEDVi and RALS correlated with RVLS (p=0.004, <0.001, r=0.2,0.3). RAEDVi was higher in older TOF, while RALS did not increase with age. RAEDVi but not RALS correlated with RV systolic pressure(r=0.2, 0). Neither RAEDVi nor RALS was associated with tricuspid regurgitation grade or peak oxygen uptake (r=0.1, 0). Positive correlation was observed for RVEDVi with RAEDVi (p=0.035, r=0.2) and a trend toward negative correlation with RALS (p=0.09, r=0.1).

CONCLUSION

RALS, RAEDVi and RAEF are abnormal in TOF. Reduced RALS indicates decreased RA reservoir function. Because they correlate with other functional RV indices, these abnormalities may represent RA diastolic burden from chronic RV dysfunction in TOF. The young cohort age might explain the absence of RALS correlation to tricuspid regurgitation and peak oxygen uptake.

Left ventricular regional myocardial motion and twist function in repaired tetralogy of Fallot evaluated by magnetic resonance tissue phase mapping

OBJECTIVES

We aimed to characterise regional myocardial motion and twist function in the left ventricles (LV) in patients with repaired tetralogy of Fallot (rTOF) and preserved LV global function.

METHODS

We recruited 47 rTOF patients and 38 age-matched normal volunteers. Tissue phase mapping (TPM) was performed for evaluating the LV myocardial velocity in longitudinal, radial, and circumferential (Vz, Vr, and VØ) directions in basal, middle, and apical slices. The VØ peak-to-peak (PTP) during systolic phases, the rotation angle of each slice, and VØ inconsistency were computed for evaluating LV twist function and VØ dyssynchrony.

RESULTS

As compared to the controls, the rTOF patients presented decreased RV ejection fraction (RVEF) (p = 0.002) and preserved global LV ejection fraction (LVEF). They also demonstrated decreased systolic and diastolic Vz in several LV segments and higher diastolic Vr in the septum (all p < 0.05). A lower VØ PTP, higher VØ inconsistency, and reduced peak net rotation angle (all p < 0.05) were observed. The aforementioned indices demonstrated an altered LV twist function in rTOF patients in an early disease stage.

CONCLUSIONS

MR TPM could provide information about early abnormalities of LV regional motion and twist function in rTOF patients with preserved LV global function.

KEY POINTS

• Patients with rTOF presented significantly reduced systolic and diastolic Vz in the LV. • rTOF patients demonstrated significantly increased diastolic Vr in the septum. • Abnormal characteristics of the segmental dynamic velocity evolution were shown in rTOF. • rTOF patients presented altered circumferential rotation and velocity inconsistency in early stage.

Timely Pulmonary Valve Replacement May Allow Preservation of Left Ventricular Circumferential Strain in Patients with Tetralogy of Fallot

INTRODUCTION

Patients with Tetralogy of Fallot (TOF) and pulmonary insufficiency and a dilated right ventricle (RV) may suffer from a reduction in left ventricular (LV) performance. It is not clear whether timely pulmonary valve replacement (PVR) preserves LV mechanics.

METHODS

Ten TOF patients who underwent PVR were identified from hospital records, and pre- and postoperative cardiac magnetic resonance images were post-processed with a semi-automatic tissue tracking software. LV circumferential strain, time to peak strain, and torsion were compared before and after PVR. A control group of 10 age-matched normal volunteers was assessed as a comparison.

RESULTS

LV circumferential strain did not change before vs. after PVR (basal -18.3 ± 3.7 vs. -20.5 ± 3%, p = 0.082; mid-ventricular -18.4 ± 3.6 vs. -19.1 ± 2%, p = 0.571; apical -22.7 ± 5.2 vs. -22.1 ± 4%; p = 0.703). There was also no difference seen between the baseline strain and normal controls (control basal -18.2 ± 3.3%, p = 0.937; mid -18 ± 3.2%, p = 0.798; apex -24.1 ± 5%, p = 0.552). LV torsion remained unchanged from baseline to post PVR [systolic 2.75 (1.23-9.51) °/cm vs. 2.3 ± 1.2°/cm, p = 0.285; maximum 5.5 ± 3.5°/cm vs. 2.34 (1.37-8.07) °/cm, p = 0.083]. There was no difference in time to measured peak LV circumferential strain before vs. after PVR (basal 0.44 ± 0.1 vs. 0.43 ± 0.05, p = 0.912; mid-ventricular 0.42 ± 0.08 vs. 0.38 ± 0.06, p = 0.186; apical 0.40 ± 0.08 vs. 0.40 ± 0.06, p = 0.995). At the same time, pulmonary regurgitation and RV end-diastolic and end-systolic volume indices decreased and LV end-diastolic volume increased after PVR. RV and LV ejection fractions remained constant.

CONCLUSION

PVR allows for favorable remodeling of both ventricular volumes for TOF patients with significant pulmonary regurgitation. In this cohort, LV myocardial functional parameters such as circumferential strain, time to peak strain, and LV torsion were normal at baseline and remain unchanged after PVR.

Impact of surgical pulmonary valve replacement on ventricular mechanics in children with repaired tetralogy of Fallot

Impaired ventricular myocardial mechanics are observed in patients with repaired tetralogy of Fallot (rTOF). Effects of pulmonary valve replacement (PVR) on ventricular remodeling are controversial. The objective was to assess the impact of surgical PVR on ventricular mechanics in pediatric patients after rTOF. Speckle-tracking analysis was performed in 50 rTOF children, aged 12.6 ± 3.3 years, pre-operatively and 14.5 ± 2.2 months post-PVR. Early post-operative studies 2.2 ± 0.6 months post-PVR were performed in 28 patients. Cardiac magnetic resonance (CMR) pre- and post-PVR was collected. Mid-term post-PVR right ventricular (RV) longitudinal strain increased above pre-operative strain (-19.2 ± 2.7 to -22.0 ± 3.0%, p < 0.001) with increases observed in individual RV segments. Left ventricular (LV) strain did not differ at medium-term follow-up. LV and RV longitudinal strain was reduced early post-operatively, followed by recovery of biventricular systolic strain by mid-term follow-up. CMR RV end-diastolic indexed volumes correlated with RV strain pre-operatively (r = 0.432, p = 0.005) and at mid-term follow-up (r = 0.532, p = 0.001). Volume-loaded RVs had reduced early RV basal longitudinal strain compared to pressure-loading conditions. Reversed basal counterclockwise rotation was associated with lower mid-term global LV and basal RV strain compared to patients with normal rotation. An increase in mid-term global and regional RV strain beyond pre-operative values suggests positive RV remodeling and adaptation occurs in children post-PVR. Patients with larger pre-operative RV volumes had lower RV strain post-operatively. The impact of LV rotation on RV mechanics highlights the presence of ventriculo-ventricular interactions. These findings have important clinical implications in pediatric rTOF patients towards identifying pre-operative factors that predict RV post-operative remodeling.

Increased left ventricular myocardial extracellular volume is associated with longer cardiopulmonary bypass times, biventricular enlargement and reduced exercise tolerance in children after repair of Tetralogy of Fallot

BACKGROUND

Unfavorable left ventricular (LV) remodelling may be associated with adverse outcomes after Tetralogy of Fallot (TOF) repair. We sought to assess T1 cardiovascular magnetic resonance (CMR) markers of diffuse LV myocardial fibrosis in children after TOF repair, and associated factors.

METHODS

In this prospective, cross-sectional study, native (=non-contrast) T1 times and extracellular volume fraction (ECV) were quantified in the LV myocardium using CMR. Results were related to ventricular volumes and function, degree of pulmonary regurgitation, as well as surgical characteristics, and exercise capacity.

RESULTS

There was no difference in native T1 times or ECV between 31 TOF patients (age at CMR 13.9 ± 2.4 years, 19 male) and 15 controls (age at CMR 13.4 ± 2.6 years, 7 male). Female TOF patients had higher ECVs than males (25.2 ± 2.9 % versus 22.7 ± 3.3 %, p < 0.05). In the patient group, higher native T1 and ECV correlated with higher Z-Scores of right and left ventricular end-diastolic volumes, but not with reduced left and right ventricular ejection fraction or higher pulmonary regurgitation fraction. Longer cardiopulmonary bypass and aortic cross clamp times at surgery correlated with increased native T1 times and ECVs (r = 0.48, p < 0.05 and r = 0.65, p < 0.01, respectively). Maximum workload (percent of predicted for normal) correlated inversely with ECV (r = -0.62, p < 0.05). Higher native T1 times correlated with worse LV longitudinal (r = 0.50, p < 0.05) and mid short axis circumferential strain (r = 0.38, p < 0.05).

CONCLUSIONS

As compared to controls, TOF patients did not express higher markers of diffuse fibrosis. Longer cardiopulmonary bypass and aortic cross clamp times at surgery as well as biventricular enlargement and reduced exercise tolerance are associated with markers of diffuse myocardial fibrosis after TOF repair. Female patients have higher markers of diffuse myocardial fibrosis than males.

Left and right ventricular dyssynchrony and strains from cardiovascular magnetic resonance feature tracking do not predict deterioration of ventricular function in patients with repaired tetralogy of Fallot

BACKGROUND

Patients with repaired tetralogy of Fallot (rTOF) suffer from progressive ventricular dysfunction decades after their surgical repair. We hypothesized that measures of ventricular strain and dyssynchrony would predict deterioration of ventricular function in patients with rTOF.

METHODS

A database search identified all patients at a single institution with rTOF who underwent cardiovascular magnetic resonance (CMR) at least twice, >6 months apart, without intervening surgical or catheter procedures. Seven primary predictors were derived from the first CMR using a custom feature tracking algorithm: left (LV), right (RV) and inter-ventricular dyssynchrony, LV and RV peak global circumferential strains, and LV and RV peak global longitudinal strains. Three outcomes were defined, whose changes were assessed over time: RV end-diastolic volume, and RV and LV ejection fraction. Multivariate linear mixed models were fit to investigate relationships of outcomes to predictors and ten potential baseline confounders.

RESULTS

One hundred fifty-three patients with rTOF (23 ± 14 years, 50 % male) were included. The mean follow-up duration between the first and last CMR was 2.9 ± 1.3 years. After adjustment for confounders, none of the 7 primary predictors were significantly associated with change over time in the 3 outcome variables. Only 1-17 % of the variability in the change over time in the outcome variables was explained by the baseline predictors and potential confounders.

CONCLUSIONS

In patients with repaired tetralogy of Fallot, ventricular dyssynchrony and global strain derived from cine CMR were not significantly related to changes in ventricular size and function over time. The ability to predict deterioration in ventricular function in patients with rTOF using current methods is limited.

Impact of surgical correction of tetralogy of fallot on short-term right and left ventricular function as determined by 2-dimensional speckle tracking echocardiography

Right ventricular (RV) and left ventricular (LV) dysfunction is an important determinant of poor clinical status in repaired patients with tetralogy of Fallot (TOF). The purpose of our study is to assess the impact of surgical repair on short-term RV and LV function by 2-dimensional speckle tracking echocardiography (STE).Sixty-seven patients (median age 12 months) with TOF before and 6 months after repair and 35 healthy subjects were studied. The patients were divided into the younger (age at surgery ≤12 months) and older (age at surgery >12 months) subgroups. RV and LV global longitudinal systolic strain and strain rate (SR), and LV global circumferential and radial systolic strain and SR were measured by STE. After repair, RV longitudinal strain and SR increased in the younger patients, whereas RV longitudinal SR was decreased in the older patients. LV deformation parameters were unchanged in all patients. In the multivariate analysis, patients with better RV and LV deformation parameters preoperatively were identified to have better RV and LV strain and SR postoperatively (P < 0.05 for all). The surgical approach of the pulmonary valve ring was predictive of RV and LV systolic function postoperatively (P < 0.05 for all).After TOF repair, short-term RV function improvement is identified in the younger but not in the older patients, whereas LV function is unchanged in all patients. The preoperative RV and LV deformational indices are the determinant of postoperative biventricular function improvement. STE appears to be a valuable tool for assessment of biventricular function after congenital heart disease surgery.

Impact of Right-Sided-Catheter-Based Valve Implantation on Decision-Making in Congenital Heart Disease

There is a growing appreciation for the adverse long-term impact of right-sided valvular dysfunction in patients with congenital heart disease. Although right-sided valvular stenosis and/or regurgitation is often better tolerated than left-sided valvular dysfunction in the short and intermediate term, the long-term consequences are numerous and include, but are not limited to, arrhythmias, heart failure, and multi-organ dysfunction. Surgical right-sided valve interventions have been performed for many decades, but the comorbidities associated with multiple surgeries are a concern. Transcatheter right-sided valve replacement is safe and effective and is being performed at an increasing number of centers around the world. It offers an alternative to traditional surgical techniques and may potentially alter the decision making process whereby valvular replacement is performed prior to the development of long-term sequelae of right-sided valvular dysfunction.

Reference Ranges of Left Ventricular Strain Measures by Two-Dimensional Speckle-Tracking Echocardiography in Children: A Systematic Review and Meta-Analysis

BACKGROUND

Establishment of the range of reference values and associated variations of two-dimensional speckle-tracking echocardiography (2DSTE)-derived left ventricular (LV) strain is a prerequisite for its routine clinical adoption in pediatrics. The aims of this study were to perform a meta-analysis of normal ranges of LV global longitudinal strain (GLS), global circumferential strain (GCS), and global radial strain (GRS) measurements derived by 2DSTE in children and to identify confounding factors that may contribute to variance in reported measures.

METHODS

A systematic review was launched in MEDLINE, Embase, Scopus, the Cumulative Index to Nursing and Allied Health Literature, and the Cochrane Library. Search hedges were created to cover the concepts of pediatrics, STE, and left-heart ventricle. Two investigators independently identified and included studies if they reported 2DSTE-derived LV GLS, GCS, or GRS. The weighted mean was estimated by using random effects models with 95% CIs, heterogeneity was assessed using the Cochran Q statistic and the inconsistency index (I(2)), and publication bias was evaluated using the Egger test. Effects of demographic (age), clinical, and vendor variables were assessed in a metaregression.

RESULTS

The search identified 2,325 children from 43 data sets. The reported normal mean values of GLS among the studies varied from -16.7% to -23.6% (mean, -20.2%; 95% CI, -19.5% to -20.8%), GCS varied from -12.9% to -31.4% (mean, -22.3%; 95% CI, -19.9% to -24.6%), and GRS varied from 33.9% to 54.5% (mean, 45.2%; 95% CI, 38.3% to 51.7%). Twenty-six studies reported longitudinal strain only from the apical four-chamber view, with a mean of -20.4% (95% CI, -19.8% to -21.7%). Twenty-three studies reported circumferential strain (mean, -20.3%; 95% CI, -19.4% to -21.2%) and radial strain (mean, 46.7%; 95% CI, 42.3% to 51.1%) from the short-axis view at the midventricular level. A significant apex-to-base segmental longitudinal strain gradient (P < .01) was observed in the LV free wall. There was significant between-study heterogeneity and inconsistency (I(2) > 94% and P < .001 for each strain measure), which was not explained by age, gender, body surface area, blood pressure, heart rate, frame rate, frame rate/heart rate ratio, tissue-tracking methodology, location of reported strain value along the strain curve, ultrasound 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 = .40).

CONCLUSIONS

This study defines reference values of 2DSTE-derived LV strain in children on the basis of a meta-analysis. In healthy children, mean LV GLS was -20.2% (95% CI, -19.5% to -20.8%), mean GCS was -22.3% (95% CI, -19.9% to -24.6%), and mean GRS was 45.2% (95% CI, 38.3% to 51.7%). LV segmental longitudinal strain has a stable apex-to-base gradient that is preserved throughout maturation. Although variations among different reference ranges in this meta-analysis were not dependent on differences in demographic, clinical, or vendor parameters, age- and vendor-specific referenced ranges were established as well.

Left Ventricular Myocardial Function in Children With Pulmonary Hypertension: Relation to Right Ventricular Performance and Hemodynamics

BACKGROUND

Through ventricular interdependence, pulmonary hypertension (PH) induces left ventricular (LV) dysfunction. We hypothesized that LV strain/strain rate, surrogate measures of myocardial contractility, are reduced in pediatric PH and relate to invasive hemodynamics, right ventricular strain, and functional measures of PH.

METHODS AND RESULTS

At 2 institutions, echocardiography was prospectively performed in 54 pediatric PH patients during cardiac catheterization, and in 54 matched controls. Patients with PH had reduced LV global longitudinal strain (LS; -18.8 [-17.3 to -20.4]% versus -20.2 [-19.0 to -20.9]%; P=0.0046) predominantly because of reduced basal (-12.9 [-10.8 to -16.3]% versus -17.9 [-14.5 to -20.7]%; P<0.0001) and mid (-17.5 [-15.5 to -19.0]% versus -21.1 [-19.1 to -23.0]%; P<0.0001) septal strain. Basal global circumferential strain was reduced (-18.7 [-15.7 to -22.1]% versus -20.6 [-19.0 to -22.5]%; P=0.0098), as were septal and free-wall segments. Mid circumferential strain was reduced within the free-wall. Strain rates were reduced in similar patterns. Basal septum LS, the combined average LS of basal and mid interventricular septal segments, correlated strongly with degree of PH (r=0.66; P<0.0001), pulmonary vascular resistance (r=0.60; P<0.0001), and right ventricular free-wall LS (r=0.64; P<0.0001). Brain natriuretic peptide levels correlated moderately with septal LS (r=0.48; P=0.0038). PH functional class correlated moderately with LV free-wall LS (r=-0.48; P=0.0051). The septum, shared between ventricles and affected by septal shift, was the most affected LV region in PH.

CONCLUSIONS

Pediatric PH patients demonstrate reduced LV strain/strain rate, predominantly within the septum, with relationships to invasive hemodynamics, right ventricular strain, and functional PH measures.

Normal ranges of left ventricular strain in children: a meta-analysis

AIMS

The definition of normal values of two-dimensional speckle-tracking echocardiography derived left ventricular (LV) deformation parameters, is of critical importance for the routine application of this modality in children. The objectives of this study were to perform a meta-analysis of normal ranges for longitudinal, circumferential and radial strain/strain rate values and to identify confounders that may contribute to differences in reported measures.

METHODS AND RESULTS

A systematic search was conducted. Studies describing normal healthy subjects and observational studies that used control groups as a comparison were included. Data were combined using a random-effect model. Effects of demographic, clinical and equipment variables were assessed through meta-regression. The search identified 1,192 subjects form 28 articles. Longitudinal strain (LS) normal mean values varied from -12.9 to -26.5 (mean, -20.5; 95% CI, -20.0 to -21.0). Normal mean values of circumferential strain (CS) varied from -10.5 to -27.0 (mean, -22.06; 95% CI, -21.5 to -22.5). Radial strain (RS) normal mean values varied from 24.9 to 62.1 (mean, 45.4; 95% CI, 43.0 to 47.8). Meta-regression showed LV end diastolic diameter as a significant determinant of variation for LS. Longitudinal systolic strain rate (LSRs) was significantly determined by the age and RS by the type of vendor used.

CONCLUSION

Variations among different normal ranges were dependent on the vendor used, LV end-diastolic diameter and age. Vendor-independent software for analyzing myocardial deformation in children, using images from different vendors would be the ideal solution for strain measurements or else using the same system for patient's follow up.

Relation of biventricular strain and dyssynchrony in repaired tetralogy of fallot measured by cardiac magnetic resonance to death and sustained ventricular tachycardia

Ventricular strain and dyssynchrony can be measured in patients with repaired tetralogy of Fallot (TOF), but their effect on clinical outcomes is poorly understood. The purpose of this study was to investigate if ventricular strain and dyssynchrony measured by cardiac magnetic resonance feature tracking are associated with death and sustained ventricular tachycardia. Patients with TOF who died or had ventricular tachycardia (TOF case, n = 16) were compared with age-matched patients with TOF with no adverse outcome (TOF control, n = 32). For each patient, midventricular short-axis and 4-chamber cine steady-state free precession images were analyzed using cardiac magnetic resonance feature-tracking software. Peak left ventricular (LV) and right ventricular (RV) global circumferential and longitudinal strain and indexes of dyssynchrony were compared between groups. Compared with the TOF control group, median strain values were significantly lower for the TOF case group for both the LV (circumferential: 17% vs 23%, p = 0.003; longitudinal: 13% vs 18%, p <0.001) and the RV (circumferential: 10% vs 16%, p = 0.001; longitudinal: 11% vs 18%, p <0.001). In a multivariate model including strain and dyssynchrony parameters, RV and LV longitudinal strain were strongly associated with the adverse outcome (p = 0.003 and 0.04, respectively; area under the curve = 0.92). No differences in ventricular dyssynchrony were identified between the groups. In conclusion, patients with TOF in this cohort who experienced adverse outcomes had lower values of all strain parameters than those who did not, and impaired longitudinal strain of both ventricles was strongly associated with adverse clinical outcomes.

Long-term follow-up in repaired tetralogy of fallot: can deformation imaging help identify optimal timing of pulmonary valve replacement?

BACKGROUND

Novel echocardiographic techniques based on myocardial deformation have not been extensively evaluated to assess right ventricular (RV) and left ventricular (LV) response after pulmonary valve replacement (PVR) in patients with repaired tetralogy of Fallot.

METHODS

Between 2003 and 2012, 133 patients undergoing first-time PVR after tetralogy of Fallot repair underwent echocardiographic assessment at Mayo Clinic. The last echocardiogram before PVR and 1 year after surgery were retrospectively analyzed with Velocity Vector Imaging.

RESULTS

Mean age at PVR was 35.5 ± 16.2 years (54% women). Longitudinal peak systolic strain and strain rate before PVR were low: for the left ventricle, -14.8 ± 3.5% and -0.8 ± 0.2 sec(-1), and for the right ventricle, -16.2 ± 4.1% and -0.9 ± 0.3 sec(-1), respectively. There was no significant change in either parameter after surgery. A close correlation between LV and RV deformational parameters was found before PVR and was maintained after surgery. In the multivariate analysis, patients with better LV and RV peak systolic strain preoperatively were found to have better LV and RV peak systolic strain after surgery (P = .004 and P = .006, respectively). However, patients with the most improvement in deformation were those with worse RV function preoperatively (P = .002). Mean New York Heart Association class at early follow-up improved from 2.2 ± 0.8 to 1.2 ± 0.6 (P < .0001); RV peak systolic strain was the only factor associated with symptomatic improvement.

CONCLUSION

LV and RV systolic and diastolic deformational parameters were decreased in patients with repaired tetralogy of Fallot undergoing PVR, and there was no significant change after surgery. However, preoperative systolic deformational parameters were predictive of postoperative ventricular function and New York Heart Association class after PVR and may be helpful to identify optimal timing for surgical intervention in this cohort.

Diffuse myocardial fibrosis following tetralogy of Fallot repair: a T1 mapping cardiac magnetic resonance study

BACKGROUND

Adverse ventricular remodeling after tetralogy of Fallot (TOF) repair is associated with diffuse myocardial fibrosis.

OBJECTIVE

The goal of this study was to measure post-contrast myocardial T1 in pediatric patients after TOF repair as surrogates of myocardial fibrosis.

MATERIALS AND METHODS

Children after TOF repair who underwent cardiac magnetic resonance imaging with T1 mapping using the modified look-locker inversion recovery (MOLLI) sequence were included. In addition to routine volumetric and flow data, we measured post-contrast T1 values of the basal interventricular septum, the left ventricular (LV) lateral wall, and the inferior and anterior walls of the right ventricle (RV). Results were compared to data from age-matched healthy controls.

RESULTS

The scans of 18 children who had undergone TOF repair and 12 healthy children were included. Post-contrast T1 values of the left ventricular lateral wall (443 ± 54 vs. 510 ± 77 ms, P = 0.0168) and of the right ventricular anterior wall (333 ± 62 vs. 392 ± 72 ms, P = 0.0423) were significantly shorter in children with TOF repair than in controls, suggesting a higher degree of fibrosis. In children with TOF repair, but not in controls, post-contrast T1 values were shorter in the right ventricle than the left ventricle and shorter in the anterior wall of the right ventricle than in the inferior segments. In the TOF group, post-contrast T1 values of the RV anterior wall correlated with the RV end-systolic volume indexed to body surface area (r = 0.54; r(2) = 0.30; P = 0.0238).

CONCLUSION

In children who underwent tetralogy of Fallot repair the myocardium of both ventricles appears to bear an abnormally high fibrosis burden.

Impaired right and left ventricular function in asymptomatic children with repaired tetralogy of Fallot by two-dimensional speckle tracking echocardiography study

BACKGROUND

Early detection of right ventricular (RV) and left ventricular (LV) dysfunction in patients with repaired tetralogy of Fallot (TOF) is essential because dysfunction is correlated with a poor clinical outcome. The aim of this study was to assess RV and LV function in asymptomatic children with repaired TOF by two-dimensional ultrasound speckle tracking echocardiography (STE).

METHODS

Fifty-six asymptomatic children with a preserved biventricular ejection fraction (EF) after repair of TOF and 35 healthy control subjects were studied. RV and LV strain and strain rate were measured by STE. RVEF and pulmonary regurgitation (PR) were assessed using cardiac magnetic resonance imaging.

RESULTS

Compared with the control subjects, RV regional longitudinal strain and strain rate and global longitudinal strain (GLS) and strain rate (GLSR) were impaired in children with repaired TOF. Likewise, LV circumferential and radial strain and strain rate were reduced in patients with TOF. In contrast, longitudinal strain and strain rate did not differ between the groups. RV and LV GLSR were correlated with postoperative follow-up period (r1 = -0.44; r2 = -0.48). RV GLS and GLSR were associated with RVEF (r1 = 0.64; r2 = 0.60) and PR (r1 = -0.48; r2 = -0.49). LV circumferential strain rate was related to PR (r = -0.45).

CONCLUSIONS

STE can identify abnormalities that may represent early impairment of RV and LV systolic function in postoperative TOF patients with a preserved EF. PR is associated with decreased biventricular performance in repaired patients. STE-derived strain and strain rate may be useful indices for detecting the early deterioration of biventricular performance in patients with TOF.

Adverse biventricular remodeling in isolated right ventricular hypertension is mediated by increased transforming growth factor-β1 signaling and is abrogated by angiotensin receptor blockade

The pressure-loaded right ventricle (RV) adversely affects left ventricular (LV) function. We recently found that these ventricular-ventricular interactions lead to LV myocardial fibrosis through transforming growth factor-β1 (TGF-β1) signaling. We investigated the mechanisms mediating biventricular fibrosis in RV afterload and their potential modification by angiotensin receptor blockade. An adjustable pulmonary artery band (PAB) was placed in rabbits. In sham-operated control rabbits, the band was left uninflated (n = 6). In the RV afterload group, the PAB was sequentially inflated to generate systemic RV pressure at 28 days (n = 8). In a third group, the PAB was inflated to systemic levels, and the angiotensin receptor blocker losartan was added (n = 6). Five weeks after surgery, the animals were killed for assessments of biventricular hypertrophy, fibrosis, apoptosis, and the components of their signaling pathways. PAB animals developed biventricular hypertrophy, fibrosis, and apoptosis, versus sham rabbits, in which these conditions were decreased with losartan. RV and LV TGF-β1, connective tissue growth factor (CTGF) (CCN2), endothelin-1 (ET-1), endothelin receptor B, and matrix metalloproteinase 2/9 mRNA levels were increased in PAB animals versus sham animals, and decreased with losartan. Given the marked biventricular CTGF up-regulation in PAB and down-regulation with losartan, we investigated CTGF signaling. RV and LV Smad 2/3/4 protein levels and LV RhoA mRNA levels were increased with PAB and reduced with losartan. In conclusion, isolated RV afterload induces biventricular fibrosis and apoptosis, which are reduced by angiotensin receptor blockade. Adverse ventricular-ventricular interactions induced by isolated RV afterload appear to be mediated through TGF-β1-CTGF and ET-1 pathways.