Effect of Chronic Right Ventricular Volume Overload on Ventricular Interaction in Patients after Tetralogy of Fallot Repair

Right-Left Ventricular Interdependence in Repaired Tetralogy of Fallot Patients With Right Ventricular Heart Failure

BACKGROUND

Patients with repaired tetralogy of Fallot (rTOF) continue to face a heightened risk of deteriorating cardiac function, and quantitative techniques of cardiac MRI-derived cardiac structure and function provide an opportunity to explore the causes and mechanisms of cardiac deterioration.

PURPOSE

To explore right-left ventricular interdependence in rTOF patients before and after the onset of right ventricular (RV) heart failure.

STUDY TYPE

Retrospective.

POPULATION

One hundred eighteen rTOF patients (21.85 [16.74, 29.20] years, 58 females) and 34 controls (23.5 [21, 26.5] years, 17 females) that underwent cardiac MRI were analyzed, with rTOF patients being further subdivided into those with preserved RV function (N = 54) and those that experienced RV heart failure (N = 64).

FIELD STRENGTH/SEQUENCE

3.0 T/balanced steady-state free precession sequence.

ASSESSMENT

RV, left ventricular (LV), and septal strain; RV and LV volume.

STATISTICAL TESTS

Chi-squared tests or Fisher's exact test, One-way ANOVAs with Bonferroni's post hoc test, Pearson/Spearman correlation, and multivariate backward linear regression analysis. A two-tailed P < 0.05 was deemed as the significance threshold.

RESULTS

The MRI-derived RV, LV, and septal strain decreased sequentially in controls, patients with preserved RV function, and patients with RV heart failure, with a good intra-observer (0.909-0.964) and inter-observer (0.879-0.937) agreement. Correlations between LV and RV strain were found to change sequentially with RV function and were the closest in rTOF patients with RV heart failure (r = -0.270 to 0.506). Correlations between RV volume and septal strain was variable in controls (r = 0.483 to -0.604), patients with preserved RV function (r = -0.034 to -0.295), and patients with RV heart failure (r = -0.026 to 0.500). Multivariate analyses revealed that the RV longitudinal strain was independently correlated with LV strain in three directions in rTOF patients with RV heart failure (Radial -0.70 [-1.33, -0.06]; Circumferential 0.44 [0.17, 0.72]; Longitudinal 0.54 [0.26, 0.81]).

DATA CONCLUSION

In rTOF patients, the coupling between RV volume and septal strain was broken during RV function compensation, and the adverse effect of RV on LV deformation was highest in patients with RV heart failure.

EVIDENCE LEVEL

4 TECHNICAL EFFICACY: Stage 5.

Myocardial, Valvular and Vascular Abnormalities in Repaired Tetralogy of Fallot

Tetralogy of Fallot is the most common heart defect associated with cyanosis characterized by the co-occurrence of pulmonary stenosis, right ventricular hypertrophy, and ventricular septal defect with over-riding of the aorta. The present review purposed to summarize myocardial, valvular and vascular abnormalities, which were described in a series of patients following repair of tetralogy of Fallot. It was also aimed to describe potential differences in these parameter using different surgical strategies.

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.

Biventricular interaction and aortic function in adult patients with repaired tetralogy of Fallot: a two-dimensional-three-dimensional speckle-tracking echocardiographic study

Aims

In patients late after correction of tetralogy of Fallot (TOF), the combined effects of pre-operative hypertrophy and hypoxia, ventricular interdependence, acquired post-operative lesions such as pulmonary or aortic regurgitation, and congenital vasculopathy may result in impaired right ventricular (RV) and left ventricular (LV) function. The aim of the present study was to investigate the interventricular interactions in repaired TOF (rTOF) and the impact of aortic function on biventricular performance using two-dimensional (2D-STE) and three-dimensional speckle-tracking echocardiography (3D-STE).

Methods and results

Twenty-five adult patients with rTOF and 25 age- and gender-matched healthy controls were studied. LV and RV volumes were determined by 3D-STE and cardiac magnetic resonance. LV and RV longitudinal strains (LVLS and RVLS) and LV and RV area strains (LVAS and RVAS) and LV twist/rotation were calculated by 3D-STE. Ascending aorta circumferential strain (AAo-CS) was obtained using 2D-STE. LV 3D-STE parameters were decreased in rTOF patients compared with controls even in patients with normal ejection fraction. AAo-CS was decreased (6.7 ± 1.9 vs. 10.1 ± 2.6, P = 0.003) in rTOF patients compared with controls even in the presence of normal aortic dimensions and correlated with AAo diameter (r = -0.69, P = 0.0001), LV twist (r = 0.54, P = 0.004), LVAS (r = -0.56, P = 0.003), and RVLS (r = -0.39, P = 0.036). LVAS and AAo-CS were associated with disease severity (peak oxygen consumption and arrhythmia occurrence). Significant improvement in global χ 2 value was noted with RV 3D-STE parameters + LVAS + AAo-CS compared with RV dysfunction alone for detecting exercise capacity impairment (from 77.1 to 84.4 to 91.2, P = 0.003).

Conclusion

Speckle-tracking echocardiography revealed subtle LV and AAo dysfunction in adults with rTOF. A correlation was observed between LV and RV strain changes and between AAo strain impairment and LV/RV dysfunction. LV and AAo changes had an incremental value in evaluating disease severity.

Impact of pulmonary valve replacement on left and right ventricular function using strain analysis, in children with repaired tetralogy of Fallot

BACKGROUND

In repaired Tetralogy of Fallot (rTOF), pulmonary regurgitation and resulting right ventricular (RV) and left ventricular (LV) dysfunction are associated with adverse clinical outcomes. We performed an echocardiographic assessment of LV and RV function using Global Longitudinal Strain (GLS) and conventional echo method prior to and following Pulmonary Valvular Replacement (PVR) to help inform proper timing of operation.

RESULTS

A total of 30 rTOF patients (12.17 ± 2.5 years, 70% male) were included. Regarding to LV function, the study revealed a significant reverse correlation between LV GLS (absolute value) and early (mean = 10.4 days) and late (mean = 7.4 months) postop LVEF. Paired T-Test showed significant difference between GLS of LV and RV before and late after operation (op), however, without significant changes early postop. Late postop significant improvements occurred in other conventional echo indices of LV and RV function as well. There was also a significant correlation between echo-measured LVEF & Fraction Area Change (RV FAC) and MRI-derived LVEF & RVEF, respectively.

CONCLUSION

In this cross-sectional study in rTOF patients, RV and LV GLS as well as conventional echocardiographic indices regarding LV and RV function improved significantly after 6 months (mean = 7.4mo) following PVR.

Evaluation of ventricular function and myocardial deformation in children with repaired tetralogy of Fallot by real-time three-dimensional (four-dimensional) echocardiography

AIM

The left and right ventricular dysfunction are important clinical course indicators in patients with repaired tetralogy of Fallot. This study aimed to evaluate ventricular volumes, functions, and myocardial deformation in children with repaired tetralogy of Fallot by real-time three-dimensional (four-dimensional) echocardiography and compared with healthy children. It also aimed to investigate the relationships between ventricular volumes, functions, and myocardial deformation parameters in the patients.

MATERIALS AND METHODS

In this cross-sectional study, 35 patients (mean age 15.1 ± 2.8 years, 54% male) and 35 healthy controls of similar age, gender, and body measurements underwent echocardiography. End-diastolic volume index, end-systolic volume index, and ejection fractions of both ventricles; global longitudinal, circumferential, radial strain, twist, and torsion of the left ventricle; the longitudinal strain of the right ventricle free wall and septum were measured.

RESULTS

Left ventricular ejection fraction, global circumferential and radial strain, twist and torsion were significantly lower in patients compared with controls. Left ventricular ejection fraction correlated with global circumferential (r = -0.446, p < 0.001) and radial strain (r = -0.433, p < 0.001) in the patients. Right ventricular volumes were significantly higher, and ejection fraction was significantly lower in patients compared with controls. All right ventricular parameters correlated with each other in the patients.

CONCLUSION

Left ventricular contraction pattern was changed, circumferential and radial fibres were most affected in the patients. Right ventricular dilatation and dysfunction were detected, and right ventricular ejection fraction correlated well with strain measurements of the right ventricle.

15-Year follow-up of regional right and left ventricular function after the Senning operation: a Colour-Doppler myocardial imaging study

INTRODUCTION

Despite right ventricular (RV) dysfunction being a major concern in Senning patients, long-term follow-up data is lacking. This study aimed (1) at evaluating regional (base-mid-apex) RV and left ventricular (LV) function using Colour-Doppler myocardial imaging over a 15-year follow-up period and (2) at comparing results with matched controls.

METHODS

For the longitudinal analysis (2004-2019), we compared systolic and diastolic function in 10 Senning patients. For the cross-sectional analysis, we compared the subaortic RV (sRV) of Senning patients with the RV and LV of matched controls and the subpulmonary LV (spLV) of Senning patients with the LV of matched controls.

RESULTS

The longitudinal analysis of sRV function showed a significant decrease in apical peak systolic strain (-17 ± 7% vs -12 ± 4%; p = 0.025) and apical peak systolic strain rate (-1.1 ± 0.3s^-1 vs -0.8 ± 0.4s^-1; p = 0.012). spLV function showed a significant decrease in peak systolic velocity (mid; p = 0.013 and apex; p = 0.011) and peak systolic strain rate (mid; p = 0.048). The cross-sectional analysis revealed significant lower values for basal, mid and apical peak systolic velocity, peak systolic strain rate, peak systolic strain of the sRV of Senning patients when compared to both LV and RV of matched controls (all p < 0.05).

CONCLUSION

Our study showed that systolic and diastolic sRV function did not change over a 15-year follow-up period, except in the apical region. There was a decline in spLV systolic function, which may be of clinical value. On the other hand, when compared to age- and gender-matched controls, the sRV of Senning patients exhibits significantly decreased measurements of longitudinal systolic function.

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.

Right Ventricular Flow Dynamics in Dilated Right Ventricles: Energy Loss Estimation Based on Blood Speckle Tracking Echocardiography-A Pilot Study in Children

Using blood speckle tracking (BST) based on high-frame-rate echocardiography (HFRE), we compared right ventricle (RV) flow dynamics in children with atrial septal defects (ASDs) and repaired tetralogy of Fallot (rTOF). Fifty-seven children with rTOF with severe pulmonary insufficiency (PI) (n = 21), large ASDs (n = 11) and healthy controls (CTL, n = 25) were included. Using a flow phantom, we studied the effects of imaging plane and smoothing parameters on 2-D energy loss (EL). RV diastolic EL was similar in ASD and rTOF, but both were greater than in CTL. Locations of high EL were similar in all groups in systole, occurring in the RV outflow tract and around the tricuspid valve leaflets in early diastole. An additional apical early diastolic area of EL was noted in rTOF, corresponding to colliding tricuspid inflow and PI. The flow phantom revealed that EL varied with imaging plane and smoothing settings but that the EL trend was preserved if kept consistent.

Impaired right and left ventricular function and relaxation induced by pulmonary regurgitation are not reversed by tardive antifibrosis treatment

Pulmonary regurgitation (PR) after repair of tetralogy of Fallot (rTOF) is associated with progressive right (RV) and left (LV) ventricular dysfunction and fibrosis. However, angiotensin II receptor blockade therapy has shown mixed and often disappointing results. The aim of this study was to serially assess changes in biventricular remodeling, dysfunction, and interactions in a rat model of isolated severe PR and to study the effects of angiotensin II receptor blockade. PR was induced in Sprague-Dawley rats by leaflet laceration. Shams (n = 6) were compared with PR (n = 5) and PR + losartan treatment (n = 6). In the treatment group, oral losartan (50 mg·kg^-1·day^-1) was started 6 wk after PR induction and continued for 6 wk until the terminal experiment. In all groups, serial echocardiography was performed every 2 wk until the terminal experiment where biventricular myocardium was harvested and analyzed for fibrosis. PR and PR + losartan rats experienced early progressive RV dilatation by 2 wk which then stabilized. RV systolic dysfunction occurred from 4 wk after insult and gradually progressed. In PR rats, RV dilatation caused diastolic LV compression and impaired relaxation. PR rats developed increased RV fibrosis compared with shams. Although losartan decreased RV fibrosis, RV dilatation and dysfunction were not improved. This suggests that RV dilatation is an early consequence of PR and affects LV relaxation. RV dysfunction may progress independent of further remodeling. Reduced RV fibrosis was not associated with improved RV function and may not be a viable therapeutic target in rTOF with predominant RV volume loading.NEW & NOTEWORTHY The time-course of RV dilatation and the mechanisms of biventricular dysfunction caused by PR have not been well characterized and the effect of losartan in volume-overloaded RV remains controversial. Our findings suggest that severe PR induces early onset of RV dilatation and dysfunction with little progression after the first 4 wk. The RV dilatation distorts LV geometry with associated impaired LV relaxation. Losartan reduced RV fibrosis but did not reverse RV dilatation and dysfunction.

Impact of pulmonary valve replacement on left ventricular rotational mechanics in repaired tetralogy of Fallot

BACKGROUND

In repaired tetralogy of Fallot (rTOF), abnormal left ventricular (LV) rotational mechanics are associated with adverse clinical outcomes. We performed a comprehensive analysis of LV rotational mechanics in rTOF patients using cardiac magnetic resonance (CMR) prior to and following surgical pulmonary valve replacement (PVR).

METHODS

In this single center retrospective study, we identified rTOF patients who (1) had both a CMR ≤ 1 year before PVR and ≤ 5 years after PVR, (2) had no other intervening procedure between CMRs, (3) had a body surface area > 1.0 m2 at CMR, and (4) had images suitable for feature tracking analysis. These subjects were matched to healthy age- and sex-matched control subjects. CMR feature tracking analysis was performed on a ventricular short-axis stack of balanced steady-state free precession images. Measurements included LV basal and apical rotation, twist, torsion, peak systolic rates of rotation and torsion, and timing of events. Associations with LV torsion were assessed.

RESULTS

A total of 60 rTOF patients (23.6 ± 7.9 years, 52% male) and 30 healthy control subjects (20.8 ± 3.1 years, 50% male) were included. Compared with healthy controls, rTOF patients had lower apical and basal rotation, twist, torsion, and systolic rotation rates, and these parameters peaked earlier in systole. The only parameters that were correlated with LV torsion were right ventricular (RV) end-systolic volume (r = - 0.28, p = 0.029) and RV ejection fraction (r = 0.26, p = 0.044). At a median of 1.0 year (IQR 0.5-1.7) following PVR, there was no significant change in LV rotational parameters versus pre-PVR despite reductions in RV volumes, RV mass, pulmonary regurgitation, and RV outflow tract obstruction.

CONCLUSION

In this comprehensive study of CMR-derived LV rotational mechanics in rTOF patients, rotation, twist, and torsion were diminished compared to controls and did not improve at a median of 1 year after PVR despite favorable RV remodeling.

Multi-plane echocardiographic assessment of right ventricular function in adults with repaired Tetralogy of Fallot

In patients with repaired Tetralogy of Fallot (ToF), detailed assessment of right ventricular (RV) function is important for management and timing of possible pulmonary valve re-intervention. The aim of this study was to evaluate RV function using two-dimensional multi-plane echocardiography (2D MPE), a novel four-wall imaging method obtained from one apical acoustic window utilising electronic plane rotation. In sixty-two ToF patients (aged - 28 [22, 39] years, 65% male), systolic function of four different RV walls (lateral, anterior, inferior and inferior coronal) were evaluated using MPE. Tricuspid annular plane systolic excursion (TAPSE), tricuspid annular peak systolic velocity (RV-S′) and RV wall longitudinal strain (RV-LS) measurements were compared with those of matched healthy individuals. 2D MPE measurements were highly feasible across the four RV walls (93.5–100% for TAPSE/S′; 66.1–95.1% for RVLS) and could be performed more reliably than 3D RV ejection fraction (RVEF − 56.5%). All functional values were significantly reduced when compared to the control group (p < 0.001). Higher RV-LS values were seen in the lateral (− 17.8 ± 4.5%) and inferior (− 17.8 ± 4.2%) walls compared to the anterior (− 15.9 ± 3.8%) and inferior coronal (− 15.1 ± 3.9%) walls. 3D RVEF correlated strongest with RV-LS values from the lateral (r − 0.50; p = 0.002) and anterior walls (r − 0.74; p < 0.001) and furthermore the four-wall average (r − 0.57; p = 0.001). 2D MPE evaluation of the RV is highly feasible in ToF patients. This novel method provides new insights into regional RV wall function, enabling a more comprehensive and quantitative approach to RV assessment in daily clinical practice.

Right ventricular regional deformation analysis in patients operated for tetralogy of Fallot

PURPOSE

We aimed to compare the findings of a segmental speckle-tracking strain of right ventricle with those of cardiac magnetic resonance imaging in this setting.

METHODS

In 26 patients with operated tetralogy of Fallot (mean age, 15.35 ± 2.3 years; range 11-18 years), right ventricular segmental speckle-straining (the basal, mid, apical segments of right ventricular septum and lateral free wall, and right ventricular apex) were determined using two-dimensional echocardiography. The echocardiographic findings were compared to right ventricular ejection fraction, right ventricular indexed end-diastolic volume, indexed end-systolic volume and pulmonary regurgitation fraction at cardiac magnetic resonance.

RESULTS

Right ventricular global speckle strain was -18.6 ± 3.7and lateral free wall strain was -17.8 ± 4.9. Indexed right ventricular end diastolic volume was 171.7 ± 23.3 ml/m², indexed right ventricular end systolic volume was 95.1 ± 35.0 ml/m² and right ventricular ejection fraction was 44.76 ± 9.39%. Basal inferior septum is correlated with indexed right ventricular end-diastolic volume (RVEDV; r = -0.521, p = 0.015) and pulmonary regurgitation fraction (r = -0.584, p = 0.015). Cardiac magnetic resonance (CMR)-derived RVEDV is correlated with lateral free wall (r = -0.465, p = 0.034) and Global RV (r = 0.442, p = 0.045).

CONCLUSION

Right ventricular basal inferior septal and apical longitudinal strain correlates with the measures of right ventricular performance on CMR. These parameters would be useful to monitor right ventricular performance in patients after tetralogy of Fallot repair.

Left ventricular rotational abnormalities in adult patients with corrected tetralogy of Fallot following different surgical procedures (Results from the CSONGRAD Registry and MAGYAR-Path Study)

Background

Tetralogy of Fallot (TOF) is the most common cyanotic congenital heart disease (CHD). Abnormal aortic dimensions and elasticity parameters have been long described for corrected TOF (cTOF) together with left ventricular (LV) rotational abnormalities, but results are conflicting. The present study focuses on investigating LV rotational mechanics in cTOF, and possible correlation of these parameters with aortic elasticity. It was also aimed to be examined whether different surgical strategies have any effect on these results.

Methods

The study involved 26 adult cTOF patients, from which 14 had palliative surgery first and a late total correction (pcTOF), while early total correction was the treatment of choice in 12 patients (etrTOF). Their results were compared to those of 37 age- and gender-matched healthy adults. Routine transthoracic two-dimensional Doppler echocardiography extended with assessment of aortic elastic properties and three-dimensional speckle-tracking echocardiography (3DSTE) was performed in all cTOF patients and controls.

Results

Sixteen out of 26 cTOF patients showed normally directed LV rotational mechanics, while apical or basal LV rotations were in the same clockwise or counterclockwise directions in 7 and 3 cTOF cases, respectively (LV 'rigid body rotation', RBR). Significantly reduced LV apical rotation and twist could be demonstrated in all cTOF patients with preserved LV basal rotation regardless of previous procedure. pcTOF patients showed significantly reduced LV apical rotation as compared to that of etrTOF cases. Significant correlations could be demonstrated between LV apical rotation and aortic stiffness index (r=-0.55, P=0.03) and aortic distensibility (r=0.52, P=0.04).

Conclusions

Significant LV rotational abnormalities could be demonstrated in cTOF with the high prevalence of LV-RBR. pcTOF patients showed significantly reduced LV apical rotation as compared to that of etrTOF cases. Unexpected abnormal physiologic response of LV rotational mechanics to increased aortic stiffness can be detected in cTOF patients without LV-RBR.

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.

Right ventricular dilatation in patients with pulmonary regurgitation after repair of tetralogy of Fallot: How fast does it progress?

Objective

Pulmonary valve regurgitation (PR) and right ventricular (RV) dilatation are important residual findings after surgical repair of tetralogy of Fallot (TOF). We sought to describe the natural course of RV dilatation over time in patients with severe PR after TOF repair and to determine risk factors for quick progression of RV dilatation and dysfunction.

Methods

Data of 85 consecutive TOF patients with PR and RV dilatation, undergoing serial cardiovascular magnetic resonance (CMR) scans between July 2002 and December 2016 in two institutions, were retrospectively reviewed. The dataset was analyzed regarding right and left ventricular (LV) volume and function and potential risk factors of progressive RV dilatation.

Results

There was no significant increase in RV end-diastolic volumes (RVEDV_i) indexed body surface area (BSA) (median 150 [81-249] vs. 150 [82-260] mL/m²) and end-systolic volumes indexed for BSA (RVESV_i) (75 [20-186] vs. 76 [39-189] mL/m²) between the first and last CMR in the overall group. Similarly, there were no significant changes in LV volumes indexed for BSA (LVEDV_i 78 [56-137] vs. 81 [57-128] mL/m² and LV end-systolic volume index 34 [23-68] vs. 35 [18-61] mL/m2). Global function remained also unchanged for both ventricles. RVEDVi increased statistically significantly (≥20 mL/m2) in twenty patients (24%) from 154 mL/m² (87-237) to 184 mL/m² (128-260, P < 0.001). LV dimensions showed a similar trend with LVEDVi increase from 80 ml/m² (57-98) to 85 ml/m² (72-105, P = 0.002). Shorter time interval between repair and first CMR was the only risk factor predictive for progressive RV dilatation.

Conclusion

In the majority of patients with repaired TOF and severe PR, RV dilatation is unchanged during a follow-up of 3 years. RV dilatation seems to progress early after surgery and subsequently stabilize. RV dilatation significantly progresses in a subgroup of 24% of patients, with a shorter time interval since surgical repair.

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.

Diagnosis and treatment of adults with congenital heart disease

Approximately 50 million adults worldwide have known congenital heart disease (CHD). Among the most common types of CHD defects in adults are atrial septal defects and ventricular septal defects followed by complex congenital heart lesions such as tetralogy of Fallot. Adults with CHDs are more likely to have hypertension, cerebral vascular disease, diabetes and chronic kidney disease than age-matched controls without CHD. Moreover, by the age of 50, adults with CHD are at a greater than 10% risk of experiencing cardiac dysrhythmias and approximately 4% experience sudden death. Consequently, adults with CHD require healthcare that is two- to four-times greater than adults without CHD. This paper discusses the diagnosis and treatment of adults with atrial septal defects, ventricular septal defects and tetralogy of Fallot.

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.

CT quantification of ventricular volumetric parameters based on semiautomatic 3D threshold-based segmentation in porcine heart and children with tetralogy of Fallot: accuracy and feasibility

Background

To investigate the accuracy and feasibility of CT in quantification of ventricular volume based on semiautomatic three-dimensional (3D) threshold-based segmentation in porcine heart and children with tetralogy of Fallot (TOF).

Methods

Eight porcine hearts were used in the study. The atria were resected and both ventricles of the eight porcine hearts were filled with solidifiable silica gel and performed CT scanning. The water displacement volume of silica gel casting mould was referred as gold standard of ventricular volume. Results of left and right ventricular volumes measured by CT were compared with reference standard. Twenty-three children diagnosed with TOF were retrospectively included. The ventricular volumetric parameters were assessed by cardiac CT before and 6 months after surgery.

Results

Left ventricular and right ventricular volumes of porcine hearts measured by CT were highly correlated to casting mould (r=0.845, p=0.008; r=0.933, p=0.001), and there were no statistically significant differences (t=−1.059, p=0.325; t=−1.121, p=0.299). In children with TOF, right ventricular end-systole volumes 6 months after operation were higher than that before surgery, 21.93±4.44 vs 19.80±4.52 mL/m2, p=0.001. Right ventricular ejection fractions 6 months after surgery were lower compared with that before surgery 59.79%±4.26% vs 63.05%±5.04%, p=0.000.

Conclusions

CT is able to accurately assess ventricular volumetric parameters based on semiautomatic 3D threshold-based segmentation. Both of the right and left ventricular volumetric parameters could be evaluated by CT in children with TOF.

Emerging clinical applications of strain imaging and three-dimensional echocardiography for the assessment of ventricular function in adult congenital heart disease

Management of congenital heart disease (CHD) in adults (ACHD) remains an ongoing challenge due to the presence of residual hemodynamic lesions and development of ventricular dysfunction in a large number of patients. Echocardiographic imaging plays a central role in clinical decision-making and selection of patients who will benefit most from catheter interventions or cardiac surgery.. Recent advances in both strain imaging and three-dimensional (3D)-echocardiography have significantly contributed to a greater understanding of the complex pathophysiological mechanisms involved in CHD. The aim of this paper is to provide an overview of emerging clinical applications of speckle-tracking imaging and 3D-echocardiography in ACHD with focus on functional assessment, ventriculo-ventricular interdependency, mechanisms of electromechanical delay, and twist abnormalities in adults with tetralogy of Fallot (TOF), a systemic RV after atrial switch repair or in double discordance ventricles, and in those with a Fontan circulation.

Association of left ventricular size with regional right ventricular mechanics in Hypoplastic Left Heart Syndrome

BACKGROUND

In Hypoplastic Left Heart Syndrome (HLHS), RV dysfunction is associated with poor outcomes. However, the effect of varying LV size on regional RV mechanics and outcome has not been studied.

METHODS

Twenty newborns (0-7 days) with HLHS had pre-stage 1 and pre-stage 2 echocardiograms prospectively protocoled for strain analysis of the apical 4-chamber view. RV longitudinal strain was analyzed, and LV size was classified as diminutive (no visible LV chamber) or moderate size (visible LV chamber). Clinical outcome was reported as alive vs death or transplant (D-TP) at final clinical follow-up (pre-stage 3). Groups were compared with t-test, Fisher's Exact, and ANOVA tests as appropriate.

RESULTS

At pre-stage 1, infants with a diminutive LV (7/20, 35%) vs a moderately hypoplastic LV (13/20, 65%) did not have significantly different global RV strain (-18.4 ± 2.6% vs -18.8 ± 3.2%; p = 0.83). However, basal septal strain was significantly diminished in the moderately hypoplastic LV group vs the diminutive LV group (-4.4 ± 6.0% vs -14.7 ± 3.3%; p < 0.005). There was severely diminished septal strain in nearly all (11/13) of the moderately hypoplastic group. At the pre-stage II echo, global RV strain between groups remained similar (p = 0.76) as did the diminished septal strain in the moderate LV group (p = 0.86). The moderately hypoplastic LV group had worse clinical outcomes (6/13 D-TP vs 0/7 D-TP; p = 0.05).

CONCLUSIONS

In this small HLHS cohort, diminished septal strain leading to asymmetric RV mechanics may be associated with poor outcomes in those with larger LV/septal size.

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.

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.

Ventricular Torsion in Young Patients With Single-Ventricle Anatomy

BACKGROUND

In normal left ventricles, clockwise basal rotation and counterclockwise apical rotation result in systolic torsion. Torsion is important for contractile efficiency and may be especially important in single-ventricle (SV) physiology. However, little is known about torsion in patients with SVs. The aim of this study was to measure torsion in SVs and to determine its relationship with other measures of ventricular function. The hypothesis was that torsion would be decreased in all SVs, most significantly in single right ventricles, and that it would correlate with other measures of ventricular function.

METHODS

A prospective cross-sectional study was performed in 61 patients with SVs undergoing pre- or post-Fontan cardiac catheterization and 30 matched control subjects. Echocardiography, catheterization, and cardiac magnetic resonance imaging were performed under the same anesthetic. Torsion and strain were measured using speckle-tracking echocardiography. Intracardiac pressures, pulmonary vascular resistance, and cardiac magnetic resonance imaging-derived ventricular volume and ejection fraction were measured.

RESULTS

Thirty-five patients were left ventricular dominant, 15 were right ventricular dominant, 10 were codominant, and one had indeterminate morphology. Thirty-seven patients were pre-Fontan and 24 were post-Fontan. Patients with SVs had similar overall torsion as control subjects (median, 1.7°/cm vs 1.65°/cm; P = NS); however, they had decreased or reversed basal rotation (-0.32°/cm vs -0.93°/cm, P < .0001) and increased apical rotation (1.45°/cm vs 1.06°/cm, P = .0065). There were no differences on the basis of ventricular dominance or palliative stage. Torsion did not significantly correlate with other echocardiographic, catheter-based, or cardiac magnetic resonance imaging measures of cardiac function.

CONCLUSIONS

Single left and right ventricles exhibit preserved torsion, mainly because of preserved or increased apical rotation. Possible mechanisms of torsion in single right ventricles include myofiber remodeling and altered ventricular-ventricular interactions. Understanding myocardial deformation in SVs will improve the ability to interpret ventricular function in this precarious population.

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.

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.

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.

Global Deformation Parameters Response to Exercise in Adolescents with Repaired Tetralogy of Fallot

Exercise stress echocardiography is rarely used in the follow-up of children with congenital heart disease following surgical repair. There are no data on global longitudinal strain (GLS) and global circumferential strain (GCS) during exercise in adolescents with repaired tetralogy of Fallot (TOF). The purpose of this prospective study was to investigate GLS and GCS using speckle tracking two-dimensional echocardiography (2D-STE) at rest and during exercise in adolescents with repaired TOF. Twenty patients with repaired TOF and 20 controls were included. The subjects exercised on a semi-supine cycle ergometer using a two-staged 3-min step protocol of 20-40 W at 60-75 rpm. Exercise images with 2D-STE measurements were available for all 40 subjects. In the study group, the GLS values changed significantly between the baseline and third and sixth minute of exercise (-18.10 ± 2.20, -16.23 ± 4.47, -14.22 ± 2.63, respectively, p < 001). GCS did not vary significantly from baseline to end of the exercise testing (-17.49 ± 5.14, -17.15 ± 9.20, -15.66 ± 3.59, respectively, p > 0.05). There was a statistically significant difference between the Stage I longitudinal strain values of the study and control groups (-14.26 ± 9.13 and -20.22 ± 2.88, respectively, p = 0.02) but no significant difference between the Stage II values of these groups (-14.22 ± 2.63 and -15.11 ± 2.45, respectively, p > 0.05). The results revealed significant changes in GLS during exercise in patients with repaired TOF. Data gathered from deformation analysis of 2D-STE during exercise testing can enhance the ability to detect subtle ventricular dysfunction in the follow-up of children with repaired TOF.

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.

Assessing utility of exercise test in determining exercise prescription in adolescent and adult patients with repaired tetralogy of fallot

Parameters from cardiopulmonary exercise test (CPET) are useful prognostic factors for patients with repaired tetralogy of fallot (TOF). Its application in exercise prescription remains unclear. This study sought to define its role. We made current exercise recommendations in repaired TOF patients according to European Society of Cardiology (ESC) guideline, which were based on ventricular function, pressure/volume load, pulmonary artery pressure, hypoxemia and arrhythmic burden both at rest and during exercise. CPET parameters (peak oxygen consumption, oxygen uptake efficiency plateau, and E/CO₂ slope), along with cardiothoracic ratio, ventricular arrhythmia, QRS duration and NYHA functional status, were used to calculate "score to exercise". 112 repaired TOF adolescent and adult aged 32.6 ± 10.8 (14.05- to 56.99-year-old, median 30.1) years received exercise recommendations by ESC guideline, which suggested high, moderate and low intensity sports for 45 (40.2 %), 45 (40.2 %), and 22 (19.6 %) patients, respectively. The optimal cut-off values were 67 and 77 % for peak VO₂, 86 and 100 % for OUEP, 22 and 28 for E/CO₂ slope to correlate to the exercise intensity recommendation. But, individual CPET parameter had low consistency (41-46 %) in making decisions of exercise intensity compared to ESC recommendations. Using the "score to exercise", the consistency rate could be increased to 74.1 %. With "score to exercise" recommended exercise intensity, follow-up result revealed no adverse event related to sports. Individual CPET parameter did not correlate well to the exercise recommendation from ESC. We proposed a scoring system, "score to exercise", which incorporates three CPET parameters with cardiothoracic ratio, ventricular arrhythmia, QRS duration and NYHA functional status. Score to exercise is easy to be assessed and provides useful information for exercise recommendation in patients with repaired TOF.

Early changes in cardiovascular structure and function in adolescents with type 1 diabetes

Background

Children with type 1 diabetes (T1D) are at higher risk of early adult-onset cardiovascular disease. We assessed cardiovascular structure and function in adolescents with T1D compared with healthy controls and the relationships between peripheral vascular function and myocardial parameters.

Methods and results

199 T1D [14.4 ± 1.6 years, diabetes duration 6.2 (2.0–12.8) years] and 178 controls (14.4 ± 2.1 years) completed endothelial function by flow mediated vasodilatation (FMD), arterial stiffness using pulse wave velocity (PWV) along with M-mode, pulse wave and tissue Doppler, and myocardial deformation echocardiographic imaging. Systolic (113 ± 10 vs. 110 ± 9 mmHg; p = 0.0005) and diastolic (62 ± 7 vs. 58 ± 7 mmHg; p < 0.0001) blood pressures, carotid femoral PWV and endothelial dysfunction measurements were increased in T1D compared with controls. Systolic and diastolic left ventricular dimensions and function by M-mode and pulse wave Doppler assessment were not significantly different. Mitral valve lateral e’ (17.6 ± 2.6 vs. 18.6 ± 2.6 cm/s; p < 0.001) and a’ (5.4 ± 1.1 vs. 5.9 ± 1.1 cm/s; p < 0.001) myocardial velocities were decreased and E/e’ (7.3 ± 1.2 vs. 6.7 ± 1.3; p = 0.0003) increased in T1D. Left ventricular mid circumferential strain (−20.4 ± 2.3 vs. −19.5 ± 1.7 %; p < 0.001) was higher, whereas global longitudinal strain was lower (−19.0 ± 1.9 vs. −19.8 ± 1.5 % p < 0.001) in T1D.

Conclusions

Adolescents with T1D exhibit early changes in blood pressure, peripheral vascular function and left ventricular myocardial deformation indices with a shift from longitudinal to circumferential shortening. Longitudinal follow-up of these changes in ongoing prospective trials may allow detection of those most at risk for cardiovascular abnormalities including hypertension that could preferentially benefit from early therapeutic interventions.

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.

NT-proBNP Indicates Left Ventricular Impairment and Adverse Clinical Outcome in Patients With Tetralogy of Fallot and Pulmonary Regurgitation

BACKGROUND

The goal of this study was to interrelate N-terminal B-type natriuretic peptide (NT-proBNP) levels and cardiac magnetic resonance imaging-derived ventricular function, mass, and volumes in adults with pulmonary regurgitation after Fallot repair and to evaluate the prognostic relevance of these parameters regarding adverse clinical outcome.

METHODS

Eighty-one patients (aged 26.3 ± 7.4 years; male sex, 45.7%; New York Heart Association class I, 72.8%; pulmonary valve velocity, < 3 m/s) were included. At baseline cardiac magnetic resonance imaging and NT-proBNP measurements were performed.

RESULTS

During a mean observation time of 6.9 ± 2.6 years, 13 patients (16.1%) had sustained supraventricular arrhythmias or heart failure (2.4 per 100 patient-years). Multivariate Cox analysis identified NT-proBNP, left ventricular (LV) end-systolic volume index and LV ejection fraction, right ventricular (RV) end-diastolic volume index, and tricuspid regurgitation as independent predictors of adverse events. NT-proBNP correlated with LV but not with RV parameters. In receiver operating characteristic curve analysis using significant variables of the multivariate analysis, NT-proBNP was superior to all other parameters to detect patients at risk (area under the curve [AUC], 0.873; 95% confidence interval, 0.772-0.974). LV end-systolic volume index (AUC, 0.734), RV end-diastolic volume index (AUC, 0.645) und tricuspid regurgitation (AUC, 0.747) showed lower diagnostic accuracy.

CONCLUSIONS

Even in mildly symptomatic patients with pulmonary regurgitation after Fallot repair NT-proBNP is a strong predictor of adverse outcome. It is rather associated with LV but not with RV impairment. In severe pulmonary regurgitation an increase in the level of NT-proBNP and LV impairment seem to provide additional useful information for the timing of pulmonary valve replacement.

Advanced echocardiography in adult zebrafish reveals delayed recovery of heart function after myocardial cryoinjury

Translucent zebrafish larvae represent an established model to analyze genetics of cardiac development and human cardiac disease. More recently adult zebrafish are utilized to evaluate mechanisms of cardiac regeneration and by benefiting from recent genome editing technologies, including TALEN and CRISPR, adult zebrafish are emerging as a valuable in vivo model to evaluate novel disease genes and specifically validate disease causing mutations and their underlying pathomechanisms. However, methods to sensitively and non-invasively assess cardiac morphology and performance in adult zebrafish are still limited. We here present a standardized examination protocol to broadly assess cardiac performance in adult zebrafish by advancing conventional echocardiography with modern speckle-tracking analyses. This allows accurate detection of changes in cardiac performance and further enables highly sensitive assessment of regional myocardial motion and deformation in high spatio-temporal resolution. Combining conventional echocardiography measurements with radial and longitudinal velocity, displacement, strain, strain rate and myocardial wall delay rates after myocardial cryoinjury permitted to non-invasively determine injury dimensions and to longitudinally follow functional recovery during cardiac regeneration. We show that functional recovery of cryoinjured hearts occurs in three distinct phases. Importantly, the regeneration process after cryoinjury extends far beyond the proposed 45 days described for ventricular resection with reconstitution of myocardial performance up to 180 days post-injury (dpi). The imaging modalities evaluated here allow sensitive cardiac phenotyping and contribute to further establish adult zebrafish as valuable cardiac disease model beyond the larval developmental stage.

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.