Left ventricular mechanics in repaired tetralogy of Fallot with and without pulmonary valve replacement: analysis by three-dimensional speckle tracking echocardiography

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.

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

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

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.

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.

Left ventricular strains correlate with aortic elastic properties in adult patients with corrected tetralogy of Fallot (Results from the CSONGRAD Registry and MAGYAR-Path Study)

Background

Aortopathy is a common phenomenon in tetralogy of Fallot (TOF). The current study was designed to detect left ventricular (LV) deformation abnormalities and its relation to aortic stiffness in corrected TOF (cTOF) using the novel three-dimensional (3D) speckle-tracking echocardiography (3DSTE). Detailed comparative analysis between patients with early palliation-late correction (pcTOF) and early total reconstruction (etrTOF) was also performed.

Methods

The present study consisted of 28 cTOF patients (35.0±15.7 years, 11 males) from which 15 and 13 proved to be pcTOF and etrTOF, respectively. Their clinical parameters were compared to those of 39 matched healthy adults (35.5±6.0 years, 16 males).

Results

cTOF patients showed significantly lower global LV longitudinal, circumferential and area strains as compared to controls. In etrTOF patients, global LV 3D strain was higher than in controls. In pcTOF patients, all LV strains proved to be significantly lower as compared to those of etrTOF patients and controls. In all cTOF patients, several moderate correlations could be detected between LV strain parameters and aortic elastic properties.

Conclusions

Significant LV deformational abnormalities could be demonstrated in cTOF patients. etrTOF patients have beneficial LV strain parameters as compared to those of pcTOF patients. LV strains show correlations with aortic elastic properties.

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.

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

Background

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

Methods and Results

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

Conclusions

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

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

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

Diminished Cardiac Performance and Left Ventricular Dimensions in Neonates with Congenital Diaphragmatic Hernia

INTRODUCTION

Newborns with congenital diaphragmatic hernia (CDH) have varying degrees of pulmonary hypoplasia and pulmonary hypertension (PH), and there is limited evidence that cardiac dysfunction is present. We sought to study early neonatal biventricular function and performance in these patients by reviewing early post-natal echocardiography (ECHO) measurements and comparing them to normal term newborns.

METHODS

Retrospective case-control study reviewing clinical and ECHO data on term newborns with CDH and normal controls born between 2009 and 2016. Patients were excluded if major anomalies, genetic syndromes, or no ECHO available. PH was assessed by ductal shunting and tricuspid regurgitant jet velocity. Speckle-tracking echocardiography was used to assess myocardial deformation using velocity vector imaging.

RESULTS

Forty-four patients with CDH and 18 age-matched controls were analyzed. Pulmonary pressures were significantly higher in the CDH cohort (systolic pulmonary arterial pressure to systolic blood pressure of 103 ± 13 vs. 78 ± 29%, p = 0.0001). CDH patients had decreased RV fractional area change (FAC - 28.6 ± 11.1 vs. 36.2 ± 9.6%, p = 0.02), tricuspid annular plane of systolic excursion (TAPSE-5.6 ± 1.6 vs. 8.6 ± 1.6 mm, p = 0.0001), and RV outflow tract stroke distance (8.6 ± 2.7 vs. 14.0 ± 4.5 cm, p = 0.0001) compared with controls. The left ventricular (LV) ejection fraction was similar in both groups, but CDH patients had a decreased LV end-diastolic volume by Simpson's rule (2.7 ± 1.0 vs. 5.0 ± 1.8 mL, p = 0.0001) and LVOT stroke distance (9.7 ± 3.4 vs. 12.6 ± 3.6 cm, p = 0.004). Biventricular global longitudinal strain (GLS) was markedly decreased in the CDH population compared to controls (RV-GLS: - 9.0 ± 5.3 vs. - 19.5 ± 1.4%, p = 0.0001; LV GLS: - 13.2 ± 5.8 vs. - 20.8 ± 3.5%, p = 0.0001).

CONCLUSION

CDH newborns have evidence of biventricular dysfunction and decreased cardiac output. Abnormal function may be a factor in the non-response to pulmonary arterial vasodilators in CDH patients. A two-pronged management strategy aimed at improving cardiac function, as well as reducing pulmonary artery pressure in CDH newborns, may be warranted.

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.

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.

Following up adult patients with tetralogy of fallot: The role of echocardiography

Tetralogy of Fallot (TOF) is one of the most common cyanotic congenital heart diseases. With surgical repair and the advances in postoperative care, contemporary mortality has dramatically improved and an increasing number of patients survive into adulthood, leading to a growing number of adult TOF. However, residual anatomic and hemodynamic abnormalities are encountered in nearly all patients, making follow-up mandatory. Furthermore, mortality starts to increase 25 years after surgery, emphasizing that, in adult TOF, closer monitoring is necessary. We review here the role of echocardiography in the follow-up of the TOF patients, emphasizing the role of multiple echocardiographic techniques. © 2016 Wiley Periodicals, Inc. J Clin Ultrasound 45:79-95, 2017.

Postsystolic Shortening Is Associated with Altered Right Ventricular Function in Children after Tetralogy of Fallot Surgical Repair

The aim of the study was to determine whether segmental interactions, as expressed by postsystolic shortening (PSS), affects RV mechanics and are connected with impaired systolic and diastolic function in rTOF children. Patients and Methods: 55 rTOF adolescent (study group), and 34 healthy volunteers (control group) were examined using classical Doppler flow (Doppler), Tissue Doppler Imaging (TDI) and Speckle Tracking Echocardiography (STE). PSS was found to occur when time to peak (TTP) was longer than pulmonary valve closure time (PVCT). TTP and strain were derived from RV lateral segments—basal (BL), medial (ML) and apical (AL) in STE. PVCT was measured from the beginning of QRS complex in the ECG to the termination of Doppler flow at the pulmonary valve. TDI was obtained at the lateral tricuspid annulus site and the systolic (S′), early (E′) and late diastolic (A’) peak velocities were measured along with isovolumic contraction (IVCT), and relaxation (IVRT) time. PW was used to measure early tricuspid inflow velocity (E) for calculating the E/E’ ratio. The TDI data in patients with PSS presence (TTP>PVCT) and those in whom it did not occur (TTP≤PVCT) were compared. Results: PSS in BL, ML and AL were observed respectively in: 27(51,9%), 9 (18%), and 8 (16,7%) patients. Mean values of TTP in BL, ML, and AL were respectively: 420.6±55.5ms, 389.8±50.0ms and 366.7±59.0ms. PVCT mean value was 396.6±33.5ms. In the study group, the mean E’ in TTP>PVCT was significantly lower (4.8±1.8 cm/s) compared to mean E’ in TTP≤PVCT (8.4±2.6 cm/s), p<0.01. The average E/E’ was significantly higher in TTP>PCVT than in TTP≤PVCT, respectively 21.6±7.3 vs 12.2±5.1, p<0.05. IVRT was significantly prolonged in TTP>PVCT compared to IVRT in TTP≤PVCT, respectively 95.9±38.7 vs 77.0±35.1, p<0.05. Furthermore, in TTP>PVCT, significantly higher strain in BL (-28.8±8.7%) was observed when compared to that parameter in TTP≤PVCT (-35.3±13.1%), p <0.05. Conclusions: Tissue Doppler Echocardiography and Speckle Tracking Echocardiography are useful techniques for detecting regional systolic and diastolic dysfunction in children after Tetralogy of Fallot surgical repair. Postsystolic shortening in the basal lateral segment is commonly seen in children after the Tetralogy of Fallot surgical repair, and is associated with altered right ventricular systolic and diastolic function.

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.

Role of Three-Dimensional Speckle Tracking Echocardiography in the Quantification of Myocardial Iron Overload in Patients with Beta-Thalassemia Major

BACKGROUND

The new three-dimensional speckle tracking echocardiography (3DSTE) may enable comprehensive quantification of global left ventricular (LV) myocardial mechanics.

METHODS

Twenty-four patients aged 29.3 ± 5.2 years and 22 controls were studied. 3DSTE was performed to assess LV 3D global strain, twist and torsion, ejection fraction, and systolic dyssynchrony index (SDI). The LV SDI was calculated as % of SD of times-to-peak strain of 16 segments/RR interval. The global performance index (GPI) was calculated as (global 3D strain·torsion)/SDI. Area under the receiver operating characteristic curve (AUC) was calculated to determine the capability of 3DSTE parameters to discriminate between patients with (cardiac magnetic resonance T2* <20 ms) and those without myocardial iron overload.

RESULTS

Compared with controls, patients had significantly lower LV global 3D strain (P < 0.001), twist (P = 0.01), torsion (P = 0.04), and ejection fraction (P < 0.001) and greater SDI (P < 0.001). The GPI was lower in patients than controls (P < 0.001). T2* value correlated positively with global 3D strain (r = 0.74, P < 0.001) and GPI (r = 0.63, P = 0.001), and negatively with SDI (r = -0.44, P = 0.03). The AUCs of GPI, global 3D strain, ejection fraction, torsion, and 1/SDI were 0.94, 0.90, 0.87, 0.82, and 0.70, respectively. The GPI cutoff of 2.7°/cm had a sensitivity of 94.9% and a specificity of 88.9% of differentiating patients with from those without myocardial iron overload.

CONCLUSIONS

The LV composite index of strain, torsion, and dyssynchrony derived from 3DSTE enables sensitive detection of myocardial iron overload in patients with thalassemia.

Speckle-Tracking Echocardiographic Measures of Right Ventricular Function Correlate With Improvement in Exercise Function After Percutaneous Pulmonary Valve Implantation

BACKGROUND

Speckle-tracking echocardiographic (STE) measures of right ventricular (RV) function appear to improve after transcatheter pulmonary valve implantation (TPVI). Measures of exercise function, such as ventilatory efficiency (the minute ventilation [VE]/carbon dioxide production [VCO2] slope), have been shown to be prognostic of mortality in patients who may require TPVI. The aim of this study was to evaluate the correlation between STE measures of RV function and changes in VE/VCO2 after TPVI.

METHODS

Speckle-tracking echocardiography and cardiopulmonary exercise testing were performed at baseline and 6 months after TPVI in 24 patients from four centers. Conventional echocardiographic measures of RV function were also assessed. Echocardiographic and exercise stress test results were interpreted by single blinded observers at separate core laboratories.

RESULTS

All patients demonstrated relief of pulmonary regurgitation and stenosis after TPVI. Improvements in RV longitudinal strain (-16.9 ± 3.5% vs -19.7 ± 4.3%, P < .01) and strain rate (-0.9 ± 0.4 vs. -1.2 ± 0.4 s(-1), P < .01) were noted. The VE/VCO2 slope improved (32.4 ± 5.7 vs 31.5 ± 8.8, P = .03). No other significant echocardiographic or exercise changes were found. On multivariate regression, the change in VE/VCO2 was independently associated with change in RV longitudinal early diastolic strain rate (P < .001) and tricuspid A velocity (P < .001). Preintervention RV longitudinal strain was found to be a predictor of change in VE/VCO2 after TPVI (r = -0.60, P < .001).

CONCLUSIONS

STE measures of RV function appear to hold the potential for use as predictors of improved outcomes in patients requiring TPVI. Future studies should directly assess the prognostic significance of STE measures of RV function in this population.

Functional assessment for congenital heart disease

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