Integrated analysis of atrioventricular interactions in tetralogy of Fallot

Longitudinal Evaluation of Atrial Function in Patients with Tetralogy of Fallot

Atrial function provides insight into ventricular diastolic function. Invasive assessment of left ventricular (LV) diastolic function correlates with development of sustained ventricular tachyarrhythmias in patients with repaired tetralogy of Fallot (rTOF). Non-invasive assessment of atrial function may prove key towards assessment of diastolic function. We longitudinally evaluated the progression of biatrial function in patients with rTOF, regardless of pulmonary valve replacement (PVR). Patients with rTOF who had multiple CMR were identified. CMR examinations were retrospectively reviewed. Left (LA) and right (RA) atrial size and function were measured in the two and four-chamber views and assessed over time and after PVR. Left and right atrial reservoir, conduit, pump strain and strain rates were determined using tissue tracking. Thirty-six patients with rTOF were identified (64% male), ten (28%) had PVR during the study. Median age of PVR was 16.5 years. No improvement in RA or LA function was observed after PVR. A decline in RA reservoir strain rate (p < 0.05) and RA pump strain (p < 0.05) were observed despite improvements in right ventricular systolic function (p < 0.05). In patients who had multiple CMR without PVR, RA reservoir strain rate (p < 0.05) and pump strain rate (p < 0.05) worsened over time. LA pump strain decreased over time in all patients. There is progressive decline of several RA functional parameters over time. No significant improvement in LA or RA function after PVR was observed. Additional studies are needed to understand how these changes may relate to poor outcomes and potentially better guide timing of PVR.

Atrioventricular Area Difference Aids Diastolic Filling in Patients with Repaired Tetralogy of Fallot

A hydraulic force aids diastolic filling of the left ventricle (LV) and is proportional to the difference in short-axis area between the left ventricle and atrium; the atrioventricular area difference (AVAD). Patients with repaired Tetralogy of Fallot (rToF) and pulmonary regurgitation (PR) have reduced LV filling which could lead to a negative AVAD and a hydraulic force impeding diastolic filling. The aim was to assess AVAD and to determine whether the hydraulic force aids or impedes diastolic filling in patients with rToF and PR, compared to controls. Twelve children with rToF (11.5 [9-13] years), 12 pediatric controls (10.5 [9-13] years), 12 adults with rToF (21.5 [19-27] years) and 12 adult controls (24 [21-29] years) were retrospectively included. Cine short-axis images were acquired using cardiac magnetic resonance imaging. Atrioventricular area difference was calculated as the largest left ventricular short-axis area minus the largest left atrial short-axis area at beginning of diastole and end diastole and indexed to height (AVADi). Children and adults with rToF and PR had higher AVADi (0.3 cm2/m [- 1.3 to 0.8] and - 0.6 [- 1.5 to - 0.2]) at beginning of diastole compared to controls (- 2.7 cm2/m [- 4.9 to - 1.7], p = 0.015) and - 3.3 cm2/m [- 3.8 to - 2.8], p = 0.017). At end diastole AVADi did not differ between patients and controls. Children and adults with rToF and pulmonary regurgitation have an atrioventricular area difference that do not differ from controls and thus a net hydraulic force that contributes to left ventricular diastolic filling, despite a small underfilled left ventricle due to pulmonary regurgitation.

Prognostic value of left atrial strain in patients with tetralogy of fallot

To demonstrate prognostic utility of left atrial strain (LAS) in adult patients with repaired Tetralogy of Fallot (rTOF). Adults patients with rTOF were prospectively enrolled in this study between years 2011 and 2015. Left atrium (LA) phasic functions were assessed using 2D speckle tracking echocardiography. Association of LA strain (LAS) with primary (any cardiovascular event) and secondary (death, heart failure or arrhythmia) composite endpoints was assessed using Cox regression analysis. Hundred-and-twelve rTOF patients, in whom LAS was feasible and were in sinus rhythm, were included in the final analysis (age 33 ± 10 years, 68[61%] male). Median duration of follow-up was 8.6 [4.2-9.7] years in the study group. Primary composite endpoint was reached in 48 patients (mean event-free survival time: 7.2 [6.6-7.9] years), and secondary composite endpoint was reached in 22 patients (mean event-free survival time: 8.7 [8.1-9.2] years). LA reservoir strain (LAS-r) was defined as tertile groups (1st tertile < 33%, 2nd tertile = 33-44%, 3rd tertile > 44%). Decreasing tertiles of LAS-r was associated with primary and secondary composite endpoints in Kaplan-Meier analysis (p = 0.02 and 0.002, respectively). In univariable Cox-regression, both decreasing LAS-r and LAS-r tertiles were associated with primary and secondary composite endpoints. Adjusted by initial repair age and NT-proBNP quartiles, increased LAS-r was associated with significantly decreased occurrence of experiencing any events (HR = 0.97, CI 0.93-0.99, p < 0.001). Decreasing LAS-r was still associated with primary endpoint when adjusted by left atrium volume index (LAVImax) (HR = 0.96, CI 0.92-0.99, p = 0.01), left ventricle global longitudinal strain (HR = 0.96, CI 0.93-0.99, p < 0.001) or right ventricle free wall longitudinal strain (HR = 0.96, CI 0.93-0.99, p = 0.03). Assessment of LA mechanics with the use of STE has incremental utility in determination of mortality and morbidity in rTOF, and may be implemented in clinical practice.

The hemodynamic cardiac profiler volume-time curves and related parameters: an MRI validation study

Background.The hemodynamic cardiac profiler (HCP) is a new, non-invasive, operator-independent screening tool that uses six independent electrode pairs on the frontal thoracic skin, and a low-intensity, patient-safe, high-frequency applied alternating current to measure ventricular volume dynamics during the cardiac cycle for producing ventricular volume-time curves (VTCs).Objective.To validate VTCs from HCP against VTCs from MRI in healthy volunteers.Approach.Left- and right-ventricular VTCs were obtained by HCP and MRI in six healthy participants in supine position. Since HCP is not compatible with MRI, HCP measurements were performed within 20 min before and immediately after MRI, without intermittent fluid intake or release by participants. Intraclass correlation coefficients (ICCs) were calculated to validate HCP-VTC against MRI-VTC and to assess repeatability of HCP measurements before and after MRI. Bland-Altman plots were used to assess agreement between relevant HCP- and MRI-VTC-derived parameters. Precision of HCP's measurement of VTC-derived parameters was determined for each study participant by calculating the coefficients of variation and repeatability coefficients.Main results.Left- and right-ventricular VTC ICCs between HCP and MRI were >0.8 for all study participants, indicating excellent agreement between HCP-VTCs and MRI-VTCs. Mean (range) ICC of HCP right-ventricular VTC versus MRI right-ventricular VTC was 0.94 (0.88-0.99) and seemed to be slightly higher than the mean ICC of HCP left-ventricular VTC versus MRI-VTC (0.91 (0.80-0.96)). The repeatability coefficient for HCP's measurement of systolic time (tSys) was 45.0 ms at a mean value of 282.9 ± 26.3 ms. Repeatability of biventricular HCP-VTCs was excellent (ICC 0.96 (0.907-0.995)).Significance.Ventricular volume dynamics measured by HCP-VTCs show excellent agreement with VTCs measured by MRI. Since abnormal tSys is a sign of numerous cardiac diseases, the HCP may potentially be used as a diagnostic screening tool.

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.

Use of Cardiovascular Magnetic Resonance for Risk Stratification in Repaired Tetralogy of Fallot

The risk of premature death in adult patients with repaired tetralogy of Fallot is real and not inconsiderable. From the third decade of life, the incidence of malignant ventricular arrhythmia (VA) is known to exponentially rise. Progressive adverse mechanoelectrical modelling because of years of volume and/or pressure overload from residual pulmonary valve dysfunction and ventricular scar creates the perfect catalyst for VA. Although potentially lifesaving, implantable cardiac defibrillators are associated with substantial psychological and physical morbidity. Better selection of patients most at risk of VA, so that implantable cardiac defibrillators are not inflicted on patients who will never need them, is therefore crucial and has inspired research on this topic for several decades. Cardiovascular magnetic resonance (CMR) enables noninvasive, radiation-free clinical assessment of anatomy and function, making it ideal for the lifelong surveillance of patients with congenital heart disease. Gold standard measurements of ventricular volumes and systolic function can be derived from CMR. Tissue characterization using CMR can identify a VA substrate and provides insight into myocardial disease. We detail risk factors for VA identified using currently available CMR techniques. We also discuss emerging and advanced CMR techniques that have not all yet translated into routine clinical practice. We review how CMR-defined predictors of VA in repaired tetralogy of Fallot can be incorporated into risk scores with other clinical factors to improve the accuracy of risk prediction and to allow for pragmatic clinical application. Finally, we discuss what the future may hold.

Abnormal left atrial compliance is associated with a history of life-threatening arrhythmia in corrected Tetralogy of Fallot

Objectives

The objectives of this study were to examine left atrial (LA) function and compliance using two-dimensional (2D) strain analysis in adult patients with corrected Tetralogy of Fallot (c-ToF) and to investigate the relationships between LA function and patient characteristics, especially history of life-threatening arrhythmia (h-LTA).

Methods

Fifty-one c-ToF patients (34 males; age, 39 ± 15 years; h-LTA, n = 13) were included in this retrospective monocenter study. In addition to a 2D standard echocardiography examination, 2D strain analysis was performed to assess left ventricular (LV) and LA functions, including peak-positive LA strain (LAS-reservoir function) and LA compliance [defined as the ratio LAS/(E/Ea)].

Results

Patients with h-LTA were older and exhibited a longer QRS duration. LV ejection fraction, LAS and LA compliance were significantly lower in the group of patients with h-LTA. Indexed LA and RA volumes, RV end-diastolic area was significantly higher and RV fractional area change significantly lower in the h-LTA group. LA compliance was the best echocardiographic predictor for h-LTA (AUC: 0.839; p < 0.001). Moderate inverted correlations were found between LA compliance and age and QRS duration. Among the echocardiographic parameters, LA compliance was moderately inversely correlated with RV end-diastolic area (r = -0.40, p = 0.01).

Conclusion

We documented abnormal LAS and LA compliance values in adult c-ToF patients. Further study is needed to determine how best to incorporate LA strain, particularly LA compliance, into multiparametric predictive models for LTA in c-ToF patients.

Normal Ranges of Right Atrial Strain: A Systematic Review and Meta-Analysis

BACKGROUND

Standard measures for the clinical assessment of right atrial (RA) function are lacking.

OBJECTIVES

In this systematic review and meta-analysis, the authors sought to report a reference range for RA deformation parameters in healthy subjects and to identify factors that contribute to reported variations.

METHODS

The authors conducted a comprehensive search of MEDLINE; MEDLINE In-Process & Other Non-Indexed Citations; Embase; Scopus; and the Cochrane Central Register of Controlled Trials from database inception through October 2021. Studies were included if they reported RA strain or strain rate (SR) using 2-dimensional speckle-tracking echocardiography in healthy volunteers or apparently healthy control patients. Data were extracted by 1 reviewer and then reviewed by 2 independent reviewers. Conflicts were resolved through consensus. Data were combined using the method developed by Siegel and adjusted using the restricted maximum likelihood random-effects model. The normal range was defined as the 95% CI of the mean. Heterogeneity was assessed by the Cochran Q-statistic and the inconsistency index (I²). The quality of the included studies and publication bias were assessed. Effects of clinical variables were sought in a metaregression.

RESULTS

The search identified 4,111 subjects from 21 studies. The average RA reservoir strain was 44% (95% CI: 25%-63%), contractile strain was 17% (95% CI: 2%-32%), and conduit strain was 18% (95% CI: 7%-28%), with significant between-study heterogeneity and inconsistency. The systolic SR was 2.1 s^-1 (95% CI: 0.9-3.4 s^-1), early-diastolic SR was -2.0 s^-1 (95% CI: -3.3 to -0.8 s^-1), and late-diastolic SR was -1.9 s^-1 (95% CI: -2.4 to -1.3 s^-1), with nonsignificant heterogeneity and inconsistency. Ranges remained wide in healthy volunteers. The metaregression identified only age as significantly associated with systolic SR and no other significant determinants of variation among normal ranges of strain.

CONCLUSIONS

There are wide reference ranges for RA deformation, and these may limit the utility of this test in clinical practice.

The Use of Automated Atrial CMR Measures and a Novel Atrioventricular Coupling Index for Predicting Risk in Repaired Tetralogy of Fallot

Atrial size and function have been recognized as markers of diastolic function, and diastolic dysfunction has been identified as a predictor of adverse outcomes in repaired tetralogy of Fallot (rTOF). This was a retrospective single-center study with the objective of investigating the use of atrial measurements obtained via CMR for predicting outcomes in rTOF patients. Automated contours of the left and right atria (LA and RA) were performed. A novel parameter, termed the Right Atrioventricular Coupling Index (RACI), was defined as the ratio of RA end-diastolic volume to right ventricle (RV) end-diastolic volume. Patients were risk-stratified using a previously validated Importance Factor Score for the prediction of life-threatening arrhythmias in rTOF. Patients with a high-risk Importance Factor Score (>2) had a significantly larger minimum RA volume (p = 0.04) and RACI (p = 0.03) compared to those with scores ≤2. ROC analysis demonstrated RACI to be the best overall predictor of a high-risk Importance Factor Score (AUC 0.73, p = 0.03). Older age at the time of repair and a diagnosis of pulmonary atresia were associated with a larger RACI. Automated atrial CMR measurements are easily obtained from standard CMRs and have the potential to serve as noninvasive predictors of adverse outcomes in rTOF.

The right ventricle in tetralogy of Fallot: adaptation to sequential loading

Right ventricular dysfunction is a major determinant of outcome in patients with complex congenital heart disease, as in tetralogy of Fallot. In these patients, right ventricular dysfunction emerges after initial pressure overload and hypoxemia, which is followed by chronic volume overload due to pulmonary regurgitation after corrective surgery. Myocardial adaptation and the transition to right ventricular failure remain poorly understood. Combining insights from clinical and experimental physiology and myocardial (tissue) data has identified a disease phenotype with important distinctions from other types of heart failure. This phenotype of the right ventricle in tetralogy of Fallot can be described as a syndrome of dysfunctional characteristics affecting both contraction and filling. These characteristics are the end result of several adaptation pathways of the cardiomyocytes, myocardial vasculature and extracellular matrix. As long as the long-term outcome of surgical correction of tetralogy of Fallot remains suboptimal, other treatment strategies need to be explored. Novel insights in failure of adaptation and the role of cardiomyocyte proliferation might provide targets for treatment of the (dysfunctional) right ventricle under stress.

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.

Right atrial function early after tetralogy of Fallot repair

Diastolic dysfunction after repair for Tetralogy of Fallot (TOF) is associated with adverse long-term outcomes. Right atrial (RA) mechanics as a proxy of right ventricular (RV) diastolic function in the early post-operative period after surgical repair for TOF has not been reported. We sought to evaluate RA and RV strain prior to hospital discharge after TOF repair and to identify important patient factors associated with strain using a machine learning method. Single center retrospective cohort study of TOF patients undergoing surgical repair, with analysis of RA and RV strain from pre-and post-operative echocardiograms. RA function was assessed by the peak RA strain, systolic RA strain rate, early diastolic RA strain rate and RA emptying fraction. RV systolic function was measured by global longitudinal strain. Pre- and post-operative values were compared using Wilcoxon rank sum test. Gradient boosted machine (GBM) models were used to identify the most important predictors of post-operative strain. In total, 153 patients were enrolled, median age at TOF repair 3.5 months (25th-75th percentile: 2.2- 5.2), mostly male (67%), and White (64.1%). From pre-to post-operative period, there was significant worsening in all RA parameters and in RV strain. GBM models identified patient, anatomic, and surgical factors that were strong predictors of post-operative RA and RV strain. These factors included pulmonary valve and branch pulmonary artery Z scores, birth weight, gestational age and age at surgery, pre-operative RV fractional area change and oxygen saturation, type of outflow tract repair, duration of cardiopulmonary bypass, and early post-operative partial arterial pressure of oxygen. There is significant worsening in RA and RV strain early after TOF repair, indicating early alteration in diastolic and systolic function after surgery. Several patient and operative factors influence post-operative RV function. Most of the factors described are not readily modifiable, however they may inform pre-operative risk-stratification. The clinical application of RA strain and the prognostic implication of these early changes merit further study.

Interplay between right atrial function and liver stiffness in adults with repaired right ventricular outflow obstructive lesions

AIMS

This study determined the associations between right atrial (RA) and right ventricular (RV) mechanics and liver stiffness in adults with repaired tetralogy of Fallot (TOF), pulmonary atresia with intact ventricular septum (PAVIS), and pulmonary stenosis (PS).

METHODS AND RESULTS

Ninety subjects including 26 repaired TOF, 24 PAIVS, and 20 PS patients and 20 controls were studied. Hepatic shear wave velocity and tissue elasticity (E), measures of liver stiffness, were assessed by two-dimensional shear wave elastography, while RA and RV mechanics were assessed by speckle tracking echocardiography. Deformation analyses revealed worse RV systolic strain and strain rate, and RA peak positive and total strain, and strain rates at ventricular systole and at early diastole in all of the patient groups compared with controls (all P < 0.05). Compared with controls, all of the patient groups had significantly greater shear wave velocity and hepatic E-value (all P < 0.05). Shear wave velocity and hepatic E-value correlated negatively with RV systolic strain rate, and RA positive strain, total strain, and strain rate at ventricular systole and at early diastole (all P < 0.05). Multivariate analyses revealed RA strain rate at early diastole (P = 0.015, P < 0.001), maximum RA size (P < 0.001, P < 0.001), and severity of pulmonary regurgitation (P = 0.05, Pp = 0.014) as significant correlates of shear wave velocity and hepatic E-value.

CONCLUSION

In adults with repaired TOF, PAIVS, and PS, RA dysfunction and pulmonary regurgitation are associated with liver stiffness.

Favorable Atrial Remodeling After Percutaneous Pulmonary Valve Implantation and Its Association With Changes in Exercise Capacity and Right Ventricular Function

Background

Right atrial (RA) dilatation and impaired right ventricular (RV) filling are common in patients with RV outflow tract dysfunction. We aimed to study potential correlations between atrial function with clinically relevant hemodynamic parameters and to assess the predictive impact of atrial performance on the recovery of exercise capacity and RV pump function after percutaneous pulmonary valve implantation (PPVI).

Methods and Results

Altogether, 105 patients with right ventricular outflow tract dysfunction (median age at PPVI, 19.2 years; range, 6.2–53.4 years) who underwent cardiac magnetic resonance imaging before and 6 months after PPVI were included. RA and left atrial maximal and minimal volumes as well as atrial passive and active emptying function were assessed from axial cine slices. RA emptying function was inversely related to invasive RV end‐diastolic pressure, and RA passive emptying correlated significantly with peak oxygen uptake. After PPVI, a significant decrease in RA minimum volume was observed, whereas RA passive emptying function improved, and RA active emptying function decreased significantly. Patients with predominant right ventricular outflow tract stenosis showed more favorable changes in RA active and left atrial passive emptying than those with primary volume overload. None of the RA and left atrial emptying parameters was predictive for recovery of peak oxygen uptake or RV ejection fraction.

Conclusions

In patients with right ventricular outflow tract dysfunction, impaired RA emptying assessed by cardiac magnetic resonance imaging was associated with increased RV filling pressures and lower exercise capacity. PPVI leads to a reduction in RA size and improved passive RA emptying function. However, RA function was not associated with improved exercise performance and RV pump function.

Impairment of left atrial function in pediatric patients with repaired tetralogy of Fallot: a cardiovascular magnetic resonance imaging study

We aimed to assess left atrial (LA) strain before LA dilatation in patients with repaired tetralogy of Fallot (rTOF) compared with healthy controls. We also determined the effects of right atrial (RA) dilatation on LA performance using cardiovascular magnetic resonance-feature tracking (CMR-FT). Forty-nine pediatric patients with rTOF and 36 age- and sex-matched healthy controls were prospectively recruited between June 2017 and August 2019. Balanced steady-state free precession (2D b-SSFP) cine, 2D late gadolinium enhancement (LGE) and phase-contrast (PC) sequences were acquired on 1.5 and 3.0 Tesla scanners. Both ventricular and atrial volumes and ejection fraction were measured. Left ventricular (LV) strain and diastolic strain rates were evaluated between the rTOF patient and control groups. LA reservoir (Ɛs), conduit (Ɛe), and booster strain (Ɛa) were determined at LV end-systole, LV diastasis, and pre-LA systole, respectively. The first derivatives of the respective strains yielded corresponding peak strain rates. Statistical analysis was performed using the t-test and Mann-Whitney test for parametric and non-parametric variables, respectively. Correlations were assessed using Pearson's correlation coefficient for normally distributed variables and Spearman's correlation coefficient for non-parametric data. Intra-observer and inter-observer variabilities of LA strain and strain rate measurements were determined from ten randomly selected rTOF patients and ten control subjects. LA strain was significantly lower in patients with rTOF compared with controls (Ɛs, P < 0.001; Ɛe, P = 0.002; Ɛa, P < 0.001). The correlations between LA strain and RA stroke volume indices (SVi) and RA ejection fraction (EF) were moderate (Ɛs and SVi, r = 0.538, P < 0.001; Ɛs and RA EF, r = 0.493, P < 0.001; Ɛe and SVi, r = 0.532, P < 0.001; Ɛe and RA EF, r = 0.466, P < 0.001). LA strain and strain rates had good reproducibility in intra-observer and inter-observer analyses. LA strain and strain rates decreased in pediatric patients with rTOF compared with controls before LA enlargement. A dysfunction in LA performance might precede LV dysfunction in patients with rTOF, even in the early stages after repair.

Atrial and Ventricular Deformation Analysis in Normal Fetal Hearts Using Two-Dimensional Speckle Tracking Echocardiography

OBJECTIVE

Two-dimensional speckle tracking echocardiography (2D-STE)-based strain values of the left and the right ventricle have been established; however, less is known about atrial deformation. The aim of our study was to assess both atrial strain and ventricular strain using 2D-STE in a cardiac 4-chamber view and to investigate the effect of possible influencing factors such as gestational age.

METHODS

Fetal echocardiography was performed on a Toshiba Aplio 500 ultrasound system. Based on an apical or basal 4-chamber view of the fetal heart, left and right ventricular longitudinal peak systolic strain (LVLPSS and RVLPSS) as well as left and right atrial longitudinal peak systolic strain (LALPSS and RALPSS) were assessed by 2D-STE.

RESULTS

A total of 101 healthy fetuses were included. The mean gestational age (GA) was 26.0 ± 5.6 weeks. GA was significantly positively correlated (p < 0.05) with LVLPSS and RVLPSS and significantly negatively correlated (p < 0.05) with LALPSS and RALPSS. The mean values for LVLPSS and RVLPSS were -17.44 ± 2.29% and -16.89 ± 1.72%. The mean values for LALPSS and RALPSS were 34.09 ± 4.17% and 35.36 ± 2.90%.

CONCLUSION

Ventricular and atrial deformation analysis in 2D-STE was technically feasible and showed comparable values to current data. For future research on myocardial function (MF) of the fetus, considering GA as an influencing factor for deformation analysis seems to be adequate. Especially, atrial deformation analysis allows the assessment of diastolic myocardial function. Further research needs to clarify the clinical meaning of these myocardial deformation indices in fetuses at risk.

Atrial Function and Its Role in the Non-invasive Evaluation of Diastolic Function in Congenital Heart Disease

Diastolic dysfunction has correlated with adverse outcomes in various forms of unrepaired and repaired or palliated congenital heart disease (CHD). The non-invasive assessment of diastolic function in pediatric and adult patients with CHD remains challenging. Atrial size has a pivotal role in the evaluation of diastolic function; however, a growing body of evidence supports the additional role of atrial function as a more sensitive parameter of ventricular diastolic dysfunction. While the importance of atrial function is becoming clearer in adult acquired heart disease, it remains ambiguous in those with CHD. In this review we set the stage with the current understanding of diastolic function assessment in CHD, followed by insight into atrial form and function including its non-invasive assessment, and conclude with the current knowledge of atrial function in CHD. A general pattern of decrease in reservoir and conduit function with compensatory increase followed by decompensatory decrease in contractile function seems to be the common pathway of atrial dysfunction in most forms of CHD.

Atrial function in Fontan patients assessed by CMR: Relation with exercise capacity and long-term outcomes

OBJECTIVE

To assess the role of atrial function on exercise capacity and clinical events in Fontan patients.

DESIGN

We included 96 Fontan patients from 6 tertiary centers, aged 12.8 (IQR 10.1-15.6) years, who underwent cardiac magnetic resonance imaging and cardiopulmonary exercise testing within 12 months of each other from 2004 to 2017. Intra-atrial lateral tunnel (ILT) and extracardiac conduit (ECC) patients were matched 1:1 with regard to age, gender and dominant ventricle. The pulmonary venous atrium was manually segmented in all phases and slices. Atrial function was assessed by volume-time curves. Furthermore, atrial longitudinal and circumferential feature tracking strain was assessed. We determined the relation between atrial function and exercise capacity, assessed by peak oxygen uptake and VE/VCO₂ slope, and events (mortality, listing for transplant, re-intervention, arrhythmia) during follow-up.

RESULTS

Atrial maximal and minimal volumes did not differ between ILT and ECC patients. ECC patients had higher reservoir function (21.1 [16.4-28.0]% vs 18.2 [10.9-22.2]%, p = .03), lower conduit function and lower total circumferential strain (13.8 ± 5.1% vs 18.0 ± 8.7%, p = .01), compared to ILT patients. Only for ECC patients, a better late peak circumferential strain rate predicted better VE/VCO₂ slope. No other parameter of atrial function predicted peak oxygen uptake or VE/VCO₂ slope. During a median follow-up of 6.2 years, 42 patients reached the composite end-point. No atrial function parameters predicted events during follow-up.

CONCLUSIONS

ECC patients have higher atrial reservoir function and lower conduit function. Atrial function did not predict exercise capacity or events during follow-up.

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.

Speckle Tracking of the Basal Lateral and Septal Wall Annular Plane Systolic Excursion of the Right and Left Ventricles of the Fetal Heart

OBJECTIVE

Annular plane systolic excursion (APSE) has been evaluated for the right (RV) and left (LV) ventricles using M-mode echocardiography. This study examined APSE using 2-dimensional speckle tracking (2DST) of the lateral and septal annuli of the RV and LV in normal fetuses.

METHODS

Two hundred normal fetuses were prospectively examined between 20 and 40 weeks' gestation, in which the end-diastolic and end-systolic lengths were measured from the apex to the insertion of the annuli into the lateral and septal walls of the RV and LV using 2DST. Subtracting the end-systolic from the end-diastolic length resulted in the APSE measurement. The APSE values from the ventricular and septal locations were regressed against biometric and gestational age independent variables, and the mean and standard deviation computed using fractional polynomial analysis. Within-subject repeated measures of variance were used to compare results within and between the right ventricular and left ventricular basal APSE values.

RESULTS

When regressed against the independent variables the R² for the APSE of the right ventricular lateral wall ranged from 0.39 to 0.40, the left ventricular lateral wall 0.29 to 0.31, the right ventricular septal wall 0.22 to 0.40, and the left ventricular septal wall 0.05 to 0.07. There was a significant difference (P < .001) for APSE between the right ventricular and left ventricular lateral wall and their respective septal annuli, the left ventricular and right ventricular lateral wall annuli, and the left ventricular and right ventricular septal annuli.

CONCLUSIONS

The right ventricular and left ventricular lateral and septal wall APSE can be computed using 2DST and are associated with changing fetal biometric and age measurements.

Right atrial function by speckle tracking echocardiography in atrial septal defect: Prediction of atrial fibrillation

BACKGROUND

Most antiarrhythmic interventional therapies for atrial fibrillation (AF) have been provided with special focus on the treatment of left-sided valvular disease and enlarged left atrium but few studies have assessed AF associated with congenital heart disease and dilated right atrium.

HYPOTHESIS

We hypothesized that right atrial (RA) function assessed by two-dimensional (2DSTE) and three-dimensional (3DSTE) speckle-tracking echocardiography in patients with atrial septal defect (ASD) before and after percutaneous trancatheter closure could predict paroxysmal atrial fibrillation (PAF) development.

METHODS

Seventy-three patients with hemodynamically significant secundum ASD were prospectively studied and followed up for 6 months after occluder insertion and compared with a normal age-matched group (n = 73). A subgroup of 17 patients who developed PAF after device implantation was also studied. RA peak global longitudinal strain (PS) was determined using 2DSTE. Standard deviations (SDs) of times to peak strain (TPS) were calculated as indices of dyssynchrony. RA volumes, emptying fraction (EF), and expansion index (EI) were determined using 3DSTE.

RESULTS

RA-PS, EF, and EI (pre-closure values) were reduced in patients with atrial devices compared with controls, and further reductions were observed in patients with PAF. Pre-closure 3D-RA-EI (P = 0.009) and RA-TPS (P = 0.023) were independent predictors of PAF by multivariate analysis after adjustment for age and left atrial dysfunction. The areas under the ROC-curve (AUC) for 3D-RA-EI, RA-PS, RA-TPS (pre-closure values) showed high discriminative values(from 0.76 to 0.85) in predicting PAF. By combining 3D-RA-EI and RA-TPS, the AUC increased to 0.90.

CONCLUSIONS

Two-dimensional and three-dimensional speckle tracking echocardiography was clinically helpful in ASD patients in revealing right atrial dilatation and dysfunction pre-existent to device closure and associated with PAF development. RA parameters had a higher association with PAF compared to both the size of the implanted device and left atrial indices.

Longitudinal Annular Systolic Displacement Compared to Global Strain in Normal Fetal Hearts and Those With Cardiac Abnormalities

OBJECTIVES

The purpose of this study was to compare a new technique that measures the midventricular basal-apical longitudinal diastolic and systolic lengths, computes the longitudinal displacement fractional shortening, and compares it to global strain.

METHODS

Two hundred control fetuses were examined between 20 and 40 weeks' gestation, in whom the longitudinal displacement fractional shortening was computed from end-diastolic and end-systolic lengths measured from the apex to the mid portion of the distance between the level of the basal lateral and septal walls using 2-dimnsional speckle tracking. In addition, global strain was computed using speckle tracking. A correlation analysis was used to compare the longitudinal displacement fractional shortening to global strain. The longitudinal displacement fractional shortening of the right ventricle (RV) and left ventricle (LV) was measured in 10 fetuses with heart abnormalities.

RESULTS

The longitudinal displacement fractional shortening for the RV (mean ± SD, 22.94% ± 4.73%) and LV (21.05% ± 4.21%) was independent of gestational age and other biometric growth parameters, as was global strain (RV, -22.7% ± 4.07%); LV, -22.93% ± 3.52%). The RV longitudinal displacement fractional shortening was greater than that of the LV (P < .024). The correlations between the longitudinal displacement fractional shortening and global strain were 0.95 for the RV and 0.97 for the LV. Comparing the longitudinal displacement fractional shortening and global strain in fetuses with abnormal cardiac findings showed concordant findings in 9 of 10 fetuses.

CONCLUSIONS

The RV and LV longitudinal displacement fractional shortening can be computed from 2-dimensional images of the 4-chamber view and correlated with global strain. The longitudinal displacement fractional shortening was significantly greater for the RV than the LV and was abnormal in fetuses with RV and LV cardiac abnormalities.

Isolated pulmonary regurgitation causes decreased right ventricular longitudinal function and compensatory increased septal pumping in a porcine model

Aim

Longitudinal ventricular contraction is a parameter of cardiac performance with predictive power. Right ventricular (RV) longitudinal function is impaired in patients with free pulmonary regurgitation (PR) following corrective surgery for Tetralogy of Fallot (TOF). It remains unclear whether this is a consequence of the surgical repair, or whether it is inherent to PR. The aim of this study was to assess the relationship between longitudinal, lateral and septal pumping in a porcine model of isolated PR.

Methods

Piglets were divided into a control (n = 8) group and a treatment (n = 12) group, which received a stent in the pulmonary valve orifice, inducing PR. After 2–3 months, animals were subjected to cardiac magnetic resonance imaging. A subset of animals (n = 6) then underwent percutaneous pulmonary valve replacement (PPVR) with follow‐up 1 month later. Longitudinal, lateral and septal contributions to stroke volume (SV) were quantified by measuring volumetric displacements from end‐diastole to end‐systole in the cardiac short axis and long axis.

Results

PR resulted in a lower longitudinal contribution to RV stroke volume, compared to controls (60.0 ± 2.6% vs. 73.6 ± 3.8%; P = 0.012). Furthermore, a compensatory increase in septal contribution to RVSV was observed (11.0 ± 1.6% vs. −3.1 ± 1.5%; P < 0.0001). The left ventricle (LV) showed counter‐regulation with an increased longitudinal LVSV. Changes in RV longitudinal function were reversed by PPVR.

Conclusion

These findings suggest that PR contributes to decreased RV longitudinal function in the absence of scarring from cardiac surgery. Measurement of longitudinal RVSV may aid risk stratification and timing for interventional correction of PR in TOF patients.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Quantifying right atrial filling and emptying: A 4D-flow MRI study

PURPOSE

To quantitatively characterize the central role of vortex formation on the flow patterns and energy transfer within the right atrium (RA).

MATERIALS AND METHODS

4D-flow magnetic resonance imaging (MRI) data with multiple encoding velocities was acquired in 12 healthy subjects at 3T. Particles entering the RA were classified according to the origin of entry. Vortex membership was numerically derived by assessing the location of pathline center of curvature relative to the vortex core, defined by Q-criteria. Flow dynamics and energetics were assessed using paired t-tests.

RESULTS

The majority of flow (74%) passes through the RA in a single beat, with a very small volume fraction retained longer than two beats (<1%). RA flow was dominated by a governing vortex, comprising 79% of total flow, and acting to preserve kinetic energy. Flow comprising the vortex enters the RA significantly earlier than nonvortex flow (P < 0.01). The majority of nonvortex flow enters the RA during systole, traversing the RA via a direct path with a significantly shorter residence time and distance traveled (both P < 0.01).

CONCLUSION

Blood flow momentum is preserved during systole within a dominant vortex, which we are able to characterize numerically using a semiautomated approach. Our analytical approach has potential for application to understanding right heart function in health and disease.

LEVEL OF EVIDENCE

1 J. Magn. Reson. Imaging 2017;45:1046-1054.

Three-Dimensional Tricuspid Annular Motion Analysis from Cardiac Magnetic Resonance Feature-Tracking

Right ventricular (RV) dysfunction is known to be highly correlated with mortality and morbidity; nevertheless, imaging-based assessment of RV anatomy and physiology lags far behind that of the left ventricle. In this study, we advance RV imaging using cardiac magnetic resonance (CMR) to accomplish the following aims: (i) track the motion of six tricuspid annular (TA) sites using a semi-automatic tracking system; (ii) extract clinically important TA measurements-systolic velocity (Sm), early diastolic velocity (Em), late diastolic velocity (Am), and TA plane systolic excursion (TAPSE)-for each TA site and compare these CMR-derived measurements in healthy subjects vs. patients with heart failure, repaired tetralogy of Fallot, pulmonary hypertension, and hypertrophic cardiomyopathy; (iii) investigate how the TA motion related measurements compare with information provided by invasive right heart catheterization (RHC); (iv) evaluate the rate of change in surface area swept out by the reconstructed tricuspid annulus over time and (v) assess the reproducibility of this CMR-based technique. Results indicate that TA motion parameter data obtained in three dimensions using the proposed CMR-based systematic methodology achieve superior diagnostic performance (Sm: AUC = 0.957; TAPSE: AUC = 0.981) compared to two-dimensional CMR imaging. Both Sm and TAPSE from CMR correlated positively with dP/dt _max/IP from RHC (Sm: r = 0.621, p < 0.01; TAPSE: r = 0.648, p < 0.01). Our highly reproducible and robust methodology holds potential for extending CMR imaging to characterization of TA morphology and dynamic behaviour, eventually leading to deeper understanding of RV function and improved diagnostic capability.

Assessment of inter-atrial, inter-ventricular, and atrio-ventricular interactions in tetralogy of Fallot patients after surgical correction. Insights from two-dimensional speckle tracking and three-dimensional echocardiography

BACKGROUND

We aimed to assess biatrial size and function, interactions on atrial and ventricular levels, and atrio-ventricular coupling in patients after tetralogy of Fallot repair.

METHODS

A total of 34 patients with a mean age of 20.9±9 years, and 35 healthy controls, underwent two-dimensional speckle tracking echocardiography for ventricular and atrial strain measurements and real-time three-dimensional echocardiography to assess ventricular and atrial volumes.

RESULTS

When compared with controls, tetralogy of Fallot patients had significantly reduced right atrial peak atrial longitudinal strain (p<0.01), right atrial peak atrial contraction strain (p<0.01), right atrial ejection fraction (p<0.01), left atrial peak atrial longitudinal strain (p<0.01), left atrial peak atrial contraction strain (p<0.05), and left atrial ejection fraction (p<0.01). In the tetralogy of Fallot group, left ventricular ejection fraction was negatively related to the right ventricular end-systolic volume normalised to body surface area (r=-0.62, p<0.01). An association was found in patients between the right atrial peak longitudinal strain and mean right ventricular strain (r=0.64, p<0.01). In patients, the left atrial peak longitudinal strain correlated negatively with right atrial end-diastolic volume normalised to body surface area (r=-0.67, p<0.01), whereas the left atrial ejection fraction correlated weakly with left ventricular ejection fraction (r=0.41, p<0.05).

CONCLUSIONS

In asymptomatic tetralogy of Fallot patients, biatrial dysfunction exists and can be quantified via two-dimensional speckle tracking echocardiography as well as real-time three-dimensional echocardiography. Different forms of interactions on atrial and ventricular levels are evident among such cohorts.

Right Atrial Volume is Increased in Corrected Tetralogy of Fallot and Correlates with the Incidence of Supraventricular Arrhythmia: A CMR Study

The aim of this study was to evaluate right atrial (RA) volume in corrected Tetralogy of Fallot (cTOF) and assess its correlation with the occurrence of supraventricular (SV) arrhythmia. Cardiac magnetic resonance imaging (CMR) and 24-h Holter were performed in n = 67 consecutive cTOF patients (age 30 ± 11.3 years). The CMR protocol included standard HASTE, SSFP cine, and blood flow measurements. Correlations between arrhythmia in ECG, heart volume, and functional parameters were investigated by negative binominal regression. Patients' characteristics (mean ± SD) included mean RA volume of 49 ± 19 ml/m(2) (HASTE sequence), mean right ventricular (RV) end-diastolic volume of 98 ± 27 ml/m(2), mean pulmonary valve regurgitation fraction (PR) of 21 ± 19 %, BMI of 25 kg/m(2), and heart rate of 75/min. Twenty-eight out of 67 patients experienced SV arrhythmia including SV couplets or bigeminus or longer non-sustained SV tachycardia (SVT) episodes. RA volume index was identified as an independent risk factor for different degrees of SV arrhythmia (SV couplets/bigeminus p < 0.001, SVT p < 0.001). Further risk factors for SV arrhythmia were male gender (p = 0.023) and decreased left ventricular (LV) ejection fraction (EF) (LV EF p < 0.001). RA volume is increased in adult patients with cTOF with larger RA volumes relating to higher incidence of SV arrhythmia. SV arrhythmia also appeared more often in male patients and those with decreased LV EF. Risk stratification according to these parameters could help to optimize early prevention and adjusted individual therapy to improve patient outcome and quality of life.

Left ventricular systolic dysfunction in asymptomatic Marfan syndrome patients is related to the severity of gene mutation: insights from the novel three dimensional speckle tracking echocardiography

Background

In asymptomatic Marfan syndrome (MFS) patients we evaluated the relationship between the types of fibrillin-1 (FBN1) gene mutation and possible altered left ventricular (LV) function as assessed by three-dimensional speckle tracking echocardiography (3D-STE).

Methods and Results

Forty-five MFS patients (mean age 24±15 years) and 40 age-matched healthy controls were studied. Genetic evaluation for the FBN1 gene was carried on 32 MFS patients. Gene mutation (n = 15, 47%) was classified as mild when the mutation resulted in nearly normally functioning protein, while mutations resulting in abnormally function protein were considered to be severe (n = 17, 53%). All patients and controls underwent 3D-STE for evaluation of LV function by an echocardiographer blinded to the results of the genetic testing. Compared to controls, MFS patients had significantly lower 3D-STE derived LV ejection fraction (EF, 57.43±7.51 vs. 62.69±4.76%, p = 0.0001), global LV longitudinal strain (LS, 14.85±2.89 vs. 17.90±2.01%, p = 0.0001), global LV circumferential strain (CS, 13.93±2.81 vs. 16.82±2.17%, p = 0.0001) and global LV area strain (AS, 25.76±4.43 vs. 30.51±2.61%, p = 0.0001). Apart from the global LV LS all these parameters were significantly lower in patients with severe gene mutation than in those with mild mutation (p<0.05). In the multivariate linear regression analysis only the type of mutation had a significant influence on the 3D-STE derived LVEF (p = 0.017), global CS (p = 0.005) and global AS (p = 0.03).

Conclusions

In asymptomatic MFS patients latent LV dysfunction can be detected using 3D STE. The LV dysfunction is mainly related to the severity of gene mutation, suggesting possible primary cardiomyopathy in MFS patients.

Tricuspid repair at pulmonary valve replacement does not alter outcomes in tetralogy of Fallot

BACKGROUND

Chronic pulmonary regurgitation after tetralogy of Fallot repair often leads to progressive right ventricle dilation, dysfunction, and frequently, pulmonary valve replacement. For those with significant tricuspid regurgitation at the time of pulmonary valve replacement, it is unknown whether concomitant tricuspid valve repair improves postoperative outcomes.

METHODS

This is a retrospective review of patients after tetralogy of Fallot repair who underwent pulmonary valve replacement between 1999 and 2012. Preoperative and postoperative echocardiograms were assessed for tricuspid regurgitation (vena contracta) and right ventricular size and function (Tomtec software).

RESULTS

Sixty-two patients underwent pulmonary valve replacement. Thirty-six (58%) had greater than or equal to moderate tricuspid regurgitation on preoperative echocardiogram. Significant predictors were not identified. Of the 36, 18 (50%) underwent concomitant tricuspid valve repair at the time of pulmonary valve replacement. After surgery, there was a significant reduction in the degree of tricuspid regurgitation (p < 0.001) and measures of right ventricular size (p < 0.05) in both cohorts. Between surgical groups, there was no statistical difference in the grade of tricuspid regurgitation (p = 0.47) or measures of right ventricular size (p > 0.4) at 6-month follow-up.

CONCLUSIONS

Tricuspid regurgitation is a common finding in repaired tetralogy of Fallot, although risk factors for its development remain unclear. After pulmonary valve replacement with or without tricuspid valve repair there is significant improvement in the degree of tricuspid regurgitation and right ventricular size. Finally, 6 months after pulmonary valve replacement there were no statistical differences between those patients undergoing concomitant tricuspid valve repair and those undergoing pulmonary valve replacements alone.

Right ventricle-pulmonary circulation dysfunction: a review of energy-based approach

Patients with repaired or palliated right heart congenital heart disease (CHD) are often left with residual lesions that progress and can result in significant morbidity. However, right ventricular-pulmonary arterial evaluation and the timing of reintvervention is still subjective. Currently, it relies on symptomology, or RV imaging-based metrics from echocardiography or MR derived parameters including right ventricular (RV) ejection fraction (EF), end-systolic pressure (ESP), and end-diastolic volume (EDV). However, the RV is coupled to the pulmonary vasculature, and they are not typically evaluated together. For example, the dysfunctional right ventricular-pulmonary circulation (RV-PC) adversely affects the RV myocardial performance resulting in decreased efficiency. Therefore, comprehensive hemodynamic assessment should incorporate changes in RV-PC and energy efficiency for CHD patients. The ventricular pressure-volume relationship (PVR) and other energy-based endpoints derived from PVR, such as stroke work (SW) and ventricular elastance (Ees), can provide a measure of RV performance. However, a detailed explanation of the relationship between RV performance and pulmonary arterial hemodynamics is lacking. More importantly, PVR is impractical for routine longitudinal evaluation in a clinical setting, because it requires invasive catheterization. As an alternative, analytical methods and computational fluid dynamics (CFD) have been used to compute energy endpoints, such as power loss or energy dissipation, in abnormal physiologies. In this review, we review the causes of RV-PA failure and the limitation of current clinical parameters to quantify RV-PC dysfunction. Then, we describe the advantage of currently available energy-based endpoints and emerging energy endpoints, such as energy loss in the Pas or kinetic energy, obtained from a new non-invasive imaging technique, i.e. 4D phase contrast MRI.

Cardiac function after repair of tetralogy of fallot: how are the atria performing? pilot study by cardiac magnetic resonance imaging

The atria of the heart function as reservoir, conduit, and active pump and are critical for ventricular filling and cardiac output. We sought to evaluate right (RA) and left atrial (LA) function in patients after tetralogy of Fallot (TOF) repair by using cardiovascular magnetic resonance. Twelve TOF patients, age 16.7 ± 6.1 years, weight 50.9 ± 14.9 kg, were compared to 10 healthy volunteers, age 18.8 ± 6.8 years, weight 52.3 ± 20.8 kg. Both atria and both ventricles were imaged in short-axis planes by Steady State Free Precession. Volume changes and all derived atrial functional parameters were calculated from the volume/time curves obtained after segmentation on the cine images. Blood flow across the AV valves was used to define ventricular diastolic dysfunction. TOF patients showed similar maximal RA volume compared to controls, but increased volumes at mid-diastole (p < 0.05), resulting in a decreased cyclic volume change and atrial filling fraction (p < 0.01), and a decreased passive emptying volume and fraction (p < 0.01). In patients with diastolic dysfunction, conduit volume was increased (p < 0.05), and active emptying volume and fraction tended to be increased, respectively. No significant changes were found in LA, except for a decreased passive emptying fraction (p < 0.05). RA function and particularly reservoir function are impaired in TOF patients. The RA conduit/reservoir ratio is increased and reflects the lost of the ability of the atrium to fill the ventricle by pulsatile flow.

Regional analysis of longitudinal systolic function of the right ventricle after corrective surgery of tetralogy of Fallot using myocardial isovolumetric acceleration index

To assess regional longitudinal systolic function of the right ventricle in patients with repaired tetralogy of Fallot (TOF) by tissue Doppler imaging-derived isovolumetric acceleration (IVA) index and determine the effect of right-ventricular (RV) enlargement on regional systolic function. In 30 consecutive TOF patients and 30 age-matched controls, myocardial velocity of the RV ventricular free wall in the basal and middle regions were examined in the apical four-chamber view. Peak myocardial velocity during IVA was recorded on the free RV wall. IVA index was calculated as the difference between baseline and peak velocity divided by their time interval. In 23 of the studied TOF patients, magnetic resonance imaging was performed on the same day to determine global RV volume and ejection fraction. IVA index of the RV lateral free wall was significantly lower in the basal (8.31 ± 6.00 vs. 19.00 ± 10.85 m/s(2), p = 0.0001) and middle segments (6.56 ± 5.22 vs. 16.17 ± 7.44 m/s(2), p = 0.0001) in patients than in controls. Among TOF patients, a negative correlation was found between IVA index in the middle segment and RV end-diastolic volume/body surface area (r = -0.549, p < 0.01). Similar to other longitudinal RV wall parameters, the IVA index showed a decreased value in the RV free wall, which is related to the impaired regional and global longitudinal RV systolic dysfunction. RV enlargement adversely affects regional longitudinal systolic function.

Atrial mechanics after surgical repair of tetralogy of Fallot

BACKGROUND

Ventricular diastolic dysfunction in patients with repaired tetralogy of Fallot (TOF) may affect atrial mechanics. This study aimed to explore right atrial (RA) and left atrial (LA) mechanics in repaired TOF patients and their relationship with ventricular diastolic function.

METHODS

Fifty-four patients (36 males), aged 17.8 ± 8.3 years, who had undergone TOF repair at 3.9 ± 3.3 years and 40 healthy subjects aged 16.9 ± 6.3 years (P = 0.57) were studied. Right and LA peak positive, peak negative, and total strain, strain rate at ventricular systole (SRs ), early diastole (SRed ), and atrial contraction (SRac ), and electromechanical delay were determined using speckle tracking echocardiography (STE). Ventricular diastolic function was assessed by tissue Doppler imaging and STE. Ventricular volumes and pulmonary regurgitant volume were derived from 3D echocardiography.

RESULTS

Compared with controls, patients had significantly lower RA and LA peak positive and total strain, SRs , SRed , and SRac (all P < 0.001). The timing of RA (178 ± 33 msec vs. 152 ± 17 msec, P < 0.001) and LA (170 ± 32 msec vs. 152 ± 24 msec, P = 0.006) electromechanical coupling (EMC) was significantly longer in patients than in controls. The RA total strain, SRs , SRed , SRac , and EMC correlated positively with corresponding LA parameters (all P < 0.001). The RA and LA total strain and SRed were associated positively with diastolic annular velocities and strain rates of respective ventricles (all P < 0.05). The LA SRed correlated negatively with pulmonary regurgitant volume (r = -0.33, P = 0.016) and RV end-diastolic volume (r = -0.33, P = 0.015).

CONCLUSION

Mechanics of both atria are impaired in patients after repair of TOF and are associated with diastolic performance of the respective ventricles.

Surgery impacts right atrial function in tetralogy of Fallot

OBJECTIVE

To analyze the impact of surgery and pericardial integrity on right atrial function and total heart volume variation in the setting of pulmonary valve insufficiency.

METHODS

Right atrial function and total heart volume variation were analyzed in 2 subgroups of patients with pulmonary valve insufficiency compared with healthy controls: group 1 with surgically repaired tetralogy of Fallot (n = 20 patients) and group 2 after balloon angioplasty of pulmonary valve stenosis in patients with isolated valve disease without surgery (n = 7 patients). Volumetric analysis of magnetic resonance imaging data revealed parameters of atrial function (reservoir, conduit, and pump functions and cyclic volume change) and of total heart volume (end-diastolic and end-systolic total heart volume and the variation). Statistical analysis included uncorrected and corrected pairwise comparisons and the calculation of groupwise Pearson correlation coefficients.

RESULTS

In group 1 with a pulmonary regurgitation fraction of 31.0% ± 14.9%, right atrial function was clearly impaired, with reduced reservoir and elevated conduit function, and total heart volume variation was elevated to 13.9% ± 3.4%. In group 2 with a pulmonary regurgitation fraction of 22.8% ± 6.9%, the values were close to normal, with unaffected atrial function and a total heart volume variation of 9.9% ± 3.3%.

CONCLUSIONS

The hydrodynamic effect of pulmonary valve insufficiency alone is likely not the only reason for impaired right atrial function and elevated total heart volume variation in patients with tetralogy of Fallot; it is rather the scar in the right atrium, the injured pericardium, and the disease itself that are responsible for the energetically unfavorable alterations.

Altered diastolic left atrial and ventricular performance in asymptomatic patients after repair of tetralogy of Fallot

We evaluated the interaction of left atrial and ventricular diastolic performance in asymptomatic children and young adults after ToF-repair (n=25). Those young people, as well as 25 age matched healthy children and young adults were examined using non-invasive conventional echocardiography. Regional systolic and diastolic myocardial strain and strain rate in left atrium and ventricle were analysed using 2D-speckle-tracking (Vivid VII, EchoPacGE). We collected planimetric data about the left atrial and ventricular performance during systole (volumetric LVEF, LV-Tei-Index, MV-E/E'-Ratio) and diastole (LAEF, LVEDV, left atrial volume). Registration of right pulmonary-venous inflow-patterns during ventricular systole, diastole and active atrial contraction was used to support assessment of left atrial function. To verify the timing of left atrial contraction and possible electromechanical delay we measured several ECG-related time-intervals. Statistical analysis included Mann-Whitney-U-Test, Bonferroni-Holm-Test and two-tailed Spearman-Correlation. Systolic pulmonary-venous inflow in ToF-patients was not different compared to the controls. Early diastolic pulmonary-venous inflow was significantly higher in ToF-patients as well as the LV-Tei-Index. The MV-E/E'-ratio, which is closely related to LVEDP, was significantly higher in ToF-patients and correlated with the early diastolic pulmonary venous inflow parameters such as the maximum diastolic bloodflow speed. Diastolic left atrial and ventricular strain and strain rate in ToF-patients did not differ from those in the controls. During late diastole there was a significantly premature timing of maximum myocardial strain rate of the interatrial septum and time-ratio of P-wave origin to maximum reverse pulmonary-venous blood flow and the duration of one heart action. Furthermore the maximum late diastolic reverse pulmonary-venous blood flow was significantly higher in ToF-patients. Those observations indicate a premature active left atrial contraction in late diastole in ToF-patients compared to the controls. In asymptomatic young patients after ToF-repair earlier and increased left atrial contraction was found, which may indicate adaptive compensatory mechanisms to overcome latent and asymptomatic altered systolic and diastolic left ventricular performance. Extensive assessment of left atrial parameters including the pulmonary veins should be considered in terms of an entire evaluation of left heart function in patients after ToF-repair.

The Role of Tricuspid Valve Surgery in the Late Management of Tetralogy of Fallot

While surgical repair of tetralogy of Fallot (TOF) is generally associated with good early outcomes, late complications affect long-term survival and may require reoperation. Pulmonary regurgitation (PR) and tricuspid regurgitation (TR) may increase the risk of arrhythmias, reduced cardiac function, and sudden death. Tricuspid valve function can be compromised secondarily in the setting of PR or directly as a result of injury or alteration of the valve related to the original TOF repair. This article reviews the etiologic mechanisms, pathophysiological implications, and surgical interventions for TR. Effective management following TOF repair requires consideration of TR to optimize late outcomes.

Right atrial volume and phasic function in pulmonary hypertension

BACKGROUND

Few studies have focused on right atrial (RA) structure and function in pulmonary hypertension (PH). We sought to evaluate RA volume and phasic function using cardiac magnetic resonance (CMR), and to examine their clinical relevance in PH.

METHODS

We prospectively studied 50 PH patients and 21 control subjects. RA volume and indices of phasic function (reservoir volume, ejection fraction [EF], and conduit volume) were evaluated by CMR.

RESULTS

Maximum RA volume index was significantly higher in PH patients (56 [44-70] ml/m(2)) than in controls (40 [30-48] ml/m(2)) (p<0.001). Reservoir volume index was significantly lower in PH than in controls (p<0.001), but conduit volume index was higher in PH than in controls (p=0.008). RA EF was similar when comparing the two groups (p=0.925). Interestingly, RA EF was increased in PH patients with WHO functional class III patients as compared with controls (p<0.001) but was reduced in advanced PH patients with WHO functional class IV (p<0.01). Maximum RA volume and RA EF significantly correlated with pulmonary hemodynamic indices, atrial and brain natriuretic hormone levels, and CMR-derived right ventricular indices. By contrast, RA reservoir volume correlated with cardiac index and 6-minute walk distance.

CONCLUSIONS

PH is associated with increased size, decreased reservoir function, and increased conduit function of the right atrium. RA systolic function indicated by RA EF increases in patients with mild to moderate PH but decreases in patients with advanced PH. Varying associations between RA indices and conventional PH indices suggest their unique role in the management of PH.

Left ventricular long-axis function: reference values of the mitral annular plane systolic excursion in 558 healthy children and calculation of z-score values

BACKGROUND

Longitudinal myocardial function has gained more interest in the last years. The mitral annular plane systolic excursion (MAPSE) is an echocardiographic measurement to assess left ventricular (LV) long-axis function in adults. The aim of this study was to evaluate MAPSE values in a healthy pediatric population and to propose reference values.

METHODS

A prospective study was conducted in a group of 558 healthy children and adolescents (age day 1 to 18 years) (body surface area [BSA] 0.18-2.21 m(2)). We determined the effects of age and BSA on MAPSE values and a possible correlation of MAPSE values with LV ejection fraction values.

RESULTS

The MAPSE ranged from a mean of 0.57 cm (z-score ±2: 0.38-0.76 cm) in neonates to 1.63 cm (z-score ±2: 1.31-1.95 cm) in 18-year-old adolescents. The MAPSE values showed a positive correlation with age (r = 0.87, P < .001) and BSA (r = 0.89, P < .001) with a nonlinear course. There was no significant difference in MAPSE values between females or males. A positive correlation was found between MAPSE values and LV ejection fraction values (r = 0.28, P < .001).

CONCLUSIONS

Z-scores of MAPSE values were calculated, and percentile charts were established to serve as reference data in patients with congenital heart disease or heart failure in the future.

Abnormal right atrial and right ventricular diastolic function relate to impaired clinical condition in patients operated for tetralogy of Fallot

BACKGROUND

Atrial enlargement may reflect ventricular diastolic dysfunction. Although patients with tetralogy of Fallot (TOF) have been studied extensively, little is known about atrial size and function. We assessed bi-atrial size and function in patients after TOF repair, and related them to biventricular systolic and diastolic function, and clinical parameters.

METHODS

51 Patients (21 ± 8 years) and 30 healthy controls (31 ± 7 years) were included and underwent magnetic resonance imaging to assess bi-atrial and biventricular size, systolic and diastolic function. Patients also underwent exercise testing, and N-terminal prohormone brain natriuretic peptide (NT-proBNP) assessment.

RESULTS

In patients, right atrial (RA) minimal volume (34 ± 8 ml/m(2) vs. 28 ± 8 ml/m(2), p=0.001) and late emptying fraction were increased; RA early emptying fraction was decreased. Patients had longer right ventricular (RV) deceleration time (0.24 ± 0.10 vs. 0.13 ± 0.04, p<0.001), reflecting impaired RV relaxation, and larger RV volumes. Patients with end-diastolic forward flow (EDFF) had larger RA and RV size, abnormal RA emptying, higher NT-proBNP levels, higher VE/VCO2 slope (ventilatory response to carbon dioxide production), and the most abnormal LV diastolic function (impaired compliance). Patients with abnormal RA emptying (reservoir function <30% and pump function >24%) had higher NT-proBNP levels and worse exercise capacity. RA minimal volume was associated with RV end-diastolic volume (r=0.35, p=0.013).

CONCLUSIONS

In TOF patients with moderate RV dilatation, abnormal bi-atrial function and biventricular diastolic dysfunction are common. Abnormal RA emptying was associated with signs of impaired clinical condition, as was the presence of EDFF. These parameters, together with RA enlargement, could serve as useful markers for clinically relevant RV diastolic dysfunction.

4D cardiovascular magnetic resonance velocity mapping of alterations of right heart flow patterns and main pulmonary artery hemodynamics in tetralogy of Fallot

BACKGROUND

To assess changes in right heart flow and pulmonary artery hemodynamics in patients with repaired Tetralogy of Fallot (rTOF) we used whole heart, four dimensional (4D) velocity mapping (VM) cardiovascular magnetic resonance (CMR).

METHODS

CMR studies were performed in 11 subjects with rTOF (5M/6F; 20.1 ± 12.4 years) and 10 normal volunteers (6M/4F; 34.2 ± 13.4 years) on clinical 1.5T and 3.0T MR scanners. 4D VM-CMR was performed using PC VIPR (Phase Contrast Vastly undersampled Isotropic Projection Reconstruction). Interactive streamline and particle trace visualizations of the superior and inferior vena cava (IVC and SVC, respectively), right atrium (RA), right ventricle (RV), and pulmonary artery (PA) were generated and reviewed by three experienced readers. Main PA net flow, retrograde flow, peak flow, time-to-peak flow, peak acceleration, resistance index and mean wall shear stress were quantified. Differences in flow patterns between the two groups were tested using Fisher's exact test. Differences in quantitative parameters were analyzed with the Kruskal-Wallis rank sum test.

RESULTS

4D VM-CMR was successfully performed in all volunteers and subjects with TOF. Right heart flow patterns in rTOF subjects were characterized by (a) greater SVC/IVC flow during diastole than systole, (b) increased vortical flow patterns in the RA and in the RV during diastole, and (c) increased helical or vortical flow features in the PA's. Differences in main PA retrograde flow, resistance index, peak flow, time-to-peak flow, peak acceleration and mean wall shear stress were statistically significant.

CONCLUSIONS

Whole heart 4D VM-CMR with PC VIPR enables detection of both normal and abnormal right heart flow patterns, which may allow for comprehensive studies to evaluate interdependencies of post-surgically altered geometries and hemodynamics.