A single-centre, retrospective study of mid-term outcomes of aortic arch repair using a standardized resection and patch augmentation technique.

OBJECTIVES: The aim of this study was to evaluate the mid-term outcomes after the repair of aortic arch using a standard patch augmentation technique. METHODS: The study included all patients who underwent repair of a hypoplastic/interrupted aortic arch (IAA) in a single institute from June 2012 to December 2019 by a standardized patch augmentation (irrespective of concomitant intra-cardiac lesions). End points evaluated were reintervention for arch obstruction and persistent/new-onset hypertension. RESULTS: The study included 149 patients [hypoplastic aortic arch, n = 92 (62%), IAA, n = 9 (6%), Norwood procedure, n = 48 (32%)]. The patch material used for augmentation of the aortic arch included pulmonary homograft (n = 120, 81%), homograft pericardium (n = 18, 12%), CardioCel® (n = 9, 6%) and glutaraldehyde-treated autologous pericardium (n = 2, 1%). The median age and weight at surgery were 7 days [interquartile range (IQR) 5-17 days] and 3.5 kg (IQR 3-3.9 kg), respectively. The median follow-up was 3.27 years (IQR 1.28, 5.08), range (0.02, 8.76). Freedom from reintervention at 1, 3 and 5 years was 95% [95% confidence interval (CI) = 89%, 98%], 93% (95% CI = 86%, 96%) and 93% (95% CI = 86%, 96%) respectively. One patient (0.6%) had persistent hypertension 8 years after correction for interrupted arch with truncus arteriosus. CONCLUSIONS: Repair of hypoplastic/IAA by transection and excision of all ductal tissue and standardized patch augmentation provide good mid-term durability. The freedom from reintervention at 5 years is >90%. The incidence of persistent systemic hypertension following arch reconstruction is low. The technique is reproducible and applicable irrespective of underlying arch anatomy.

Three-Dimensional Echocardiography Right Ventricular Volumes and Ejection Fraction Reference Values in Children: A North American Multicentre Study.

BACKGROUND: Three-dimensional echocardiography (3DE) evaluation of right ventricular (RV) volumes and ejection fraction (EF) is increasingly used for clinical serial assessments and management in children. This study aims to generate sex-specific reference values and z-score equations for RV volumetric parameters, independent of age and body size indices, derived from multiple populations across North America. METHODS: We prospectively recruited 455 healthy children (ages 0 to 18 years) from 5 centres. 3DE of the RV were acquired using various vendors with analyses performed offline using vendor-independent software. 3DE datasets with all walls of the RV endocardium visible were included. We reported data on RV EF, and generated z scores for end-systolic volumes (ESV), end-diastolic volumes (EDV) and stroke volume (SV). Differences between the sexes were explored. RESULTS: Of 455 3DE datasets, 312 (68%) met imaging criteria for analysis. Median age was 10.1 years (interquartile ratio [IQR]: 5.6, 14.0) with 17% being younger than 3 years of age. The mean and standard deviation for RV EDV, ESV, and SV for male and female patients were reported. We provided a downloadable z-score calculator with height and weight as independent variables to facilitate clinical utility. Although statistically significant differences between male and female RVEF was present (female 52.9 ± 3.9% vs male 51.6 ± 3.5%, P = 0.006), after adjusting for age, height, and weight, the magnitude of difference was clinically insignificant. CONCLUSIONS: Sex-specific reference values for pediatric RV volumes and EF, and z-score equations were derived from children 3DE datasets across 5 centres in North America.

Echocardiographic Predictors of Ductal Tissue-Related Branch Pulmonary Artery Stenosis in Pulmonary Atresia.

Branch pulmonary artery (PA) stenosis due to ductus arteriosus (DA) tissue (DA-PS) contributes to the morbidity associated with pulmonary atresia (PAtr). We sought to identify preoperative echocardiographic features predictive of DA-PS. Patients consecutively encountered with PAtr and a DA-dependent pulmonary circulation at birth who underwent intervention in our program over a 5-year period were identified and records reviewed. Preoperative echocardiograms were reviewed to identify features that predicted postoperative DA-PS. Seventy patients with PAtr met inclusion criteria and 36 (51%) had DA-PS. At preoperative echocardiography, the proximal diameter of the PA ipsilateral to the DA was smaller in those with versus without DA-PS (Z-score - 4.8 ± 1.7 vs - 1.1 ± 1.7, respectively p < 0.001). PA origins could not be imaged on the same axial plane in 21/36 (58%) with versus 2/34 (6%) without DA-PS. Patients with DA-PS had an obtuse posterior angle of the PA bifurcation compared to those without (128 ± 17° and 87 ± 21°, p < 0.001), and a posterior angle of > 100° best predicted DA-PS with a sensitivity of 97% and specificity of 76%. An abnormal PA relationship and/or an obtuse posterior bifurcation angle had a sensitivity, specificity, positive and negative predictive value for DA-PS of 78%, 94%, 90% and 86%, respectively. Finally, DA insertion was into the ipsilateral PA in 26/36 (72%) of cases with DA-PS. A smaller proximal ipsilateral PA diameter, inability to image the PAs in the same plane, a posterior PA bifurcation angle of > 100°, and insertion of the DA in the ipsilateral PA demonstrated by echo are useful in identifying patients at risk for DA-PS.

Insights from 3D Echocardiography in Hypoplastic Left Heart Syndrome Patients Undergoing TV Repair.

BACKGROUND: Tricuspid regurgitation (TR) in hypoplastic left heart syndrome (HLHS) is associated with morbidity and mortality. TR mechanisms and the impact of tricuspid valve repair (TVR) are unclear. We examined HLHS TR mechanisms, TVR's impact on tricuspid valve (TV), and features of poor TVR durability. METHODS: We retrospectively compared 35 HLHS TVR cases and 35 age/stage-matched HLHS controls who do not undergo TVR. Pre-operative 3-dimensional echocardiography (3DE) assessed overall TV morphology (prolapse, normal, tethered), leaflet morphology, vena contracta area, and TR location. Two-dimensional echocardiography measured TV annulus diameter, RV fractional area change (RVFAC), sphericity, and TR grade at three time points (pre-op, early post-op, and latest follow-up). RESULTS: Pre-op, TVR group, and controls had no difference in age, RV function or shape, or TV dimension. TVR group most commonly had anterior leaflet prolapse followed by septal leaflet prolapse or tethering. TR jet arises centrally (63%) and anterior septally (26%). Posterior annuloplasty (69%), commissuroplasty (37%), and leaflet repair (37%) were surgical techniques commonly performed. At early post-op, TR grade and TV annulus decreased. At latest follow-up, TV annulus remained reduced; however, 50% had significant TR. 25% required TV reoperation. Larger vena contracta at TVR was associated with significant TR. CONCLUSION: HLHS patients undergoing TVR had more anterior leaflet prolapse and central TR. While TVR initially reduces annular size and TR grade, 50% redevelop significant TR despite maintained annular reduction. The association of greater TR severity prior to repair with post-op recurrence raises the consideration for earlier repair of TR in HLHS patients.

Tricuspid Valve Tethering Is Associated with Residual Regurgitation after Valve Repair in Hypoplastic Left Heart Syndrome: A Three-Dimensional Echocardiographic Study.

BACKGROUND: Tricuspid valve regurgitation (TR) is a risk factor for morbidity and mortality in children with hypoplastic left heart syndrome (HLHS). Surgical tricuspid valve (TV) repair is common, but durable repair remains challenging. The aim of this study was to examine mechanisms of TR requiring surgery, features associated with unsuccessful repair, and TV changes after surgical repair. METHODS: Thirty-six patients with HLHS requiring TV repair (TVR) and 36 matched control subjects with HLHS were assessed using two-dimensional and three-dimensional echocardiography. Using three-dimensional echocardiography, TV coordinates from the annulus, leaflet, and ventricle were used to measure annular, leaflet, prolapse, and tethering values and anterior papillary muscle angle. TR grade and ventricular size, function, and shape were assessed using two-dimensional echocardiography. RESULTS: Patients requiring TVR had greater total leaflet prolapse, larger TV annular and leaflet areas, and flatter annuli, with no difference in tethering, coaptation index, or anterior papillary muscle angle. In patients with HLHS, successful TVR at follow-up (58%) was associated with preoperative total leaflet prolapse (especially posterior). Unsuccessful repair was associated with preoperative tethering of the septal leaflet. TVR in patients with HLHS caused a reduction of total annular and leaflet size and reduced prolapse and tethering of the posterior leaflet but did not affect anterior leaflet prolapse or septal leaflet tethering. CONCLUSIONS: Features associated with TVR include a flattened and dilated TV annulus with leaflet prolapse. The additional presence of a tethered septal leaflet before TVR is associated with significant postoperative TR. Current surgical techniques, predominantly posterior annuloplasty and commissuroplasty, adequately address annular size and posterior leaflet pathology, but not septal leaflet tethering. Individualized and innovative surgical techniques are vital to improve surgical repair success.

Dynamic Systolic Changes in Tricuspid Regurgitation Vena Contracta Size and Proximal Isovelocity Surface Area in Hypoplastic Left Heart Syndrome: A Three-Dimensional Color Doppler Echocardiographic Study.

BACKGROUND: The aims of this study were to investigate the dynamic changes in the vena contracta (VC) and proximal isovelocity surface area (PISA) through systole in patients with hypoplastic left heart syndrome and tricuspid regurgitation and to identify the stage of systole (early, mid, or late) in which VC and PISA radius are optimal. METHODS: Twenty-eight patients with hypoplastic left heart syndrome were prospectively studied using continuous two-dimensional (2D) and three-dimensional (3D) echocardiography. Two-dimensional VC width, 3D VC area, and PISA radii (2D and 3D) were measured frame by frame throughout systole. The maximal 2D VC width, 3D VC area, and PISA radii in the first, middle, and last thirds of systole were compared, and correlations were explored with 3D tricuspid annular areas, right atrial volumes, and right ventricular volumes. RESULTS: In all, 35 data sets that met inclusion criteria were analyzed. On frame-by-frame analysis, maximal 2D VC width and 3D VC area were found in the first third of systole in 17% and 20% of studies, in the second third in 34% and 31%, and in the final third in 49% and 49%. Similarly, the maximal 2D and 3D PISA radii were found in the first third of systole in 26% and 17% of studies, in the second third in 28% and 34%, and in the final third in 46% and 49%. CONCLUSIONS: In hypoplastic left heart syndrome, detailed temporal analysis of tricuspid regurgitation-associated VC and PISA by 2D and 3D echocardiography reveals no reliable pattern predicting when in systole these parameters peak. Frame-by-frame measurement is necessary for identification of maximal VC and PISA radius on 2D and 3D color Doppler echocardiography because the severity of tricuspid regurgitation could be underestimated because of temporal variability in VC and PISA.

Tricuspid Regurgitation in Hypoplastic Left Heart Syndrome: Three-Dimensional Echocardiography Provides Additional Information in Describing Jet Location.

BACKGROUND: Twenty-five percent of patients with hypoplastic left heart syndrome (HLHS) require tricuspid valve (TV) repair. The location of tricuspid regurgitation (TR) is important in determining the type of repair performed. Studies using three-dimensional echocardiography (3DE) have reported a high incidence of error on two-dimensional echocardiography (2DE) for the identification of TV leaflets. The aim of this study was to compare assessment of TR on 3DE and 2DE in patients with HLHS (jet location, TR grade, and reproducibility). METHODS: A retrospective, single-center review was performed. Fifty-six patients with HLHS with available two-dimensional and three-dimensional echocardiograms, and mild or greater TR, were included. TR location, grade, vena contracta area, and TV annular diameter were measured on 2DE and 3DE. Reproducibility was assessed by blinded reviewers. RESULTS: Three-dimensional echocardiography identified the primary jet location as central (57%) followed by anteroseptal (36%). There was poor agreement between findings on 3DE and 2DE for jet location (κ = 0.05; 95 CI, -0.08 to 0.19). Interobserver reproducibility for location on 3DE was excellent (κ = 0.8), whereas reproducibility for 2DE was poor (κ = 0.32). The most common jet location pre-Norwood and pre-Glenn was central (70%), whereas pre-Fontan and post-Fontan, jet location was central (45%) and anteroseptal (48%). Vena contracta area on 2DE correlated moderately with vena contracta area on 3DE (r = 0.60, P < .0001). TV annular diameters on 2DE and 3DE for lateral (r = 0.85, P < .0001) and anteroposterior (r = 0.74, P = .001) dimensions were strongly correlated. CONCLUSIONS: In children with HLHS, assessment of TR location on 2DE had poor agreement with assessment on 3DE and was poorly reproducible. In contrast, TR jet location on 3DE was highly reproducible. Pre-Glenn, a central TR jet was the most common, while post-Glenn, central and anteroseptal locations were equal, highlighting the importance of preoperative identification of TR jet location in patients with HLHS.

Right Ventricular Remodeling in Hypoplastic Left Heart Syndrome is Minimally Impacted by Cardiopulmonary Bypass: A Comparison of Norwood vs. Hybrid.

Right ventricular (RV) remodeling in hypoplastic left heart syndrome (HLHS) begins prenatally and continues through staged palliations. However, it is unclear if the most marked observed remodeling post-Norwood is secondary to cardiopulmonary bypass (CPB) exposure or if it is an adaptation intrinsic to the systemic RV. This study aims to determine the impact of CPB on RV remodeling in HLHS. Echocardiograms of HLHS survivors undergoing stage 1 Norwood (n = 26) or Hybrid (n = 20) were analyzed at pre- and post-stage 1, pre- and post-bidirectional cavo-pulmonary anastomosis (BCPA), and pre-Fontan. RV fractional area change (FAC), vector velocity imaging for longitudinal & derived circumferential deformation (global radial shortening (GRS) = peak radial displacement/end-diastolic diameter), and deformation ratio (longitudinal/ circumferential) were assessed. Both groups had similar age, clinical status and functional parameters pre-stage 1. No difference in RV size and sphericity at any stage between groups. RVFAC was normal (> 35%) throughout for both groups. Both Norwood and Hybrid patients had increased GRS (p = 0.0001) post-stage 1 and corresponding unchanged longitudinal strain, resulting in decreased deformation ratio (greater relative RV circumferential contraction), p = 0.0001. Deformation ratio remained decreased in both groups in subsequent stages. Irrespective of timing of the first CPB exposure, both Norwood and Hybrid patients underwent similar RV remodeling, with relative increase in circumferential to longitudinal contraction soon after stage 1 palliation. The observed RV remodeling in HLHS survivors were minimally impacted by CPB.

A Novel Right Ventricular Volume and Pressure Loaded Piglet Heart Model for the Study of Tricuspid Valve Function.

Heart conditions in which the tricuspid valve (TV) faces either increased volume or pressure stressors are associated with premature valve failure. Mechanistic studies to improve our understanding of the underlying pathophysiology responsible for the development of premature TV failure are lacking. Due to the inability to conduct these studies in humans, an animal model is required. In this manuscript, we describe the protocols for a novel chronic recovery infant piglet heart model for the study of changes in the TV when placed under combined volume and pressure stress. In this model, volume loading of the right ventricle and the TV is achieved through the disruption of the pulmonary valve. Then pressure loading is accomplished through the placement of a pulmonary artery band. The success of this model is assessed at four weeks post intervention surgery through echocardiography, intracardiac pressure measurement, and pathologic examination of the heart specimens.

Quantitative Assessment of Left Ventricular Dysfunction in Fetal Ebstein's Anomaly and Tricuspid Valve Dysplasia.

BACKGROUND: Fetal Ebstein's anomaly and tricuspid valve dysplasia (EA/TVD) are associated with high perinatal mortality relative to pulmonary atresia with intact ventricular septum (PAIVS), despite both requiring redistribution of the cardiac output (CO) to the left ventricle (LV). LV dysfunction is suspected to contribute to adverse outcomes in EA/TVD. OBJECTIVE: We sought to examine global and segmental LV function in fetal EA/TVD with comparison to normal controls and PAIVS. We hypothesized that LV dysfunction in EA/TVD is associated with abnormal LV remodeling and interventricular mechanics. METHODS: We retrospectively identified 63 cases of fetal EA/TVD (40 with retrograde ductal flow) and 22 cases of PAIVS encountered from 2004 to 2015 and compared findings to 77 controls of comparable gestational age. We measured the combined CO and global LV function using two-dimensional, Doppler-derived, deformational (six-segmental vector velocity imaging) and dyssynchrony indices (DIs; SD of time to peak), and a novel global DI. RESULTS: EA/TVD fetuses demonstrated abnormal LV global systolic function with reduced ejection fraction, fractional area change, and CO, while in PAIVS we observed a normal ejection fraction, fractional area change, and CO. PAIVS, but not EA/TVD, demonstrated increased LV sphericity, suggestive of remodeling, and associated enhanced radial function in the third trimester. In contrast, while EA/TVD fetuses had normal LV segmental longitudinal strain, there was abnormal radial segmental deformation and LV dyssynchrony with increased SD of time to peak and DI. CONCLUSIONS: Fetal EA/TVD is associated with a lack of spherical remodeling and presence of mechanical dyssynchrony, which likely contribute to reduced CO and ejection fraction. Clinical monitoring of LV function is warranted in fetal EA/TVD. Further studies incorporating quantification of LV function into prediction models for adverse outcomes are required.

The incremental benefit of color tissue doppler in fetal arrhythmia assessment

BACKGROUND: Accurate fetal arrhythmia (FA) diagnosis is key for effective management. Currently, FA assessment relies on standard echocardiography-based techniques (M mode and spectral Doppler), which require adequate fetal position and cursor alignment to define temporal relationships of mechanical events. Few data exist on the application of color Doppler tissue imaging (c-DTI) in FA assessment. The aim of this study was to examine the feasibility and clinical applicability of c-DTI in FA assessment in comparison with standard techniques. METHODS: Pregnancies with diagnosed FA were prospectively recruited to undergo c-DTI following fetal echocardiography. Multiple-cycle four-chamber clips in any orientation were recorded (mean frame rate, 180 ± 16 frames/sec). With offline analysis, sample volumes were placed on atrial (A) and ventricular (V) free walls for simultaneous recordings. Atrial and ventricular rates, intervals (for atrial-ventricular conduction and tachyarrhythmia mechanism), and relationships were assessed to decipher FA mechanism. FA diagnosis by c-DTI, conventional echocardiographic techniques, and postnatal electrocardiography and/or Holter monitoring were compared. RESULTS: FA was assessed by c-DTI in 45 pregnancies at 15 to 39 weeks, including 16 with atrial and/or ventricular ectopic beats; 18 with supraventricular tachyarrhythmias, including ectopic atrial tachycardia in 11, atrioventricular reentrant tachycardia in four, atrial flutter in two, and intermittent atrial flutter and junctional ectopic rhythm in one; three with ventricular tachycardias; and eight with bradycardias or atrioventricular conduction pathology, including five with complete atrioventricular block (AVB), one with first-degree AVB evolving into complete AVB, one with second-degree AVB, and one with sinus bradycardia. After training, FA diagnosis by c-DTI could be made irrespective of fetal orientation within 10 to 15 min. FA diagnosis by c-DTI concurred with standard techniques in 41 cases (91%), with additional findings identified by c-DTI in 10. c-DTI led to new FA diagnoses in four cases (9%) not definable by standard techniques. FA diagnosis by c-DTI was confirmed in all 20 with persistent arrhythmias after birth, including three with new diagnoses defined by c-DTI. c-DTI was particularly helpful in deciphering SVT mechanism (long vs short ventricular-atrial interval) in all 18 cases, whereas standard techniques permitted definition in only half. CONCLUSIONS: c-DTI with offline analysis permits rapid and accurate definition of FA mechanism, providing new information in nearly one-third of affected pregnancies. AU

The Incremental Benefit of Color Tissue Doppler in Fetal Arrhythmia Assessment.

BACKGROUND: Accurate fetal arrhythmia (FA) diagnosis is key for effective management. Currently, FA assessment relies on standard echocardiography-based techniques (M mode and spectral Doppler), which require adequate fetal position and cursor alignment to define temporal relationships of mechanical events. Few data exist on the application of color Doppler tissue imaging (c-DTI) in FA assessment. The aim of this study was to examine the feasibility and clinical applicability of c-DTI in FA assessment in comparison with standard techniques. METHODS: Pregnancies with diagnosed FA were prospectively recruited to undergo c-DTI following fetal echocardiography. Multiple-cycle four-chamber clips in any orientation were recorded (mean frame rate, 180 ± 16 frames/sec). With offline analysis, sample volumes were placed on atrial (A) and ventricular (V) free walls for simultaneous recordings. Atrial and ventricular rates, intervals (for atrial-ventricular conduction and tachyarrhythmia mechanism), and relationships were assessed to decipher FA mechanism. FA diagnosis by c-DTI, conventional echocardiographic techniques, and postnatal electrocardiography and/or Holter monitoring were compared. RESULTS: FA was assessed by c-DTI in 45 pregnancies at 15 to 39 weeks, including 16 with atrial and/or ventricular ectopic beats; 18 with supraventricular tachyarrhythmias, including ectopic atrial tachycardia in 11, atrioventricular reentrant tachycardia in four, atrial flutter in two, and intermittent atrial flutter and junctional ectopic rhythm in one; three with ventricular tachycardias; and eight with bradycardias or atrioventricular conduction pathology, including five with complete atrioventricular block (AVB), one with first-degree AVB evolving into complete AVB, one with second-degree AVB, and one with sinus bradycardia. After training, FA diagnosis by c-DTI could be made irrespective of fetal orientation within 10 to 15 min. FA diagnosis by c-DTI concurred with standard techniques in 41 cases (91%), with additional findings identified by c-DTI in 10. c-DTI led to new FA diagnoses in four cases (9%) not definable by standard techniques. FA diagnosis by c-DTI was confirmed in all 20 with persistent arrhythmias after birth, including three with new diagnoses defined by c-DTI. c-DTI was particularly helpful in deciphering SVT mechanism (long vs short ventricular-atrial interval) in all 18 cases, whereas standard techniques permitted definition in only half. CONCLUSIONS: c-DTI with offline analysis permits rapid and accurate definition of FA mechanism, providing new information in nearly one-third of affected pregnancies.

Early tricuspid regurgitation in hypoplastic left heart syndrome is not related to right ventricular function or mechanical dyssynchrony

BACKGROUND: Tricuspid regurgitation (TR) is associated with morbidity and mortality in hypoplastic left heart syndrome (HLHS). We have previously demonstrated that TR prior to stage 2 (S2) surgical palliation is related to tricuspid valve (TV) abnormalities, including dilated annulus and increased leaflet prolapse. Right ventricular (RV) dysfunction and mechanical dyssynchrony have been reported as causes for TR. Thus, we hypothesized that TR and abnormal TV parameters are associated with RV dysfunction. Objective: This study explored the relationship between TV and RV function using quantitative three dimensional echocardiography (3DE) measure of TV parameters and speckle tracking echocardiography (STE) of RV deformation, in HLHS with and without TR. METHODS: Forty-four HLHS patients with median age of 4.7 months (IQR 3.9-5.3) were prospectively recruited prior to S2 palliation. TV parameters assessed using 3DE, included vena contracta area (VCA), leaflet area, prolapse volume, tethering volume, annular bending angle and papillary muscle angle. RV systolic function was assessed by fractional area change and STE derived longitudinal and circumferential strain, strain rate and mechanical dyssynchrony index (MDI). The group was divided into those with (group A) and those without (group B) significant TR by qualitative assessment. RV functional parameters were compared between the two groups using Mann-Whitney signed rank test and Spearman correlation of TV leaflet and annulus area, prolapse and tethering volume, bending angle and VCA, to longitudinal and circumferential strain, strain rate and MDI were performed. RESULTS: Fourteen patients (32%) had moderate or greater TR (group A). RV function parameters were not different between group A and group B. There was no correlation between all 3DE TV parameters and STE RV deformation parameters. CONCLUSION: Contrary to our hypothesis, HLHS RV systolic dysfunction and mechanical dyssynchrony do not play a significant role in early TR. This finding suggests the mechanisms of early TR in HLHS are likely to be secondary to valve and leaflet differences. (AU)

Speckle tracking echocardiography and magnetic resonance imaging derived circumferential strain rate are closely associated in the single right ventricle

BACKGROUND: Previous studies suggest right ventricular (RV) circumferential strain and strain rate from speckle tracking echocardiography (STE) is useful to assess function, despite imaging limitations of RV short axis and tracking algorithms designed for left ventricles. OBJECTIVE: This study compares STE strain and strain rate in patients with single RV to magnetic resonance imaging (MRI) derived strain and strain rate, using proprietary MRI deformation software with published validation in hypoplastic left heart syndrome. Strain and strain rate relationships to MRI derived volumes and function is explored. METHODS: Single RVs patients (n = 25) with STE and MRI performed with an interval up to 35 days, prior to stage 2 palliation (median age 3.9, range 0.9 - 6 months) were compared. STE (GE EchoPAC) and MRI derived longitudinal and circumferential strain and strain rate were analyzed offline. MRI RV end-diastolic (iEDV), end-systolic (iESV) volumes indexed to body surface area and ejection fraction were measured. Bland-Altman plot assessed agreement between the STE and MRI derived deformation measures. Correlations between variables were computed. RESULTS: STE and MRI strain rate had the best agreement between methods, longitudinal strain rate (bias -0.04%; SD 0.26) and circumferential strain rate (bias 0.16 %; SD 0.20) while STE and MRI strain had minimal bias and an acceptable limits of agreement, longitudinal strain (bias 0.4 %; SD 3.2) and circumferential strain (bias -1.7 %; SD 4.4). Greater STE and MRI derived strain and strain rate is associated with smaller iEDV, iESV and greater ejection fraction (see table). MRI circumferential strain and strain rate has a greater correlation with volumes and ejection fraction than MRI longitudinal strain and strain rate. STE circumferential strain rate was best correlated MRI derived volumes and ejection fraction. CONCLUSION: In single RV, STE and MRI derived strain and strain rate showed good agreement, with strain rate having the best equivalency. Furthermore, STE an MRI circumferential strain rate was the most consistently related to MRI derived RV size and function. This study reaffirms the performance of commercially available STE software in single RV and further emphasizes the importance of including circumferential deformation in routine evaluation. (AU)

The incremental benefit of color tissue doppler in fetal arrhythmia assessment

BACKGROUND: Accurate fetal arrhythmia diagnosis is key for effective management. Standard echo-based techniques (M-mode and spectral Doppler) require adequate fetal position and cursor alignment to define temporal relationships of mechanical events. Little data exists on the application of cTDI in fetal rhythm assessment. OBJECTIVE: We sought to determine the benefit of color tissue Doppler imaging (cTDI) in fetal arrhythmia assessment over conventional fetal echo techniques. METHODS: Pregnancies with a diagnosis of fetal arrhythmia were prospectively recruited to undergo cTDI following fetal echocardiography. Multiple cycle 4-chamber clips in any orientation were recorded (frame rates >180 fps). With offline analysis, sample-volumes were placed on atrial (A) and ventricular (V) free walls with simultaneous recordings. A and V rates, intervals and relationships were evaluated. RESULTS: Arrhythmias were assessed in 45 fetuses by cTDI at 15-39 weeks and included: 11 atrial and 5 ventricular ectopic beats; 18 supraventricular tachyarrhythmias (SVT) including ectopic atrial tachycardia in 11, AV re-entry SVT in 4, atrial flutter (AF) in 2, intermittent AF and junctional ectopic rhythm in 1; ventricular tachycardias in 3; 8 bradycardias or AV conduction pathology including complete AV block (AVB) in 5, 1 AVB evolving into complete AVB in 1, 2 AVB in 1, sinus bradycardia in 1. Arrhythmia diagnosis by cTDI could be made irrespective of orientation of the fetus, after training, within 10-15 minutes. cTDI findings concurred with the diagnosis by standard techniques in 95% of cases and added new findings in 29%. In 5%, cTDI provided a new diagnosis, confirmed postnatally. In cases with SVT, cTDI permitted assessment of A-V and V-A intervals elucidating arrhythmia mechanism in all, whereas standard techniques had failed to define mechanism in 45%. CONCLUSION: cTDI with offline analysis permits rapid and accurate definition of fetal arrhythmia mechanism, providing new information in a significant proportion of affected pregnancies. (AU)

Active right atrial emptying fraction predicts reduced survival and increased adverse events in childhood pulmonary arterial hypertension.

BACKGROUND: Right atrial (RA) function has been studied rarely in childhood pulmonary arterial hypertension (PAH). We sought to determine if RA and right ventricular (RV) area changes measured by echocardiography predicted outcomes. METHODS: We reviewed data from children with PAH undergoing cardiac catheterization and echocardiography. RA and RV areas were obtained from the apical 4-chamber view. Clinical worsening indicated initiation of parenteral prostanoid therapy, heart and/or lung transplantation, Potts shunt surgery or death. RESULTS: We studied 57 children (27 females), median age 3 years (range 0.30-17 years), body surface area 0.56 m2 (0.2-1.8), follow up 3 years (0.21-8.35), time to clinical worsening was 1.14 years (0.03-6.14) and mortality was 1.55 years (range 0.88-4.95). We determined from receiver operator curves that RA active emptying fraction (RA EaF) ≥60% predicted clinical worsening (sensitivity 78%, specificity 69%, AUC 0.7) and mortality (sensitivity 100%, specificity 65%, AUC 0.82). RV fractional area change (RVFAC) <25% predicted clinical worsening (sensitivity 72%, specificity 79%, AUC 0.85) and death (sensitivity 67%, specificity 69%, AUC 0.77). The combination of RA EaF ≥60% and RVFAC <33% were best predictors of clinical worsening (sensitivity 72%, specificity 82%, partial AUC 0.65) and mortality (sensitivity 100%, specificity 77%, partial AUC 0.75). CONCLUSION: In childhood PAH, RA EaF ≥ 60% and RVFAC <25% were associated with poor outcomes. RA EaF ≥60% and RVFAC <33% were best predictors of clinical worsening and may be useful markers in children with PAH who require closer observation and more intensive therapy.

Reduced Right Ventricular Fractional Area Change, Strain, and Strain Rate before Bidirectional Cavopulmonary Anastomosis is Associated with Medium-Term Mortality for Children with Hypoplastic Left Heart Syndrome.

BACKGROUND: Ventricular dysfunction is associated with increased morbidity and mortality in children with hypoplastic left heart syndrome. The aim of this study was to assess the diagnostic performance of conventional and speckle-tracking echocardiographic measures of right ventricular (RV) function before bidirectional cavopulmonary anastomosis palliation in predicting death or need for heart transplantation (HTx). METHODS: RV fractional area change (RVFAC) and longitudinal and circumferential strain and strain rate (SR) were measured in 64 prospectively recruited patients with hypoplastic left heart syndrome from echocardiograms obtained before bidirectional cavopulmonary anastomosis surgery. The composite end point of death or HTx was examined. Receiver operating characteristic analysis was performed, and cutoff values optimizing sensitivity and specificity were derived. RESULTS: At a median follow-up of 5.0 years (interquartile range, 2.8-6.4 years), 13 patients meeting the composite end point had lower longitudinal strain and SR, circumferential SR, and RVFAC compared with survivors (n = 51). The conventional cutoff of RVFAC < 35% was specific for death or HTx (86%) but had poor sensitivity (46%), with an area under the curve of 0.73. Speckle-tracking echocardiographic variables showed similar areas under the curve (range, 0.69-0.79), with negative predictive values >90%. Addition of speckle-tracking echocardiographic variables to RVFAC < 35% showed no added benefit. However, in a subpopulation of patients with RVFAC ≥ 35% (n = 44), those meeting the composite end point (n = 7) had lower longitudinal SR (median, -1.0 1/sec [interquartile range, -0.8 to -1.1 1/sec] vs -1.21/sec [interquartile range, -1.0 to -1.3 1/sec], P = .03). Interobserver reproducibility was superior for longitudinal strain and SR (intraclass correlation coefficient > 0.92) compared with RVFAC (intraclass correlation coefficient = 0.75). CONCLUSIONS: Children with hypoplastic left heart syndrome with normal RVFAC and ventricular deformation before bidirectional cavopulmonary anastomosis have a low likelihood of death or HTx in the medium term. In the presence of reduced RVFAC, speckle-tracking echocardiography does not provide additional prognostic value. However, in patients with "normal" RVFAC, it may have a role in improving outcome prediction and warrants further investigation.

Tricuspid Valve Adaptation during the First Interstage Period in Hypoplastic Left Heart Syndrome.

BACKGROUND: Tricuspid regurgitation (TR) is an important risk factor for morbidity and mortality in hypoplastic left heart syndrome (HLHS), yet the evolution of tricuspid valve (TV) dysfunction in HLHS is poorly understood. This study sought to examine changes in TV function in HLHS between the first two stages of surgical palliation and to determine the mechanism of TR at the time of stage two surgery-bidirectional cavopulmonary anastomosis (BCPA). METHODS: We prospectively investigated 44 infants at two time points-prior to Norwood-Sano (T1 - median age 5.4 days) and prior to BCPA (T2 - median age 4.7 months) using two-dimensional (2DE) and three-dimensional echocardiography (3DE). Right ventricular (RV) size, function and shape was assessed with 2DE. Extracted spatial coordinates from 3DE were used to calculate TV leaflet and annular area, tethering and prolapse volumes, bending angle, and coaptation index. TR was graded qualitatively, and 2D and 3D vena contracta (VC) were measured. RESULTS: The cohort from T1 to T2 had increased indexed leaflet and annular area (P < .0001) and tethering volume (P < .0001), with no change in coaptation. Significant TR was present in 14 infants (32%) at T2 and was associated with greater leaflet (P = .02) and annular areas (P = .002) and greater prolapse volume (P = .008), but not tethering volume or reduced coaptation. At latest follow-up (median 23 months), 13 patients died or required transplantation. Only 3DE VC at T2 was associated with death or transplantation. CONCLUSIONS: The TV in HLHS adapts to interstage stressors (increased preload and afterload) by increasing leaflet size to maintain adequate leaflet coaptation. Significant TR at T2 was associated with greater leaflet size and prolapse. This may represent TV maladaptation from an excessive response in leaflet expansion to stressors.

Right Atrial Dysfunction in the Fetus with Severely Regurgitant Tricuspid Valve Disease: A Potential Source of Cardiovascular Compromise.

BACKGROUND: In severe right heart obstruction (RHO), redistribution of cardiac output to the left ventricle (LV) is well tolerated by the fetal circulation. Although the same should be true of severely regurgitant tricuspid valve disease (rTVD) with reduced or no output from the right ventricle, affected fetuses more frequently develop hydrops or suffer intrauterine demise. We hypothesized that right atrium (RA) function is altered in rTVD but not in RHO, which could contribute to differences in outcomes. METHODS: Multi-institutional retrospective review of fetal echocardiograms performed over a 10-year period on fetuses with rTVD (Ebstein's anomaly, tricuspid valve dysplasia) or RHO (pulmonary atresia/intact ventricular septum, tricuspid atresia) and a healthy fetal control group. Offline velocity vector imaging and Doppler measurements of RA size and function and LV function were made. RESULTS: Thirty-four fetuses with rTVD, 40 with RHO, and 79 controls were compared. The rTVD fetuses had the largest RA size and lowest RA expansion index, fractional area of change, and RA indexed filling and emptying rates compared with fetuses with RHO and controls. The rTVD fetuses had the shortest LV ejection time and increased Tei index with a normal LV ejection fraction. RA dilation (odds ratio, 1.27; 95% CI, 1.05-1.54) and reduced indexed emptying rate (odds ratio, 2.49; 95% CI, 1.07-5.81) were associated with fetal or neonatal demise. CONCLUSIONS: Fetal rTVD is characterized by more severe RA dilation and dysfunction compared with fetal RHO and control groups. RA dysfunction may be an important contributor to reduced ventricular filling and output, potentially playing a critical role in the worsened outcomes observed in fetal rTVD.

Impaired Single Right Ventricular Function Compared to Single Left Ventricles during the Early Stages of Palliation: A Longitudinal Study.

BACKGROUND: Single right ventricles (SRV) are postulated to be disadvantaged compared with single left ventricles (SLV). We compared the evolution of SRV versus SLV function during infancy using conventional measures and speckle-tracking echocardiography (STE). We hypothesized that the SRV is mechanically disadvantaged during early infancy. METHODS: SRVs (n = 32) were compared with SLVs (n = 16) at the neonatal (presurgery) and pre-bidirectional cavopulmonary anastomosis (pre-BCPA) stages. Functional measures (fractional area change, indexed ventricular annular plane systolic excursion [iVAPSE], isovolumic acceleration [IVA], myocardial performance index, E and A velocities, tissue Doppler imaging annular velocities and STE-measured global longitudinal and circumferential strain, strain rate [SR], and early diastolic SR [EDSR]) were compared between SRV and SLV at each stage and between presurgery and pre-BCPA. RESULTS: Compared with SLV, presurgery SRV had lower circumferential strain (-10.6% vs -16.5%; P = .0002) and EDSR (1.41%/sec vs 2.13%/sec; P = .001). Pre-BCPA SRV had decreased IVA (1.2 vs 2.1 m/sec2; P = .006): longitudinal strain (-15.3% vs -19.1%; P = .001), SR (-0.97%/sec vs -1.53%/sec; P = .0001), EDSR (1.5%/sec vs 2.1%/sec; P = .001); circumferential strain (-10.6% vs -14.9%; P = .002), SR (-0.8%/sec vs -1.21%/sec; P = .0001), and EDSR (1.3%/sec vs 1.8%/sec; P = .009). SRV showed reduction of iVAPSE, IVA, s', e', a' velocities, longitudinal strain, SR, EDSR, and circumferential SR (P < .05) from presurgery to pre-BCPA, while circumferential strain was unchanged. SLV showed no significant change in these parameters during this interval. CONCLUSIONS: The progressive reduction in SRV longitudinal and circumferential function suggests that SRV may have a mechanical disadvantage from birth and progressive impairment with age.