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.

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.

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.

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.

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.

Measurements of changes in left ventricular volume, strain, and twist during isovolumic relaxation using MRI.

Left ventricular (LV) active relaxation begins before aortic valve closure and is largely completed during isovolumic relaxation (IVR), before mitral valve opening. During IVR, despite closed mitral and aortic valves, indirect assessments of LV volume have suggested volume increases during this period. The aim of this study is to measure LV volume throughout IVR and to determine the sources of any volume changes. For 10 healthy individuals (26.0 + or - 3.8 yr), magnetic resonance imaging was used to measure time courses of LV volume, principal myocardial strains (circumferential, longitudinal, radial), and LV twist. Mitral leaflet motion was observed using echocardiography. During IVR, LV volume measurements showed an apparent increase of 4.6 + or - 1.5 ml (5.0 + or - 2.0% of the early filling volume change), the LV untwisted by 4.5 + or - 1.9 degrees (36.6 + or - 18.0% of peak systolic twist), and changes in circumferential, longitudinal, and radial strains were +0.87 + or - 0.64%, +0.93 + or - 0.57%, and -1.46 + or - 1.66% (4.2 + or - 3.3%, 5.9 + or - 3.3%, and 5.3 + or - 7.5% of peak systolic strains), respectively. The apparent changes in volume correlated (P < 0.01) with changes in circumferential, longitudinal, and radial strains (r = 0.86, 0.69, and -0.37, respectively) and untwisting (r = 0.83). The closed mitral valve leaflets were observed to descend into the LV throughout IVR in all subjects in apical four- and three-chamber and parasternal long-axis views by 6.0 + or - 3.3, 5.1 + or - 2.4, and 2.1 + or - 5.0 mm, respectively. In conclusion, LV relaxation during IVR is associated with changes in principal strains and untwisting, which are all correlated with an apparent increase in LV volume. Since closed mitral and aortic valves ensure true isovolumic conditions, the apparent volume change likely reflects expansion of the LV myocardium and the inward bowing of the closed mitral leaflets toward the LV interior.

Stereoscopic Display Is Superior to Conventional Display for Three-Dimensional Echocardiography of Congenital Heart Anatomy.

BACKGROUND: Three-dimensional echocardiography (3DE) improves visualization of cardiac lesions. Current viewing of 3DE studies on a conventional display diminishes the encoded stereoscopic (stereo) information for depth perception. This study aims to evaluate clinician subjective and objective experience of stereo display compared with nonstereo display of 3DE in congenital heart disease. METHODS: In this prospective study, 22 cardiologists, advanced cardiology trainees, and cardiothoracic surgeons used a commercially available stereo display system with proprietary software to view 10 3DE data sets, alternating between simple and complex lesions. In part A, participants viewed each data set, randomized to 1 minute of stereo display followed by 1 minute of nonstereo display, or vice versa. In part B, participants could freely toggle between stereo and nonstereo display for an additional 90 seconds per data set. Participants answered a series of questions and rated their subjective experience using stereo versus nonstereo display mode on a Likert scale. Objective data on time spent in each display mode during part B and duration of interaction and degree of movement of the 3DE data set in parts A and B were also collected. RESULTS: All clinician groups found stereo display preferable to nonstereo display of 3DE (P < .0001). Viewing complex lesions was rated lower than simple lesions when using nonstereo display (P < .01). Simple and complex lesions were equally well rated when using stereo display (P = .14). When given a choice of display modes in part B, participants spent more time in stereo display (P < .0001) and interacted more with the 3DE data sets in stereo display (P < .0001). CONCLUSIONS: Interactive stereoscopic display of 3DE was preferred over conventional nonstereo display by all clinician groups for viewing both simple and complex lesions. This preference is especially true for viewing complex lesions.

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.

Effectiveness of prenatal diagnosis of congenital heart defects in South Australia: a population analysis 1999-2003.

AIMS: To report on the efficiency of fetal echocardiography, outcome after prenatal diagnosis of congenital heart disease (CHD) and the effectiveness of South Australia's obstetric screening program in detecting CHD. METHODS: A retrospective audit of our institutional cardiac database, the South Australia Birth Defects Register and the South Australia Pregnancy Outcome Unit from 1999 to 2003. RESULTS: CHD was present in 10.7 per 1000 births and was potentially detectable in 5.2 per 1000 births. Of these, only 22.5% were referred for fetal echocardiography. Prenatal detection of transposition of the great arteries occurred in four of 27 (14.8%), atrioventricular septal defect in five of 21 (23.8%), tetralogy of Fallot in seven of 28 (25.0%) and hypoplastic left heart syndrome in 20 of 33 (60.6%). Fetal echocardiography had 95.2% sensitivity, 99.5% specificity, 99.0% positive predictive value and 97.6% negative predictive value for CHD. A prenatal diagnosis of CHD resulted in termination in 30.1%, stillbirth in 7.8% and neonatal death in 3.9% of cases. CONCLUSION: Routine obstetric ultrasound detects CHD infrequently. Outflow tract lesions are most commonly missed. Fetal echocardiography is an accurate tool for prenatal diagnosis of CHD. Pregnancy outcomes after prenatal diagnosis are comparable to other Australasian and western countries, suggesting uniformity in parental counselling and population behaviour. Strategies that improve routine obstetric ultrasound detection of CHD are likely to yield the greatest impact.

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.

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.

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.

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.

Increased common atrioventricular valve tenting is a risk factor for progression to severe regurgitation in patients with a single ventricle with unbalanced atrioventricular septal defect.

OBJECTIVE: Significant atrioventricular valve regurgitation (AVVR) increases mortality in patients with unbalanced atrioventricular septal defects (uAVSDs) and a single ventricle. We tested the hypothesis that abnormal leaflet tethering is associated with progressive AVVR in patients with a single ventricle with uAVSD. METHODS: We retrospectively reviewed the initial presentation and prebidirectional cavopulmonary anastamosis echocardiograms of 46 consecutive patients with uAVSD with single ventricle palliation. AVVR was graded as moderate to severe if the sum of vena contracta width to dominant valve annulus ratio was ≥ 0.33. We measured tenting height, annular to leaflet angle and annular diameter, indexed to patient size where appropriate. Multivariate analysis of variables to predict progressive AVVR was performed. RESULTS: At follow-up of 3.3 ± 2.4 years, 24 patients had mild AVVR (Group A) and 22 had moderate to severe AVVR. Overall mortality was 6%, whereas 10 had valve repair/replacement surgery. Of 22 patients with severe AVVR at follow-up, 9 had severe AVVR at initial presentation (Group B), whereas 13 had mild AVVR at presentation but developed severe AVVR at their prebidirectional cavopulmonary anastamosis echocardiogram (Group C). Group A patients had a smaller tenting height at initial presentation compared with patients in Group B and Group C, and also had early progressive reduction of indexed tenting height (P < .01). An absolute tenting height >6 mm (odds ratio, 6.6; 95% confidence interval, 1.1-39.0; P = .03) at the initial echocardiogram was identified as an independent predictor of subsequent severe AVVR. CONCLUSIONS: Early leaflet tethering is predictive of subsequent AVVR in patients with a single ventricle with uAVSD. Patients with competent AVV had progressive reduction in the degree of leaflet tethering, whereas patients with AVVR did not. This may represent an important adaptive process to maintain valve competency in uAVSD.

Tricuspid regurgitation in hypoplastic left heart syndrome: mechanistic insights from 3-dimensional echocardiography and relationship with outcomes.

BACKGROUND: Our purpose was to test the following hypotheses: (1) patients with hypoplastic left heart syndrome who develop significant tricuspid regurgitation (TR) or require tricuspid valve (TV) surgery in the medium term have detectable TV abnormalities by 3-dimensional echocardiography (3DE) prestage 1 palliation and (2) TR is associated with reduced survival and increased TV intervention. METHODS AND RESULTS: Infants were prospectively studied with 3DE and 2DE prestage 1 and followed up for the end points of TR, TV surgery, transplantation, or death. From prestage 1 3DE, spatial coordinates of TV annulus and leaflets were extracted; annulus size, leaflet area, prolapse volume, tethering volume, bending angle, and papillary muscle angle were measured. TR was assessed prestage 1 and at latest follow-up. Of 70 patients, 62 (88.6%) had mild or less TR and 8 (11.4%) had moderate or greater TR prestage 1. Prestage 1 tethering volume correlated to leaflet area (r=0.736; P<0.001), annulus area (r=0.651; P<0.001), right ventricular end-diastolic area (r=0.347; P=0.003), fractional area change (r=-0.387; P<0.001), and TR grade (r=0.447; P<0.001). At follow-up, 46 (65.7%) had mild or less TR (group A) and 24 (34.3%) had moderate or greater TR (group B). Prestage 1 3DE showed greater TV tethering volume and flatter annulus in group B. Survival was better in group A. CONCLUSIONS: Increased TV tethering volume and flatter bending angle prestage 1 palliation is associated with TV failure at medium-term follow-up. Increased prestage 1 tethering is related to having larger TV annulus, larger leaflet area, larger right ventricular size, and reduced systolic function. TR progression results in increased TV intervention and decreased survival.

Spontaneous endogenous microbubbles in a child with Berlin heart ventricular assist device.

We report the case of an 11-year-old boy with familial dilated cardiomyopathy on biventricular assist devices (Berlin Heart EXCOR) who was found to have spontaneous endogenous microbubbles in the left ventricular (LV) cavity on routine echocardiogram. Although no major sequelae resulted from the presence of these microbubbles, it did however lead to several noninvasive investigations. To our knowledge, this is a novel observation of spontaneous endogenous microbubbles in a patient with a Berlin Heart. The unknown clinical significance of this phenomenon highlights the need for further studies.

Newer imaging modalities in the assessment of heart function in single ventricle hearts.

The limitations of geometry assumptions in 2-dimensional echocardiographic assessment of the single ventricle (SV) have been overcome by recent advances in 3-D echocardiography. Improved reproducibility for measuring ventricular volumes and ejection fraction using 3-D echocardiography makes it ideally suited for serial monitoring of SV systolic function and should be considered in routine echocardiography imaging protocols for SV. The moderate correlation of Doppler derived E/e' ratio with invasive ventricular end diastolic pressure in SV, suggests it might be useful in the assessment of SV diastolic function. Speckle tracking imaging is intensely studied and promises to be a simple and repeatable imaging tool for quantifying SV function. In contrast, the advances in cardiac magnetic resonance imaging techniques promise to offer insights into the pathogenesis of myocardial dysfunction in SV. Late gadolinium enhancement imaging is a robust tool in assessing macroscopic myocardial scarring and T1 mapping and stress perfusion imaging are newer modalities that might improve understanding of the mechanisms in progressive myocardial dysfunction in SV hearts.

Tricuspid valve repair improves early right ventricular and tricuspid valve remodeling in patients with hypoplastic left heart syndrome.

OBJECTIVE: Tricuspid regurgitation is a significant risk factor for reoperation and mortality in patients with hypoplastic left heart syndrome. The effects of tricuspid valve repair on quantitative measures of right ventricle and tricuspid valve remodeling have not been well documented. METHODS: We reviewed retrospectively the 2-dimensional echocardiograms of 17 tricuspid valve repairs (male, n = 12; female, n = 5; median age, 30 months; age range, 1.5-53 months) performed 1 month before and after tricuspid valve repair between 2005 and 2011. From the apical 4-chamber view, we measured right ventricle end-diastolic area, right ventricle fractional area change, and tricuspid valve leaflet coaptation length. The severity of tricuspid regurgitation was graded qualitatively. A 2-sided paired t test was used to compare changes in tricuspid valve and right ventricle outcomes, and the Wilcoxon signed-rank test was used to compare changes in tricuspid regurgitation grades. RESULTS: Right ventricle end-diastolic area decreased significantly after tricuspid valve repair from 14.1 ± 5.2 to 11.8 ± 3.9 cm(2) (P = .001), whereas right ventricle fractional area change declined from 44.4% ± 6.4% to 39.7% ± 8.5% (P = .016). The coaptation length of the lateral and septal leaflet improved significantly after tricuspid valve repair (0.4 ± 2.4 mm vs 3.1 ± 2.7 mm, P = .002; 2.0 ± 2.7 vs 3.4 ± 2.0 mm, P = .036; respectively). Furthermore, the tricuspid regurgitation grade improved after tricuspid valve repair (3.1 ± 0.6 to 1.7 ± 0.9, P < .001). CONCLUSIONS: Tricuspid valve repair improved significantly the tricuspid valve coaptation length and reduced right ventricle volume in children with hypoplastic left heart syndrome. Further follow-up of decreased right ventricle function is required to determine whether this is a temporary phenomenon related to reduced right ventricle preload, permanent right ventricle dysfunction from late repair of the tricuspid valve, or unavoidable sequelae of a right ventricle exposed to systemic vascular resistance.