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 Unique Intracardiac Shunt: Identifying Complex Anatomy in Reoperative Adult Congenital Heart Disease.

Adult patients with repaired congenital heart disease are presenting with previously unseen types of residual lesions and consequences of prior repair. Patients with d-transposition of the great arteries repaired with atrial switch operations are returning with dysrhythmias and atrioventricular valve disease requiring intervention. We present the challenging case of a young adult with a residual shunt identified on preoperative three-dimensional transthoracic echocardiography, the precise anatomy of which was only characterized intraoperatively.

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.

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.

Impaired Left Ventricular Reserve in Childhood Cancer Survivors Treated With Anthracycline Therapy.

BACKGROUND: Childhood cancer survivors show evidence of diffuse myocardial fibrosis that is related to exercise capacity. The mechanism of reduced exercise tolerance in anthracycline cardiotoxicity remains unclear. We explored the determinants of exercise intolerance by evaluating left ventricular (LV) distensibility and functional reserve. METHODS: Patients (n = 22) and healthy controls (n = 10) underwent two-dimensional echocardiography while supine, upright, and during cycle exercise. LV distensibility was measured as the change in end-diastolic cavity area (EDCA) from supine to the upright position. LV functional reserve was assessed during peak exercise, and measured as the exercise-induced change in systolic circumferential strain rate (SR) and early-diastolic SR (EDSR). The peak rate of oxygen consumption was measured by indirect calorimetry. RESULTS: Median age of patients was 16 years (range 8-19) and controls 14 years (range 8-19). Median time since anthracycline therapy was 6 years (range 2-16). Peak oxygen consumption was significantly lower in patients compared to controls (35 ml/kg/min [28-60] vs. 45 ml/kg/min [44-53], P = 0.005). Transitioning from the supine position to the upright position caused a similar reduction in LV EDCA, suggesting similar LV distensibility between patients (-22% [-46 to -4]) and controls (-20% [-46 to -3], P = 0.3). However, during exercise, both systolic SR and EDSR reserve were significantly impaired in patients (∆SR: 93% [14-308], ∆EDSR: -4.5% [-88 to 121]) compared to controls (∆SR: 128% [54-230], P = 0.046; ∆EDSR: 74% [22-234], P = 0.02). CONCLUSIONS: Our findings suggest that impaired LV contractility and functional reserve play a role in the reduced exercise capacity in anthracycline cardiotoxicity rather than LV distensibility.

Three-dimensional echocardiography for the assessment of atrioventricular valves in congenital heart disease: past, present and future.

Echocardiography has developed as an imaging technology over 60 years to become the mainstay for investigating heart disease, providing invaluable structural and functional information. In the last 20 years, 3-dimensional echocardiography (3DE) has emerged as an adjunct to 2-dimensional echocardiography in adult and congenital heart disease. Early work with 3-dimensional imaging of the mitral valve describing normal annular shape and function significantly changed the understanding of mitral valve dynamics. Further work led to our current understanding of the mitral valve working as a unit, with all components vital to its normal function. With improving technology and ease of use, similar 3DE techniques have been used in congenital heart disease to study the unique anatomy and function of atrioventricular (AV) valves, specifically the tricuspid valve in hypoplastic left heart syndrome, and the left AV valve in atrioventricular septal defects. This paper describes the role of 3DE in assessing AV valve function in normal valves, and in congenital heart disease.

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.

Three-dimensional echocardiography in the assessment of congenital mitral valve disease.

Congenital mitral valve abnormalities are rare and cause mitral stenosis, regurgitation, or a combination of the two. Three-dimensional echocardiography has provided new insight into the structure and function of both normal and abnormal mitral valves. Three-dimensional imaging permits accurate anatomic diagnosis and enhances two-dimensional echocardiographic data. Moreover, it enables echocardiographers to communicate effectively with cardiothoracic surgeons when displaying, analyzing, and describing pathology. The purpose of this report is to review congenital mitral valve disease, focusing on the benefits of three-dimensional echocardiography in its evaluation.

Effectiveness of prenatal screening for congenital heart disease: assessment in a jurisdiction with universal access to health care.

BACKGROUND: Neonates with certain forms of severe congenital heart disease (CHD) diagnosed prenatally might have better outcomes in comparison with those diagnosed after birth. The proportion of prenatally detected neonates with severe CHD and the effect of prenatal diagnosis on clinical outcomes have not been previously investigated in Canada. METHODS: We retrospectively studied infants in Alberta, Canada, who required surgical or catheter intervention for CHD at younger than 1 year of age, between January 2007 and December 2010, and pregnancy terminations affected by CHD. RESULTS: Of the 374 subjects identified (327 infants, 47 pregnancies with termination), 188 (50%) were detected prenatally. Failure of prenatal diagnosis was associated with anomalies not involving the 4-chamber view on ultrasound (odds ratio, 1.86; 95% confidence interval, 1.48-2.35; P < 0.001) and region of residence (P = 0.04). Prenatal detection was associated with fewer days to hospital admission (P < 0.001), fewer days to surgery (P = 0.003), and greater use of prostaglandins (P = 0.001). Infants diagnosed prenatally who underwent surgery within 15 days of age had higher preductal O2 saturations (P = 0.04), fewer days to admission (P = 0.03), and less frequently required preoperative intubation (P = 0.004), and inotropes (P = 0.001). Pregnancy termination occurred among 49% of fetuses detected before 24 weeks' gestation. CONCLUSIONS: Only 50% of fetuses and/or neonates with severe CHD managed in Alberta have a prenatal diagnosis. The likelihood of prenatal detection is influenced by the status of the 4-chamber view on ultrasound and the region of maternal residence indicating heterogeneous access to fetal echocardiography within Alberta. Prenatal detection might improve clinical outcomes for neonates with severe CHD.

The assessment of atrial function in single ventricle hearts from birth to Fontan: a speckle-tracking study by using strain and strain rate.

BACKGROUND: Single ventricle (SV) exercise performance is impaired and limited by reduced ventricular preload reserve. The atrium modulates ventricular filling, and enhancement of atrial compliance can increase cardiac performance. We aimed to study atrial mechanics in SV hearts across staged surgical palliation compared with healthy children by using novel speckle-tracking echocardiography techniques. METHODS: A cross-sectional study of 81 patients with SV (1 day to 6.5 years) at 4 stages of surgical palliation (presurgery, 22; prebidirectional cavopulmonary anastomosis, 23; pre-Fontan, 22; post-Fontan, 14). The dominant atrium was assessed with speckle-tracking echocardiography for active (εact), conduit (εcon), and reservoir (εres) strain; strain rate (SR); and εact/εres ratio before each stage of surgical palliation. Findings were compared with the left atrium of 51 healthy children (1 day to 5.5 years). RESULTS: Single ventricle atrial size was increased (P < .01), and atrial εres was decreased (P < .01) compared with healthy controls. SV atrial εcon (P < .01) and SRcon (P < .0001) was decreased, increased εact persisted (P < .05), and εact/εres was increased (P < .001) between surgical stages. Although the expected maturational trend of increasing εcon, decreasing εact, and εact/εres occurred in SV, they lagged behind healthy maturational changes (P < .0001). CONCLUSION: Single ventricle atrium is dilated, has deceased compliance, decreased early diastolic emptying, and increased reliance on active atrial contraction for ventricular filling. This deviates from normal early childhood maturational changes and appears to parallel those of an atrium facing early ventricular diastolic dysfunction.

Partial zone of apposition closure in atrioventricular septal defect: are papillary muscles the clue.

BACKGROUND: Long-term survival after atrioventricular septal defect repair is excellent; however, postoperative left atrioventricular valve regurgitation affects morbidity and quality of life. Left atrioventricular valve regurgitation is the most common reason for reoperation after repair and it is critical that clinicians recognize pathologic mechanisms pre-repair. METHODS: In this single-center experience, we identified a pattern of left atrioventricular valve abnormality in 5 cases presenting for routine surgical repair between 1 month and 24 years of age. We reviewed two-dimensional and real-time three-dimensional echocardiographic and surgical findings to assess for specific valvar or sub-valve abnormalities, including short chordae, commissural deformities, and an eccentric zone of apposition. Two-dimensional echocardiography was used to assess the degree of preoperative and postoperative left atrioventricular valve regurgitation. RESULTS: Abnormal features identified included short, thickened chordae, poorly formed superior-mural commissure, and an eccentric zone of apposition. At surgical repair, 2 patients had limited closure of the zone of apposition, as part of a complete repair, and developed only mild left atrioventricular valve regurgitation in short-term follow-up. Two further patients had attempted complete closure of the zone of apposition with moderate postoperative regurgitation ultimately necessitating left atrioventricular valve replacement. CONCLUSIONS: This uncommon form of atrioventricular septal defect is identifiable with echocardiography and may be associated with significant postoperative regurgitation if the zone of apposition is completely sutured at time of repair. Limited closure of the zone of apposition may improve postoperative regurgitation.

Quantitative real-time three-dimensional echocardiography provides new insight into the mechanisms of mitral valve regurgitation post-repair of atrioventricular septal defect.

BACKGROUND: Mechanisms of mitral valve regurgitation after atrioventricular septal defect repair are unclear. METHODS: To gain further insight into mitral valve regurgitation, real-time three-dimensional echocardiography was performed in 53 patients after atrioventricular septal defect repair (30 partial and 23 complete) and 40 controls. Mitral valve {x, y, z} coordinates from the annulus, leaflet surface, papillary muscle, and chordal attachments were recorded. Vena contracta area of the regurgitant jet(s) and volume of leaflet prolapse and tethering were measured. RESULTS: Twenty-three patients had mild (group 1) and 30 moderate (group 2) mitral valve regurgitation. Patients in both groups 1 and 2 had more circular annuli than controls. Annular area was greater in group 2 than in group 1 and controls (P < .01). Group 2 had more frequent segmental prolapse in the superior-mural leaflet segment. The anterolateral papillary muscle was more laterally displaced in group 2 than in controls and group 1 at end-diastole (P = .01 and P = .05) and formed a more acute angle with the mitral valve annulus than in controls or group 1 (P = .01). CONCLUSIONS: In patients with atrioventricular septal defects, significant mitral valve regurgitation is associated with leaflet prolapse, larger annular area, and lateral papillary muscle displacement.

Single right ventricles have impaired systolic and diastolic function compared to those of left ventricular morphology.

BACKGROUND: Differences in single right ventricle (SRV) and single left ventricles (SLV) function are poorly described, although myocardial dysfunction is an important risk factor for morbidity and mortality. The aims of this study were to compare function between patients with SRVs and those with SLVs using newer echocardiographic techniques and to determine differences across staged palliation. METHODS: In this cross-sectional study comparing 30 patients with SRVs and 30 with SLVs of similar ages (2.5 ± 1.7 vs 2.6 ± 1.6 years), patients were matched for surgical stage (20 pre-bidirectional cavopulmonary anastomosis, 20 pre-Fontan, and 20 post-Fontan patients). Circumferential and longitudinal strain, strain rate (SR), early diastolic SR, postsystolic strain index, and myocardial dyssynchrony index were measured. Comparisons between SRV and SLV parameters were made as a whole group and by subanalysis at each surgical stage. RESULTS: Patients with SRVs had reduced systolic SRs (circumferential: -1.0%/sec vs -1.2%/sec, P = .01; longitudinal: -1.1%/sec vs -1.3%/sec, P = .002), reduced early diastolic SRs (circumferential: 1.4%/sec vs 1.9%/sec, P = .03; longitudinal: 1.6%/sec vs 2.2%/sec, P = .001), and increased circumferential postsystolic strain indexes (8% vs 0%, P < .0001). Subanalysis at each surgical stage showed that the greatest disparity in systolic parameters occurred before bidirectional cavopulmonary anastomosis (longitudinal SR, P = .009; postsystolic strain index, P = .005) and that parity was regained after the Fontan procedure, while traditional diastolic parameters (E velocity, P = .004; E/E' ratio, P = .0003) were reduced in patients with SRVs after the Fontan procedure. CONCLUSIONS: The SRV has reduced contractility and diastolic function compared with the SLV. Ventricular systolic performance in patients with SRVs was poorest before bidirectional cavopulmonary anastomosis, while differences in diastolic function were more prominent after Fontan completion.

Evaluation of atrioventricular septal defects by three-dimensional echocardiography: benefits of navigating the third dimension.

Atrioventricular septal defects comprise a disease spectrum characterized by deficient atrioventricular septation, with several common features seen in all affected hearts and variability in atrioventricular valve morphology and interatrial and interventricular communications. Atrioventricular septal defects are among the more common defects encountered by pediatric cardiologists and echocardiographers. Despite advances in understanding, standard two-dimensional echocardiography may not be the optimal method for the morphologic and functional evaluation of this lesion, particularly malformations of the atrioventricular valve(s). In this review, the authors summarize the role of three-dimensional echocardiography in the diagnostic evaluation of atrioventricular septal defects.

Serial assessment of right ventricular volume and function in surgically palliated hypoplastic left heart syndrome using real-time transthoracic three-dimensional echocardiography.

BACKGROUND: Right ventricular (RV) failure is a major cause of morbidity and mortality in patients with hypoplastic left heart syndrome (HLHS), but the longitudinal course of RV volumes through staged palliation (SP) has not been previously investigated. The aim of this study was to evaluate RV volume and function longitudinally through SP of HLHS using real-time three-dimensional echocardiography. METHODS: A total of 18 subjects with HLHS were prospectively studied at four time points from diagnosis through stage 2 (SP2). Real-time three-dimensional echocardiographic full-volume data sets were acquired in high-frame rate mode with electrocardiographic gating. Volumetric and functional analyses were performed using a semiautomatic contour detection algorithm. Eighteen age-matched and sex-matched normal infants (aged 0-6 months) were studied at comparable time points as controls. RESULTS: Presurgical examinations (pre-stage 1 [SP1]; n = 18) were performed at a mean age of 4 days, post-SP1 examinations (n = 17) at a mean age of 20 days, pre-SP2 examinations (n = 14) at a mean age of 4.6 months, and post-SP2 examinations (n = 14) at a mean age of 5.5 months, constituting a total of 63 examinations. The mean values of RV end-diastolic volume indexed to body surface area (EDVi) at the four time points were 87 ± 30, 104 ± 39, 112 ± 34, and 102 ± 35 mL/m(2), respectively. There was an increase in EDVi (P = .024) from pre-SP1 to post-SP1 but no significant change between post-SP1 and pre-SP2. The decrease in EDVi after SP2 did not reach statistical significance. Mean RV ejection fractions (EFs) were 50 ± 5%, 45 ± 5%, 46 ± 5%, and 38 ± 4%, respectively. There was a trend toward decreasing EF throughout SP, with statistically significant decreases from pre-SP1 to post-SP1 (P = .003) and from pre-SP2 to post-SP2 (P < .001). In normal infants, the mean RV EDVi was 50 ± 10 mL/m(2) (approximately half that of patients with HLHS), and the mean EF was 51 ± 3%. There was good interobserver agreement for EDVi, end-systolic volume indexed to body surface area, and EF. CONCLUSIONS: Real-time three-dimensional echocardiography is a reproducible means for evaluating RV volumes and EFs in patients with HLHS. Indexed RV diastolic volume remains stable to slightly increased, and RV EF deteriorates as the first two stages of surgical palliation are accomplished. The findings of this study highlight the adverse physiology of HLHS, which deteriorates even among early survivors despite SP.

Novel insights into RV adaptation and function in hypoplastic left heart syndrome between the first 2 stages of surgical palliation.

OBJECTIVES: This study sought to examine the changes in ventricular function of hypoplastic left heart syndrome (HLHS) between the first 2 stages of surgical palliation. BACKGROUND: The mortality risk between first and second stages of surgical palliation in HLHS remains high. Right ventricular (RV) dysfunction predicts mortality. Postulated mechanisms include a maladaptive contraction pattern, myocardial ischemia, or contraction asynchrony. Speckle tracking imaging allows accurate measurement of myocardial deformation without geometric assumptions. METHODS: Prospective echocardiography pre-Norwood and pre-bidirectional cavopulmonary anastomosis (BCPA) examinations were performed in 20 HLHS patients, with comparisons made between stages. Measurements of ventricular function included: longitudinal/circumferential strain ratio, reflecting changes in contraction pattern; post-systolic strain index, a potential marker of myocardial ischemia; and mechanical dyssynchrony index. Relationships between echocardiographic variables and magnetic resonance imaging RV parameters before BCPA were examined. RESULTS: Before BCPA, myocardial contractility estimated by isovolumic acceleration and strain rate was reduced, paralleled by an increased in post-systolic strain index (p < 0.01). Right ventricular longitudinal/circumferential strain ratio decreased, becoming similar to a left ventricle-like contraction pattern, and this correlated with decreased mechanical dyssynchrony index (r = 0.65, p < 0.01), magnetic resonance imaging RV end-diastolic volume (r = 0.65, p < 0.05) and mass (r = 0.71, p < 0.01). Ventricular strain (r = -0.72, p < 0.01), strain rate (r = -0.85, p < 0.001), and mechanical dyssynchrony index (r = -0.73, p < 0.01) correlated linearly with magnetic resonance imaging-derived RV ejection fraction. CONCLUSIONS: Reduced RV contractility occurred before BCPA. RV with a left ventricle-like contraction pattern was associated with improved contraction synchrony as well as a reduction in RV size and mass in HLHS. The finding of increased post-systolic strain index before BCPA is novel and its potential link with myocardial ischemia warrants further investigation. RV strain, strain rate, and contraction synchrony measured by speckle tracking imaging correlated closely with ventricular function and might be useful for monitoring ventricular function in HLHS.

Two-dimensional versus transthoracic real-time three-dimensional echocardiography in the evaluation of the mechanisms and sites of atrioventricular valve regurgitation in a congenital heart disease population.

BACKGROUND: Data are lacking on the utility of real-time three-dimensional (3D) echocardiography (RT3DE) in congenital abnormalities of the atrioventricular (AV) valves. The purpose of this study was to determine whether transthoracic RT3DE is superior to combined transthoracic echocardiography and two-dimensional (2D) transesophageal echocardiography in determining mechanisms and sites of AV valve regurgitation in congenital heart disease. METHODS: Between January 2005 and November 2007, 48 consecutive patients were studied prior to AV valve repair (22 left AV valves and 26 tricuspid valves) using 2D transthoracic echocardiography, 2D transesophageal echocardiography, and transthoracic RT3DE. Ages ranged from 24 days to 30 years. The 2D data were reviewed by blinded observers, and the real-time 3D data by a separate observer. In all patients, surgical findings were documented by a surgical report, while in 40, video recordings were also available. Surgical findings were used as the reference standard for structural abnormalities; RT3DE was the reference standard for the site of AV valve regurgitation. RESULTS: Compared with 2D echocardiography, RT3DE provided superior detail of the mural leaflet and anterior commissural abnormalities for the left AV valve. For the tricuspid valve, improved detection of leaflet abnormalities, prolapse of the anterior and posterior leaflets, and commissural pathology was observed by RT3DE. Apart from a central location, surgical saline testing correlated poorly with jet location on RT3DE. CONCLUSION: RT3DE provides complementary information as to the mechanisms and sites of AV valve failure in congenital heart disease.

Defining left ventricular apex-to-base twist mechanics computed from high-resolution 3D echocardiography: validation against sonomicrometry.

OBJECTIVES: To compute left ventricular (LV) twist from 3-dimensional (3D) echocardiography. BACKGROUND: LV twist is a sensitive index of cardiac performance. Conventional 2-dimensional based methods of computing LV twist are cumbersome and subject to errors. METHODS: We studied 10 adult open-chest pigs. The pre-load to the heart was altered by temporary controlled occlusion of the inferior vena cava, and myocardial ischemia was produced by ligating the left anterior descending coronary artery. Full-volume 3D loops were reconstructed by stitching of pyramidal volumes acquired from 7 consecutive heart beats with electrocardiography gating on a Philips IE33 system (Philips Medical Systems, Andover, Massachusetts) at baseline and other steady states. Polar coordinate data of the 3D images were entered into an envelope detection program implemented in MatLab (The MathWorks, Inc., Natick, Massachusetts), and speckle motion was tracked using nonrigid image registration with spline-based transformation parameterization. The 3D displacement field was obtained, and rotation at apical and basal planes was computed. LV twist was derived as the net difference of apical and basal rotation. Sonomicrometry data of cardiac motion were also acquired from crystals anchored to epicardium in apical and basal planes at all states. RESULTS: The 3D dense tracking slightly overestimated the LV twist, but detected changes in LV twist at different states and showed good correlation (r = 0.89) when compared with sonomicrometry-derived twist at all steady states. In open chest pigs, peak cardiac twist was increased with reduction of pre-load from inferior vena cava occlusion from 6.25 degrees +/- 1.65 degrees to 9.45 degrees +/- 1.95 degrees . With myocardial ischemia from left anterior descending coronary artery ligation, twist was decreased to 4.90 degrees +/- 0.85 degrees (r = 0.8759). CONCLUSIONS: Despite lower spatiotemporal resolution of 3D echocardiography, LV twist and torsion can be computed accurately.