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Objectives: Many patients with Fontan physiology are unable to achieve the minimum criteria for peak effort during cardiopulmonary exercise testing. The purpose of this study is to determine the influence of physical activity and other clinical predictors related to achieving peak exercise criteria, signified by respiratory exchange ratio ≥ 1.1 in youth with Fontan physiology. Methods: Secondary analysis of a cross-sectional study of 8–18-year-olds with single ventricle post-Fontan palliation who underwent cardiopulmonary exercise testing (James cycle protocol) and completed a past-year physical activity survey. Bivariate associations were assessed by Wilcoxon rank-sum test and simple regression. Conditional inference forest algorithm was used to classify participants achieving respiratory exchange ratio > 1.1 and to predict peak respiratory exchange ratio. Results: Of the n = 43 participants, 65% were male, mean age was 14.0 ± 2.4 years, and 67.4% (n = 29) achieved respiratory exchange ratio ≥ 1.1. Despite some cardiopulmonary exercise stress test variables achieving statistical significance in bivariate associations with participants achieving respiratory exchange ratio > 1.1, the classification accuracy had area under the precision recall curve of 0.55. All variables together explained 21.4% of the variance in respiratory exchange ratio, with peak oxygen pulse being the most informative. Conclusion: Demographic, physical activity, and cardiopulmonary exercise test measures could not classify meeting peak exercise criteria (respiratory exchange ratio ≥ 1.1) at a satisfactory accuracy. Correlations between respiratory exchange ratio and oxygen pulse suggest the augmentation of stroke volume with exercise may affect the Fontan patient’s ability to sustain high-intensity exercise.

Background: Understanding the clinical course and short-term outcomes of suspected myocarditis after the coronavirus disease 2019 (COVID-19) vaccination has important public health implications in the decision to vaccinate youth. Methods: We retrospectively collected data on patients Results: We report on 139 adolescents and young adults with 140 episodes of suspected myocarditis (49 confirmed, 91 probable) at 26 centers. Most patients were male (n=126, 90.6%) and White (n=92, 66.2%); 29 (20.9%) were Hispanic; and the median age was 15.8 years (range, 12.1–20.3; interquartile range [IQR], 14.5–17.0). Suspected myocarditis occurred in 136 patients (97.8%) after the mRNA vaccine, with 131 (94.2%) after the Pfizer-BioNTech vaccine; 128 (91.4%) occurred after the second dose. Symptoms started at a median of 2 days (range, 0–22; IQR, 1–3) after vaccination. The most common symptom was chest pain (99.3%). Patients were treated with nonsteroidal anti-inflammatory drugs (81.3%), intravenous immunoglobulin (21.6%), glucocorticoids (21.6%), colchicine (7.9%), or no anti-inflammatory therapies (8.6%). Twenty-six patients (18.7%) were in the intensive care unit, 2 were treated with inotropic/vasoactive support, and none required extracorporeal membrane oxygenation or died. Median hospital stay was 2 days (range, 0–10; IQR, 2–3). All patients had elevated troponin I (n=111, 8.12 ng/mL; IQR, 3.50–15.90) or T (n=28, 0.61 ng/mL; IQR, 0.25–1.30); 69.8% had abnormal ECGs and arrhythmias (7 with nonsustained ventricular tachycardia); and 18.7% had left ventricular ejection fraction Conclusions: Most cases of suspected COVID-19 vaccine myocarditis occurring in persons

Objectives:Many children diagnosed with COVID-19 infections did not require hospitalisation. Our objective was to analyse electrocardiographic changes in children with asymptomatic, mild or moderate COVID-19 who did not require hospitalisationMethods:All children are seen in a paediatric cardiology clinic who had asymptomatic, mild or moderate COVID-19 that did not require hospitalisation and had at least one electrocardiogram after their diagnosis were included in this retrospective analysis. Records were reviewed to determine COVID-19 disease severity and presence of Long COVID. Rhythm assessment, atrial enlargement, ventricular hypertrophy, PR/QRS/QT interval duration and ST-T wave abnormalities were analysed by a paediatric electrophysiologist. Clinically ordered echocardiograms were reviewed for signs of myopericarditis (left ventricular ejection fraction and pericardial effusion) on any subject with an electrocardiographic abnormality.Results:Of the 82 children meeting inclusion criteria (14.4 years, range 1–18 years, 57% male), 17 patients (21%) demonstrated electrocardiographic changes. Ten patients (12%) had electrocardiogram of borderline significance, which included isolated mild PR prolongation or mild repolarisation abnormalities. The other seven patients (9%) had concerning electrocardiographic findings consisting of more significant repolarisation abnormalities. None of the patients with an abnormal electrocardiogram revealed any echocardiographic abnormality. All abnormal electrocardiograms normalised over time except in two cases. Across the entire cohort, greater COVID-19 disease severity and long COVID were not associated with electrocardiographic abnormalities.Conclusions:Electrocardiographic abnormalities are present in a minority of children with an asymptomatic, mild or moderate COVID-19 infection. Many of these changes resolved over time and no evidence of myopericarditis was present on echocardiography.

Background The Long-ter M O U tcomes after the Multisystem Inflammatory S yndrome I n C hildren (MUSIC) study aims to characterize the frequency and time course of acute and long-term cardiac and non-cardiac sequelae in multisystem inflammatory syndrome in children associated with COVID-19 (MIS-C), which are currently poorly understood. Methods This multicenter observational cohort study will enroll at least 600 patients Conclusion The MUSIC study, with the largest cohort of MIS-C patients and the longest follow-up period to date, will make an important contribution to our understanding of the acute cardiac and non-cardiac manifestations of MIS-C and the long-term effects of this public health emergency.

Background Right ventricular global longitudinal strain (RVGLS) has emerged as an important technique for clinical evaluation of (RV) function. The routine application of RVGLS in pediatrics remains limited by a lack of data on agreement between vendors. The aim of this study was to investigate intervendor agreement for RVGLS between the two commonly used analysis vendors in pediatrics, hypothesizing that RVGLS has good intervendor agreement, although it is likely lower than intravendor agreement (inter- and intraobserver reproducibility). Methods Seventy infants and children with normal cardiac anatomy and varying ventricular function were included after prospectively obtaining RV-focused four-chamber apical images on the GE Vivid E95. Images were analyzed for RVGLS at acquired frame rates in EchoPAC (GE) and TomTec (TT) and in the compressed Digital Imaging and Communications in Medicine format in TT. Intraclass correlation coefficients and Bland-Altman plots were used to test intervendor agreement and intravendor reproducibility. Results RVGLS measurements were equally feasible using TT and EchoPAC analysis (92%). There was good to excellent agreement for RVGLS between TT and EchoPAC analysis, with a relatively higher intraclass correlation coefficient between GE and TT at the acquired frame rate (0.85) than between GE and TT at the compressed frame rate (0.75) and significantly higher agreement in patients with abnormal RV function (0.7–0.9) than those with normal function (0.4–0.6). Intra- andinterobserver reproducibility for RVGLS was excellent (intraclass correlation coefficient = 0.74–0.96). Heart rate ≥ 100 beats/min and acquisition frame rate/heart rate ≤ 0.7 were associated with diminished agreement, especially when compressed data were involved. Conclusions RVGLS analyzed using EchoPAC and TT show good agreement, especially when analyzed at acquisition frame rates and in the setting of abnormal RV function. Otherwise, RVGLS should ideally be analyzed using the same vendor, and intervendor comparisons should be undertaken with caution, particularly if data are in a compressed format.

Introduction: Children with a single ventricle post-Fontan palliation are at increased risk of poor outcomes with peak oxygen consumption acting as a surrogate outcome marker. The purpose of this study is to evaluate the relationship between peak oxygen consumption and echocardiographic measures of ventricular function and deformation, including ventricular global longitudinal strain and dyssynchrony, in children and adolescents following Fontan palliation. Methods: Patients (age 8–21 years) with single ventricle post-Fontan palliation were prospectively recruited and participated in an echocardiogram, including views optimised for two-dimensional speckle tracking, and a cardiopulmonary exercise test on a cycle ergometer to maximal volitional fatigue. Results: Thirty-eight patients (mean age 13.7 ± 2.3 years) post-Fontan palliation had either a single left ventricular (n = 20), single right ventricular (n = 14), or biventricular (n = 4) morphology. Peak oxygen consumption (24.9 ± 5.6 ml/kg/minute) was correlated with global longitudinal strain (r = −0.435, p = 0.007), a strain discoordination time to peak index (r = −0.48, p = 0.003), and the presence of an electro-mechanical dyssynchrony strain pattern (p = 0.008). On multivariate regression modelling, these three variables were associated with peak oxygen consumption independently of age and sex. The single right ventricular group had evidence of possible diastolic dysfunction by E/e’ compared to the single left ventricular and biventricular groups (p = 0.001). Conclusions: Strain analysis measures are correlated with peak oxygen consumption in this cohort of children, adolescents, and young adults following Fontan palliation, suggesting that ventricular mechanics may influence the efficiency of the Fontan circulation.

Hematopoietic growth factors (HGFs) are a group of glycoproteins, termed colony stimulating factors (CSFs) or interleukins (ILs) that are believed to control the proliferation, differentiation and survival of hematopoietic stem and/ or progenitor cells

In Hypoplastic Left Heart Syndrome (HLHS), RV dysfunction is associated with poor outcomes. However, the effect of varying LV size on regional RV mechanics and outcome has not been studied.Twenty newborns (0-7 days) with HLHS had pre-stage 1 and pre-stage 2 echocardiograms prospectively protocoled for strain analysis of the apical 4-chamber view. RV longitudinal strain was analyzed, and LV size was classified as diminutive (no visible LV chamber) or moderate size (visible LV chamber). Clinical outcome was reported as alive vs death or transplant (D-TP) at final clinical follow-up (pre-stage 3). Groups were compared with t-test, Fisher's Exact, and ANOVA tests as appropriate.At pre-stage 1, infants with a diminutive LV (7/20, 35%) vs a moderately hypoplastic LV (13/20, 65%) did not have significantly different global RV strain (-18.4 ± 2.6% vs -18.8 ± 3.2%; p = 0.83). However, basal septal strain was significantly diminished in the moderately hypoplastic LV group vs the diminutive LV group (-4.4 ± 6.0% vs -14.7 ± 3.3%; p 0.005). There was severely diminished septal strain in nearly all (11/13) of the moderately hypoplastic group. At the pre-stage II echo, global RV strain between groups remained similar (p = 0.76) as did the diminished septal strain in the moderate LV group (p = 0.86). The moderately hypoplastic LV group had worse clinical outcomes (6/13 D-TP vs 0/7 D-TP; p = 0.05).In this small HLHS cohort, diminished septal strain leading to asymmetric RV mechanics may be associated with poor outcomes in those with larger LV/septal size.

We report a rare case of anomalous aortic origin of the right coronary artery from the posterior/non-coronary sinus of Valsalva in a 9-year-old male diagnosed during the workup of premature ventricular contractions. The finding was initially noted on transthoracic echocardiogram and further confirmed with computed tomography. The anomalous coronary artery shows a wide ostium with no intramural or interarterial course.

Patients with systemic right ventricles frequently experience progressive heart failure and conduction abnormalities leading to abnormal ventricular activation. Activation delay-induced mechanical dyssynchrony can contribute to ventricular failure and is identified by a classic strain pattern of paradoxical opposing wall motion that is an excellent predictor of response to cardiac resynchronization therapy in adults with left bundle branch block. The specific aims of this study were to compare right ventricular (RV) mechanics in an adult systemic right ventricle population versus control subjects, evaluate the feasibility of this RV strain pattern analysis, and determine the frequency of the classic pattern.Young adults (n = 25) with d-transposition of the great arteries, status post Mustard or Senning palliation (TGA-MS), were ambispectively enrolled and compared with healthy young adults (n = 30) who were prospectively enrolled. All subjects were imaged using novel three-apical view (18-segment) RV longitudinal speckle-tracking strain analysis (EchoPAC) and electrocardiographic data.Patients with TGA-MS had diminished RV global peak systolic strain compared with control subjects (-12.0 ± 4.0% vs -23.3 ± 2.3%, P .001). Most patients with TGA-MS had intrinsic or left ventricular paced right bundle branch block. A classic pattern was present in 11 of 25 subjects (44%), but this pattern would have been missed in four of 11 based only on the RV four-chamber (six-segment) model. Only three subjects underwent cardiac resynchronization therapy. Both subjects who had the classic pattern responded to cardiac resynchronization therapy, whereas the one nonresponder did not have the classic pattern.Systemic right ventricles demonstrated decreased function and increased mechanical dyssynchrony. The classic pattern of activation delay-induced mechanical dyssynchrony was frequently seen in this TGA-MS population and associated with activation delays. This comprehensive RV approach demonstrated incremental value.

Background Pediatric dilated cardiomyopathy (DCM) is associated with death or transplantation and is typically considered a homogeneous process affecting global left ventricular (LV) function. However, assessment of regional abnormalities that contribute to pumping inefficiencies is lacking. The aim of this study was to define regional strain patterns of mechanical inefficiency in the broader context of LV discoordination (dysfunction and timing abnormalities) and to evaluate their associations with LV function and clinical outcomes. Methods Multiplanar apical LV echocardiographic images from patients with pediatric DCM ( n = 56) and control subjects ( n = 20) were analyzed by two-dimensional longitudinal speckle-tracking strain analysis to identify segmental strain patterns and global contraction groups. Clinical outcome (death or transplantation vs transplantation-free survival) and echocardiographic data were evaluated. Outcome groups were compared using the Fisher exact test, the χ 2 test, or analysis of variance (with P values ≤ .05 considered to indicate statistical significance). Results Of 56 patients with DCM, 29 (52%) progressed to death or transplantation. Five segmental strain patterns were observed that were used to define seven contraction groups by regional contractility and/or timing discoordination. The group(s) with the most discoordination had the most LV dysfunction ( P = .0004) and a trend toward the highest frequency of death or transplantation ( P = .069). Interreader reproducibility of segmental strain patterns agreed in 165 or 180 (92%) segments tested (κ = 0.90). Control subjects had normal strain patterns. Conclusions A heterogeneous mixture of abnormalities in the regional wall mechanics that lead to inefficient pump mechanics through functional and timing abnormalities were seen in this cohort and were categorized into natural subgroups. More severe LV discoordination was associated with increased LV dysfunction and a trend toward death or transplantation.

Nearly all individuals with Down Syndrome (DS) display pathology associated with Alzheimer's disease (AD) beginning as early as age 30. Previous research in typically developed adults suggests that increased moderate-to-vigorous physical activity (MVPA) may improve cognitive function and protect against age-related structural and functional changes in the brain; however, the potential impact of increased MVPA on the development of AD in adults with DS has not been evaluated. Despite the potential positive impact of MVPA on cognition and AD risk, participation in MVPA among young adults with DS is low. The limited research evaluating strategies for increasing MVPA in adults with DS has been unsuccessful in increasing MVPA. Results from our preliminary investigation where we remotely delivered real-time MVPA, led by a trained health educator, to groups of adults with DS in their homes via video conferencing on a tablet computer demonstrated high attendance, increased MVPA during group sessions, and improvements in cognitive function. However, the sustainability, impact on total daily MVPA, optimal session frequency, and potential impacts on cognitive function and brain health of remotely delivered group MVPA sessions in adults with DS are unknown. Therefore, we will conduct a trial in 80 non-demented adults with DS to determine the feasibility and potential efficacy of remotely delivered group MVPA sessions to increase daily MVPA, relative to a usual care control. Secondarily we will assess the impact of MVPA on cardiovascular fitness, quality of life, cognitive function and brain parameters related to AD. NCT registration NCT04048759.

Objective The aim of the study was to determine right and left ventricle deformation parameters in patients with transposition of the great arteries who had undergone atrial or arterial switch procedures. Setting Patients with transposition are born with a systemic right ventricle. Historically, the atrial switch operation, in which the right ventricle remains the systemic ventricle, was performed. These patients have increased rates of morbidity and mortality. We used cardiac MRI with Velocity Vector Imaging analysis to characterize and compare ventricular myocardial deformation in patients who had an atrial switch or arterial switch operation. Design Patients with a history of these procedures, who had a clinically ordered cardiac MRI were included in the study. Consecutive 20 patients (75% male, 28.7 ± 1.8 years) who underwent atrial switch operation and 20 patients (60% male, 17.7 ± 1.9 years) who underwent arterial switch operation were included in the study. Four chamber and short-axis cine images were used to determine longitudinal and circumferential strain and strain rate using Vector Velocity Imaging software. Results Compared with the arterial switch group, the atrial switch group had decreased right ventricular ejection fraction and increased end-diastolic and end-systolic volumes, and no difference in left ventricular ejection fraction and volumes. The atrial switch group had decreased longitudinal and circumferential strain and strain rate. When compared with normal controls multiple strain parameters in the atrial switch group were reduced. Conclusions Myocardial deformation analysis of transposition patients reveals a reduction of right ventricular function and decreased longitudinal and circumferential strain parameters in patients with an atrial switch operation compared with those with arterial switch operation. A better understanding of the mechanisms of right ventricle failure in transposition of great arteries may lead to improved therapies and adaptation.

Varying degrees of heart failure is common in infants with complex single ventricular heart disease. Sometimes the heart failure is progressive without a clear etiology and unresponsive to intense pharmacotherapy creating a critical management dilemma. These infants typically share a common history of repeated and lengthy intensive care unit (ICU) admissions and they often require temporizing measures of extracorporeal membrane oxygenation (ECMO), or ventricular assist device (VAD) before progressing to cardiac transplantation or death.

There are two major functional applications for speckle tracked strain used in the study of cardiac function: global and regional. This chapter is about regional functional strain assessment. The basics of ultrasound speckle tracking and strain are discussed in detail elsewhere in this volume and this current chapter assumes a familiarity with these principles.

Measurement of myocardial global longitudinal strain (GLS) is no longer a research tool. Rather, GLS is now used for risk assessment and management of patients with a wide variety of clinical disorders. GLS is clearly a useful supplement to routine quantitative analysis of left ventricular performance along with ejection fraction and left ventricular diameters.

Progressive heart failure leading to transplantation or death is common in pediatric dilated cardiomyopathy (DCM), and treatment options are limited. Select children with DCM have improved after cardiac resynchronization therapy (CRT), but predicting response is challenging. Nonetheless, considering the frequency of death or transplantation in this population, identifying any candidate would be valuable. Classic-pattern dyssynchrony (CPD) identifies mechanical dyssynchrony patterns consistent with underlying electrical activation delays and strongly predicts CRT response in adult DCM but has not been evaluated in pediatric DCM. The aim of this study was to test the hypothesis that CPD is present in a subgroup of patients with pediatric DCM and is associated with activation delays.Fifty-nine subjects with pediatric DCM (left ventricular end-diastolic diameter Z score2 and left ventricular ejection fraction40%) who underwent echocardiography with a functional protocol with apical images optimized for two-dimensional speckle-tracking strain analysis (EchoPAC) were retrospectively analyzed for CPD. Electrocardiograms were evaluated for activation delays (prolonged QRS duration and strict criteria for left bundle branch block [LBBB]). Forty control subjects with no cardiac disease and good imaging widows were also analyzed.The mean age was 5.4 years (range, 1 day to 20 years); idiopathic DCM was most common (57%). Severe cardiomyopathy was present in 75% (end-diastolic diameter Z score4.6 and left ventricular ejection fraction32%). CPD was identified in seven subjects (12%), and prolonged QRS durations were present in 13 (22%), but only two subjects met strict criteria for LBBB. Six of seven subjects in the CPD group had prolonged QRS durations, and two of seven had LBBB. No control subjects had CPD. The CPD analysis was highly feasible and reproducible.In this severely affected cohort, the small CPD subgroup is potentially important because their progressive disease may respond to CRT. CPD is associated with activation delays, although not necessarily strict LBBB. This has important potential implications for prospective evaluation of CRT in this disease.

Objectives: To evaluate feasibility, efficacy, and safety of an approach to atrial septal defect (ASD) occlusion in children ≤20 kg that eliminates cardiac wall erosion risk. Background: Cardiac wall erosion is a potentially catastrophic complication of ASD device closure. The HELEX Septal Occluder (HSO) is a compliant device with no reports of erosion. The HSO is technically difficult to deploy in smaller children and cannot be used to close larger defects. To eliminate wall erosion risk, we use the HSO when feasible and surgery for larger defects. Methods: Retrospective review of ASD procedures performed in children ≤20 kg. Results: Between January 2006 and January 2011, 60 children underwent ASD closure. HSO placement was successful in 32 of 34 patients, and surgical closure was successful in all of 28 patients. Surgical patients were younger (35.1 ± 12.6 vs. 47.4 ± 15.3 months, P < 0.01) and smaller (15.3 ± 3.2 vs. 12.6 ± 4.3 kg; P < 0.01) with larger ASDs (15.8 ± 4.5 vs. 9.8 ± 3.0 mm; P < 0.01). No surgical patients demonstrated residual leak. Residual leak was seen in 14 of 32 (44%) HSO patients on postprocedure day #1 and in 1 of 26 (3.8%) with ≥6 months follow-up. Indications for surgery included: deficient inferior/superior rims (n = 17), provider preference (n = 2), and HSO device not feasible (n = 9). Serious adverse events included device embolization with percutaneous retrieval (n = 1) and postpericardiotomy syndrome without intervention (n = 1). Conclusions: The HSO can be safely used in most children ≤20 kg. Our approach to ASD closure is associated with minimal morbidity and good short-term results. This approach requires no more than a 15% increase in surgical referrals and eliminates risk of cardiac wall erosion. © 2012 Wiley Periodicals, Inc.

A neonate with pulmonary atresia and intract ventricular septum, ventriculocoronary sinusoids, bilateral coronary ostial atresia, and a rare collateral vessel between the descending thoracic aorta and the coronary system is described. The clinical course in this infant included extracorporeal life support and coil occlusion of the collateral in order to manage multiple ischemic events.

Purpose: We evaluated the prevalence of cardiovascular abnormalities and the efficacy and safety of enzyme replacement therapy in patients with late-onset Pompe disease. Methods: Ninety patients were randomized 2:1 to enzyme replacement therapy or placebo in a double-blinded protocol. Electrocardiograms and echocardiograms were obtained at baseline and scheduled intervals during the 78-week study period. Baseline cardiovascular abnormalities, and efficacy and safety of enzyme replacement therapy were described. Three pediatric patients were excluded. Results: Eighty-seven patients were included. Median age was 44 years; 51% were men. At baseline, a short PR interval was present in 10%, 7% had decreased left ventricular systolic function, and 5% had elevated left ventricular mass on echocardiogram (all in mild range). There was no change in cardiovascular status associated with enzyme replacement therapy. No significant safety concerns related to enzyme replacement therapy were identified. Conclusions: Although some patients with late-onset Pompe disease had abnormalities on baseline electrocardiogram or echocardiogram, those classically seen in infantile Pompe disease, such as significant ventricular hypertrophy, were not noted. Cardiovascular parameters were not impacted by enzyme replacement therapy, and there were no cardiovascular safety concerns. The cardiovascular abnormalities identified may be related to Pompe disease or other comorbid conditions.

The biogenesis of multimeric protein complexes of the inner mitochondrial membrane in yeast requires a number of nuclear-coded ancillary proteins. One of these, Pet100p, is required for cytochrome c oxidase. Previous studies have shown that Pet100p is not required for the synthesis, processing, or targeting of cytochrome c oxidase subunits to the mitochondrion nor for heme A biosynthesis. Here, we report that Pet100p does not affect the localization of cytochrome c oxidase subunit polypeptides to the inner mitochondrial membrane but instead functions after they have arrived at the inner membrane. We have also localized Pet100p to the inner mitochondrial membrane in wild type cells, where it is present in a subassembly (Complex A) with cytochrome c oxidase subunits VII, VIIa, and VIII. Pet100p does not interact with the same subunits after they have been assembled into the holoenzyme. In addition, we have identified two subassemblies that are present in pet100 null mutant cells: one subassembly (Complex A′) is composed of subunits VII, VIIa, and VIII but not Pet100p, and another subassembly (Complex B) is composed of subunits Va and VI. Because pet100 null mutant cells lack assembled cytochrome c oxidase but accumulate Complexes A′ and B it appears likely that these subassemblies of cytochrome c oxidase subunits are intermediates along an assembly pathway for holocytochrome c oxidase and that Pet100p functions in this pathway to facilitate the interaction(s) between Complex A′ and other cytochrome c oxidase subassemblies and subunits.

Speckle-tracking strain is almost universally cited as being independent of angle of insonation, but there are minimal confirmatory studies, and this claim may not be consistent with the known limitations of ultrasound axial and lateral spatial resolution. The aim of this study was to assess the influence of angle and depth on longitudinal peak systolic strain (LPS).Thirty-four healthy pediatric subjects (age range, 6-18 years; 47% male) with normal cardiac anatomy and good image quality were prospectively imaged. Angular comparisons of LPS were investigated by examining interangle reproducibility on the basis of one standard and one alternative image acquisition relative to intraobserver reproducibility of two standard views of the same left ventricular segments. A single-window comparison was used to evaluated septal LPS: standard apical four-chamber versus right ventricular centered four-chamber. Two paired standard and alternative window comparisons were as follows: (1) four-chamber: standard apical versus subcostal; and (2) three-chamber: standard apical versus parasternal long-axis.The global LPS intraobserver difference using the paired standard and alternative window comparisons was lower than the interangle difference in global LPS (-1.0 ± 0.1% vs -2.1 ± 2.4%). Intraobserver reproducibility was significantly higher than interangle reproducibility (intraclass correlation coefficient = 0.9 vs 0.29, P .001). Similar results were found in the segmental strain analysis. Interangle reproducibility was significantly decreased compared with intraobserver reproducibility in the septal single-window comparison. Target depth assessment demonstrated a systematic bias between the near-field and far-field segments.Echocardiographically derived LPS values were modestly dependent on angle of insonation and target depth in this pediatric population. Normal strain ranges derived from standard apical images should not be applied to strain derived from sub-costal images, off-axis apical imaging, or applications in which a standard window cannot be defined.

BACKGROUND: Although quantitative right ventricular (RV) strain analysis may be useful in congenital and acquired heart disease populations with RV failure, a comprehensive, standardized approach is lacking. An 18-segment RV strain analysis obtained from three standardized RV apical echocardiographic images was used to determine the feasibility, normal values, and reproducibility of the method in normal adults.METHODS: Forty healthy, prospectively enrolled volunteers with no cardiac histories and normal QRS durations underwent echocardiography optimized for strain analysis including three RV apical views. Two-dimensional speckle-tracking longitudinal strain analysis was performed using EchoPAC software. Eleven retrospectively identified subjects with RV disease were included as a pilot population. All had been imaged using the same protocol including the three RV apical views.RESULTS: All control subjects had normal anatomic morphology and function by echocardiography. Feasibility of the RV strain analysis was good (adequate tracking in 696 of 720 segments [97%]). RV global peak systolic strain was -23 ± 2%. Peak strain was highest in the RV free wall and lowest in the septum. Dyssynchrony indices demonstrated no dyssynchrony using left ventricular criteria. Reproducibility of most strain measures was acceptable. This methodology identified important disease not seen in the four-chamber apical view alone in the pilot population of 11 patients with RV disease. Strain patterns and values were different from those in the control population, indicating that differences do exist from normal.CONCLUSIONS: Eighteen-segment RV strain analysis is feasible, with strain measures falling into discrete ranges in this normal population. Those with RV disease illustrate the potential utility of this approach. These data indicate that this model can be used for more detailed studies evaluating abnormal RV populations, in which its full potential can be assessed.

The biogenesis of multimeric protein complexes of the inner mitochondrial membrane in yeast requires a number of nuclear-coded ancillary proteins. One of these, Pet100p, is required for cytochrome c oxidase. Previous studies have shown that Pet100p is not required for the synthesis, processing, or targeting of cytochrome c oxidase subunits to the mitochondrion nor for heme A biosynthesis. Here, we report that Pet100p does not affect the localization of cytochrome c oxidase subunit polypeptides to the inner mitochondrial membrane but instead functions after they have arrived at the inner membrane. We have also localized Pet100p to the inner mitochondrial membrane in wild type cells, where it is present in a subassembly (Complex A) with cytochrome c oxidase subunits VII, VIIa, and VIII. Pet100p does not interact with the same subunits after they have been assembled into the holoenzyme. In addition, we have identified two subassemblies that are present in pet100 null mutant cells: one subassembly (Complex A') is composed of subunits VII, VIIa, and VIII but not Pet100p, and another subassembly (Complex B) is composed of subunits Va and VI. Because pet100 null mutant cells lack assembled cytochrome c oxidase but accumulate Complexes A' and B it appears likely that these subassemblies of cytochrome c oxidase subunits are intermediates along an assembly pathway for holocytochrome c oxidase and that Pet100p functions in this pathway to facilitate the interaction(s) between Complex A' and other cytochrome c oxidase subassemblies and subunits.