Lower prevalence of aortic dilatation among preemptive pediatric renal transplant recipients - A cross-sectional cohort study.

BACKGROUND: Aortic dilatation is a cardiovascular complication in pediatric renal transplant recipients and may have an increased risk of aortic dissection, aortic rupture, and death. Studies failed to show an association between blood pressure and aortic dilatation; however, 24-hours ambulatory blood pressure monitoring (ABPM) was not performed. There was also no comparison between preemptive transplantation and dialysis. METHODS: After ethics approval, a retrospective cross-sectional study was performed on all prevalent pediatric renal transplant recipients from a single tertiary care center. The presence of aortic dilatation was determined using standard echocardiographic measurements, and those with other risk factors for aortic dilatation were excluded. Associations between 24-hours ABPM, renal function, dialysis history, and aortic dimensions were determined. RESULTS: We enrolled 37 participants with the following characteristics: 46% female, mean age 14.5 ± 3.7 years, 16% preemptive transplantation, and median end-stage renal disease (ESRD) combined vintage (time from ESRD onset to echocardiogram) 597 days (range 289-1290 days). We found 16/37 patients (43%) with aortic dilatation at any level, mostly mild. There was no association between 24-hours ABPM measurements and aortic dilatation. None of the preemptively transplanted children had aortic dilatation. CONCLUSION: This study confirms a high prevalence of aortic dilatation among pediatric renal transplant recipients, which appears to be independent of hypertension on 24-hour ABPM. Patients with preemptive renal transplantation did not have aortic dilatation, suggesting that the effects of dialysis may contribute to the high prevalence of this complication. Pediatric cardiologists need to carefully assess aortic dimensions in these at-risk patients.

Relationship between serum inflammatory markers and vascular function in a cohort of adolescents with type 1 diabetes.

OBJECTIVE: The contribution of inflammation to endothelial/vascular dysfunction in early Type I Diabetes (T1D) is not well understood. The objective of this study was to examine the interaction between systemic inflammation and vascular function in adolescent's with and without-T1D. METHODS: 51 subjects from our observational cohort of adolescents with T1D (JDRF-CCTN), and 59 healthy controls (HC) were studied. Serum cytokines-chemokines were quantified using Human 41-Plex Array, and vascular function was measured by Flow Mediated Dilatation (FMD), Pulse Wave Velocity (PWV) and Blood Pressure (BP). Factor Analysis was used to identify pro- and anti-inflammatory cytokine-chemokine factors, which were then correlated with vascular outcomes. RESULTS: Three pro-inflammatory factors were identified in HC and three in TID, and a single anti-inflammatory factor in both groups. In HC there was a positive correlation (r=0.33; p=0.01) between control proinflammatory Factor 1 and systolic BP and a negative correlation between control proinflammatory Factor 3(r=-0.29; p=0.02) and diastolic BP. Control proinflammatory Factor 2 correlated positively with PWV. In TID subjects, no correlations were found between any of the pro-inflammatory factors and the vascular measurements. No correlations were found between the anti-inflammatory factors and BP, FMD and PWV in either HC or T1D. Levels of pro-inflammatory analytes, EGF, GRO, PDGF-BB, PDGF-AA and sCD40L were significantly higher in T1D. CONCLUSIONS: The cytokine-chemokine signature in early T1D, prior to the development of arterial disease, is significantly different from that seen in healthy controls. This may be relevant to pathophysiology, determining risk and identifying target cytokines-chemokines for intervention in T1D.

Longitudinal assessment of myocardial function in childhood chronic kidney disease, during dialysis, and following kidney transplantation.

BACKGROUND: Childhood chronic kidney disease (CKD) and dialysis are associated with increased long-term cardiovascular risk. We examined subclinical alterations in myocardial mechanics longitudinally in children with CKD, during dialysis, and following renal transplantation. METHODS: Forty-eight children with CKD (stage III or higher) who received kidney transplants from 2008 to 2014 were included in a retrospective study and compared to 192 age- and sex-matched healthy children. Measurements of cardiac systolic and diastolic function were performed, and global longitudinal strain (GLS) and circumferential strain (GCS) were measured by speckle-tracking echocardiography at CKD, during dialysis, and 1 year following kidney transplantation. Mixed-effects modeling examined changes in GLS and GCS over different disease stages. RESULTS: Children with CKD had a mean age of 10 ± 5 years and 67% were male. Eighteen children received preemptive transplantation. Children with CKD had increased left ventricular mass, lower GLS, and impaired diastolic function (lower E/A ratio and E' velocities) than healthy children. Changes in left ventricular diastolic parameters persisted during dialysis and after renal transplantation. Dialysis was associated with reduced GLS compared to CKD (ß = 1.6, 95% confidence interval 0.2-3.0); however, this was not significant after adjustment for systolic blood pressure and CKD duration. Post-transplantation GLS levels were similar to those at CKD assessment. GCS was unchanged during dialysis but significantly improved following transplantation. CONCLUSIONS: There are differences in diastolic parameters in childhood CKD that persist during dialysis and after transplantation. Systolic parameters are preserved, with significant improvement in systolic myocardial deformation following transplantation. The impact of persistent diastolic changes on long-term outcomes requires further investigation.

Maternal hypothyroidism may be associated with CHD in offspring.

OBJECTIVES: This study tested whether mothers with maternal hypothyroidism have increased odds of CHD in their offspring, and examined the relationship between CHD, maternal thyroid function, and nausea and vomiting in pregnancy. BACKGROUND: Maternal hypothyroidism increases the risk for foetal demise and prematurity and can have a negative impact on neurodevelopment. Prior studies have postulated a relationship between maternal thyroid function, CHD, and maternal nausea and vomiting in pregnancy. METHODS: A cross-sectional case-control study was conducted over a 17-month period to obtain a history of maternal thyroid status and nausea and vomiting in pregnancy. Paediatric echocardiograms were evaluated for CHD by a blinded paediatric cardiologist. Logistic regression analysis was performed to examine the association between CHD and maternal hypothyroidism. RESULTS: Of the 998 maternal-child pairs, 10% (98/998) of the mothers reported a history of prenatal hypothyroidism. The overall prevalence of CHD in the study sample was 63% (630/998). Mothers with a history of hypothyroidism were significantly more likely to have offspring with CHD compared with mothers without a history of hypothyroidism (72 versus 62%; p=0.04). The adjusted odds ratio (95% confidence interval) of CHD in offspring associated with reported maternal hypothyroidism was 1.68 (1.02-2.78). CONCLUSION: This study suggests that maternal hypothyroidism is a risk factor for the development of CHD. Further prospective investigations are necessary to confirm this association and delineate pathogenic mechanisms.

Regional Vascular Changes and Aortic Dilatation in Pediatric Patients With Bicuspid Aortic Valve.

BACKGROUND: Bicuspid aortic valve (BAV) is the most common congenital heart disease, often associated with valve dysfunction, coarctation of the aorta, and ascending aorta dilatation. Aortic dilatation might result from abnormal regional hemodynamics or inherent vascular disease. Vascular function in pediatric BAV remains poorly characterized. METHODS: A cross-sectional study was performed to evaluate vascular function in 142 children with BAV aged 7-18 years compared with healthy control children. Echocardiography was performed to assess aortic dimensions, BAV function, and vascular function (aortic arch pulse wave velocity [PWV]), carotid intima media thickness, and aortic stiffness and distensibility). Carotid-femoral and carotid-radial PWV were assessed using tonometry. Vascular function was compared for 4 patient groups stratified according to aortic dilatation and a history of coarctation of the aorta. Multivariate regression analysis was performed to determine predictors of aortic dilatation. RESULTS: Children with BAV had stiffer and less distensible ascending aortas with higher aortic arch PWV compared with control children. Carotid-femoral and carotid-radial PWV were not increased in patients with BAV, and the vascular assessment of the abdominal aorta was unremarkable. Multivariate regression revealed that aortic arch PWV was the only vascular function parameter that was associated with aortic dilatation. CONCLUSIONS: Children with BAV have differences in vascular function that are confined to their proximal aorta, even in normal functioning BAV. The observed differences in vascular function are likely multifactorial, with contributions from abnormal regional flow and a potential localized primary aortopathy.

Diagnosis of Pediatric Hypertension: European Society of Hypertension-Recommended 24-Hour vs. 24-Hour-Day-Night Ambulatory Blood Pressure Thresholds.

BACKGROUND: The impact of diagnosing pediatric hypertension based on all three-24-hour, day and night ambulatory blood pressure (ABP) thresholds (combined ABP threshold) vs. conventionally used 24-hour ABP threshold is not known. METHODS: In this cross-sectional, retrospective study from a tertiary care outpatient clinic, we evaluated the diagnosis of hypertension based on the 24-hour European Society of Hypertension (ESH) and combined ESH ABP thresholds in untreated children with essential hypertension. The American Academy of Pediatrics (AAP) and Fourth Report thresholds were used to classify office blood pressure (OBP). RESULTS: In 159 children, aged 5-18 years, the 24-hour ESH and combined ESH thresholds classified 82% (95th confidence interval (CI) 0.68, 0.97) ABP similarly with the area under the curve (AUC) of 0.86 (95th CI 0.80, 0.91). However, the AUC of the 2 ABP thresholds was significantly higher in the participants with office hypertension than office normotension, with OBP classified by the AAP (AUC 0.93, 95th CI 0.84, 0.98 vs. 0.80, 95th CI 0.71, 0.88) or Fourth Report (AUC 0.93, 95th CI 0.83, 0.98 vs. 0.81, 95th CI 0.73, 0.88) threshold. With OBP classified by the either OBP threshold, the combined ESH threshold diagnosed significantly more masked hypertension (MH) (difference 15%, 95th CI 4.9, 24.7; P = 0.00); however, the diagnosis of white coat hypertension (WCH) by the 2 ABP thresholds did not differ significantly (difference 4%, 95th CI 1.8, 10; P = 0.16). CONCLUSIONS: In children with essential hypertension, the 24-hour and combined ESH thresholds have a stronger agreement for diagnosing WCH than MH.

Valve disease and aortopathy associations of bicuspid aortic valve phenotypes differ between men and women.

OBJECTIVE: Determine whether associations between bicuspid aortic valve (BAV) phenotypes, valve disease and aortopathy differ between sexes. METHODS: 1045 patients with BAV (76.0% men, n=794) from two surgical centres were included in this cross-sectional study. Valve phenotype was classified intraoperatively as right-left (RL), right-non-coronary (RN), left-non-coronary (LN) or 2-sinus BAV. Echocardiography was used to determine type and degree of valve disease, and aortic dimensions. Aortic dilatation was defined as diameter ≥4.5 cm. RESULTS: RL was the most common phenotype (73.6%), followed by RN (16.2%), 2-sinus BAV (9.2%) and LN (1.1%), with no difference in phenotype distribution between men and women (p=0.634). Aortic valve insufficiency (AI) prevalence differed significantly with valve phenotype in men (p=0.047), with RL and LN having the highest prevalence (34.1% and 44.0%, respectively). In women, RN had a higher proportion of AI than RL (21.3% vs 7.3%, p=0.017). Men with RL had larger root dimensions, in particular at the sinus (mean difference 0.24 cm compared with RN, p=0.002). Men with 2-sinus BAV had the highest prevalence of root phenotype dilatation (7.0%, other phenotypes ≤2.3%, p=0.031), whereas women with 2-sinus BAV did not have root dilatation and smaller sinus dimensions (mean difference: 0.35 cm compared with RL, p=0.021). Aortic root segments were larger in men with AI compared with aortic stenosis (sinus mean difference: 0.40 cm, p<0.001). The difference was even larger in women (mean difference: 0.78 cm, p<0.001), and women with AI also had larger tubular segments (mean difference: 0.61 cm, p=0.001). CONCLUSIONS: There are significant sex differences in clinical associations of BAV phenotypes, which should be considered in further studies on the role of phenotypes in individualised patient management.

Comparative Analysis of American Heart Association and European Society of Hypertension Ambulatory Blood Pressure Thresholds for Diagnosing Hypertension in Children.

INTRODUCTION: The influence of using 24-hour ambulatory blood pressure (ABP) thresholds recommended by the American Heart Association (AHA) (24-hour mean ABP >95th percentile and ABP load >25%) or the European Society of Hypertension (ESH) (mean 24-hour ABP >95th percentile or >130/80 mm Hg if mean ABP 95th percentile exceeds 130/80 mm Hg) on the diagnosis of pediatric hypertension has been understudied. METHODS: In a cross-sectional, retrospective study of 159 children from a tertiary care outpatient clinic, we classified office blood pressure (OBP) as normotension or hypertension based on the OBP thresholds recommended by the American Academy of Pediatrics (AAP) and the fourth report on the diagnosis, evaluation, and treatment of high blood pressure in children and adolescents (herein referred to as the fourth report) by the National High Blood Pressure Educational Program Working Group on High Blood Pressure in Children and Adolescents separately. Thereafter, we evaluated the agreement between the ambulatory AHA and ESH thresholds for diagnosing normotension, white-coat hypertension (WCH), masked hypertension (MH), and hypertension based on the patient's ABP and OBP hypertension pattern. RESULTS: With office hypertension as per the AAP thresholds, the AHA and ESH thresholds classified 85% of subjects similarly into normotension, WCH, MH, and hypertension (κ = 0.78; 95% CI, 0.67-0.89). The agreement between the AHA and ESH thresholds did not change when OBP was reclassified by the fourth-report OBP thresholds (κ = 0.77; 95% CI, 0.65-0.88). With OBP classified by either AAP or fourth-report thresholds, the ESH thresholds diagnosed 6% to 7% more children as hypertensive, whereas the AHA threshold classified 11% more children as normotensive. CONCLUSION: The AHA and ESH thresholds have good agreement in classifying OBP. However, the ESH threshold classifies more OBP as hypertensive and the AHA threshold classifies more OBP as normotensive.

Prenatal Diagnosis of Transposition of the Great Arteries Reduces Postnatal Mortality: A Population-Based Study.

BACKGROUND: Transposition of the great arteries (TGA) may present as a life-threatening neonatal malformation. Although prenatal detection facilitates the perinatal management, the impact on outcome is controversial. METHODS: This study reviewed the differences in prenatal diagnosis of TGA from 2009 to 2014 among the 5 geographic areas in Ontario and compared the management, morbidity, and mortality among neonates with a prenatal (prenatal cohort; n = 70) vs a postnatal (postnatal cohort; n = 76) anomaly diagnosis. Cases were identified from prospective databases of the provincial cardiac tertiary centres and the coroner's office. RESULTS: Prenatal TGA detection rates varied significantly among areas (median: 50%; range: 14% to 72%; P = 0.03). Compared with the postnatal cohort, time from birth to tertiary care admission (1.4 vs 10.4 hours, P < 0.001), prostaglandin therapy (0.1 vs 5.3 hours; P < 0.001), balloon atrial septostomy (5.3 vs 14.9 hours; P <0.001), and arterial switch operation (6 vs 9 days, P = 0.002) was significantly shorter in the prenatal cohort. Although other preoperative variables-including the need of ventilation and mechanical support, morbidity score, and lowest pH and preductal oxygen saturations-were comparable, a prenatal diagnosis was associated with improved 1-year survival (odds ratio: 0.108; 95% confidence interval, 0.013-0.88; P = 0.0184). CONCLUSIONS: Prenatal diagnosis of TGA significantly shortened time intervals from birth to neonatal care and surgery and was associated with improved survival. The prenatal detection rate of TGA in Ontario was low (50% or less) outside of Metropolitan Toronto, suggesting the need for new strategies to further improve intraprovincial detection rates.

Predictors of Bicuspid Aortic Valve-Associated Aortopathy in Childhood: A Report From the MIBAVA Consortium.

BACKGROUND: Bicuspid aortic valve (BAV) is the most prevalent congenital heart defect affecting 1% to 2% of the population. It is associated with ascending aorta dilatation. Valve morphology, aortic stenosis (AS), and aortic insufficiency (AI) have been proposed as potential risk factors; however, evaluating their role is difficult, as these factors are inherently related. The aim of this study was to determine whether BAV morphology and dysfunction are independent determinants for ascending aorta dilatation in pediatric patients. METHODS: A multicenter, retrospective, cross-sectional study of pediatric BAV patients followed since 2004 was performed. Imaging data were assessed for BAV morphology, severity of AS and AI, history of coarctation, and aortic dimensions. Associations were determined using multivariable regression analysis. A subset of patients undergoing aortic interventions (balloon dilation or Ross) were assessed longitudinally. RESULTS: Data were obtained from 2122 patients (68% male; median age 10.2 years). Fifty percent of patients had ascending aorta dilatation. Right and noncoronary cusp fusion, increasing AS and AI, and older age were independently associated with ascending aorta dilatation. A history of coarctation was associated with less ascending aorta dilatation. In patients with neither AS nor AI, 37% had ascending aorta dilatation (4% severe). No complications related to aortic dilatation occurred in this cohort. Aortic Z scores were determined, and a Z-score calculator was created for this population. CONCLUSIONS: In this large pediatric cohort of patients with BAV, valve morphology, AS, and AI are independently associated with ascending aorta dilatation, suggesting that hemodynamic factors influence aortopathy. However, even in BAVs with no AS or AI, there is significant ascending aorta dilatation independent of valve morphology. Interventions that led to changes in degree of AI and AS did not seem to influence change in aortic dimensions. The current BAV cohort can be used as a reference group for expected changes in aortic dimensions during childhood.

Infective Endarteritis and Mycotic Pseudoaneurysms in a Pediatric Patient With Aortic Coarctation.

An 11-year-old boy presented with Staphylococcus aureus infective endarteritis and mycotic pseudoaneurysms within the context of a previously undiagnosed aortic coarctation. He had an urgent resection of the pseudoaneurysm and coarctation repair. Nuances to his initial diagnosis and key learning points related to the complication of pseudoaneurysm are discussed.

Increased blood pressure is associated with increased carotid artery intima-media thickness in children with repaired coarctation of the aorta.

OBJECTIVES: The intima-media thickness of the common carotid artery (cIMT) is a good noninvasive surrogate marker for cardiovascular disease. Regular cIMT monitoring in children with congenital heart disease has great potential. We sought to determine which anthropomorphic and haemodynamic variables were significantly associated with the cIMT in paediatric patients with obesity and children with repaired coarctation of the aorta (CoA). METHODS: We measured the cIMT in 143 children aged 5 to less than 18 years including normal weight controls (n = 44), children with overweight/obesity (n = 73) and children with repaired CoA (n = 26). cIMT was compared and the association between the cIMT and patient characteristics, including obesity and blood pressure (BP), was investigated. RESULTS: BMI z score, sex and the presence of CoA were significant independent predictors of cIMT. The cIMT was significantly greater in children with overweight/obesity (0.53 ±â€Š0.06 mm) relative to normal weight controls (0.51 ±â€Š0.04 mm), as well as in CoA patients with abnormally high BP (0.57 ±â€Š0.08 mm) versus CoA patients with normal BP (0.52 ±â€Š0.05 mm) and controls (0.51 ±â€Š0.04 mm). CoA patients with normal BP did not have significantly increased cIMT. CONCLUSION: cIMT was positively associated with BMI z score, male sex and CoA repair in children. The increased cIMT in children with repaired CoA was because of those with abnormally high BP, which was masked in clinic for most of these patients. These findings warrant further investigations into the cIMT and other atherosclerotic risk factors to determine their potential clinical impact in these highly susceptible patients.

Ventricular Torsion in Young Patients With Single-Ventricle Anatomy.

BACKGROUND: In normal left ventricles, clockwise basal rotation and counterclockwise apical rotation result in systolic torsion. Torsion is important for contractile efficiency and may be especially important in single-ventricle (SV) physiology. However, little is known about torsion in patients with SVs. The aim of this study was to measure torsion in SVs and to determine its relationship with other measures of ventricular function. The hypothesis was that torsion would be decreased in all SVs, most significantly in single right ventricles, and that it would correlate with other measures of ventricular function. METHODS: A prospective cross-sectional study was performed in 61 patients with SVs undergoing pre- or post-Fontan cardiac catheterization and 30 matched control subjects. Echocardiography, catheterization, and cardiac magnetic resonance imaging were performed under the same anesthetic. Torsion and strain were measured using speckle-tracking echocardiography. Intracardiac pressures, pulmonary vascular resistance, and cardiac magnetic resonance imaging-derived ventricular volume and ejection fraction were measured. RESULTS: Thirty-five patients were left ventricular dominant, 15 were right ventricular dominant, 10 were codominant, and one had indeterminate morphology. Thirty-seven patients were pre-Fontan and 24 were post-Fontan. Patients with SVs had similar overall torsion as control subjects (median, 1.7°/cm vs 1.65°/cm; P = NS); however, they had decreased or reversed basal rotation (-0.32°/cm vs -0.93°/cm, P < .0001) and increased apical rotation (1.45°/cm vs 1.06°/cm, P = .0065). There were no differences on the basis of ventricular dominance or palliative stage. Torsion did not significantly correlate with other echocardiographic, catheter-based, or cardiac magnetic resonance imaging measures of cardiac function. CONCLUSIONS: Single left and right ventricles exhibit preserved torsion, mainly because of preserved or increased apical rotation. Possible mechanisms of torsion in single right ventricles include myofiber remodeling and altered ventricular-ventricular interactions. Understanding myocardial deformation in SVs will improve the ability to interpret ventricular function in this precarious population.

Non-invasive measurement of cardiac output in children with repaired coarctation of the aorta using electrical cardiometry compared to transthoracic Doppler echocardiography.

OBJECTIVE: To evaluate the equivalence of the ICON® electrical cardiometry (EC) haemodynamic monitor to measure cardiac output (CO) relative to transthoracic Doppler echocardiography (TTE) in paediatric patients with repaired coarctation of the aorta (CoA). APPROACH: A group of n = 28 CoA patients and n = 27 matched controls were enrolled. EC and TTE were performed synchronously on each participant and CO measurements compared using linear regression and Bland-Altman analysis. The CoA group was further subdivided into two groups, with n = 10 and without n = 18 increased left ventricular outflow tract velocity (iLVOTv) for comparison. MAIN RESULTS: CO measurements from EC and TTE in controls showed a strong correlation (R = 0.80, p < 0.001) and an acceptable percentage error (PE) of 28.1%. However, combining CoA and control groups revealed a moderate correlation (R = 0.57, p < 0.001) and a poor PE (44.2%). We suspected that the CO in a subset of CoA participants with iLVOTv was overestimated by TTE. Excluding the iLVOTv CoA participants improved the correlation (R = 0.77, p < 0.001) and resulted in an acceptable PE of 31.2%. SIGNIFICANCE: CO measurements in paediatric CoA patients in the absence of iLVOTv are clinically equivalent between EC and TTE. The presence of iLVOTv may impact the accuracy of CO measurement by TTE, but not EC.

Mechanics of the Functionally Univentricular Heart-How Little Do We Understand and Why Does It Matter?

Despite improved surgical techniques, preoperative and postoperative care, patients with functionally univentricular hearts (UVH) continue to have high morbidity and mortality and a decreased lifespan. Ventricular systolic and diastolic dysfunction is a major contributing factor to Fontan patient outcome. The evaluation of ventricular function in patients with UVH is particularly challenging. At a cellular and ultrastructural level, there are inherent differences between single and biventricular right and left ventricles. In addition, there are variable loading conditions throughout the stages of single ventricle palliation as well as variable ventricular remodelling in response to these changes. We will discuss the traditional and newer, advanced echocardiographic techniques that have been applied to evaluate ventricular function in patients with UVH. Each method has inherent advantages and disadvantages when applied to this population. The use of novel techniques including deformational imaging and 3-dimensional echocardiography will hopefully provide a more comprehensive understanding of the performance of the single ventricle, and how ventricular dysfunction affects the clinical status of patients after Fontan palliation.

The Impact of Infective Endocarditis Prophylaxis Recommendations on the Practices of Pediatric and Adult Congenital Cardiologists.

BACKGROUND: Compliance with the April 2007 American Heart Association (AHA) infective endocarditis (IE) guidelines is not well described. We sought to evaluate the impact of these guidelines on the clinical practices of pediatric and adult congenital cardiologists. METHODS: We conducted a 2-centre retrospective cohort study, including patients who had at least 1 outpatient cardiology visit after April 1, 2008 and had 1 of 11 prespecified high- or low-risk congenital cardiac lesions. High-risk lesions required prophylaxis per the AHA guidelines; low-risk patients no longer required prophylaxis. Cardiology clinic letters were reviewed to determine if antibiotic prophylaxis and oral hygiene were addressed and whether prophylaxis was recommended. Comparisons were made before April 2007 vs at least 1 year after guideline publication. RESULTS: We included 238 high-risk and 201 low-risk patients. IE prophylaxis was recommended for all study patients before April 2007. After April 2008, IE prophylaxis recommendations were reduced by 44.9% for low-risk patients (P < 0.0001) and 9.3% for high-risk patients (P = 0.0156). IE prophylaxis recommendations were documented in the medical record of 92% of patients (95% confidence interval, 88%-95%) before April 2007 vs 81% (77%-84%) after April 2008. Oral hygiene was emphasized for only 44% and 28% of patients before and after guideline revision (P = 0.0005). CONCLUSIONS: The 2007 AHA guidelines resulted in significantly fewer recommendations for IE prophylaxis in low-risk patients. However, cardiologists continue to recommend prophylaxis for some low-risk patients and advise some high-risk patients against prophylaxis. These findings suggest disagreement or uncertainty within the cardiology community regarding current IE guidelines.

Echocardiographic assessment of ventricular function in pediatric patients: a comprehensive guide.

Assessment of ventricular function is an important part of every echocardiographic examination. Specific pediatric guidelines on quantification of ventricular function are available, but technology evolves quickly and it generally takes long before newer techniques are integrated into routine clinical practice and are adopted by the guidelines. In the current overview, we would like to present our experience with integrating newer echocardiographic techniques for assessing ventricular function in children using a comprehensive state-of-the-art echocardiographic functional protocol. This protocol is used for specific patient populations such as pediatric patients with cardiomyopathy, post-transplant patients and oncology patients. We present the practical aspects of the protocols, their rationale and how this can be applied in clinical practice.

Recurrent exacerbations of protein-losing enteropathy after initiation of growth hormone therapy in a Fontan patient controlled with spironolactone.

Protein-losing enteropathy (PLE) is a rare, but serious complication in single ventricle patients after Fontan palliation, and is associated with a 5-year mortality of 46%. We describe a patient with PLE after Fontan palliation who achieved remission with high-dose spironolactone (an aldosterone antagonist), but had three exacerbations each temporally correlated with the use of growth hormone (an aldosterone agonist). Because of the opposing mechanisms of action of these two medications, caution might be indicated when using growth hormone for patients with PLE who are successfully treated with spironolactone.

Effects of stretch on work from fast and slow muscles of mice: damped and undamped energy release.

Stretching active muscle increases the work performed during subsequent shortening. The effects of a preceding stretch on work done by the undamped or lightly damped series compliance (SC) and by the contractile component (CC), which includes cross bridges and damped elements, were assessed using mouse soleus (slow) and extensor digitorum longus (fast) muscles with limited tendon. Increasing stretch amplitude (0-10% fibre length) increased work done by the SC up to a limit, but did not effect work done by the CC. Increasing stretch velocity (10-100% Vmax) had almost no effect on work done by either component. Increasing the delay between the end of stretch and onset of shortening (0-60 ms) caused a decrease in SC work, with no effect on CC work. Recoil of the SC was responsible for 50-70% of the total work done during shortening after stretch. Usually only 10-40% of the energy imparted during the stretch was recovered as work during subsequent shortening; large stretches and long delays between stretch and shortening further reduced this recovery by one third to one fifth. Results are interpreted in the context of a loss of energy stored in the SC owing to forcible detachment of cross bridges with large stretches and cyclic detachment with long delays.