Heart Rate Variability in Children With Fontan Circulation: Lateral Tunnel and Extracardiac Conduit

The technique in Fontan surgery has developed from the lateral tunnel (LT) toward the extracardiac conduit (EC) used to reduce long-term complications such as atrial arrhythmia and sinus node dysfunction. Heart rate variability (HRV) examines cardiac nervous activity controlling the sinus node. This study aimed to investigate HRV in a cohort of children with univentricular hearts, focusing on the relation between HRV and surgical procedure. For 112 children with Fontan circulation, HRV was analyzed using power spectral analysis. Spectral power was determined in three regions: very-low-frequency (VLF), low-frequency (LF), and high-frequency (HF) regions. Patients were compared with 66 healthy controls subject. Patients with LT were compared with patients who had EC. The children with Fontan circulation showed a significantly reduced HRV including total power (P < 0.0001), VLF (P < 0.0001), LF (P < 0.0001), and HF (P = 0.001) compared with the control subjects. The LT and EC patients did not differ significantly. Reduced HRV was found in both the LT and EC patients. In terms of HRV reduction, EC was not superior to LT.     

Peak Circulatory Power as an Indicator of Clinical Status in Children After Fontan Procedure

Peak circulatory power (CircP), a product of peak exercise oxygen uptake (VO₂) and peak mean or systolic arterial blood pressure, has proved to be a strong predictor of poor outcome in adults with congenital heart disease. This study sought to compare CircP with other cardiopulmonary exercise (CPX) test variables and to assess whether CircP is superior in categorizing patients into well-functioning vs. poorly functioning at-risk groups in the pediatric population after a Fontan procedure. The CPX test reports of 50 patients were retrospectively reviewed after the Fontan procedure. The patients were divided into two groups. The well-functioning group included patients in New York Heart Association (NYHA) classes 1 and 2 (n = 36). The poorly functioning at-risk group included patients in NYHA classes 3 and 4 and those with significant indicators or outcomes of a poor prognosis (n = 14). The patients in the well-functioning group had significantly higher CircP values based on mean blood pressure (MBP) (P < 0.001), higher CircP values based on systolic blood pressure (SBP) (P < 0.001), and higher peak VO₂ (P = 0.004) than those in the poorly functioning at-risk group. At a cutoff value less than 2100.4 mmHg/mlO₂/kg/min, CircP MBP had a sensitivity of 85% in categorizing children to the poorly functioning at-risk group. CircP correlated well with the clinical status of our patients. CircP and peak VO₂ did not differ significantly in ability to identify poorly functioning patients. Further prospective analysis is needed to assess whether CircP can serve as a prognostic marker for the pediatric population after Fontan procedure.     

Echocardiographic Evaluation of Children With Systemic Ventricular Dysfunction Treated With Carvedilol

Echocardiography is used to measure the therapeutic effectiveness of heart failure therapy in adults and children. The purposes of this study were (1) to assess baseline echocardiographic predictors of clinical outcome, (2) to investigate changes in echocardiographic parameters, and (3) to compare these echocardiographic changes with changes in plasma levels of b-type natriuretic peptide (BNP) in a population of children with systemic ventricular dysfunction and symptomatic heart failure treated with carvedilol or placebo. All available baseline and 6-month echocardiograms from Pediatric Carvedilol Trial (PCT) participants (carvedilol n = 161; placebo n = 55) were reviewed. Systolic and diastolic sphericity index (SI; n = 110), TEI index (n = 145), and systemic ventricular dP/dt (n = 70) were measured. The PCT composite definition of clinical outcome (i.e., worsened, improved, or unchanged) was used. For all patients, baseline TEI index was a predictor of worsened outcome. Only children treated with carvedilol showed a significant decrease in systolic SI (P ≤ 0.0001), diastolic SI (P ≤ 0.0001), and TEI index (P = 0.02). An inverse correlation between changes in BNP and changes in dP/dt (r = –0.45, P = 0.04) was found only in the carvedilol group. In conclusion, TEI index predicted outcome in children with systemic ventricular dysfunction and heart failure. Carvedilol may have a beneficial effect on reversal of left ventricular remodeling and global ventricular function in pediatric heart failure.     

Myocardial Performance in Asphyxiated Full-Term Infants Assessed by Doppler Tissue Imaging

The aim of this study was to assess myocardial performance of full-term infants with perinatal asphyxia using Doppler tissue imaging (DTI) and to correlate it with serum cardiac troponin T (cTnT) concentrations. Twenty-five asphyxiated and 20 nonasphyxiated term infants were investigated. Serum cTnT concentrations were measured between 12 and 24 h of life. Conventional two-dimensional Doppler echocardiography and DTI were done during the first 72 h of life. Right ventricular (RV) and left ventricular (LV) Tei indexes were significantly higher in asphyxiated neonates (mean ± SD: 0.45 ± 0.05 vs. 0.28 ± 0.05, P < 0.001 and 0.51 ± 0.04 vs. 0.38 ± 0.04, P < 0.001, respectively). Mitral and tricuspid systolic (Sm) velocities were significantly lower in asphyxiated neonates (mean ± SD: 5.06 ± 0.89 vs. 6.89 ± 0.94 cm/s, P < 0.001 and 5.78 ± 0.58 vs. 6.69 ± 0.87 cm/s, P < 0.001, respectively). cTnT concentrations were significantly higher in asphyxiated neonates [median (range): 0.17 (0.05–0.23) vs. 0.03 (0–0.07) μg/l, P < 0.001)], and they correlated positively with the LV Tei index (r = 0.67, P < 0.001) and the RV Tei index (r = 0.68, P < 0.001) and negatively with the mitral systolic (Sm) velocity (r = –0.68, P < 0.001) and tricuspid systolic (Sm) velocity (r = –0.41, P = 0.01). A higher cTnT was a significant predictor of mortality, whereas fractional shortening (FS) and DTI measurements did not show any significant predictive value. The DTI technique appears to be more sensitive than conventional echocardiography in the early detection of myocardial dysfunction induced by perinatal asphyxia in full-term infants.     

Heart rate variability and exercise capacity of patients with repaired tetralogy of Fallot

Heart rate variability (HRV) has been used as a reliable method to detect cardiac autonomic nervous system activity. Peak oxygen uptake (VO₂ peak) has been a predictor of death for adults with repaired tetralogy of Fallot (TOF). This study investigated the correlation between HRV and exercise capacity in 30 patients with TOF after surgery for total correction. The median age of the patients was 14 years (range, 9–25 years), and the median follow-up period was 11.6 months (range, 5.3–20.2 months). Low- and high-frequency-domain HRV significantly correlated with VO₂ peak (r = 0.56, P = 0.001 and r = 0.44, P = 0.02, respectively). After the 1-year follow-up evaluation, VO₂ peak and HRV analysis did not differ from those at entry to the study. However, low- and high-frequency-domain HRV still correlated significantly with VO₂ peak (r = 0.43, P = 0.03 and r = 0.52, P = 0.007, respectively). Left ventricular early diastolic myocardial velocity was most closely correlated with the VO₂ peak (r = 0.51, P = 0.005). Impaired cardiovascular autonomic control and left ventricular diastolic dysfunction may be responsible for exercise intolerance in patients with repaired TOF. Long-term follow-up evaluation with exercise testing and 24-h Holter monitoring are warranted.     

Outcomes of Hypoplastic Left Heart Syndrome in Low-Birth-Weight Patients

The objective of this study was to assess outcomes of hypoplastic left heart syndrome (HLHS) patients weighing ≤2.5 kg throughout staged palliation. We performed a single-center retrospective review. Abstracted data included gestational age, birth weight, presence of noncardiac anomalies, and survival through Fontan. Fifty-two patients met inclusion criteria, with a median birth weight of 2.14 kg and gestational age of 36 weeks. Five patients received comfort care only. Of 47 patients who underwent initial surgical palliation, 51% survived to initial hospital discharge. Birth weight and gestational age (GA) were similar between survivors and nonsurvivors. Compared with survivors, risk factors for death prior to initial hospital discharge were as follows: small for GA (P = 0.005), noncardiac anomalies (P = 0.04), need for post-perative extracorporeal membrane oxygenation (P = 0.0004), and conversion from initial palliation to Sano shunt (n = 5, no survivors). Operative survival following Stage 2 palliation was 91% (21/23) and 94% after Fontan (17/18). Overall survival for palliated patients from birth through Fontan was 36%. Low-birth-weight neonates with HLHS have poor overall survival through the Fontan operation, with highest mortality following Stage 1 palliation. Being small for GA and the presence of noncardiac anomalies are important preoperative risk factors for early mortality.     

Management of Moderate Functional Tricuspid Valve Regurgitation at the Time of Pulmonary Valve Replacement: Is Concomitant Tricuspid Valve Repair Necessary?

Congenital heart defects with a component of pulmonary stenosis are often palliated in childhood by disrupting the pulmonary valve. Patients often undergo subsequent pulmonary valve replacement (PVR) to protect the heart from the consequences of pulmonary regurgitation. In the presence of associated moderate functional tricuspid valve (TV) regurgitation, it is unclear what factors contribute to persistent TV regurgitation following PVR. In particular, it is unknown whether PVR alone will reduce the right ventricular (RV) size and restore TV function or whether concomitant TV annuloplasty is required as well. Thirty-five patients were analyzed. Each patient underwent initial palliation of congenital pulmonary stenosis or tetralogy of Fallot, underwent subsequent PVR between 2002 and 2008, and had at least moderate TV regurgitation at the time of valve replacement. Serial echocardiograms were analyzed. Pulmonary and TV regurgitation, along with RV dilation and dysfunction, were scored (0, none; 1, mild; 2, moderate; 3, severe). RV volume and area were also calculated. Potential risk factors for persistent postoperative TV regurgitation were evaluated. One month following PVR, there was a significant reduction in pulmonary valve regurgitation (mean, 3 vs. 0.39; P < 0.0001) and TV regurgitation (mean, 2.33 vs. 1.3; P < 0.0001). There were also significant reductions in RV dilation, volume, and area. There were no significant further improvements in any of the parameters at 1 and 3 years. There was no difference in the degree of TV regurgitation postoperatively between those patients who underwent PVR alone and those who underwent concomitant tricuspid annuloplasty (mean, 1.29 vs. 1.31; P = 0.81). We conclude that following PVR, improvement in TV regurgitation and RV size occurs primarily in the first postoperative month. TV function improved to a similar degree with or without annuloplasty.     

Significance of Circulating Hepatocyte Growth Factor in Protein-Losing Enteropathy After Fontan Operation

The purpose of this study was to measure serum hepatocyte growth factor (HGF) and elucidate the relationship between HGF and protein-losing enteropathy (PLE) after Fontan operation (FO). Ten patients with PLE (mean age 15.7 ± 8.7 years) who underwent FO were enrolled. Control group 1 comprised 20 patients without PLE after FO, and control group 2 comprised 10 patients with nephrotic syndrome (NS). Serum HGF, vascular endothelial growth factor, albumin, and random stool alpha-1 antitrypsin concentration were measured. Transthoracic echocardiography was completed. Serum HGF level was significantly greater in the PLE patients (0.61 ± 0.27 ng/ml) after FO than in the two control groups (0.41 ± 0.12 ng/ml [P = 0.024] for the Fontan group without PLE and 0.26 ± 0.12 ng/ml [P = 0.002] for the patients with NS). Serum albumin of patients with PLE (2.82 ± 0.96 g/dl) showed significantly lower levels compared with those of patients without PLE after FO (4.30 ± 0.37 g/dl, P < 0.001) but significantly greater levels compared with patients with NS (1.91 ± 0.33 g/dl, P = 0.019). Patients with greater serum HGF levels showed significant correlation with lower serum albumin level (P = 0.006, r = −0.495). Because serum HGF levels were significantly greater in patients with PLE after FO, HGF may play a role in the development of PLE after FO.     

Outcomes of Infants Undergoing Superior Cavopulmonary Connection in the Presence of Ventricular Dysfunction

Outcomes in patients with ventricular dysfunction undergoing superior cavopulmonary connection (SCPC) are not well known. We reviewed records of patients undergoing SCPC at our center from December 2005 to October 2009 and studied those whose pre-SCPC echocardiograms demonstrated at least moderate systemic ventricular dysfunction. Of the 213 patients undergoing SCPC, 19 (9%) met inclusion criteria. Diagnoses were hypoplastic left heart syndrome (n = 18) and rightward unbalanced atrioventricular canal with pulmonary stenosis (n = 1). In those surviving >2 months after SCPC, ventricular function was assessed by echocardiography 4.9 (range 3.5 to 9.7) months after SCPC and was improved in ten of 17 (59%), unchanged in six of 17 (35%), and worsened in one of 17 (16%) patients. After SCPC, three patients died, and one underwent heart transplant 21.9 months after SCPC. Transplant-free survival was attained by 15 of 19 (79%) patients during follow-up of 33.0 months (range 10.8 to 51.4). Fontan completion was performed on six survivors on reaching an appropriate age. Ventricular dysfunction before SCPC is not uncommon and occurs primarily in patients with a morphologic right ventricle. Ventricular performance improves in the majority of patients after SCPC, and midterm outcomes are comparable with previous reports, suggesting that these patients remain candidates for staged palliation.     

Serial Cardiopulmonary Exercise Testing in Patients with Previous Fontan Surgery

Patients with previous Fontan surgery have reduced peak oxygen consumption (Vo ₂), and data regarding progression of exercise intolerance is limited. The purpose of this study was to assess the evolution of exercise tolerance in patients with previous Fontan surgery. We performed a retrospective cohort study of patients with previous Fontan surgery who underwent cardiopulmonary exercise testing between November 2002 and January 2009. Patients were required to have completed at least two tests, with adequate levels of effort, ≥6 months apart. We identified 78 patients (55% male) who had undergone a total of 215 cardiopulmonary exercise tests. Age at initial study was 19.7 ± 10.2 years; time interval since previous Fontan surgery 13.3 ± 5.7 years; and time interval between the initial and the most recent exercise test was 3.0 ± 1.4 years. Morphologic left ventricle was present in 58 (74.4%) patients. At baseline, peak Vo ₂ averaged 24.7 ± 7.0 ml/kg/min (63.7% ± 15.8% predicted). At most recent study, peak Vo ₂ averaged 23.2 ± 7.2 ml/kg/min, (60.4% ± 13.9% predicted). Percent predicted peak Vo ₂ declined slowly, with a mean rate of decline of 1.25 ± 0.36 percentage points/y (p < 0.001). Most of the decline occurred in patients < 18 years of age (mean rate of decline 1.78 ± 0.46 percentage points/y; p = 0.0004). Thereafter, the rate of decline was less marked (mean rate of decline 0.54 ± 0.57 percentage points/y; p = not significant). Ventricular morphology, type of Fontan procedure, and cardiac medications were not predictive of progressive exercise intolerance. In conclusion, although the exercise function of previous Fontan patients tends to decline during late adolescence, it appears to stabilize during early adulthood.     

Renal Function of Patients with a Failing Fontan Circuit Undergoing Total Cavopulmonary Revision Surgery

This report characterizes renal dysfunction after total cavopulmonary (TCPC) revision surgery for atriopulmonary Fontan (APF) circulations, a known risk factor for a poor outcome. The perioperative data for 23 consecutively identified patients were reviewed. The preoperative mean glomerular filtration rate (GFR) was 101 ± 30 ml/min/1.73 m², decreasing to 65 ± 41 ml/min/1.73 m² early in the postoperative period. The preoperative GFR was highly correlated with age at APF (r = −0.5; p = 0.024), age at TCPC (r = −0.5; p = 0.01), and mixed venous saturation (r = 0.6; p = 0.01). Three of four patients requiring renal replacement therapy (RRT) died at a median age of 3 months (range, 18 days to 9 months). Determinants of early GFR and RRT were preoperative GFR (p = 0.016) and creatinine (p = 0.035). Younger age at primary Fontan (p = 0.008), higher preoperative mixed venous saturation (p = 0.019), and higher preoperative blood pressure (p = 0.006) independently predicted better GFRs at the latest follow-up evaluation. Renal function declines acutely after TCPC revision, often necessitating RRT. A requirement for RRT marks greater mortality. Higher preoperative creatinine levels identify those at greatest risk.     

A comparison of left ventricular volumes and regurgitant fraction by Doppler echocardiography and angiography in children

Regurgitant fraction calculations by echocardiography were compared to angiocardiography in 11 patients with mitral regurgitation. Although there was a very good correlation when compared with angiocardiography (r = 0.99, SEE: 6.26, P< 0.001), two-dimensional echocardiography underestimated left ventricular end-diastolic volumes (P < 0.05). The mean regurgitant fraction was 36.2 ± 13.5% by echocardiography and 43.6 ± 15.7% (P< 0.05) by angiography. Most of the variability in measuring the regurgitant fraction is attributed to the left ventricular volume measurements. In conclusion, regurgitant fraction calculations of mitral regurgitation by echocardiography compares favorably to angiography. Since the severity of mitral regurgitation is an important determinant of prognosis, quantification of the regurgitant fraction may be useful in the long term follow-up of those patients.     

Late Pulmonary Valve Replacement in Congenital Heart Disease Patients Without Original Congenital Pulmonary Valve Pathology

Many congenital heart defects with pulmonary valve pathology are repaired or palliated in childhood. It is anticipated that these patients will need subsequent pulmonary valve replacement due to the pulmonary regurgitation or right ventricular dilation/failure that results from their original operation. Interestingly, some patients with prior congenital heart surgery and no congenital pulmonary valve pathology require pulmonary valve replacement in adulthood. The current study analyzed this subset of patients. The pediatric and adult congenital cardiac surgical databases at a large academic center were reviewed from 2001 to 2008 for pulmonary valve replacements. Patients without congenital pulmonary valve disease were identified. Preoperative, operative, and postoperative data were analyzed. Between 2001 and 2008, five patients with congenital heart disease but no pulmonary valve pathology underwent late pulmonary valve replacement. The initial congenital diagnoses were coarctation/ventricular septal defect (n = 3), complete atrioventricular septal defect (n = 1), and anomalous left coronary artery from the pulmonary artery (PA) (n = 1). All five patients had undergone main PA manipulation during their previous operations. Four of these patients had received PA banding and debanding, and one had received a Takeuchi tunnel repair and revision. All the patients underwent pulmonary valve replacement secondary to pulmonary regurgitation and right ventricular dilation. The average time from the last previous operation to the time of pulmonary valve replacement was 20.8 ± 9.1 years. Bioprosthetic valves were used for all the pulmonary valve replacements, and there were no mortalities. Patients who have undergone previous PA manipulation, regardless whether congenital pulmonary pathology is present, may be at risk for pulmonary valve replacement in adulthood. This report describes five cases of patients with a history of congenital heart surgery but no congenital pulmonary valve pathology who required pulmonary valve replacement due to the consequences of prolonged pulmonary regurgitation. Although pulmonary regurgitation may be well tolerated for many years, it is further evidence for the importance of close follow-up assessment and monitoring of young adults with congenital heart disease.     

Doppler myocardial performance index in assessment of ventricular function in children with single ventricles

Background  Quantitative assessment of ventricular function in children with single ventricles is both difficult and subjective because of asymmetric ventricular geometry. The Doppler myocardial performance index (MPI) allows the assessment regardless of ventricular shape. This study was designed to evaluate the feasibility of MPI in assessing ventricular function in children with single ventricles before and after total cavopulmonary connection (TCPC). Methods  Subjects consisted of 161 pediatric patients with single ventricles and 80 normal children without heart disease. The maximum positive rate of ventricular pressure change (Max dp/dt) was obtained in 58 patients by cardiac catheterization. Sixty-eight children with single ventricles received TCPC. MPI was calculated from Doppler tracings of ventricular inflow and outflow, then MPI of single ventricles before and after surgery and normal heart were compared. Results  Normal MPI value was 0.30±0.08 in the left ventricle and 0.26±0.08 in the right ventricle. Compared to normal children, MPI was significantly higher in 161 children with single ventricles (0.54±0.11, P<0.001). MPI correlated inversely with Max (dp/dt) (r=−0.77, P<0.01), and was positively related to age (r=0.54, P<0.01) in patients with single ventricles. MPI did not differ significantly before and after surgery in 68 patients with single ventricles (0.55±0.21 vs 0.51±0.20, P>0.05). However, MPI in 48 patients of <6 years old decreased significantly (0.55±0.21 vs 0.48±0.18, P<0.05), suggesting improved ventricular function. Conclusions  Compared to normal children, ventricular function is impaired in patients with single ventricles and may worsen with age. MPI provides an accurate method for assessing ventricular function in children with single ventricles before and after TCPC.     

Elevated tricuspid regurgitation velocity in congenital hemolytic anemias: Prevalence and laboratory correlates

Elevated tricuspid valve regurgitation jet velocity (TRV ≥ 2.5 m/s) is associated with mortality among adults with sickle cell disease (SCD), but correlative biomarkers are not studied according to treatment exposure or genotypes. To investigate the associations between biomarkers and TRV elevation, we examined the relationship between TRV and hemolytic, inflammatory, and cardiac biomarkers, stratified by disease‐modifying treatments and SCD genotype. In total, 294 participants with SCD (mean age, 11.0 ± 3.7 years) and 49 hereditary spherocytosis (HS; mean age, 22.9 ± 19.75 years) were included for comparison and enrolled. TRV was elevated in 30.7% of children with SCD overall: 18.8% in HbSC/HbSβ⁺‐thalassemia, 28.9% in untreated HbSS/HbSβ⁰‐thalassemia, 34.2% in HbSS/HbSβ⁰‐thalassemia hydroxyurea‐treated, and 57% in HbSS/HbSβ⁰‐thalassemia chronic transfusion treated. TRV was elevated in 10.7% and 27.8% in HS children and adults, respectively. In children with SCD, elevated TRV was correlated with hemoglobin (odds ratio [OR] = 0.78, P = 0.004), lactate dehydrogenase (LDH; OR = 2.52, P = 0.005), and N‐terminal pro‐brain natriuretic peptide (NT‐pro BNP; OR = 1.003, P = 0.004). In multivariable logistic regression, adjusting for genotype, sex, hemolytic index, and treatment, hemoglobin concentration remained the only significant variable associated with elevated TRV in untreated HbSS/HbSβ⁰‐thalassemia participants. TRV was not associated with inflammatory markers, other markers of hemolysis, or NT‐pro BNP in untreated HbSS/HbSβ⁰‐thalassemia. Neither hemoglobin nor LDH was associated with TRV in HbSC/HbSβ⁺‐thalassemia. These results suggest that elevated TRV is influenced by the degree of anemia, possibly reflecting sickling as part of the disease pathophysiology. Prospective studies should monitor hemoglobin concentration as children with SCD age into adulthood, prompting initiation of TRV screening and monitoring.     

Contractility Reserve in Children Undergoing Dialysis by Dobutamine Stress Echocardiography

Left ventricular hypertrophy is an adaptive mechanism in children undergoing chronic dialysis to improve contractility at rest. The aim of this study was to determine the left ventricular performance and contractility reserve by “dobutamine stress echocardiography” in children undergoing chronic dialysis. Thirty-five children undergoing dialysis and 24 healthy subjects were enrolled in this prospective study. We evaluated contractility by means of end-systolic wall stress—velocity of circumferential fiber shortening (VCFc) in 24 healthy subjects and 35 dialysis patients. Dobutamine stress echocardiography was obtained only in children undergoing dialysis. Patients were divided into two groups according to left ventricular mass index. Contractile reserve was estimated by the difference in contractility at rest versus during echocardiography. Significantly higher VCFc (p = 0.008) and VCFc (p = 0.002) differences at rest were observed in the patient group compared to healthy subjects. Children undergoing dialysis had a higher left ventricular mass index compared with controls (42.38 ± 12.41 vs. 17.57 ± 3.66 g/m^2.7, respectively; p = 0.001). Patients with left ventricular hypertrophy had a significantly lower contractile reserve compared with patients without left ventricular hypertrophy (p = 0.013). These findings suggest that children undergoing dialysis have increased left ventricular mass and contractility at rest. However, the contractile reserve during dobutamine stress echocardiography was reduced. Dobutamine stress echocardiography may identify children undergoing dialysis at risk of progressing to systolic dysfunction and heart failure.     

Outcomes of Berlin Heart EXCOR® pediatric ventricular assist device support in patients with restrictive and hypertrophic cardiomyopathy

The outcomes of pediatric ventricular assist device support in patients with diastolic heart failure have not been well described. This study reviews the North American experience with Berlin Heart EXCOR^® ventricular assist device implants in children with such physiology. The Berlin Heart clinical database was reviewed. Patients with primary diastolic dysfunction are included in this study. Twenty pediatric patients with restrictive cardiomyopathy (n = 13), hypertrophic cardiomyopathy (n = 3), or congenital heart disease with restrictive physiology (n = 4) who were supported with EXCOR^® were identified. Of these, nine (45%) were successfully bridged to transplant, one (5%) weaned from support, and 10 (50%) died after support was withdrawn. Of patients under age 3 years (n = 13), 38.5% survived, whereas those aged 3 or older (n = 7) had 71.4% survival (P = .35). Biventricular assist device (BiVAD) patients experienced a 27.3% survival, vs 77.8% for patients with left ventricular assist device only (P = .07). Primary causes of death included stroke, infection, acidosis, multisystem organ failure, and bleeding. Pediatric patients with diastolic heart failure comprise a high‐risk population for mechanical circulatory support. However, half of patients with this physiology have been successfully supported to explant with EXCOR^®. The trends toward higher mortality for younger patients and those receiving BiVAD support warrant consideration.     

Radiation doses to children during modified barium swallow studies

Background There are minimal data on radiation doses to infants and children undergoing a modified barium swallow (MBS) study. Objective To document screening times, dose area product (DAP) and effective doses to children undergoing MBS and to determine factors associated with increased screening times and effective dose. Materials and methods Fluoroscopic data (screening time, DAP, kVp) for 90 consecutive MBS studies using pulse fluoroscopy were prospectively recorded; effective dose was calculated and data were analyzed for effects of behavior, number of swallow presentations, swallowing dysfunction and medical problems. Results Mean effective dose for the entire group was 0.0826 ± 0.0544 mSv, screening time 2.48 ± 0.81 min, and DAP 28.79 ± 41.72 cGy cm². Significant differences were found across three age groups (≤1.0, >1.0–3.0 and >3.0 years) for effective dose (mean 0.1188, 0.0651 and 0.0529 mSv, respectively; P  <  0.001), but not for screening time or DAP. Effective dose was correlated with screening time (P = 0.007), DAP (P < 0.001), number of swallow presentations (P = 0.007), lower age (P = 0.017), female gender (P = 0.004), and height (P < 0.001). Screening time was correlated with total number of swallow presentations (P < 0.001) and DAP (P < 0.001). Conclusion Screening times, DAP, effective dose, and child and procedural factors associated with higher effective doses are presented for children undergoing MBS studies. This work was supported by the Royal Children’s Hospital Foundation, Brisbane.     

Independent Risk Factors for Cardiac Operations in Adults With Congenital Heart Disease: A Retrospective Study of 543 Operations for 500 Patients

Adults with congenital heart disease (CHD) are an increasing population requiring cardiac operations. To date, the perioperative risk factors for this group have not been identified. This study aimed to identify clinical, morphologic, and hemodynamic risk factors for an adverse outcome. This study retrospectively analyzed a cohort of 500 patients (ages >16 years) who underwent 543 operations between January 2004 and December 2008 at a single center. The composite end point of an adverse outcome was in-hospital death, a prolonged intensive care exceeding 4 days, or both. The composite end point was reached by 253 of the patients (50.6%). Of the 500 patients, 13 (2.6%) died within 30 days after the operation. After logistic regression analysis, the following eight items remained significant: male gender (P = 0.003; odds ratio [OR] 1.8; 95% confidence interval [CI] 1.2–2.6), cyanosis (P > 0.006; OR 3.7; 95% CI 1.5–9.4), functional class exceeding 2 (P = 0.004; OR 2.2; 95% CI 1.3–3.7), chromosomal abnormalities (P = 0.004; OR 3.3; 95% CI 1.4–7.7), impaired renal function (P = 0.019; OR 3.8; 95% CI 1.2–11.5), systemic right ventricle (RV) in a biventricular circulation (P = 0.027; OR 3.3; 95% CI 1.1–9.5), enlargement of the systemic ventricle (P = 0.011; OR 1.7; 95% CI 1.1–2.6), and operation with extracorporeal circulation (P = 0.002; OR 4.3; 95% CI 1.7–11.4). Early mortality in the current adult CHD population is low. Morbidity, however, is significant and influenced by the patients’ conditions (male gender, chromosomal abnormalities), history (cyanosis, New York Hospital Association [NYHA] class), and underlying morphology (systemic RV). This information for a large cohort of patients could help progress toward more adequate counseling for adults with a congenital heart defect.     

X-Chromosomal (p21) Muscular Dystrophy and Left Ventricular Diastolic and Systolic Function

In order to screen for cardiac abnormalities, we prospectively studied 15 patients (age 8–25 years, mean 15.5 years) with Duchenne's (DMD) (n= 9) and Becker's (BMD) (n= 6) muscular dystrophy using the echocardiogram. Data were compared to a control group of 92 healthy individuals (age 7.9–25 years, mean 14.3 years). Left ventricular filling in diastole showed a different pattern when comparing echocardiographic Doppler results in patients and controls: Patients had lower peak velocity of early left ventricular diastolic filling (E-vmax)(P < 0.0001) and smaller time velocity integral of the E-wave (E-tvi)(P < 0.0001). In contrast, the atrial component (A-vmax, A-tvi) of diastolic filling in DMD/BMD showed no significant difference to controls. The mean area of the mitral valve orifice was significantly larger in patients (P < 0.0001) without presence of mitral regurgitation. Systolic left ventricular function was significantly impaired in the DMD/BMD group; we found lower heart rate corrected fiber shortening velocity VCFc (P < 0.001) and higher peak systolic wall stress (P < 0.001) in DMD/BMD. In 8 of 15 patients, peak systolic wall stress was above 95th percentile of controls. In 6 of 15 patients, VCFc was lower than the 5th percentile of controls. Systolic and diastolic myocardial impairment was found even in young patients and at low stages of disability—equally among patients with DMD or BMD. Diastolic left ventricular impairment predominantly affected the early diastolic filling, but atrial compensation was poor. Peak systolic wall stress measurements were particularly useful in patients with CMP, reflecting the left ventricular afterload.