Patients with Fontan circulation have abnormal aortic wave propagation patterns: A wave intensity analysis study.

BACKGROUND: Elevated systemic afterload in patients with Fontan circulation may lead to impaired single ventricular function. Wave intensity analysis (WIA) enables evaluation of compression and expansion waves traveling through vasculature. We aimed to investigate the unfavorable wave propagation causing excessive afterload may be an important contributor to the overall single ventricle function and to the limited functional capacity in this patient population. METHODS: Patients with hypoplastic left heart syndrome (HLHS) (n = 25), single left ventricle (SLV) (n = 24), and normal controls (n = 10) underwent phase-contrast MRI based WIA analysis evaluated in the ascending aorta. Forward compression wave (FCW) representing dP/dt, backward compression wave (BCW) reflecting vascular stiffness, and forward decompression wave (FDW) representing LV relaxation were recorded and indexed to each other. RESULTS: FCW was lowest in HLHS patients (1098 mm5/s), and higher in the SLV group (1457 mm5/s), and controls (6457 mm5/s) (P < 0.001). BCW/FCW was increased in HLHS (0.22) and SLV (0.14) groups compared to controls (0.08) (P = 0.003). Peak VO2 correlated with FCW (R = 0.50, P = 0.015), stroke volume (R = 0.72, P < 0.001), and cardiac output (R = 0.44, P = 0.034). CONCLUSIONS: Patients with HLHS and SLV have unfavorable aortic WIA patterns with increased BCW/FCW ratio indicating increased systemic afterload due to retrograde compression waves. Reduced FCW and systolic MRI indices correlated with peak VO2 suggesting that abnormal systolic wave propagation may play a role in exercise intolerance for Fontan patients.

Is Neurodevelopment Related to Exercise Capacity in Single Ventricle Patients Who Have Undergone Fontan Palliation?

Survivors of palliative surgery for single ventricle heart disease (SVHD) are at risk of poor neurodevelopmental outcomes and reduced exercise capacity. In healthy populations, reduced exercise capacity is related to decreased cognition suggesting a possible relationship between exercise capacity and neurodevelopment. Using cardiopulmonary exercise testing (CPET) and neuropsychological testing (NPT) as indicators of exercise capacity and neurodevelopment, respectively, we hypothesized that in SVHD, higher CPET measures are related to better NPT performance. Patients were retrospectively identified. CPET variables included VO2max, anaerobic threshold, peak heart rate, ventilatory efficiency, and respiratory exchange ratio. NPT instruments were divided into domains measuring attention, executive functioning, adaptive functioning, and emotional functioning. Linear regression was used to test for associations between CPET and NPT. 23 subjects with SVHD met inclusion criteria. On both CPET and NPT, the cohort scored worse than healthy, age-matched subjects. Higher VO2max and anaerobic threshold were associated with better parent-rated overall adaptive functioning (p = 0.01 and p = 0.02, respectively). Higher peak heart rate was related to better sustained visual attention (p = 0.01). In SVHD, CPET measures indicating better exercise capacity were positively associated with a subset of scores on NPT. Larger, multisite studies implementing cardiorespiratory fitness intervention and incorporating cognitive outcome measures will be needed to better characterize the relationship between neurodevelopment and functional capacity in this population. Results may assist in providing anticipatory guidance and optimizing post-Fontan developmental trajectories.

Associations Between Socioeconomic Context and Congenital Heart Disease Related Outcomes in Adolescents and Adults.

Little is known about the relation between socioeconomic factors and health outcomes in adults and adolescents with congenital heart defects (CHD). Population-level data from the Colorado CHD surveillance system from 2011 to 2013 was used to examine the association between area deprivation and outcomes including hospitalizations, emergency department visits, cardiac procedures, all-cause and cardiac-related mortality, and major adverse cardiac events. Socioeconomic context was measured by the Area Deprivation Index at census tract level. Missing race/ethnicity was imputed using the Bayesian Improved Surname Geocoding algorithm. Generalized linear models were utilized to examine health disparities across deprivation quintiles after adjusting for insurance type, race/ethnicity, age, gender, urbanicity, and CHD severity in 5,748 patients. Cases residing in the most deprived quintile had 51% higher odds of inpatient admission, 74% higher odds of emergency department visit, 41% higher odds of cardiac surgeries, and 45% higher odds of major adverse cardiac events compared with cases in the least deprived quintile. Further, rates of hospitalizations, emergency department admissions, and cardiac surgeries were elevated in the most deprived compared with the least deprived quintile. Mortality was not significantly different across quintiles. In conclusion, findings suggest significant health equity issues for adolescent and adults with CHD based on area-based deprivation.

Population-level surveillance of congenital heart defects among adolescents and adults in Colorado: Implications of record linkage.

BACKGROUND: The objective was to describe the design of a population-level electronic health record (EHR) and insurance claims-based surveillance system of adolescents and adults with congenital heart defects (CHDs) in Colorado and to evaluate the bias introduced by duplicate cases across data sources. METHODS: The Colorado CHD Surveillance System ascertained individuals aged 11-64 years with a CHD based on International Classification of Diseases, Ninth Revision, Clinical Modification diagnostic coding between 2011 and 2013 from a diverse network of health care systems and an All Payer Claims Database (APCD). A probability-based identity reconciliation algorithm identified duplicate cases. Logistic regression was conducted to investigate bias introduced by duplicate cases on the relationship between CHD severity (severe compared to moderate/mild) and adverse outcomes including all-cause mortality, inpatient hospitalization, and major adverse cardiac events (myocardial infarction, congestive heart failure, or cerebrovascular event). Sensitivity analyses were conducted to investigate bias introduced by the sole use or exclusion of APCD data. RESULTS: A total of 12,293 unique cases were identified, of which 3,476 had a within or between data source duplicate. Duplicate cases were more likely to be in the youngest age group and have private health insurance, a severe heart defect, a CHD comorbidity, and higher health care utilization. We found that failure to resolve duplicate cases between data sources would inflate the relationship between CHD severity and both morbidity and mortality outcomes by ~15%. Sensitivity analyses indicate that scenarios in which APCD was excluded from case finding or relied upon as the sole source of case finding would also result in an overestimation of the relationship between a CHD severity and major adverse outcomes. DISCUSSION: Aggregated EHR- and claims-based surveillance systems of adolescents and adults with CHD that fail to account for duplicate records will introduce considerable bias into research findings. CONCLUSION: Population-level surveillance systems for rare chronic conditions, such as congenital heart disease, based on aggregation of EHR and claims data require sophisticated identity reconciliation methods to prevent bias introduced by duplicate cases.

Exercise Performance at Increased Altitude After Fontan Operation: Comparison to Normal Controls and Correlation with Cavopulmonary Hemodynamics.

Exercise performance declines as patients who have undergone Fontan operation enter adolescence. However, the effect of altitude on functional capacity after Fontan remains inadequately studied. Our aim was to describe exercise performance in a cohort of patients with Fontan physiology living at increased altitude and compare to a normal control group and relate these data to invasively derived hemodynamics. We hypothesized that peak oxygen consumption ([Formula: see text]) would be decreased, in association with elevated mean pulmonary artery pressure (mPAP) and pulmonary vascular resistance (PVRi). Patients were evaluated in a multidisciplinary clinic for patients with Fontan physiology. Evaluation included cardiopulmonary exercise test and cardiac catheterization at predetermined intervals. Descriptive statistics were calculated. Associations of catheterization and exercise testing measures with [Formula: see text] were estimated with Spearman correlation coefficients. One hundred patients with age- and gender-matched controls were included in the analysis. The mean age was 13.3 ± 3.9 years, with mean weight of 47.1 ± 18.4 kg. The mean [Formula: see text] was 29.0 ± 7.8 ml/kg/min, significantly lower than the control group, 40.2 ± 8.4 ml/kg/min (p < 0.0001). There was no statistically significant linear correlation between [Formula: see text] and mPAP or PVRi. We characterized exercise performance in a large cohort with Fontan physiology living at increased altitude and showed a decrease in [Formula: see text] compared to controls. Our data do not support the hypothesis that moderately increased altitude has a detrimental effect on exercise performance, nor is there a substantial link between poor cavopulmonary hemodynamics and exercise in this setting.

Pulse Oximetry Values in Newborns with Critical Congenital Heart Disease upon ICU Admission at Altitude.

Pulse oximetry screening for critical congenital heart disease (CCHD) has been recommended by the American Academy of Pediatrics (AAP). The objectives of this study are to describe saturation data, and to evaluate the effectiveness of AAP-recommended pulse oximetry screening guidelines applied retrospectively to a cohort of newborns with known CCHD at moderate altitude (5557 feet, Aurora, Colorado). Data related to seven critical congenital heart disease diagnoses were extracted from electronic health records (pulse oximetry, prostaglandin administration, and oxygen supplementation). Descriptive epidemiologic data were calculated. 158 subjects were included in this analysis; the AAP pulse oximetry screening protocol was applied to 149 subjects. Mean pre-ductal and post-ductal pulse oximetry values of the infants known to have CCHD at 24 h of life were 87.1% ± 7.2 and 87.8% ± 6.3, respectively. Infants treated with prostaglandins and oxygen had lower oximetry readings. The screening algorithm would have identified 80.5% of infants with known CCHDs (120/149 subjects). Additionally, sequential pulse oximetry screening based on the AAP-recommended protocol was able to identify a true positive screen capture rate of 80.5% at moderate altitude.

Percutaneous thoracic duct intervention to treat plastic bronchitis related to Fontan palliation.

Plastic bronchitis is a life-threatening condition of airway obstructive cast formation. This pediatric case series from a high altitude center details the course of three patients after percutaneous thoracic duct interventions for refractory plastic bronchitis, with a follow-up interval of 3.5 years. In two patients, where cisterna chyli maceration (patients 2) or thoracic duct embolization (patient 3) was performed, a sustained clinical improvement is shown, with no subsequent cast recurrence. In patient 1, cisterna chyli maceration resulted in partial improvement. Herein, a favorable outcome is shown in pediatric patients with percutaneous thoracic duct interventions for plastic bronchitis at altitude.

Evaluation of predictive models for six minute walk test among children with pulmonary hypertension.

BACKGROUND: Existing six minute walk distance (6MWD) prediction equations were developed using healthy children and include relatively small sample sizes. Children with congenital heart disease and pulmonary hypertension (PH) are often small-for-age, so the existing pediatric prediction equations are likely a poor fit for children with PH. Currently, there are no equations for 6MWD among children with PH. OBJECTIVES: Evaluate the validity of five existing pediatric prediction equations among the 6MWD of children with PH, including for each World Health Organization (WHO) class. Develop a validated predictive equation for use in children with PH. METHODS/RESULTS: The 6MWDs from 711 six minute walk tests (6MWTs) of children aged four through 18years with PH were analyzed retrospectively and were evaluated against existing pediatric prediction equations. Existing pediatric prediction equations overestimated the walk distance among our population. The predicted distances versus actual distances were significantly different for each WHO class, with higher class associated with greater difference. A new prediction equation for 6MWD among children with PH was developed and validated with 65 additional 6MWTs. Our prediction equation demonstrates higher goodness of fit for all WHO classes than the preexisting pediatric equations. CONCLUSIONS: Existing prediction equations for 6MWD among healthy children are not accurate for children with PH, particularly for children with more advanced stages of the disease (WHO classes III and IV). We present a new prediction equation for children with PH (WHO classes I through IV) that provides reference for medical care and management.

Feasibility of critical congenital heart disease newborn screening at moderate altitude.

BACKGROUND AND OBJECTIVE: Consensus guidelines have recommended newborn pulse oximetry screening for critical congenital heart disease (CCHD). Given that newborn oxygen saturations are generally lower at higher altitudes, the American Academy of Pediatrics and others recommend additional evaluation of the screening algorithm at altitude. Our objective was to evaluate the feasibility of newborn pulse-oximetry CCHD screening at moderate altitude (Aurora, CO; 1694 m). We hypothesized the overall failure rate would be significantly higher compared with published controls. METHODS: We enrolled 1003 consecutive infants at ≥35 weeks' gestation in a prospective observational study. The nationally recommended protocol for CCHD screening was adhered to with the exceptions of no reflex echocardiograms being performed and providers being informed of results only if saturations were less than predefined critical values. RESULTS: There were 1003 infants enrolled, and 988 completed the screen. The overall failure rate for completed screenings was 1.1% (95% confidence interval: 0.6%-2.0%). The first 500 infants had 1.6% fail, and the last 503 infants had 0.6% fail. Among infants who failed screening, 73% failed secondary to saturations <90%, whereas saturations between 90% and 94%, persistently >3% difference, and multiple criteria were each responsible for 9% of failures. Overall, 1.6% of all infants had incomplete screening and had not passed at the time the test was stopped. CONCLUSIONS: Pulse oximetry screening failure rates at moderate altitude are significantly higher than at sea level. Larger studies with alternative algorithms are warranted at moderate altitudes.

Restrictive lung function in pediatric patients with structural congenital heart disease.

OBJECTIVES: We sought to describe the prevalence of restrictive lung function in structural congenital heart disease and to determine the effect of cardiothoracic surgical intervention. METHODS: The data from a retrospective review of the spirometry findings from pediatric patients with structural congenital heart disease were compared with the data from 220 matched controls. Restrictive lung function was defined as a forced vital capacity of <80%, with a preserved ratio of the forced expiratory volume in the first second to forced vital capacity of >80%. RESULTS: Of the children with congenital heart disease, 20% met the criteria for restrictive lung function compared with 13.2% of the controls (P = .03). The prevalence in those with congenital heart disease without a surgical history was similar to that of the controls (odds ratio, 0.62; 95% confidence interval, 0.34-1.13). Restrictive lung function was more likely if surgical intervention had occurred within the first year of life (odds ratio, 1.96; 95% confidence interval, 1.08-3.55; P < .0001). Those who had undergone both sternotomy and thoracotomy had a greater prevalence of restrictive lung function than those who had undergone sternotomy or thoracotomy alone (54.2% vs 25.6% and 23.5%, respectively; P < .0001). The prevalence of restrictive lung function increased significantly with each additional surgical intervention (odds ratio, 1.61; 95% confidence interval, 1.29-2.01; P < .0001). CONCLUSIONS: Restrictive lung function was more prevalent in those with congenital heart disease after cardiothoracic surgical intervention than in the controls or patients without surgical intervention. The prevalence was also greater with surgical intervention at an earlier age. The risk was equivalent when sternotomy alone was compared with thoracotomy alone but was significantly greater when both sternotomy and thoracotomy were performed. The risk increased with each additional surgery performed.

Ventilatory efficiency slope correlates with functional capacity, outcomes, and disease severity in pediatric patients with pulmonary hypertension.

BACKGROUND: Cardiopulmonary exercise testing is widely used in a variety of cardiovascular conditions. Ventilatory efficiency slope can be derived from submaximal exercise testing. The present study sought to evaluate the relationship between ventilatory efficiency slope and functional capacity, outcomes, and disease severity in pediatric patients with pulmonary hypertension. METHODS: Seventy six children and young adults with a diagnosis of pulmonary hypertension (PH) performed 258 cardiopulmonary exercise tests from 2001 to 2011. Each individual PH test was matched to a control test. Ventilatory efficiency slope was compared to traditional measures of functional capacity and disease severity including WHO functional classification, peak oxygen consumption, and invasive measures of pulmonary arterial pressures and pulmonary vascular resistance. RESULTS: Ventilatory efficiency slope was significantly higher in patients with pulmonary arterial hypertension, with an estimated increase of 7.2 for each increase in WHO class (p<0.0001), compared with normal control subjects (38.9 vs. 30.9, p<0.001). Ventilatory efficiency slope correlated strongly with invasive measures of disease severity including pulmonary vascular resistance index (r =0.61), pulmonary artery pressure (r =0.58), mean pulmonary artery pressure/mean aortic pressure ratio (r =0.52), and peak VO2 (r=-0.58). Ventilatory efficiency slope in 12 patients with poor outcomes (9 death, 3 lung transplant), was significantly elevated compared to patients who did not (51.1 vs. 37.9, p<0.001). CONCLUSIONS: Ventilatory efficiency slope correlates well with invasive and noninvasive markers of disease severity including peak VO2, WHO functional class, and catheterization variables in pediatric patients with PH. Ventilatory efficiency slope may be a useful noninvasive marker for disease severity.

Constrictive pericarditis secondary to infection with Mycoplasma pneumoniae.

Pericardial effusions can be insidious, variable in presentation, and may result from a wide variety of causes. We report here a rare case of pericardial effusion in a pediatric patient secondary to infection with Mycoplasma pneumoniae that progressed to cardiac tamponade and constrictive pericarditis. The differential diagnosis of pericardial effusion is reviewed as well as current treatments for pericardial effusions and constrictive pericarditis.

Octreotide treatment of chylothorax in pediatric patients following cardiothoracic surgery.

OBJECTIVE: To analyze the efficacy and safety of octreotide treatment of persistent chylothorax in pediatric patients following cardiothoracic surgery. DESIGN: Retrospective chart review of patients admitted to the cardiac intensive care unit of a tertiary care center over a 10-year period (1998-2008). Nineteen patients were identified who underwent treatment with octreotide for persistent chylothorax following cardiothoracic surgery. We analyzed data regarding age, sex, type of cardiac lesion and surgical procedure, postoperative day octreotide therapy was initiated, maximum drainage prior to and during octreotide therapy, dose range of octreotide, days to resolution, and complications. RESULTS: Twelve patients (63%) experienced resolution of their chylothorax during octreotide treatment. Fourteen patients (74%) demonstrated a decrease in the peak effusion drainage rate following initiation of octreotide therapy, though two of these patients ultimately required further surgical intervention to achieve resolution. Octreotide treatment was associated with unchanged or increased effusion drainage rate in four patients (21%). Patients that responded to octreotide had a lower mean maximal drainage prior to octreotide initiation. Two patients experienced side effects temporally associated with octreotide therapy (transient hypoglycemia and diarrhea). No serious side effects were identified. CONCLUSIONS: Octreotide treatment of chylothorax in combination with dietary modifications in pediatric patients following cardiothoracic surgery resulted in a reduction of peak effusion drainage and eventual resolution in the majority of cases with few and transient side effects.

Ventricular ectopy following successful cryoablation for Wolff-Parkinson-White syndrome in the right posterior septum: a case report.

We report a case of new onset ventricular ectopy following cryothermal ablation of a right posterior septal accessory pathway. To our knowledge, this is the first report of secondary arrhythmias from cryothermal ablation of atrial arrhythmias.

Axillary versus infraclavicular placement for endocardial heart rhythm devices in patients with pediatric and congenital heart disease.

Our objective was to evaluate the implant and mid-term outcomes of transvenous pacemaker or internal cardioverter-defibrillator placement by alternative axillary approaches compared to the infraclavicular approach in a pediatric and congenital heart disease population. We conducted a retrospective review of all patients with new endocardial heart rhythm devices placed at 4 pediatric arrhythmia centers. A total of 317 patients were included, 63 had undergone a 2-incision axillary approach, 51 a retropectoral axillary approach, and 203 an infraclavicular approach. Congenital heart disease was present in 62% of the patients. The patients with the 2-incision axillary approach were younger and smaller. The patients with the retropectoral axillary approach were less likely to have undergone previous cardiac surgery and were more likely to have had an internal cardioverter-defibrillator placed. The duration of follow-up was 2.4 ± 1.9 years for the 2-incision axillary, 2.6 ± 2.6 years for retropectoral axillary, and 3.5 ± 1.4 years for the infraclavicular technique (p = 0.01). No differences were seen in implant characteristics, lead longevity, implant complications, lead fractures or dislodgements, inappropriate internal cardioverter-defibrillator discharges, or device infections among the 3 groups. In conclusion, our data support that the outcomes of axillary approaches are comparable to the infraclavicular approach for endocardial heart rhythm device placement and that axillary approaches should be considered a viable option in patients with pediatric and congenital heart disease.

Cryothermal catheter ablation of atrioventricular nodal reentrant tachycardia in a pediatric patient after atrioventricular canal repair.

Anatomic displacement of the atrioventricular node and associated conduction tissue in atrioventricular septal defects has been previously described. In spite of the increasing use of cryothermal catheter ablation in the pediatric population, there remains very little literature regarding its use in congenital heart disease. We describe successful cryothermal modification of the slow atrioventricular nodal pathway in a 12-year-old patient with a previously repaired partial atrioventricular septal defect and inducible atrioventricular nodal reentrant tachycardia. The use of a steerable catheter to locate the displaced His signal combined with the use of cryothermal energy allowed for the safe and effective treatment of this patient's tachycardia.

Adherence to guidelines for cardiovascular screening in current high school preparticipation evaluation forms.

We compared the content of the cardiac screening questions on US state high school athletic association preparticipation evaluation forms with current consensus recommendations. We reviewed the high school athletic association's approved, recommended, or required sports preparticipation form from each of the 50 US states and the District of Columbia, and compared the content of the personal and family history components with current recommendations for cardiac screening questions. We found that 85% of the preparticipation forms in current use contain all elements of the formerly recommended guidelines, but only 17% contain all elements of the new consensus guidelines. We conclude that although there appears to be some improvement in the content of the preparticipation forms in current use compared with previous studies, the vast majority of these forms are incomplete compared with current consensus guidelines.

Toward improved cosmetic results: a novel technique for the placement of a pacemaker or internal cardioverter/defibrillator generators in the axilla of young patients.

Surgical scars secondary to the placement of pacemakers or internal cardioverter/defibrillators in the infraclavicular area can be unsightly. This report describes a novel cosmetic approach for the placement of pacemakers or internal cardioverter/defibrillators. The approach involves a small infraclavicular incision for placement of the leads and then a larger incision hidden high up in the axilla. The theoretical advantages of this approach are improved cosmetic outcome, ease of subsequent surgeries for device generator changes, and potentially improved defibrillation thresholds.