Publications by authors named "William G. Harmon"

9 Publications

  • Page 1 of 1

Pediatric cardiomyopathies: causes, epidemiology, clinical course, preventive strategies and therapies.

Future Cardiol 2013 Nov;9(6):817-48

Department of Pediatrics, University of Miami Miller School of Medicine, 1601 NW 12th Avenue, 9th Floor, Miami, FL 33136, USA.

Pediatric cardiomyopathies, which are rare but serious disorders of the muscles of the heart, affect at least one in every 100,000 children in the USA. Approximately 40% of children with symptomatic cardiomyopathy undergo heart transplantation or die from cardiac complications within 2 years. However, a significant number of children suffering from cardiomyopathy are surviving into adulthood, making it an important chronic illness for both pediatric and adult clinicians to understand. The natural history, risk factors, prevalence and incidence of this pediatric condition were not fully understood before the 1990s. Questions regarding optimal diagnostic, prognostic and treatment methods remain. Children require long-term follow-up into adulthood in order to identify the factors associated with best clinical practice including diagnostic approaches, as well as optimal treatment approaches. In this article, we comprehensively review current research on various presentations of this disease, along with current knowledge about their causes, treatments and clinical outcomes.
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http://dx.doi.org/10.2217/fca.13.66DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3903430PMC
November 2013

Associations between fibroblast growth factor 23 and cardiac characteristics in pediatric heart failure.

Pediatr Nephrol 2013 Oct 6;28(10):2035-42. Epub 2013 Jun 6.

Division of Nephrology and Hypertension, Department of Medicine, University of Miami Miller School of Medicine, 1120 NW 14th St., Miami, FL 33136, USA.

Background: In adults with heart failure, elevated levels of fibroblast growth factor 23 (FGF23) are associated with mortality. Data on FGF23 levels in pediatric heart failure are lacking.

Patients And Methods: We conducted a cross-sectional study of 17 healthy children (mean age 13 years) and 20 pediatric patients with heart failure (mean age 12 years) who underwent echocardiography and for whom the following measurements were taken: plasma FGF23 and parathyroid hormone (PTH) and serum phosphate, creatinine and N-terminal prohormone brain natriuretic peptide (NT-proBNP). Symptom severity was assessed with the New York Heart Association and the Ross classification systems.

Results: Of the 20 patients, 11 had dilated cardiomyopathy, four had congenital heart disease, three had hypertrophic cardiomyopathy, one had a failing heart transplant and one had pulmonary hypertension. Mean phosphate levels in these patients were within the reported reference range for healthy children. Median PTH levels were in the normal range in patients and controls. The median FGF23 level was higher in patients versus controls (110.9 vs. 66.4 RU/ml; P = 0.03) and higher in patients on diuretics versus other patients (222.4 vs. 82.1 RU/ml; P = 0.01). Levels of FGF23 and NT-proBNP were directly correlated (r = 0.47, P = 0.04), and patients with greater physical functional impairment had higher FGF23 levels (142.5 in those with moderate-severe limitation vs. 92.8 RU/ml in those with no limitation; P = 0.05). Among patients with dilated cardiomyopathy, higher FGF23 levels were associated with a greater left ventricular end-diastolic diameter (r = 0.63, P = 0.04).

Conclusion: FGF23 levels are elevated in children with heart failure and are associated with diuretic use, severity of heart failure and left ventricular dilation.
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http://dx.doi.org/10.1007/s00467-013-2515-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3755096PMC
October 2013

A high school-based voluntary cardiovascular risk screening program: issues of feasibility and correlates of electrocardiographic outcomes.

Pediatr Cardiol 2013 Oct 17;34(7):1612-9. Epub 2013 Mar 17.

All Children's Hospital Heart Institute, St. Petersburg, FL, USA.

Risk factors for adult cardiovascular events can be identified from the prenatal period through childhood. We performed a cardiovascular risk-screening program in students from grades 9-12 in 7 high schools in Hillsborough County, FL. We obtained blood pressure (BP) measurements and calculated body mass index (BMI) as risk factors for future cardiovascular events as well as obtained an electrocardiogram (ECG) for the purposes of detecting possible life-threatening arrhythmias. Of ~14,000 students contacted, 600 (4 %) participated in the screening. Of these, 517 (86 %) were diagnosed with normal, 71 (12 %) with borderline, and 12 (1 %) with abnormal ECGs. Although no participant had any cardiac history, two of the abnormal ECGs indicated a cardiac diagnosis associated with the potential for sudden cardiac death. Both systolic and diastolic BP increased as the ECG diagnosis moved from normal (115.6/73.8) through borderline (121.0/75.9) to an abnormal (125.0/80.7) diagnosis (all P ≤ .0016). An increase in BMI was only observed when an ECG diagnosis was abnormal (P = .0180). Boys had a greater prevalence (18.97 %) of borderline or abnormal ECGs compared with girls (6.75 %), whereas no discernible differences were seen in ECG diagnosis between white and nonwhite individuals (15.09 and 12.26 %, respectively). Although participation rates were low, a high school-based cardiovascular risk-screening program including ECG is feasible. Although ECG diagnosis tended to be related to other known cardiovascular risk factors (BP, BMI), the utility of an abnormal ECG in adolescence as a predictor of future cardiovascular risk will require further evaluation in more controlled settings.
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http://dx.doi.org/10.1007/s00246-013-0682-8DOI Listing
October 2013

Serial measurements of serum NT-proBNP as markers of left ventricular systolic function and remodeling in children with heart failure.

Am Heart J 2010 Oct;160(4):776-83

Divisions of Pediatric Cardiology, Miami, FL, USA.

Background: Increasing serum levels of N-terminal pro-hormone brain natriuretic peptide (NT-proBNP) are associated with worsening heart failure (HF) in adults. We determined whether changes in NT-proBNP level are associated with changes in symptoms and left ventricular (LV) systolic function and remodeling in children with HF secondary to dilated cardiomyopathy.

Methods: We retrospectively examined associations between serum NT-proBNP levels and NYHA/Ross functional class, LV systolic and diastolic diameter (LVSD-z and LVDD-z), LV ejection fraction (LVEF), and LV shortening fraction (LVSF-z) using generalized linear mixed models. Fluctuation in functional class of subjects was also modeled using logistic regression and receiver operating characteristic (ROC) curves.

Results: In 36 children (14 males), a 10-fold increase in NT-proBNP serum levels was associated (P < .001) with a 9.8% decrease in LVEF, a 3.25-unit drop in LVSF-z, a 1.53-unit increase in LVDD-z, a 2.64-unit increase in LVSD-z, and an increased odds of being in functional class III/IV (OR 85.5; 95% CI, 10.9 to 671.0). An NT-proBNP level greater than 1000 pg/mL identified children constantly or intermittently in functional class III-IV with 95% sensitivity and 80% specificity. The reliability of a single NT-proBNP value was 0.61, but the means for two and three NT-proBNP values were 0.76 and 0.82, respectively.

Conclusions: In children with HF, NT-proBNP is associated with cardiac symptoms and indices of LV systolic dysfunction and remodeling. NT-proBNP >1000 pg/mL identifies highly symptomatic children. Within subject serial measurements of NT-proBNP are needed for a reliable and accurate determination of disease status and/or course.
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http://dx.doi.org/10.1016/j.ahj.2010.07.012DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2964279PMC
October 2010

Treating children with idiopathic dilated cardiomyopathy (from the Pediatric Cardiomyopathy Registry).

Am J Cardiol 2009 Jul 3;104(2):281-6. Epub 2009 Jun 3.

Department of Pediatrics, University of Miami, Leonard M. Miller School of Medicine, Miami, Florida, USA.

In 40% of children with symptomatic idiopathic dilated cardiomyopathy (IDC), medical therapy fails within 2 years of diagnosis. Strong evidence-based therapies are not available for these children, and how evidence-based therapies for adults with IDC should be applied to children is unclear. Using data from the National Heart, Lung, and Blood Institute's Pediatric Cardiomyopathy Registry, we compared practice patterns of initial therapies for children with IDC diagnosed from 1990 to 1995 (n = 350) and from 2000 to 2006 (n = 219). At diagnosis, 73% had symptomatic heart failure (HF), and 7% had > or =1 family member with IDC. Anti-HF medications were most commonly prescribed initially. Anti-HF medication use was similar across the 2 periods (84% and 87%, respectively), as was angiotensin-converting enzyme inhibitor use (66% and 70%, respectively). These medications were used more commonly in children with greater left ventricular dilation and poorer left ventricular fractional shortening and functional class (p <0.001). Beta-blocker use was 4% to 18% over the 2 periods. Treatments for pediatric IDC have changed little over the previous 25 years. Anti-HF medications remain the most common treatment, and they are often given to children with asymptomatic left ventricular dysfunction. Children with asymptomatic left ventricular dysfunction are often not offered angiotensin-converting enzyme inhibitors without echocardiographic evidence of advanced disease. In conclusion, therapeutic clinical trials are strongly indicated because practice variation is substantial and medical outcomes in these children have not improved in the previous several decades.
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http://dx.doi.org/10.1016/j.amjcard.2009.03.033DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2746101PMC
July 2009

Elevated risk of thrombosis in neonates undergoing initial palliative cardiac surgery.

Ann Thorac Surg 2007 Oct;84(4):1320-5

Department of Pediatrics, University of Rochester Medical Center, Rochester, New York, USA.

Background: Thrombotic events cause significant morbidity and mortality in children who undergo surgery for complex congenital cardiac disease. We prospectively evaluated the incidence of thrombosis and examined preoperative and postoperative laboratory tests of coagulation and inflammation in neonates experiencing initial surgical palliation for variations of single ventricle physiology.

Methods: Neonates (<30 days) requiring initial surgical palliation were studied. All subjects received aspirin from postoperative day 1 onward. Thromboses were diagnosed by serial transthoracic echocardiograms, vascular imaging, and interstage cardiac catheterizations according to predefined criteria.

Results: Twenty-two neonates, age 1 to 11 days (mean 4 +/- 2.5) were studied. Follow-up ranged from three hours to 18 months (median, 212 days). Eight infants died. Four of the 14 subjects who survived (28%), and one of the eight who died (12.5%), had evidence of thrombosis identified over a range of four hours to nine months postoperatively (median 14 days). When compared with reference values established in healthy children, preoperative subject hematocrit (Hct), platelet count, factors II, V, VII, VIII, and X, antithrombin, protein C, and soluble CD40 ligand measures were significantly lower, and the prothrombin time and partial thromboplastin time were significantly higher. Postoperative C reactive protein (CRP) was significantly higher, and Hct and platelet count significantly lower, than preoperative values. Thrombotic events were significantly related to high preoperative CRP (p = 0.02).

Conclusion: Thrombotic complications occur frequently in neonates undergoing initial palliative surgery, suggesting that aspirin therapy alone may constitute inadequate protection. Elevated preoperative CRP appears to be associated with increased thrombotic risk.
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http://dx.doi.org/10.1016/j.athoracsur.2007.05.026DOI Listing
October 2007

Duration of mechanical ventilation in life-threatening pediatric asthma: description of an acute asphyxial subgroup.

Pediatrics 2004 Sep;114(3):762-7

Division of Pediatric Critical Care, Strong Children's Research Center of the University of Rochester, Rochester, New York, USA.

Objective: Acute asphyxial asthma (AAA) is well described in adult patients and is characterized by a sudden onset that may rapidly progress to a near-arrest state. Despite the initial severity of AAA, mechanical ventilation often restores gas exchange promptly, resulting in shorter durations of ventilation. We believe that AAA can occur in children and can lead to respiratory failure that requires mechanical ventilation. Furthermore, children with rapid-onset respiratory failure that requires intubation in the emergency department (ED) are more likely to have AAA and a shorter duration of mechanical ventilation than those intubated in the pediatric intensive care unit (PICU).

Methods: An 11-year retrospective chart review (1991-2002) was conducted of all children who were aged 2 through 18 years and had the primary diagnosis of status asthmaticus and required mechanical ventilation.

Results: During the study period, 33 (11.4%) of 290 PICU admissions for status asthmaticus required mechanical ventilation. Thirteen children presented with rapid respiratory failure en route, on arrival, or within 30 minutes of arrival to the ED versus 20 children who progressed to respiratory failure later in their ED course or in the PICU. Mean duration of mechanical ventilation was significantly shorter in the children who presented with rapid respiratory failure versus those with progressive respiratory failure (29 +/- 43 hours vs 88 +/- 72 hours). Children with rapid respiratory failure had greater improvements in ventilation and oxygenation than those with progressive respiratory failure as measured by pre- and postintubation changes in arterial carbon dioxide pressure, arterial oxygen pressure/fraction of inspired oxygen ratio, and alveolar-arterial gradient. According to site of intubation, 23 children required intubation in the ED, whereas 10 were intubated later in the PICU. Mean duration of mechanical ventilation was significantly shorter in the ED group versus the PICU group (42 +/- 63 hours vs 118 +/- 46 hours). There were significantly greater improvements in ventilation and oxygenation in the ED group versus the PICU group as measured by pre- and postintubation changes in arterial carbon dioxide pressure and arterial oxygen pressure/fraction of inspired oxygen ratio.

Conclusions: AAA occurs in children and shares characteristics seen in adult counterparts. Need for early intubation is a marker for AAA and may not represent a failure to maximize preintubation therapies. AAA represents a distinct form of life-threatening asthma and requires additional study in children.
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http://dx.doi.org/10.1542/peds.2004-0294DOI Listing
September 2004

Cardiomyocyte injury to transplant: pediatric management.

Curr Opin Cardiol 2003 Mar;18(2):91-7

Division of Pediatric Cardiology, Golisano Children's Hospital at Strong, University of Rochester School of Medicine and Dentistry, New York 14642, USA.

Cardiomyocyte injury in pediatric patients has a vast number of causes, which are often distinct from the causes of adult heart failure. However, the management of pediatric heart failure and heart transplantation has generally been inferred from adult studies. New therapies show great promise for the neurohormonal regulation of heart failure and the ability to control immunosuppression after heart transplantation. Large, randomized, multicenter, controlled clinical trials are needed to determine the efficacy of these therapies in this population. This article reviews the current recommendations and evidence-based medicine, where available, for the medical management of myopathic dysfunction and transplantation in pediatric patients.
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http://dx.doi.org/10.1097/00001573-200303000-00003DOI Listing
March 2003

Myocardial and Pericardial Disease in HIV.

Curr Treat Options Cardiovasc Med 2002 Dec;4(6):497-509

Division of Pediatric Cardiology, University of Rochester Medical Center, 601 Elmwood Avenue, Box 631, Rochester, NY 14642, USA.

Cardiovascular complications are frequently encountered in the HIV-infected population. Cardiac care providers should implement appropriate preventive, screening, and therapeutic strategies to maximize survival and quality of life in this increasingly treatable, chronic disease. All HIV-infected individuals should undergo periodic cardiac evaluation, including echocardiography, in order to identify subclinical cardiac dysfunction. Left ventricular (LV) dysfunction can result from, or be exacerbated by, a variety of treatable infectious, endocrine, nutritional, and immunologic disorders. Aggressive diagnosis and treatment of these conditions may lead to improvement or even normalization of myocardial function. Endomyocardial biopsy should be considered to direct etiology-specific therapy. Standard measures for the prevention and treatment of congestive heart failure are recommended for HIV-infected patients. Afterload reduction with angiotensin-converting enzyme inhibitors may be indicated for patients with elevated afterload and preclinical LV dysfunction diagnosed by echocardiogram. However, judicious drug selection and titration are necessary in this cohort of patients with frequent autonomic dysfunction, at risk for a number of potentially lethal drug interactions. Carnitine, selenium, and multivitamin supplementation should be considered, especially in those with wasting or diarrhea syndromes. Monthly intravenous immunoglobulin (IVIG) infusions have been demonstrated to preserve LV parameters in HIV-infected children; ventricular recovery has been documented in some children with recalcitrant HIV-related cardiomyopathy following IVIG infusion. We support the use of immunomodulatory therapy in the pediatric population, and look forward to further study into the efficacy and broader application of this approach. Highly active antiretroviral therapy (HAART) may be associated with dyslipidemia and the metabolic syndrome. This should be treated with dietary and possibly with pharmacologic interventions. Drug interactions need to be considered when instituting pharmacologic therapies. Pericardial effusions are often seen in patients with advanced HIV infection. Asymptomatic effusions are most often nonspecific in nature, related to the proinflammatory milieu found in advanced AIDS. Nonspecific effusions are a marker of advanced disease and do not require exhaustive etiologic evaluation. In contrast, large or symptomatic effusions are often associated with infection or malignancy, and warrant thorough investigation and etiology-specific treatment.
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http://dx.doi.org/10.1007/s11936-002-0043-zDOI Listing
December 2002