Relationship of birth weight with congenital cardiovascular malformations in a population-based study.

INTRODUCTION: A known comorbidity of congenital cardiovascular malformations is low birth weight, but the reasons for this association remain obscure. This retrospective study examines the relationship between congenital cardiovascular malformations and the birth weight of singletons, taking into account differences in gestational age and other factors. METHODS: Using data from the retrospective, population-based Baltimore-Washington Infant Study, six types of congenital cardiovascular malformations were investigated in comparison with controls (n=3519) through linear regression: d-transposition of the great arteries (n=187), other conotruncal heart defects (n=361), endocardial cushion defects (n=281), left heart obstructive lesions (n=507), atrial septal defects (n=281), and membranous ventricular septal defects (n=622). RESULTS: Infants with conotruncal heart defects (-218 g), endocardial cushion defects with Down syndrome (-265 g), endocardial cushion defects without Down syndrome (-194 g), left heart obstructive lesions (-143 g), atrial septal defects (-150 g), and membranous ventricular septal defects (-127 g) showed significant birth weight deficits, adjusting for gestational age, and other covariates. Infants with d-transposition of the great arteries (-67 g) did not show significant birth weight deficits compared with the control group. DISCUSSION: The degree of birth weight decrement appears to be highly related to the specific type of congenital cardiovascular malformation. As a whole, these infants do not exhibit low birth weights solely because of being premature, and thus other mechanisms must underlie these associations.

Emerging Research Directions in Adult Congenital Heart Disease: A Report From an NHLBI/ACHA Working Group.

Congenital heart disease (CHD) is the most common birth defect, affecting about 0.8% of live births. Advances in recent decades have allowed >85% of children with CHD to survive to adulthood, creating a growing population of adults with CHD. Little information exists regarding survival, demographics, late outcomes, and comorbidities in this emerging group, and multiple barriers impede research in adult CHD. The National Heart, Lung, and Blood Institute and the Adult Congenital Heart Association convened a multidisciplinary working group to identify high-impact research questions in adult CHD. This report summarizes the meeting discussions in the broad areas of CHD-related heart failure, vascular disease, and multisystem complications. High-priority subtopics identified included heart failure in tetralogy of Fallot, mechanical circulatory support/transplantation, sudden cardiac death, vascular outcomes in coarctation of the aorta, late outcomes in single-ventricle disease, cognitive and psychiatric issues, and pregnancy.

Report of the National Heart, Lung, and Blood Institute Working Group on research in adult congenital heart disease.

The Working Group on research in adult congenital heart disease (ACHD) was convened in September 2004 under the sponsorship of National Heart, Lung, and Blood Institute (NHLBI) and the Office of Rare Diseases, National Institutes of Health, Department of Health and Human Services, to make recommendations on research needs. The purpose of the Working Group was to advise the NHLBI on the current state of the science in ACHD and barriers to optimal clinical care, and to make specific recommendations for overcoming those barriers. The members of the Working Group were chosen to provide expert input on a broad range of research issues from both scientific and lay perspectives. The Working Group reviewed data on the epidemiology of ACHD, long-term outcomes of complex cardiovascular malformations, issues in assessing morphology and function with current imaging techniques, surgical and catheter-based interventions, management of related conditions including pregnancy and arrhythmias, quality of life, and informatics. After research and training barriers were discussed, the Working Group recommended outreach and educational programs for adults with congenital heart disease, a network of specialized adult congenital heart disease regional centers, technology development to support advances in imaging and modeling of abnormal structure and function, and a consensus on appropriate training for physicians to provide care for adults with congenital heart disease.

Genetic and environmental influences on malformations of the cardiac outflow tract.

Congenital cardiovascular malformations are the most common form of birth defect recorded. Specific malformations of the outflow portions of the heart are termed conotruncal malformations and arise from the septation of the common conotruncus of the heart. There are multiple lines of evidence that point towards genetic-environmental interactions in the genesis of conotruncal congenital cardiovascular malformations. In particular, environmental exposures that involve vitamin A, retinol, folic acid or retinol receptors are identified as cardiac teratogens. Other environmental agents for which there is evidence of cardiac teratogenicity for outflow tract malformations include nitrofen, ambient air pollution, chlorinated hydrocarbons and pesticides. Genetic polymorphisms of xenobiotic metabolism are clearly differentiating in the effect of potential teratogens. Work in this field is at a new cusp, with the ability to measure xenobiotic exposure, document xenobiotic metabolizing genetic polymorphisms and integrate these data into models of cardiac teratogenesis.

Population-based study of l-transposition of the great arteries: possible associations with environmental factors.

BACKGROUND: L-transposition of the great arteries (l-tga) is an uncommon congenital cardiovascular malformation that occurs from abnormal looping of the primitive cardiac tube. Little is known about risk factors for the development of l-tga. METHODS: This study is a case-control study of 36 cases of l-tga compared to 3,495 population-based live born infant controls in the Baltimore Washington Infant Study (1981-1989 births). Extensive personal and occupational exposure data from parental interviews were available for all subjects. A geographic information system was used to identify potential environmental exposures, for example, hazardous waste sites prioritized for cleanup (National Priority List sites). Adjusted odds ratios (OR) and 95% confidence intervals (CI) were calculated using exact parameter estimates from logistic regression. RESULTS: Most infants with l-tga had multiple cardiovascular anomalies, with single ventricle in 47%. Over 75% of all cases of l-tga occur in two regions of contiguous cases. Within these regions, the case control OR of l-tga are 13.4 (95% CI, 4.7-37.8) Both areas are characterized by release of toxic chemicals into air and by hazardous waste sites. Parental exposures to hair dye, smoking and laboratory chemicals are also associated with case status. CONCLUSIONS: L-tga, a congenital cardiovascular malformation due to very early abnormalities in embryogenesis, is associated strongly with residency in two small regions of Maryland and District of Columbia (DC), and with other parental personal or occupational exposures. Additional research is needed to identify the components of spatial and other associations that constitute etiologic risk factors.

Risk factors for heart disease associated with abnormal sidedness.

BACKGROUND: The purpose of this study is to obtain information on potential familial and environmental risk factors for liveborn cases of heart disease associated with abnormal visceral and vascular sidedness, heterotaxy heart disease, so that hypotheses about this congenital cardiovascular malformation (CCVM) and its risk factors can be generated. We describe the characteristics of infants with heterotaxy heart malformations and case-control comparisons of interview data obtained on parental socio-demographic characteristics, occupational and household environmental exposures. METHODS: Cases and controls are drawn from the Baltimore Washington Infant Study (BWIS) a population based case control study of CCVM diagnosed in the region from 1981-89. RESULTS: Maternal diabetes (OR = 5.5, 95% CI = 1.6-19.1) and family history of malformations (OR = 5.1, 95% CI = 2.0-12.9) are strongly associated with cardiac disorders of sidedness. Cocaine use by mothers during the first trimester is associated with heterotaxy heart disease with odds of 3.7 (95% CI = 1.3-10.7). Cases of isolated dextrocardia shared risk factors with other heterotaxy malformations. The odds of a twin proband having heterotaxy heart disease is 4.8 (95% CI = 1.9-11.8) compared to singleton births. Twin probands are predominantly monozygotic twins in contrast to twin probands in other congenital cardiovascular malformations. CONCLUSIONS: Our findings are consistent with a role for multiple genetic factors in the development of left-right axis formation and with variable cardiac phenotypes according to gene expression and possible gene-environment interactions. Association with monozygotic twinning and with parental cocaine use may point to additional mechanistic clues for future research.

Transcutaneous implantation of an internal cardioverter defibrillator in a small infant with recurrent myocardial ischemia and cardiac arrest simulating sudden infant death syndrome.

This report describes the implantation of a transcutaneous ICD system using a small patch electrode in the subscapular position, and an active-can device in a 5.3-kg infant. The indication for ICD implantation was recurrent cardiac arrest in the presence of normal coronary anatomy. Metabolic evaluation suggested a defect in fatty acid oxidation.