Encyclopedia of Health and Medicine

40 The Cardiovascular System
Congenital heart disease that manifests in
adulthood, such as ASD and hypertrophic cardiomyopathy,
often produces symptoms such as
PALPITATIONS, shortness of breath, and pulmonary
or generalized EDEMA if the heart’s pumping capability
becomes ineffective (heart failure). The diagnostic
path may include ELECTROCARDIOGRAM (ECG),
ECHOCARDIOGRAM, and COMPUTED TOMOGRAPHY (CT)
SCAN or MAGNETIC RESONANCE IMAGING (MRI), and
CARDIAC CATHETERIZATION.
Treatment Options and Outlook
Minor congenital heart defects may require only
watchful waiting. Most ASDs close within 2 years
of birth and VSDs by age 7. Septal defects that persist
and cause symptoms may require surgery,
often via cardiac catheterization to patch the
defect. Surgery is the most viable treatment option
for most serious malformations of the heart.
Surgery may be corrective, in which the OPERATION
returns the heart to normal structure and function,
or palliative, in which the operation relieves
symptoms though does not restore normal structure
and function. Surgery may be isolated, in
which a single operation corrects the defect, or
staged, in which the surgeon performs several
sequential operations over a period of time. Some
congenital heart malformations require surgery
within days of birth, and others within months to
2 or 3 years.
When doctors detect significant congenital
defects before or shortly after birth, they often
administer prostaglandins to maintain a patent
ductus arteriosus. Though in ordinary circumstances
a PDA would be a heart defect, in the
presence of congenital heart defects PDA allows
continued though limited circulation of oxygenated
blood to buy time until the infant is stable
enough for surgery. In some circumstances the
neonatal cardiologist may perform a balloon septostomy
to surgically create an ASD, which further
allows a mixture of oxygenated and
deoxygenated blood to flow from the heart to the
body.
Risk Factors and Preventive Measures
Genetic factors are emerging as the likely causes,
or at least precipitating circumstances, for many
forms of congenital heart disease. There are clear
genetic links for conditions such as hypertrophic
cardiomyopathy and LQTS, for example, as well as
known correlations between specific heart malformations
and genetic disorders such as Down syndrome
and TURNER’S SYNDROME. As well, the
VACTERL constellation of birth defects speaks to
genetic underpinnings. Prevention for these kinds
of heart problems remains uncertain, though
future treatment is likely to include GENE THERAPY.
Some congenital heart malformations occur as
the result of maternal infections such as RUBELLA
(German MEASLES). Heart defects in infants are
more likely to occur with mothers who have DIA-
BETES. Numerous medications, both prescription
and over-the-counter, as well as ALCOHOL consumption
also cause specific kinds of birth defects.
Women who are pregnant or planning to become
pregnant should discuss with their doctors any
routine medications they take. Many ANTISEIZURE
MEDICATIONS and ANTIPSYCHOTIC MEDICATIONS are
especially damaging to the developing fetus.
Despite advances in gene technology and
knowledge of the body, much congenital heart
disease is idiopathic—that is, doctors do not know
why it occurs. Studies suggest that folic acid supplementation,
which doctors already recommend
to reduce the risk for NEURAL TUBE DEFECTS, also
reduces the risk for malformations of the heart.
Like the neurologic system, the cardiovascular system
evolves early in fetal development so most
malformations occur in the first weeks of pregnancy.
Doctors can detect many heart abnormalities
before birth, allowing parents and doctors to
make appropriate treatment decisions.
See also CARDIOVASCULAR DISEASE PREVENTION;
INFECTION; KAWASAKI DISEASE; SURGERY BENEFIT AND
RISK ASSESSMENT; VEIN.
coronary arteries The network of arteries that
encircles the HEART to provide its BLOOD supply.
The two primary coronary arteries, the right coronary
ARTERY and the left coronary artery, branch
from the AORTA as it arises from the left ventricle.
The left coronary artery is significantly larger and
supplies the left heart. It drops along the left
atrium, branching at the base of the left ventricle
into the left anterior descending (LAD) and circumflex
arteries. The circumflex artery wraps
behind the heart, further branching into smaller