(See also Overview of Heart Defects Overview of Heart Defects About one in 100 babies is born with a heart defect. Some are severe, but many are not. Defects may involve abnormal formation of the heart's walls or valves or of the blood vessels that enter... read more .)
When the heart and blood vessels develop in the fetus, at first there is only one large tube, called the truncus, leaving the heart. Normally, the truncus divides into two blood vessels, the pulmonary artery and the aorta (see also Normal Fetal Circulation Normal Fetal Circulation About one in 100 babies is born with a heart defect. Some are severe, but many are not. Defects may involve abnormal formation of the heart's walls or valves or of the blood vessels that enter... read more ). Sometimes the truncus does not divide and persists during fetal development and after birth. There is one valve, the truncal valve, leading into this one artery, rather than separate aortic and pulmonic valves. A single artery arises from the heart, which then gives rise directly to the pulmonary arteries. Invariably, a ventricular septal defect Atrial and Ventricular Septal Defects Atrial and ventricular septal defects are holes in the walls (septa) that separate the heart into the left and right sides. Holes can be present in the walls of the heart between the upper heart... read more 
is present, which allows both the right and left ventricles to pump blood across the truncal valve.
Persistent truncus arteriosus accounts for 1 to 2% of birth defects of the heart. Other problems that can be associated include a tight or leaky truncal valve, an interrupted aortic arch, a patent ductus arteriosus Patent Ductus Arteriosus In patent ductus arteriosus (PDA), the blood vessel connecting the pulmonary artery and the aorta (ductus arteriosus) fails to close as it usually does shortly after birth. Patent ductus arteriosus... read more 
, an atrial septal defect Atrial and Ventricular Septal Defects Atrial and ventricular septal defects are holes in the walls (septa) that separate the heart into the left and right sides. Holes can be present in the walls of the heart between the upper heart... read more , and the genetic abnormality known as DiGeorge syndrome DiGeorge Syndrome DiGeorge syndrome is a congenital immunodeficiency disorder in which the thymus gland is absent or underdeveloped at birth. Children with DiGeorge syndrome are born with several abnormalities... read more .
Persistent Truncus Arteriosus
Symptoms of Persistent Truncus Arteriosus
During the first few weeks of life, infants usually have mild cyanosis (bluish coloration of the skin) and symptoms and signs of heart failure (see figure Heart Failure: Pumping and Filling Problems Heart Failure: Pumping and Filling Problems Heart failure is a disorder in which the heart is unable to keep up with the demands of the body, leading to reduced blood flow, back-up (congestion) of blood in the veins and lungs, and/or... read more 
), including shortness of breath, rapid breathing, poor feeding, and sweating.
Diagnosis of Persistent Truncus Arteriosus
Diagnosis is suspected based on findings during a doctor's examination of the newborn, including characteristic heart murmurs. A heart murmur is a sound created by turbulent blood flow through narrowed or leaking heart valves or through abnormal heart structures. Findings from chest x-rays and ECG, done when doctors suspect a heart defect, usually provide further clues to the diagnosis. Echocardiography Echocardiography and Other Ultrasound Procedures Ultrasonography uses high-frequency (ultrasound) waves bounced off internal structures to produce a moving image. It uses no x-rays. Ultrasonography of the heart (echocardiography) is one of... read more 
(ultrasonography of the heart) confirms the diagnosis.
Cardiac catheterization Cardiac Catheterization and Coronary Angiography Cardiac catheterization and coronary angiography are minimally invasive methods of studying the heart and the blood vessels that supply the heart (coronary arteries) without doing surgery. These... read more 
, MRI, or CT is occasionally used to identify other coexisting heart problems before surgery.
Treatment of Persistent Truncus Arteriosus
Heart failure is treated with drugs to improve breathing and stabilize the infant until surgery can be done.
Surgery is usually done before the infant is 1 to 2 months old. Medical treatment is used before surgery to allow the infant to stabilize and be a better candidate for surgery. Surgery consists of placement of a patch to repair the ventricular septal defect so as to direct all blood flow from the left ventricle to the truncal valve. Then doctors separate the pulmonary arteries from the truncus and attach them to the right ventricle using a tube (conduit). After this repair, the truncus functions as the aorta.
When a conduit is placed during early infancy, its size becomes inadequate as children grow, and additional surgery is needed to enlarge the conduit. Sometimes the child's own tissue can be used to construct the pathway from the right ventricle to the pulmonary arteries and, in that case, there is the potential for growth as the child grows.
After surgical repair, affected children need to take antibiotics before visits to the dentist and before certain surgeries (such as on the respiratory tract). These antibiotics are used to prevent serious heart infections called endocarditis Infective Endocarditis Infective endocarditis is an infection of the lining of the heart (endocardium) and usually also of the heart valves. Infective endocarditis occurs when bacteria enter the bloodstream and travel... read more 
.
More Information
The following are some English-language resources that may be useful. Please note that THE MANUAL is not responsible for the content of these resources.
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American Heart Association: Common Heart Defects: Provides an overview of common birth defects of the heart for parents and caregivers
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American Heart Association: Infective Endocarditis: Provides an overview of infective endocarditis, including summarizing antibiotic use, for parents and caregivers
Drugs Mentioned In This Article
| Generic Name | Select Brand Names |
|---|---|
digoxin |
LANOXIN |
