Medical Encyclopedia


Medical Encyclopedia

Other encyclopedia topics:  A-Ag  Ah-Ap  Aq-Az  B-Bk  Bl-Bz  C-Cg  Ch-Co  Cp-Cz  D-Di  Dj-Dz  E-Ep  Eq-Ez  F  G  H-Hf  Hg-Hz  I-In  Io-Iz  J  K  L-Ln  Lo-Lz  M-Mf  Mg-Mz  N  O  P-Pl  Pm-Pz  Q  R  S-Sh  Si-Sp  Sq-Sz  T-Tn  To-Tz  U  V  W  X  Y  Z  0-9 

Truncus arteriosus

Contents of this page:


Heart, section through the middle
Heart, section through the middle
Truncus arteriosus
Truncus arteriosus

Alternative Names    Return to top


Definition    Return to top

Truncus arteriosus is a rare type of congenital heart disease characterized by a single blood vessel arising from the right and left ventricles, instead of the normal two (pulmonary artery and aorta).

There are four subtypes of truncus arteriosus, depending on the specific anatomy of the single vessel.

Causes    Return to top

In normal circulation, the pulmonary artery arises from the right ventricle, and the aorta arises from the left ventricle, which are separate from each other. Coronary arteries, which supply blood to the heart muscle, arise from the aorta, just above the valve at the entrance of the aorta.

In truncus arteriosus, a single arterial trunk arises from the ventricles. A large ventricular septal defect (hole between the two ventricles) is usually also present. As a result, the blue (unoxygenated) and red (oxygenated) blood mix completely.

Some of this mixed blood goes to the lungs, some to the coronary arteries, and the rest to the body. Usually, too much blood is sent to the lungs. Meanwhile, the blood going to the coronary arteries and the rest of the body often does not contain enough oxygen.

If left untreated, two problems occur. First, the lungs are filled with fluid, making it difficult to breathe. The second problem is that the blood vessels to the lungs become narrow and are permanently damaged. Over time, it becomes very hard for the heart to force blood to them. This is called pulmonary hypertension and it can be life-threatening.

Truncus arteriosus is very rare.

Symptoms    Return to top

Exams and Tests    Return to top

The cardiologist or pediatrician usually hears a murmur when listening to the heart with a stethoscope.

Treatment    Return to top

Surgery is needed to treat this condition. Two procedures are available. One is banding of the pulmonary arteries coming off the truncus, but it is rarely used anymore. The other procedure is called complete repair. Complete repair appears to be the preferred option but as the child grows, repeat surgical procedures may be necessary.

Outlook (Prognosis)    Return to top

Complete repair usually provides good results. Re-operation may be necessary as the patient grows. Untreated cases have a poor outcome, usually leading to death between during the first year of life. Rarely, the diagnosis is missed until early adulthood; these patients generally need a heart and a lung transplant.

Possible Complications    Return to top

When to Contact a Medical Professional    Return to top

Call your health care provider if your infant or child appears lethargic, does not eat well, appears excessively tired or mildly short of breath, or does not seem to be growing or developing normally.

If the child's skin, lips, or nail beds appear blue or if the child seems significantly short of breath, take the child to the emergency room or have the child examined promptly.

Prevention    Return to top

There is no known prevention, but early treatment can often prevent serious complications.

References    Return to top

Zipes DP, Libby P, Bonow RO, Braunwald E, eds. Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine, 8th ed. St. Louis, Mo; WB Saunders; 2007.

Update Date: 12/10/2007

Updated by: David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.; and Mark A Fogel, MD, FACC, FAAP, Associate Professor of Pediatrics and Radiology, Director of Cardiac MR, The Children's Hospital of Philadelphia.

A.D.A.M. Logo

The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed physician should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. Copyright 1997-2009, A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.