Atresia, biliary: Congenital absence or closure of the major bile ducts, the ducts that drain bile from the liver.
Biliary atresia results in a progressive inflammatory process which may lead to cirrhosis of the liver. The infant looks normal at birth but develops jaundice after the age of 2 to 3 weeks with yellowing of the eyes and skin, light-colored stools and dark urine caused by the build up of the pigment called bilirubin in the blood. The abdomen may be swollen with a firm, enlarged liver. Weight loss and irritability develop as the jaundice increases.
There is one case of biliary atresia out of every 15,000 live births. Females are affected slightly more often than males.
The preferred treatment is to attach the small intestine directly to the liver at the spot where bile is found or expected to drain. Bile flow is re-established in approximately 80% of infants who are operated before 3 months of age. Of these, about 50% will have some bile drainage and as many as 30% will have complete bile drainage. About 20% of infants will not be helped by the procedure. In these cases, the only option is a liver transplant.
Atrial: Pertaining to the atria, the upper chambers of the heart, as in atrial fibrillation and atrial septal defect.
- Atrial flutter
Atrial flutter: Well-organized but overly rapid contractions of the atrium of the heart (usually at a rate of 250-350 contractions per minute). Flutter refers to a rapid vibration or pulsation. The difference between flutter and fibrillation is that flutter is well organized while fibrillation is not. Atrial flutter is a serious and potentially unstable rhythm […]
- Atrial fibrillation
An abnormal and irregular heart rhythm in which electrical signals are generated chaotically throughout the upper chambers (atria) of the heart. Many people with atrial fibrillation have no symptoms. Among those who do, the most common symptom is an uncomfortable awareness of the rapid and irregular heartbeat (palpitations). Atrial fibrillation can promote the formation of […]
- Atrial septal defect (ASD)
Atrial septal defect (ASD): A hole in the septum, the wall, between the atria, the upper chambers of the heart. Commonly called an ASD. ASDs constitute a major class of heart formation abnormalities present at birth (congenital cardiac malformations). Normally, when clots in veins break off, they travel first to the right side of the […]
- Atrioventricular (AV)
Atrioventricular (AV): Pertaining to the atria (the upper chambers of the heart) and the ventricles (the lower chambers of the heart). The AV node is an electrical relay station between the atria and the ventricles. Electrical signals from the atria must pass through the AV node to reach the ventricles. The AV node is a […]