Congenital heart block: Difference between revisions
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==Natural History, Complications, Prognosis== | ==Natural History, Complications, Prognosis== | ||
===Prognosis=== | |||
The damaged heart may beat extremely slowly. In some cases, the heart rate is so slow that it is fatal in nearly 20% of affected babies (with most deaths occurring as [[ fetal demise]]s). Patients presenting as fetuses or at birth have significantly higher morbidity and mortality rates than do patients presenting later in childhood. | The damaged heart may beat extremely slowly. In some cases, the heart rate is so slow that it is fatal in nearly 20% of affected babies (with most deaths occurring as [[ fetal demise]]s). Patients presenting as fetuses or at birth have significantly higher morbidity and mortality rates than do patients presenting later in childhood. | ||
Revision as of 15:38, 7 February 2013
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor-In-Chief: Cafer Zorkun, M.D., Ph.D. [2]; Contributors: Adam C. Lake
Overview
Congenital heart block is a rare congenital heart disease where a slowed heart rate is caused by defects in the heart conduction system.
Pathophysiology
Scarring of the conduction system (the heart’s own natural pacemaker), a consequence of inflammation triggered by the mother’s antibodies, damages or even destroys the cells that allow the heart to beat at a normal rhythm.
Neonatal lupus (NL) is the name given to a group of conditions that can affect the babies of mothers who have certain autoantibodies against components of the body’s cells that are called SSA/Ro and SSB/La. Neonatal lupus can appear as a temporary rash that usually goes away by the time the baby is 6 months old, or very rarely an abnormal blood or liver condition that also improves with time or it can cause permanent and often life-threatening damage to the fetal heart, known as congenital heart block (CHB). In women with anti-Ro/La antibodies who are pregnant for the first time, only about 2% of the babies will develop congenital heart block. But for a woman who has already had a child with congenital heart block or neonatal lupus rash, the risk of congenital heart block in her next pregnancy is nearly 20%. Unfortunately, once complete (third degree) heart block has been unequivocally identified in a fetus, it has never been reversed with any of the therapies that have been tried to date. If a child is born to a mother with lupus, there is a chance that the child will develop neonatal lupus, especially if the mother is Anti-Ro (SS/A) positive. In the majority of cases, the mother's antibodies will clear from the child in 6 months, however, in a few cases, the affected child will develop complete congenital heart block.
Risk Factors
One form of congenital heart block occurs in babies whose mothers have autoimmune diseases, such as lupus. People who have these diseases make proteins called antibodies that attack and damage the body's tissues or cells.
Natural History, Complications, Prognosis
Prognosis
The damaged heart may beat extremely slowly. In some cases, the heart rate is so slow that it is fatal in nearly 20% of affected babies (with most deaths occurring as fetal demises). Patients presenting as fetuses or at birth have significantly higher morbidity and mortality rates than do patients presenting later in childhood.
Diagnosis
Symptoms
- Signs and symptoms depend on the type of heart block the child has. First-degree heart block rarely causes symptoms.
- Symptoms of second- and third-degree heart block include:
Electrocardiogram
Electrocardiographic findings in congenital heart block depend on the type of block.
Treatment
Surgery
Treatment depends on the type of heart block.
- First-degree heart block usually needs no treatment.
- For second-degree heart block, patient may need a pacemaker. A pacemaker is a small device that's placed under the skin of your chest or abdomen. This device uses electrical pulses to prompt the heart to beat at a normal rate.
- For third-degree heart block, patient will need a pacemaker.
Nearly all surviving children with congenital heart block require permanent implantation of an pacemaker device.
Prevention
Because it is so difficult to treat or repair the damaged heart, a high-priority strategy is to try to prevent the inflammatory process before irreversible scarring can occur. The mother of the child should consult with a rheumatologist to begin monitoring for possible autoimmune disease. Consultation with a rheumatologist is also advised for the infant, particularly if other manifestations of neonatal lupus erythematosus are present. Genetic consultation is recommended for children with first-degree relatives with structural heart disease or those with storage disorder or cardiomyopathy.
Source
Related Chapters
- Electrical conduction system of the heart
- Electrocardiogram (ECG or EKG)
- SA node
- AV node
- Second degree AV block
- Third degree AV block
- Bundle branch block
- Hemiblock
- Infra-Hisian Block
- Left anterior fascicular block
- Left posterior fascicular block
- Heart block
- Systemic lupus erythematosus
- IVIG
References
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