Congenital heart block
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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.
The most common cause of congenital complete heart block is neonatal lupus. It accounts for almost all cases presenting in the intrauterine and neonatal period. Other causes include:
- Levo transposition of great arteries
- Atrioventricular discordance
- Hurler cardiomyopathy
- Hunter cardiomyopathy
- Polysplenia with atrioventricular canal defect
Differentiating [disease name] from other Diseases
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Epidemiology and Demographics
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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
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.
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- 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:
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Other Diagnostic Studies
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Electrocardiographic findings in congenital heart block depend on the type of block.
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.
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.
- 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
- Infra-Hisian Block
- Left anterior fascicular block
- Left posterior fascicular block
- Heart block
- Systemic lupus erythematosus
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- Cutler NG, Karpawich PP, Cavitt D, et al. Steroid-eluting epicardial pacing electrodes: six year experience of pacing thresholds in a growing pediatric population. Pacing Clin Electrophysiol. Dec 1997;20(12 Pt 1):2943-8.
- Friedman DM, Kim MY, Copel JA, et al. Utility of cardiac monitoring in fetuses at risk for congenital heart block: the PR Interval and Dexamethasone Evaluation (PRIDE) prospective study. Circulation. 2008;117:485-93.
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- Karpawich PP, Walters H, Hakimi M. Chronic performance of a transvenous steroid pacing lead used as an epi- intramyocardial electrode. Pacing Clin Electrophysiol. Jul 1998;21(7):1486-8.
- Miranda-Carus ME, Boutjdir M, Tseng CE. Induction of antibodies reactive with SSA/Ro-SSB/La and development of congenital heart block in a murine model. J Immunol. Dec 1 1998;161(11):5886-92.
- Moak JP, Barron KS, Hougen TJ, et al. Congenital heart block: development of late-onset cardiomyopathy, a previously underappreciated sequela. J Am Coll Cardiol. Jan 2001;37(1):238-42.
- Neiman AR, Lee LA, Weston WL, Buyon JP. Cutaneous manifestations of neonatal lupus without heart block: characteristics of mothers and children enrolled in a national registry. J Pediatr. Nov 2000;137(5):674-80.
- Rao V, Williams WG, Hamilton RH, et al. Trends in pediatric cardiac pacing. Can J Cardiol. Dec 1995;11(11):993-9.
- Suarez-Penaranda JM, Munoz JI, Rodriguez-Calvo MS, et al. The Pathology of the heart conduction system in congenital heart block. J Clin Forensic Med. Aug-Nov 2006;13(6-8):341-3.
- Weng KP, Chiou CW, Huang SH, et al. The long-term outcome of children with isolated congenital complete atrioventricular block. Acta Paediatr Taiwan. Sep-Oct 2005;46(5):260-7.