Important
It is possible that the main title of the report Heart Block, Congenital is not the name you expected. Please check the synonyms listing to find the alternate name(s) and disorder subdivision(s) covered by this report.
Synoyms
Atrioventricular (AV) Block
Disorder Subdivision
- First Degree Congenital Heart Block
- Second Degree Con. Heart Block (Wenckebach [Mobitz I]; Mobitz II; included)
- Third Degree Congenital (Complete) Heart Block
General Discussion
Congenital Heart Block is characterized by interference with the transfer of electrical nerve impulses (conduction) that regulate the normal rhythmic pumping activity of the heart muscle (heart block). The severity of such conduction abnormalities may vary among affected individuals.
The normal heart has four chambers. The two upper chambers are known as the atria and the two lower chambers are known as the ventricles. In the mild form of heart block (First Degree), the two upper chambers of the heart (atria) beat normally, but the contractions of the two lower chambers (ventricles) slightly lag behind. In the more severe forms (Second Degree), only a half to a quarter of the atrial beats are conducted to the ventricles. In complete heart block (Third Degree), the atria and ventricles beat independently. In most cases, infants with First or Second Degree experience no symptoms (asymptomatic). However, infants with complete heart block may experience episodes of unconsciousness (syncope), breathlessness, and/or fatigue.
