Learning About Congenital Heart Block

So there we were with a diagnosis—third degree congenital heart block or third degree congenital atrioventricular block or congenital complete heart block—long, technical names for the same frightening condition. The counseling began with our team of physicians – Perinatologists, Pediatric Cardiologists, Neonatologists, Electrophysiologists. The education began on the heart and congenital heart block. What is congenital heart block? According to Web MD (http://www.webmd.com/heart-disease/heart-block-congenital):

Within the right atrium of a normal heart is a natural pacemaker that initiates and controls the heartbeat. The electrical stimulus travels from the pacemaker (SA node) to the ventricles along a very specific path consisting of conducting tissue and known as the AV (atrioventricular) node. As long as the electrical impulse is transmitted normally, the heart behaves normally.

If the transmission of the signal is impeded, the blocked transmission is known as a heart block or an AV block. If the heart block occurs in the fetus or newborn, the condition is known as congenital heart block. This condition has nothing at all to do with the flow of blood or with the blockage of a major or minor coronary artery. It is an electrical problem rather than a hydraulic one.

Heart blocks are categorized according to the degree of impairment of the patient. The categories are first, second and third degree heart block.

In summary, Grace's heart did not get the signal to pump blood from one chamber to the other. There was nothing structurally wrong with the heart. Her heart rate in utero was between 50-55 beats per minute. The normal fetal heart rate is between 120 and 160 beats per minute.
Congenital heart block mysteriously develops around the 18-24 week period in pregnancy.