Junctional rhythm occurs when the electrical impulse in the heart starts in the atrio-ventricular node (AV node) instead of the sinoatrial (SA) node. Junctional rhythms can often be normal, but sometimes they are too fast or too slow. Junctional bradycardia is a type of junctional rhythm where there heart rate is slower than the normal heart rate for the patient's age. Patients who have had heart surgery for congenital heart disease can develop junctional rhythm from damage to the AV node which causes it to fire automatically, "taking over" the SA node. Junctional rhythm can also occur if the SA node slows or is damaged from surgery.
The diagnosis of junctional rhythm is made based on specific findings noted on your electrocardiogram (ECG). Junctional rhythms may occur intermittently, or they may be permanent, depending on whether or not the SA node is able initiate the heartbeat.
After a diagnosis of junctional bradycardia has been made, your healthcare team may order additional testing. This may include a long-term monitor such as a Holter monitor to determine the frequency of the junctional bradycardia. Holters or other long-term monitors may be worn again for routine rhythm monitoring, or if there is a concern about worsening symptoms.
Another common test after the diagnosis junctional bradycardia is an exercise stress test. Exercise stress tests are performed in exercise laboratories and require electrodes to be placed on the skin just like resting ECGs. However, instead of lying down, your child engages in physical activity, like walking on a treadmill or pedaling a stationary bike, with the ECG recording the entire time. This is done to see if the impulse that starts the heart beat changes to the normal location in the SA node during exercise, or if the junctional rhythm increases in rate during exercise.
Congenital heart disease patients with junctional rhythms/junctional bradycardia may require medical therapy or a pacemaker, or sometimes both. Your cardiologist will discuss the treatment options with you.
Patients with junctional bradycardia are usually not restricted from sports or other activities, but they may experience fatigue or inability to perform activities at the same level as other people their age. If a pacemaker is required to treat the junctional bradycardia, then patients may have some lifestyle restrictions, depending on the type and location of the pacemaker.