Junctional rhythm is a heart rhythm originating in the atrioventricular node of the heart, instead of the sinoatrial node, the area normally responsible for regulating the heartbeat. It is not necessarily dangerous, but can be a sign of underlying pathology in need of treatment. An electrocardiogram will readily reveal the abnormal rhythm, and a doctor can use other diagnostic information to determine why the patient's heart rate is not normal. This will be used to decide what treatment, if any, is needed.
The atrioventricular node lies between the atria and the ventricles, acting as a literal junction. In normal sinus rhythm where the heartbeat is regulated by impulses coming from the sinoatrial node, the atria beat first, as is intended. With a junctional rhythm, the atria will still beat first, but the heart rhythm is abnormal. Some people have this type of heart rhythm with no underlying heart problems and may be perfectly healthy and active.
A junctional rhythm can be a response to a heart block, where signals from the sinoatrial mode are not being transmitted and the atrioventricular node takes over. The patient may be at increased risk of heart failure and other problems if the block is not addressed, usually by using a mechanical pacemaker to regulate the heartbeat, taking the load off the atrioventricular node. Patients may also develop this type of rhythm when they experience bradycardia, where the heartbeat is slower than usual, with this node compensating to increase the heart rate.
People having an adverse reaction to digitalis can also develop a junctional rhythm. These patients need medications to offset the digitalis and allow the sinus rhythm to take over. The cause of a junctional rhythm is often evident from a patient examination and interview, allowing a doctor to decide how to proceed with treatment. Typically a cardiologist supervises care for the patient.
In cases where the junctional rhythm does not require treatment, it is noted in the patient's chart for future reference. Care providers noting the abnormal heart rhythm can be assured that it was identified and addressed by an earlier doctor. If the heart rhythm changes again, more follow-up will be needed to find out what is happening inside the heart, and to see if interventions are needed to maintain the patient's heart health. These can include medications and the use of a mechanical pacemaker, depending on the specifics of a patient's case.