Atrioventricular (AV) Block
An atrioventricular block or AV block occurs when the electrical signals from the upper chambers of the heart, known as the atria, are not transported properly to the lower chambers, known as the ventricles. Elsewhere on this website you have read that the Sinoatrial or SA Node creates the initial electrical signal that begins the heartbeat. In a normal heart, this is well coordinated and the signal travels from the upper chambers of the heart to the lower chambers through the AV Node with no issue whatsoever.
However, when the electrical signal is delayed or blocked entirely, the ventricles must create their own contraction to ensure that the heart continues to function. The electrical signal produced in the ventricles is significantly slower than the normal conduction.
In some patients, such as children and high performing athletes, an AV block is somewhat normal. However, in most patients, AV node block does need to be treated.
Causes of an AV Block
As mentioned above, an AV block may be normal in some patients, however in most, it is not a normal occurrence and can be caused by:
- Lack of blood flow (and oxygen) to the heart known as ischemia
- Scarring of the heart, known as fibrosis
- Certain diseases
- Certain drug toxicities
- A heart attack
How we diagnose an AV block
AV blocks are diagnosed in similar fashion to other cardiac arrhythmias and can include EKG, Holter monitors, event monitors and loop recorders. Lab testing may be employed if you are electrophysiologist believes that there is an underlying cardiovascular concern.
Treatment for an AV block
Treatment will be based on several factors to determine the severity of the condition. Many patients will not require anything more than temporary medication and potentially mechanical pacing. However, patients with problematic AV block that develops into symptomatic bradycardia may require a permanent pacemaker.
As mentioned above, there are circumstances in which the AV block is caused by underlying heart disease, drug toxicity, medication or other diseases and conditions. If that is the case, treating the underlying concern may resolve the AV block without further intervention.
For more information and to speak to an experienced electrophysiologist, we suggest that you contact our office for a consultation to learn more about AV block or to discuss any potential cardiac arrhythmias that may be causing you distress.