Heart block is a problem with your heart's electrical system, which controls your heart rhythm. Heart block is also called an atrioventricular (AV) block, or a conduction disorder.
Normally, electrical signals travel from the upper chambers of your heart (atria) to the lower chambers (ventricles). The AV node is a cell cluster connecting the electrical activity – like a bridge – from the top chambers of your heart to the bottom chambers. If you have a heart block, the electrical signal does not travel through the AV node to the ventricles. The result is a heart that doesn’t function effectively, meaning your heart beats slowly or skips beats, and it cannot pump blood through its chambers and out to the body as a normal heart would.
How to Spot 2:1 AV Block on Your Watch ECG
2:1 atrioventricular (AV) block is a subtype of second-degree AV nodal block and occurs when every other P wave is not conducted through the AV node to get to the ventricles. As a result, every other P wave is not followed by a QRS complex. 2:1 AV block can possibly be from either second-degree AV nodal block type I (Wenckebach) or second-degree AV nodal block type II.
These are the following characteristics that can identify a 2:1 AV block in your ECG:
- A ratio of two P waves for every one QRS complex (2:1)
- P-R interval can be normal, prolonged (2nd-degree type II), or progressive prolongation (2nd-degree type I).
- The QRS complex can be narrow or wide.
Common Symptoms of 2:1 AV Block
Some cases of heart block may be congenital, or present at birth. But most heart blocks develop after birth. Some causes may not be preventable, while others can be prevented.
If you have a 2:1 AV block, the electrical impulses will sometimes not reach the lower chambers of your heart. This can cause your heart to skip beats, leading to an abnormal heart rhythm which affects the flow of oxygen-rich blood to your body and brain. It can cause:
- Fainting, feeling dizzy.
- Chest pain.
- Feeling tired.
- Shortness of breath.
- Heart palpitations.
- Rapid breathing.
As always, if you show signs of a potential 2:1 AV Block, contact your healthcare provider as soon as possible to rule out the presence of harmful underlying conditions.
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