A healthy human heart beats approximately 60 to 80 times a minute to push blood around the body – each of these beats is a contraction of the muscle in the heart. Now, in order to coordinate these contractions, electrical signals are used. Every muscle contraction is controlled by electrical impulses that travel between the upper and lower chambers of the heart.
A partial heart block means that these electrical impulses are partially stopped or delayed. In other words, the heart does not beat regularly as it should.
A complete heart block though is when these electrical signals have stopped entirely. As a result, the heart rate has dropped to about 40 beats per minute.
There are 3 types of heart block:
- First degree heart block: these are the least serious type of heart block and don’t generally require any treatment. There are minor disruptions such as skipped heart beats.
- Second degree heart block: in this case, there are dropped beats – due to some electrical impulses never getting to the heart. Here is where some patients may need a pacemaker and may experience some dizziness.
- Third degree heart block: these are the most serious type of heart block. Instead of of some dropped signals, there is no electrical communication between the upper and lower chambers of the heart. This is common in patients with heart disease and if a pacemaker is not installed, there is a serious risk of a heart attack.
Now, there you may have heard your cardiologist or another doctor talk about an AV bundle or bundle branch block. This refers to the bundle of heart muscle fibres that conduct electricity between the upper and lower heart chambers. Distinctions can be made between which side of the heart the blockage is at – blockages on the right side (a right branch block) is not as serious as blockages on left side (a left branch block).
Heart Block vs Coronary Artery Disease
Patients are often confused between the difference between a heart block and coronary artery disease.
Heart blockages tend to present with light headedness, palpitations and fainting (otherwise known as syncope). This is more like a blockage of the conduction or electrical system of the heart.
Coronary artery disease on the other hand is a blockage of the arteries themselves and causes more serious things such as angina and/or a heart attack.