Heart block

Your heart muscle beats because of small electrical impulses that travel through it. Heart block happens when those impulses get interrupted.

Heart block comes in a few different types, and the symptoms you get depend on which type you have.

First degree heart block is when there's a very short delay in the heart's electrical impulse.

It does not usually cause any noticeable symptoms. Most people only become aware of it when they're tested for another medical condition.

Second degree heart block comes in 2 types, called Mobitz type 1 and Mobitz type 2.

Mobitz type 1 causes the heart's electrical impulses to be delayed a little more each time, until the heart eventually skips a beat. This is the less serious type of second degree heart block, and most people won't have any symptoms. It can sometimes cause dizziness and fainting, though.

Mobitz type 2 causes irregular delays in the heart's electrical impulses, so the heart skips a beat more often. This type is more likely to cause symptoms such as:

• dizziness
• light-headedness
• fainting or collapse
• chest pain, which may be worse during physical activity like climbing the stairs
• breathlessness
• getting tired easily when doing physical activity

Third degree heart block is also known as complete heart block. In this condition, electrical impulses are not sent between the chambers of the heart.

Third degree heart block can be:

• congenital (the condition is there from birth)
• acquired (the condition develops as a result of ageing or damage to the heart)

Symptoms of third degree heart block include:

• fainting or collapse
• light-headedness
• dizziness
• breathlessness
• extreme tiredness, sometimes with confusion
• chest pain
• fatigue
• slow heart beat (bradycardia)

You or someone else has symptoms like:

• central chest pain, or discomfort in the chest that doesn't go away (it may feel like pressure, tightness or squeezing)
• pain that spreads down the left arm, or both arms, or to the neck, jaw, back or stomach
• unconsciousness
• seizures or fitting
• difficulty breathing (snoring or rasping)
• a rapid heartbeat
• a low or undetectable heartbeat
• chest pain together with breathlessness, nausea, sweating or coughing up blood

Bundle branch block means the electrical impulses travel more slowly through the heart than they normally do. It happens when there's a block in the path those impulses usually follow.

There are 2 types of bundle branch block:

• left bundle branch block: electrical impulses to the left side of the heart get delayed or blocked
• right bundle branch block: electrical impulses to the right side of the heart get delayed or blocked

Bundle branch block doesn't usually cause any symptoms.

If you don't have symptoms, heart block is usually found by chance, while you're being tested for some other condition.

When tests for heart block are needed, an electrocardiogram (ECG) is the one most often used. It shows how well your heart is working. You may also be given a portable heart rhythm monitor to wear, which checks the electrical activity of your heart over a longer period of time.

Heart block can also be found before a child is born. If a baby has congenital heart block, an ultrasound scan during pregnancy may pick it up. The scanner can measure how quickly your baby's heart is beating, and an abnormally slow heartbeat may suggest heart block.

What treatment you need for heart block usually depends on which type of heart block you have.

First degree heart block and Mobitz type 1 don't usually need treatment. Third degree (complete) heart block and Mobitz type 2 are usually treated with a pacemaker.

A pacemaker is a small metal box that's inserted under the skin. It's attached to one or more wires that run to your heart. The pacemaker sends regular impulses to the heart to keep it beating regularly.

In emergency situations, you may be given medicine to speed up your heart beat. A temporary pacemaker can also help stabilise you before you're given a permanent pacemaker.

Most people who have heart block develop it later in life, or because of another condition. This is called acquired heart block.

Acquired heart block can be caused by:

• ageing of the electrical pathways in your heart
• other heart conditions like a heart attack
• some prescription medicines
• heart surgery
• other conditions like Lyme disease

Other people are born with heart block, and this is called congenital heart block. Babies are more likely to have congenital heart block if they're born with a heart defect or if their mother has an autoimmune condition like Lupus.