Patient education: Heart block in adults (The Basics)

What is heart block? — 

This is a condition that affects the electrical system that controls the heartbeat. Mild types of heart block can cause the heart to beat more slowly than normal or to skip beats. More serious types can cause the heart to stop beating. Without emergency treatment, serious heart block can be fatal.

What causes heart block? — 

It happens when the electrical signals that tell the heart to beat either get slowed down or stopped. Most people with heart block get it from a disease, surgery, or medicine. In rare cases, people are born with heart block.

What are the symptoms of heart block? — 

The symptoms depend on the type of heart block. There are 3 types:

●First-degree – This is the mildest type. People with this type usually have no symptoms.

●Second-degree – This is more serious than first-degree heart block. Most people with second-degree heart block have no symptoms. When symptoms do happen, they include:

•Fainting

•Dizziness

•Feeling tired

•Trouble breathing

•Chest pain

●Third-degree – This is the most serious type. Nearly all people with third-degree heart block have symptoms. It can cause the same symptoms as second-degree heart block, but they can be more severe. In some cases, third-degree heart block can be life-threatening.

Is there a test for heart block? — 

Yes. Your doctor or nurse will probably do a test called an "electrocardiogram" ("ECG") (figure 1). It measures the electrical activity of the heart.

You might also need other tests to see if another condition is causing your slow heartbeat.

How is heart block treated? — 

The treatment depends on the type of heart block:

●Most people with first-degree heart block do not need treatment.

●Some people with second-degree heart block, and most people with third-degree heart block, need a pacemaker. This is a device that goes under the skin near the heart (figure 2). It sends electrical signals to the heart to help it beat at a normal rate.

When should I call the doctor? — 

Call for an ambulance (in the US and Canada, call 9-1-1) if you:

●Have trouble breathing

●Have chest pain that lasts for more than a few minutes

●Pass out

Call for advice if you do not have these problems, but you often feel like your heart is beating slowly or skipping beats.

More on this topic

Patient education: Heart block in children (The Basics)
Patient education: ECG and stress test (The Basics)
Patient education: Pacemakers (The Basics)
Patient education: Overview of heart arrhythmias (The Basics)