Heart block
In people with heart block the electrical pulses that control the heart rate are disrupted, causing the heart to beat more slowly. It's a type of arrhythmia, which is a medical term used to describe problems with the rate or rhythm of the heartbeat.
The symptoms of heart block depend on which type you have and how severe it is. Common symptoms include light-headedness, dizziness and fainting.
Heart block can have a number of different causes. It can occur if you have another heart condition or if you take certain medications. A person can be born with heart block (congenital) or it can develop over time (acquired).
Heart block is often detected during routine tests for other conditions. An ECG is the main test that's used for confirming a diagnosis of heart block. Your GP may suspect heart block based on your medical history, family history and a physical examination.
Heart block usually only needs to be treated if it's causing symptoms (symptomatic). However, most cases of acquired heart block need to be treated regardless of whether there are symptoms or not.