Bradycardia (slow heart rate): symptoms, causes and treatment

The NHS says there are different types of heart rhythm problem: a fast heartbeat (tachycardia), a slow heartbeat (bradycardia) or an irregular heartbeat where the rhythm changes. The symptoms it lists for heart rhythm problems in general are below. Having these symptoms does not necessarily mean you have a heart rhythm problem.

For heart block, which causes a slow or unsteady heartbeat, the NHS says symptoms can range from mild to severe, and that you may have no symptoms at all and only find out during tests for something else.

• Your heart pounding, racing, fluttering or missing a beat (palpitations), lasting from a few seconds up to a few minutes.

• Feeling short of breath.

• Feeling lightheaded, dizzy or like you might faint, or fainting.

• Feeling tired.

• Chest pain or discomfort.

Bradycardia is a heart rhythm in which the heart beats too slowly. The NHS includes it under heart rhythm problems, which it describes as a fault with the electrical system that makes the heart beat.

It is not always a problem. The NHS says that heart rhythm problems might not be serious, and that you usually only need treatment for heart block if it is causing symptoms. The cause and symptoms matter more than the number itself.

The NHS says heart rhythm problems happen when there is a fault with the electrical system that makes your heart beat. For heart block, a common cause of a slow heartbeat, the NHS says it is most often caused by a heart condition such as coronary heart disease, or a heart attack. Sometimes babies are born with heart block. Other possible causes of AV heart block include taking some types of medicine, infection and inflammation of the heart caused by another condition, and having heart surgery. Sometimes there is no obvious cause.

The British Heart Foundation (BHF) lists causes of AV heart block as coronary heart disease, congenital heart disease, cardiomyopathy, ageing of the electrical pathways in the heart, thickening of the heart muscle and some medicines, and says it can also happen naturally in people with a normal heart.

The BHF describes tachy-brady syndrome, in which the heart's sinus node, which tells the heart when to beat, does not work properly, so the heartbeat can become too fast or too slow, or switch between fast and slow, sometimes with sudden pauses that make you dizzy and lightheaded.

The NHS says the main test used to diagnose heart block is an electrocardiogram (ECG), which measures the electrical activity of the heart. It usually only takes a few minutes, but you may be asked to wear a portable ECG for 1 or 2 days to monitor your heart.

Other tests used, according to the NHS, include an echocardiogram or MRI scan to get a picture of the heart, exercise tests to check the heart while you use a bike or treadmill, and blood tests. The NHS ECG page explains that an ECG may be done at rest, while wearing a portable ECG over a period of time, or during exercise or after medicine that changes the heart rate. The BHF says that unless you have symptoms, heart block is often noticed during routine tests for other conditions.

The NHS says how a heart rhythm problem is treated depends on the type you have and what is causing it, and that many people do not need any treatment or only need regular check-ups. You may also need treatment for any condition causing the problem. For heart rhythm problems in general, it lists medicines to control the rate and rhythm, ablation, cardioversion and a pacemaker.

For heart block the NHS says treatment depends on the cause and whether you have symptoms. If heart block is not causing symptoms you will not usually need treatment. If you have severe symptoms you may need a pacemaker, which keeps the heart beating regularly and not too slowly, either for a short time or permanently depending on the cause.

The NHS says a pacemaker is a small device put under the skin of your chest that sends out an electrical signal to help control the heartbeat. It is fitted in hospital, usually taking about an hour, and you will usually stay overnight. For a slow heartbeat, you may be offered a leadless pacemaker, which is guided directly to the heart through a vein, with no wires and no cuts to the chest, and you can usually go home on the same day. The NHS says the battery usually lasts 6 to 7 years, and you must tell the DVLA and your insurance company that you have a pacemaker.

The NHS says to call 999 or go to A&E if you currently have heart palpitations with chest pain, shortness of breath, feeling dizzy or lightheaded, or fainting or feeling like you might faint. Do not drive yourself to A&E. If these symptoms have stopped, ask your GP surgery for an urgent appointment, call 111 or get help from 111 online.

For heart block specifically, the NHS says to get help from NHS 111 if you feel dizzy all the time or it keeps coming back, you have fainted, or you have shortness of breath that gets worse during normal activities or when you lie down. Call 999 if you have been diagnosed with heart block and have chest pain, severe difficulty breathing, feel sweaty, sick or lightheaded, or someone faints and is not breathing or cannot be woken within 1 minute.

See a GP if you think you may have heart rhythm problems, or if you have heart palpitations that keep happening or are getting worse.

The NHS describes three broad patterns of heart rhythm problem. A GP can tell them apart with an ECG or longer monitoring.

On the NHS a GP is the first step. They can arrange an ECG and refer you to a cardiologist, who may arrange longer monitoring, scans and, where needed, a pacemaker. Pacemaker follow-up is usually at a pacemaker clinic at about 6 weeks, 3 to 6 months, and at least every 12 months afterwards, the NHS says.

Some people choose to see a private cardiologist for an ECG or heart monitoring. In general terms the same tests apply. What matters is that tests are interpreted alongside your symptoms and medicines, and that any pacemaker follow-up is arranged with a pacemaker clinic so that checks are not missed.