Heart rhythm problems (arrhythmias) are experienced by more than one million people a year in the UK. They're one of the top 10 reasons why people go to hospital.
Certain types of arrhythmia can cause sudden cardiac death, which kills 100,000 people a year in the UK. Most of these deaths could be avoided.
"At least 80% of these 100,000 deaths could be avoided through better diagnosis," says Trudie Lobban, founder of the Arrhythmia Alliance charity.
There's not much you can do to prevent an arrhythmia, but there's a lot you can do to treat it. If properly diagnosed, most people can lead normal lives.
The heart's rhythm is regulated by electrical impulses. An arrhythmia is an abnormality of the heart's rhythm. It may beat too slowly, too quickly or irregularly.
These abnormalities range from a minor inconvenience or discomfort to a potentially fatal problem.
Symptoms include palpitations, blackouts, dizziness and breathlessness. In extreme cases, certain types of arrhythmia can cause sudden cardiac death. See a GP if you have any of these symptoms.
Common causes of an arrhythmia are stress, caffeine, tobacco, alcohol, diet pills and cough and cold medicines.
You may also be at risk of developing an arrhythmia if your heart tissue is damaged because of an illness, such as a heart attack.
Atrial fibrillation, a condition in which the heart beats too fast and irregularly, is the most common type of arrhythmia and a common cause of stroke.
It's estimated that 5% of people with atrial fibrillation have a stroke.
Misdiagnosis is a major factor affecting the quality of life of people with arrhythmia, says the Arrhythmia Alliance. "If your symptoms persist or there's a history of unexplained sudden death in your family, it's important for your GP to refer you to a cardiologist or an electrophysiologist," says Lobban.
There are approximately 100 electrophysiologists (cardiologists who specialise in heart rhythm disorders) in the UK.
The most effective way to diagnose an arrhythmia is by having an electrical recording of the heart called an electrocardiogram (ECG).
"If the ECG doesn't detect any abnormality, it may be necessary to arrange for further monitoring of your heart," says Lobban. This may involve having an ECG, using a small portable recording device that you take away with you for 24 to 72 hours.
"Request a copy of your ECG. This is recommended by NHS guidelines on arrhythmias and sudden cardiac death," says Lobban. "Take it with you to a consultation with a cardiologist or heart rhythm specialist and always keep a copy for future use."