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Your heart beats around 60 times a minute, delivering nutrients and removing waste from every cell in your body. It has been doing this since you were in the womb - the heart forms 18 days into foetal development and begins to pump blood about three days later. But for all we know about this vital organ, researchers are still learning new things about it. The heart is made of cardiac muscle. Unlike some muscles in the body, we can't control it. Instead, the heart's speed is controlled by the autonomic nervous system. The nerves that relay input about our required heart rate connect to a specialised centre in the wall of the right atrium (one of the heart's four chambers), known as the sinoatrial (SA) node.
The SA node is composed of specialised pacemaker cells, which send out an electrical impulse throughout the cardiomyocytes (cardiac cells), ensuring the heart beats properly.
But the SA node can be dysfunctional. These faults can be acquired or inherited. Acquired dysfunction is more common, often caused by age, certain medications and lifestyle factors such as increased BMI, diabetes and hypertension. Many people who have a dysfunction may not have symptoms. One of the most common symptoms of a dysfunctional SA node, experienced by about two million people a year in the UK, is arrhythmia. This is where the heart beats too fast, too slow or irregularly. There are a variety of treatment options for arrhythmia including cardioversion, pacemakers and cardiac ablation.