A 6-lead ECG test will be used to check your heart rhythm. An accredited cardiac consultant will then review your trace (the image of your heartbeat over a period of time). The most common type of irregular heartbeat in atrial fibrillation, which affects around 1.2 million people in the UK. People with an irregular heartbeat are 5 times more likely to suffer a stroke than those without. This is because the condition increases your risk of blood clots. But with the right treatment to control an irregular heartbeat, you can reduce your risk of stroke.