Atrial fibrillation (AF) is the most common heart rhythm condition, affecting approximately one million people in the UK. AF can increase risk of stroke compared to patients with normal heart rhythm and although AF is not usually life threatening, it can be uncomfortable and often requires treatment. Anticoagulation treatment, which helps to prevent blood clots, is a highly effective intervention and can reduce an individual’s risk of an AF-related stroke by around two-thirds.

When the heart beats normally its muscular walls contract, forcing blood around the body. In AF the heart’s upper chambers (atria) contract randomly due to abnormal electrical impulses and the heart muscle cannot relax properly between contractions. The impulses override the heart’s natural pacemaker, which can no longer control the rhythm of the heart, causing an irregular pulse rate. Disrupted blood flow can lead to clot formation in the left atrial appendage. If the clot, or part of the clot, dislodges and enters the circulation and travels to the brain, this will result in a stroke.