​Atrial fibrillation is a type of irregular heart rhythm (arrhythmia​ ). Atrial fibrillation happens when your usual heart rhythm is disrupted by the electrical impulses firing off from different places in the atria (the upper chambers of the heart) in a disorganized way, causing it to quiver instead of beating normally, which can make your heart work less efficiently. 

The most common causes of atrial fibrillation are long-term high blood pressure, blocked arteries or problems with one of your heart valves. It can also be caused by chest trauma, an overactive thyroid, too much caffeine and some medicines. It is not, however, always possible to determine a root cause
It is important to treat atrial fibrillation because it could result in interrupted blood supplies to vital organs, which in turn could cause a stroke. Treatment varies depending on the cause, the severity of the symptoms, your risk of further complications or stroke and the risk associated with the treatment. 

Most people with atrial fibrillation will need to take medication long term. There are also some interventions that may be recommended for you, such as electrical cardioversion or catheter ablation. 

The best way to improve overall heart health is through living a healthy lifestyle​.