Having atrial fibrillation, a heart problem that causes what is known as an irregular heartbeat, is the leading risk for a stroke. In fact, those with this disease have a heavily increased risk of heart disease: about 20 percent of all people who have strokes suffer from this problem, making it the single biggest contributor. Even worse, people have a 500 percent increased risk of stroke and even higher risk of heart attacks. Sometimes also called a "quivering" beat or arrhythmia, it can cause a variety of heart problems, including blood clots, stroke, heart failure, and heart attacks. The scary thing about this condition is that it often shows no symptoms until it is too late - it is estimated that nearly three million people are living with this disease, many of which may not even realize it. Understanding the treatments for this disease is so crucial to avoiding serious heart health problems.