Left untreated, atrial fibrillation can cause life-threatening complications, such as stroke or heart failure. For millions of people, a steady and predictable heartbeat has been replaced by an irregular or extremely rapid one. These abnormal heart rhythms are called arrhythmias, and the most common form is atrial fibrillation, or AFib. Cardiologist and Electrophysiologist with the MemorialCare heart and Vascular Institute at Orange Coast, Thuy Le, MD, discusses the symptoms and treatment options for AFib, along with when to seek treatment and the best course of care for this condition.