Atrial fibrillation is a condition in which the heart beats in an irregular pattern. It is caused by a problem in the heart's electrical pathways. It can be a sign of heart disease or other health problems that affect the heart.
The carotid arteries are the main blood vessels that carry blood and oxygen to the brain. When these arteries become narrowed by atherosclerosis, it’s called carotid artery disease, or carotid artery stenosis.
Stroke - where a blood vessel in the brain is blocked or bursts - is a serious condition that requires clinical care by a physician or other health care professional; brain damage can occur within minutes of having a stroke.