What Is Atrial Fibrillation? What It Means for You

Your heart has four chambers. The two upper ones, called the atria, normally squeeze in a steady, coordinated way and push blood into the two lower chambers. In atrial fibrillation, the electrical signals in the atria become disorganised, so instead of squeezing together they quiver. The result is a heartbeat that is irregular and often fast. The body system involved is the heart's electrical conduction system — the wiring, not the plumbing of the arteries, although artery disease can sit alongside it.

AFib can come and go or it can stick around. Doctors often describe an episode as paroxysmal, meaning it starts and stops on its own within seven days, or persistent, meaning it lasts longer than seven days (StatPearls, National Library of Medicine, undated). Which pattern you have is something your doctor works out from your history and from heart monitoring, and the pattern can change over time.

Symptoms vary widely. The CDC (2024-05-14) lists irregular heartbeat, palpitations (a thumping or fluttering sensation in the chest), lightheadedness, extreme fatigue, shortness of breath and chest pain — and notes that some people have no symptoms at all. MedlinePlus (NIH, 2024-05-14) describes extreme fatigue as the most common symptom.

Because blood can pool when the atria quiver, clots can form. Accounting for standard stroke risk factors, the CDC (2024-05-14) reports AFib is associated with roughly a fivefold increase in the risk of ischemic stroke — a stroke caused by a blocked vessel in the brain — and that AFib causes about 1 in 7 strokes. MedlinePlus (NIH, 2024-05-14) notes that untreated AFib can lead to stroke, heart failure, blood clots, sudden cardiac arrest, and cognitive impairment and dementia. The course differs from person to person, which is why treatment decisions belong with your healthcare provider.

Call 911 if you have chest pain or pressure, severe shortness of breath, or you faint or feel you might (Cleveland Clinic, undated).

These are drawn from the CDC (2024-05-14) and MedlinePlus (NIH, 2024-05-14). They are not listed in order of importance, because neither source ranks them that way.

• Age — not changeable. Risk rises with age, especially after 65. StatPearls (National Library of Medicine, undated) puts the lifetime risk of developing AFib at 22% by age 80.
• High blood pressure — often manageable with your doctor. The CDC reports high blood pressure accounts for about 1 in 5 cases of AFib. Blood pressure is measured in mmHg, and the targets your doctor uses can differ by age and other conditions.
• Alcohol, tobacco and stimulant use — changeable. Moderate to heavy alcohol use and smoking are listed risk factors, as is use of cocaine or methamphetamine.
• Body weight, diabetes and sleep apnea — often modifiable with medical support. Obesity, diabetes and sleep apnea (repeated pauses in breathing during sleep) all appear on the risk lists.
• Other heart conditions — partly modifiable through treatment. Heart failure, ischemic heart disease (narrowed heart arteries), heart valve disease and enlargement of the heart's left-side chambers.
• Thyroid and kidney conditions — treatable but not self-managed. Hyperthyroidism (an overactive thyroid gland) and chronic kidney disease.
• Lung disease — partly modifiable. COPD and other chronic lung conditions.
• Family history, genetics and European ancestry — not changeable. Recent surgery on the heart, lungs or esophagus is also listed as a trigger.

1. Keep a simple episode log. Note the date, the time it started and stopped, what you were doing, and what you felt — fluttering, breathlessness, fatigue, lightheadedness.
2. Record your pulse and blood pressure if you have a home monitor, writing readings in mmHg with the date. Bring the device itself if your clinic can check it against theirs.
3. Gather your records: previous EKG (electrocardiogram, a tracing of the heart's electrical activity) or echocardiogram (an ultrasound of the heart) reports, and recent blood tests. Normal lab ranges vary by laboratory, age and sex, so bring the printed report rather than a remembered number.
4. Write out every medication and supplement you take, including over-the-counter products, with how much and how often.
5. Ask relatives whether anyone has had AFib, stroke or early heart disease, since MedlinePlus (NIH, 2024-05-14) lists family history among the risk factors.
6. Write your questions down before you go in. One worth asking directly:

Ask your doctor

"What is my personal stroke risk with this rhythm, and how does that change what you recommend for me?"

1. Ask also: "Is my AFib paroxysmal or persistent, and which test would tell you?" MedlinePlus (NIH, 2024-05-14) notes a provider may order blood tests, an EKG, an echocardiogram, or ask you to wear a heart monitor.
2. Learn the stroke signs now and keep them somewhere visible: face drooping, confusion, slurred speech, dizziness or balance problems, numbness or weakness on one side, severe headache or vision trouble — call 911 or go to an emergency room immediately (Johns Hopkins Medicine, undated).