Heart Rhythm • Learn
What Is Atrial Fibrillation?
Atrial fibrillation, often called AFib, is an irregular heart rhythm where the upper chambers of the heart beat out of rhythm. This can cause palpitations, fatigue, shortness of breath, and a higher risk of blood clots and stroke.
Also called AFib, AF, irregular heartbeat, irregular heart rhythm, heart rhythm disorder, arrhythmia, rapid heartbeat, or palpitations.
Plain English
Atrial fibrillation happens when the heart’s upper chambers (the atria) beat in a fast, irregular, and uncoordinated way. Instead of squeezing smoothly, the atria may quiver or flutter. Because blood is not moving as smoothly, clots can form inside the heart and travel to the brain, causing a stroke.
Why it matters
AFib can increase the risk of stroke, blood clots, heart failure, fatigue, and reduced quality of life. Some people feel strong symptoms, while others feel nothing at all.
Key numbers and tests
Important tests include EKG, heart rate, heart rhythm, Holter or event monitors, wearable rhythm data, echocardiogram, ejection fraction, blood pressure, thyroid tests, kidney function, electrolytes, and clinical scores such as CHA2DS2-VASc and HAS-BLED.
Symptoms
Common symptoms include palpitations, racing or fluttering heartbeat, irregular pulse, shortness of breath, fatigue, weakness, dizziness, chest discomfort, and reduced exercise tolerance. Urgent symptoms include chest pain, fainting, severe shortness of breath, or stroke-like symptoms.
How it can progress
Risk factors build over time, AFib may start with occasional episodes, then become more frequent or persistent. Without proper management, AFib may increase the risk of stroke, blood clots, heart failure, and hospitalization.
Outlook
AFib is common and often manageable. Many people live active lives with AFib when stroke risk, heart rate, rhythm, and underlying risk factors such as blood pressure, sleep apnea, weight, and diabetes are managed properly.
How diet and exercise help
Reducing sodium, limiting excess alcohol and stimulants when they trigger symptoms, eating more heart-healthy foods, limiting ultra-processed foods, supporting healthy weight, and consistent safe activity can support blood pressure, weight, and overall heart fitness.
Metrics to monitor
Home metrics include heart rate and rhythm, palpitations, shortness of breath, dizziness, chest discomfort, blood pressure, sleep quality, alcohol and caffeine intake, medication adherence, and stroke-like symptoms. Report-based metrics include EKG, Holter and event monitor findings, echocardiogram, ejection fraction, left atrial size, valve findings, blood pressure trends, kidney function, electrolytes, TSH, A1C, cholesterol, BNP or NT-proBNP, and medication notes.
Common questions
What is atrial fibrillation?
Atrial fibrillation, or AFib, is an irregular heart rhythm where the upper chambers of the heart beat in an uncoordinated way.
Can AFib cause a stroke?
Yes. AFib can allow blood to pool in the heart, which can lead to clots. If a clot travels to the brain, it can cause an ischemic stroke.
Can AFib have no symptoms?
Yes. Some people do not feel AFib and only discover it through an EKG, heart monitor, wearable alert, or routine medical exam.
Do all people with AFib need blood thinners?
Not everyone. Doctors consider stroke risk, bleeding risk, age, medical history, and other factors before recommending anticoagulant medication.