Atrial fibrillation - Symptoms and causes - Mayo Clinic
Jan 14, 2026 · Atrial fibrillation (AFib) is an irregular and often very rapid heart rhythm. An irregular heart rhythm is called an arrhythmia. AFib can lead to blood clots in the heart. The condition also increases …
Atrial Fibrillation (AFib): Symptoms & Treatment - Cleveland Clinic
Apr 21, 2025 · Atrial fibrillation (AFib) is an irregular heart rhythm that begins in your heart’s upper chambers (atria). Symptoms include fatigue, heart palpitations, trouble breathing and dizziness.
What is Atrial Fibrillation? - American Heart Association
Mar 26, 2025 · Atrial fibrillation, also known as AFib or AF, can lead to blood clots, stroke, heart failure and other heart-related complications. AFib is the most common type of irregular heart rhythm.
Atrial Fibrillation (AFib): Causes, Symptoms, and Treatment
Nov 15, 2023 · Atrial fibrillation is a common heart condition that causes irregular heartbeats. Learn about its causes, symptoms, and treatment options in this comprehensive guide.
What Is Afib? - Johns Hopkins Medicine
Afib stands for atrial fibrillation (AF), which is a type of arrhythmia, or abnormal heartbeat. Afib is caused by extremely fast and irregular beats from the upper chambers of the heart (usually more than 400 …
Ask the Expert: Inside the rhythm—A clear guide to AFib
1 day ago · Atrial fibrillation is a common type of heart arrhythmia where the heart's upper chambers, called atria, quiver rapidly and irregularly. This causes the lower chambers to beat fast and unevenly, …
Atrial Fibrillation (AFib) Signs, Symptoms and Treatment
Feb 5, 2025 · Learn about the signs, symptoms and treatments of AFib, a common type of irregular heartbeat that affects an estimated 5 million Americans.
Atrial Fibrillation - What Is Atrial Fibrillation? | NHLBI, NIH
Nov 30, 2022 · Atrial fibrillation, also known as A-fib or AF, is one of the most common types of arrhythmias (irregular heart rhythms). Atrial fibrillation causes your heart to beat irregularly and …
What Is Atrial Fibrillation (AFib or AF)? Symptoms and More
Jul 17, 2025 · Atrial fibrillation (AFib) is a common heart arrhythmia that disrupts regular blood flow, increasing the risk of blood clots. Without treatment, it can lead to serious complications such as...
Atrial Fibrillation (AFib): Symptoms, Treatment, When to Worry
Sep 14, 2025 · Atrial fibrillation, often called AFib, causes an irregular and sometimes rapid heartbeat. It ranks as one of the most common arrhythmias (irregular heart rhythms).