What Is Atrial Fibrillation? Causes and Symptoms You Should Know

Here’s what AFib is doing to your ticker.

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An occasionally skipped beat is no biggie for the heart, but some abnormal heartbeats can cause the muscle to pump blood less effectively and can be life-threatening.

The most common kind of  irregular heartbeat is called atrial fibrillation, and it affects at least 2.7 million Americans, according to the American Heart Association. Atrial fibrillation, or AFib, causes abnormal, fluttering beats that can lead to stroke, blood clots, or heart failure.

AFib is caused by faulty electric impulses starting from the top right chamber of the heart, the right atrium. The sinoatrial node in this atrium normally initiates this impulse, which causes the rest of the heart to contract. But with AFib, the electric impulses are disorganized and occur throughout the two atriums.

“Because those impulses are coming from all different places, instead of contracting in one big pump, the heart actually fibrillates; it shakes,” says Michelle Weisfelner Bloom, MD, a cardiologist at Stony Brook University Medical Center.

Risk factors for AFib include:

  • High blood pressure

  • Previous heart attack

  • Previous stroke

  • Heart failure

  • Thyroid disease

  • Valve condition

  • Excess alcohol intake

  • Sleep apnea

  • Obesity

You may not experience any symptoms with atrial fibrillation, but those who do have symptoms report having palpitations (which feels like a fluttering in the heart), shortness of breath, chest discomfort, or lightheadedness.

Because not all patients experience symptoms of AFib, many people do not even realize that they have it. That could be dangerous since AFib increases your risk of stroke by four to six times, according to the National Institute of Neurological Disorders and Stroke, as well as heart failure and other heart-related problems. (Learn more about preventing and treating a stroke here.)

“If you have any symptoms that don’t feel right, you should always go and tell your doctor,” says Dr. Bloom, “because it’s very, very important for us to know if a patient is in atrial fibrillation, and you might not always know that yourself.”