Dizziness, lightheadedness, a racing heart. That's what Mellanie True Hills felt one day in 2003, while working at her desk at home in Decatur, Texas.

"I felt dizzy and lightheaded, and my right leg was numb and looked white," says Hills. By the time she arrived at the emergency room, the vision in her right eye was blurry.

Seven months earlier, Hills came close to having a heart attack and nearly died during a procedure to open her blocked coronary artery.

But this time her problem wasn't caused by a blocked artery.

It was something she had never heard of: atrial fibrillation, also called afib. Afib is the most common heart arrhythmia (irregular heart beat). It starts in the atria the heart's upper chambers, and is caused by an electrical problem there.

It turns out that the racing heart, dizziness, and lightheadedness Hills felt are all classic symptoms of atrial fibrillation. The vision problem and leg numbness she experienced were due to blood clots. When you have atrial fibrillation, blood clots can form in your heart. If one breaks free and travels to your brain, a stroke could occur. Lucky for Hills, that didn't happen.

"I feel like I got a second, third, and fourth chance at life," she says. She knew she had survived some close calls for a reason. Hills is now the CEO of the American Foundation for Women's Health and the founder of StopAfib.org.

Recognizing Afib Symptoms

There is a large range of symptoms of atrial fibrillation, says Paul Yang, MD, the director of the Stanford Cardiac Arrhythmia Service and a professor of medicine at the Stanford University School of Medicine in California. Sometimes people feel vague symptoms like tiredness, a lack of energy, and shortness of breath, especially with exertion.

On the other hand, the rapid and irregular heartbeat can cause people to feel like the heart is jumping around, thumping, racing, or galloping, says John Miller, MD, an electrophysiologist at Indiana University Health and a professor of medicine at the Indiana University School of Medicine in Indianapolis. Hills says to her it felt like "a big bass was flopping around in my chest."

However, some people notice no afib signs or symptoms at all and don't know they have the condition. Dr. Yang says it's quite common for afib to be discovered during a routine physical or when a person is hospitalized for another condition.

Other times, the first time afib is caught is after a stroke, says Dr. Miller. If you have afib, your risk for stroke is especially high if you have high blood pressure, diabetes, or congestive heart failure; if you've had a previous stroke; or if you're 75 or older.

How to Spot Subtle Afib Signs

Atrial fibrillation can be a progressive condition, meaning episodes return and can get worse over time. Spotting it early and getting treatment can relieve symptoms of atrial fibrillation and prevent complications like heart failure and stroke. Yang says if you start to feel more tired for no apparent reason, you notice a change in how much you can exert yourself, or a home blood pressure monitor repeatedly picks up an irregular heartbeat, it's time to call your doctor.

Miller adds that it's a good idea to learn how to take your own pulse to check for possible afib signs. Here's how to do it:

  • Sitting at a table, turn your left hand over so your palm is facing the ceiling. Place your index and middle finger of your right hand just below where the thumb and wrist meet on your left wrist.
  • Press lightly and feel for your pulse. Move your fingers around if you can't find it.
  • Count how many heartbeats you have in one minute (a normal resting heart rate is 60 to 100 beats a minute). Also, take note of whether the rhythm of your pulse is steady. If you detect an erratic heartbeat or skipped beats or have any other concerns about your pulse, contact your doctor.

The Toll of Atrial Fibrillation

Afib had Hills living in fear, because she never knew when an episode would happen or what she would be doing when it hit. Many people with afib may feel they are "constantly looking over their shoulders waiting for the beast to strike next," she says.

Once, while taking a walk close to home, she says her heart rate tripled. She felt like she was going to pass out. "I felt like I was going to have a stroke and die right there," she says. Hills called her husband, who arrived in minutes. An extra dose of her heart medication got her heartbeat back to normal quickly. But her unpredictable episodes of afib took a toll on the whole family — everyone was on edge.

Doctors can prescribe medication to control the rate and rhythm of the heart and blood-thinning drugs to prevent blood clots. If medications aren't enough to treat your afib, nonsurgical and surgical interventions exist to help manage atrial fibrillation symptoms and reduce your risk for stroke.

In 2005, Hills had what's called a "mini-maze" surgical procedure to disrupt the chaotic electrical signals and restore a normal heartbeat. Surgeons also removed her left atrial appendage, the spot in the heart where most afib-related blood clots form. Hills has been afib-free ever since.