Understanding atrial fibrillation: Decode the heart's electrical system and the varied beats of AFib episodes

Heart Health
Female doctor listening to heartbeat

A typical heart rhythm is reliably consistent, orchestrating the vital “lub-dub” to propel blood throughout your body. But if you have atrial fibrillation (AFib), your heart beats irregularly. AFib is one of the most common irregular heart rhythms (also known as arrhythmias), affecting over 2 million people in the U.S.

Despite its prevalence, not everyone knows exactly what happens during AFib. Understanding this, along with its symptoms and treatment options, can help you keep your heart healthier for longer.

Here’s what’s going on inside your body during atrial fibrillation — and how you can stay healthy with this condition.

What actually happens during atrial fibrillation?

Every time your heart beats, an electrical signal moves from the top chambers of your heart (the atria) to the bottom ones (the ventricles). This signal causes the ventricles to fill with blood, contract and pump blood to the rest of your body.

“Normally, this occurs at a regular rhythm. With AFib, the atria beat irregularly and don’t work with the ventricles as they should,” says Ali Keramati, MD, an electrophysiologist at Lankenau Medical Center, part of Main Line Health. 

“This leads to an abnormal and at times faster-than-normal heartbeat.”

Having atrial fibrillation doesn’t mean your heart is always beating irregularly. There are different types of AFib, and they vary in how long the irregular heartbeat lasts (called an episode) and whether or not the heartbeat returns to normal on its own.

Types of AFib include:

  • Paroxysmal fibrillation, which is when your heartbeat returns to normal on its own within 7 days and may occur anywhere from just a few times a year to a daily basis
  • Persistent AFib, which is when your heartbeat remains irregular for more than 7 days, does not return to normal on its own and needs treatment
  • Longstanding AFib, which is when your heartbeat remains irregular for more than a year
  • Permanent AFib, which is when your heartbeat is irregular indefinitely, and you and your health care provider are no longer trying to return it to a normal rhythm

The risks of untreated AFib

Untreated AFib can be dangerous for your health, putting you at risk of other heart problems and health conditions. This is because during AFib, your ventricles don’t fill completely. As a result, not enough blood gets pumped out to the rest of your body, which can lead to:

  • Chest pain
  • Blood pooling in the heart, which can lead to clots, strokes and other complications
  • Heart disease
  • Heart failure

What causes the irregular heartbeat of AFib?

“Your heartbeat relies on two major components: functioning electrical impulses and healthy heart tissue. If either is damaged, atrial fibrillation can develop,” says Dr. Keramati.

Most of the time, damage is caused by other heart conditions, like high blood pressure and coronary heart disease. Other causes include:

  • Getting older
  • Genetics
  • Infection
  • Heart structure differences
  • Heartbeats that happen too early or too frequently
  • A fast or slow heart rate

There are also lifestyle factors that can raise your risk of AFib, including excessive alcohol use, illegal drugs (such as cocaine), smoking and stress.

In some cases, including in healthy hearts, atrial fibrillation occurs without any obvious reason.

The often subtle symptoms of AFib

Some people with atrial fibrillation have noticeable symptoms, particularly heart palpitations. Heart palpitations are when it feels like your heart is fluttering, pounding, skipping a beat, beating too fast or beating too hard.

AFib symptoms may manifest subtly, either because they’re non-drastic or don’t occur very often. These include:

  • Extreme tiredness
  • Trouble breathing, particularly when exercising or lying down
  • Dizziness
  • Fainting
  • Chest pain
  • Low blood pressure

Finally, some people with AFib experience no symptoms at all.

Because AFib can be difficult to detect on your own, your health care provider will screen for it during regular check-ups by listening to your heartbeat and pulse, among other assessments.

“They may also do additional tests, especially if you have a higher risk of AFib or are experiencing symptoms. One example is wearing a Holter monitor, which is a small device you wear during your daily activities to record the rhythm of your heart,” says Dr. Keramati.

Getting your heart back in rhythm: Treatment for AFib

Preventing AFib may not be possible for everyone. However, embracing a balanced and healthy lifestyle can often lower the chances of developing heart conditions like AFib. Consider incorporating these beneficial habits into your daily routine:

  • Follow a healthy diet
  • Reduce salt intake
  • Quit smoking
  • Reduce stress
  • Minimize alcohol intake
  • Minimize the use of caffeine and other stimulants

Effective treatments for AFib are available to help slow down your heartbeat, improve regularity and prevent complications such as blood clots. These can include the lifestyle changes above, medications and medical procedures.

Some medications can help minimalize AFib symptoms. These may include medications for heart rhythm control, heart rate control and blood thinners, which can also lower your risk of stroke.

When medications don't work to correct or control AFib or when medications aren't tolerated, procedures that can keep the heart beating normally and prevent stroke include:

“At Main Line Health, patients have access to more options than ever before. These include safe, breakthrough technologies and treatments,” says Dr. Keramati. “Our cardiac physicians have been involved in research resulting in FDA-approved blood-thinning medications and devices to reduce stroke risk.”

When it comes to reducing the risk of stroke, options may include:

  • Blood thinners: These medicines, like anticoagulants, significantly cut the risk of stroke by up to 80%. However, they need monitoring due to a higher bleeding risk.
  • Left atrial appendage closure: A minimally invasive procedure is available for people who can't take blood thinners and are at risk of stroke. The procedure involves sealing off a part of the heart where clots often form and takes only 90 minutes to 2 hours. This prevents clots from reaching the brain and causing a stroke.

Preventing and treating AFib are important aspects of your heart health. By lowering your risk, paying attention to your body and staying up to date with health care check-ups, you can keep your heart in rhythm and your body healthy.

Next steps:

Make an appointment with Ali Keramati, MD
Learn more about heart and vascular care at Main Line Health
Exercise and heart health: A guide for patients with arrhythmias