Find Information About:

Drugs & Supplements

Get information and reviews on prescription drugs, over-the-counter medications, vitamins, and supplements. Search by name or medical condition.

Pill Identifier

Pill Identifier

Having trouble identifying your pills?

Enter the shape, color, or imprint of your prescription or OTC drug. Our pill identification tool will display pictures that you can compare to your pill.

Get Started

My Medicine

Save your medicine, check interactions, sign up for FDA alerts, create family profiles and more.

Get Started

WebMD Health Experts and Community

Talk to health experts and other people like you in WebMD's Communities. It's a safe forum where you can create or participate in support groups and discussions about health topics that interest you.

  • Second Opinion

    Second Opinion

    Read expert perspectives on popular health topics.

  • Community


    Connect with people like you, and get expert guidance on living a healthy life.

Got a health question? Get answers provided by leading organizations, doctors, and experts.

Get Answers

Sign up to receive WebMD's award-winning content delivered to your inbox.

Sign Up

Heart Disease Health Center

Font Size

What Are Heart Rhythm Disorders (Arrhythmias)?

Your heart is hard at work pumping blood and nutrients throughout your body. You can sometimes hear it or even feel it as it pumps at a steady pace.

The heart keeps an even, reliable rhythm that's controlled by your body’s own electrical system. When that system has issues, the rhythm changes. This is known as arrhythmia, which is a problem with the heart's rhythm.

Recommended Related to Heart Disease

Diagnosing Atherosclerosis

Atherosclerosis is sneaky. It's a process that starts early in life and progresses silently. By the time symptoms occur, atherosclerosis is advanced and represents a serious problem. There are tests for diagnosing atherosclerosis, but none of them are perfect. Some of them even have some risk of harm. So testing isn't as simple as you might think. If you're concerned about atherosclerosis, what should you do? What can you expect at the doctor's office if you ask about an atherosclerosis diagnosis?...

Read the Diagnosing Atherosclerosis article > >

Having an arrhythmia does not necessarily mean you have heart disease. There are many things that can cause your heart to flutter.

What Causes the Heart to Break Its Rhythm?

It’s possible to have a random arrhythmia even if your heart is healthy. If you do, talk to your doctor.

Arrhythmias are caused by:

  • Infection or fever
  • Physical or emotional stress
  • Diseases such as anemia or thyroid disease
  • Drugs and other stimulants, such as caffeine, tobacco, alcohol, cocaine, amphetamines, and certain over-the-counter and prescription medications
  • Your genes
  • Some heart conditions


Symptoms of a Heart Rhythm Disorder

A typical heart will beat at 60 to 100 times per minute. It can beat faster if you need it to during exercise or in a stressful situation. It can slow down while you sleep. Your heart is used to slowing down and speeding up. This is normal.

When its rhythm is interrupted, you might not notice. Some people, however, can feel it when it happens.

Common symptoms include:

  • Palpitations, or "skipped beats"
  • Thumping or fluttering in the chest
  • Sensation of the heart racing

Other symptoms include:

  • Feeling faint or tired
  • Light-headedness or passing out
  • Shortness of breath
  • Chest pain or discomfort

It's possible you may experience the sensations described above and have no arrhythmias. These symptoms may be due to anxiety, stress, or other causes besides a problem with your heartbeat.

What’s Controlling Your Heartbeat?

There’s a node in the upper right section of your heart that monitors your body’s need for blood. It’s called the sinoatrial (SA) or sinus node, and it acts like a natural pacemaker. 

It is the main control and source of each heartbeat. It can speed up your heart rate when you need it to speed up, such as during exercise or an illness or even when you feel happy.

Your SA node sends out electrical impulses across the heart. These cause the chambers to contract at specific times causing a heartbeat.

1 | 2 | 3

Today on WebMD

x-ray of human heart
A visual guide.
atrial fibrillation
Symptoms and causes.
heart rate graph
10 things to never do.
heart rate
Get the facts.
empty football helmet
red wine
eating blueberries
Simple Steps to Lower Cholesterol
Inside A Heart Attack
Omega 3 Sources
Salt Shockers
lowering blood pressure