What is an Arrhythmia?

Updated:Dec 8,2015
An arrhythmia is an abnormal heart rhythm. It may feel like fluttering or a brief pause. It may be so brief that it doesn’t change your overall heart rate (the number of times per minute that your heart beats). Or it can cause the heart rate to be too slow or too fast. Some arrhythmias don’t cause any symptoms. Others can make you feel lightheaded or dizzy.

There are two basic kinds of arrhythmias. Bradycardia is when the heart rate is too slow — less than 60 beats per minute. Tachycardia is when the heart rate is too fast — more than 100 beats per minute.

What are the signs of arrhythmia?
  • When it’s very brief, an arrhythmia can have almost no symptoms. It can feel like a skipped heartbeat that you barely notice.
  • It also may feel like a fluttering in the chest or neck.
  • When arrhythmias are severe or last long enough to affect how well the heart works, the heart may not be able to pump enough blood to the body. This can cause you to feel tired or lightheaded or may make you pass out. It can also cause death.
  • Bradycardia can cause fatigue, dizziness, lightheadedness, fainting or near-fainting spells, or, in extreme cases, cardiac arrest.
  • Tachycardia can reduce the heart’s ability to pump, causing shortness of breath, chest pain, lightheadedness or loss of consciousness. If severe, it can also cause heart attack or death.
How are arrhythmias treated?

Before treatment, it’s important for the doctor to know where an arrhythmia starts in the heart and whether it’s abnormal. An electrocardiogram (ECG or EKG)  is often used to diagnose arrhythmias. It creates a graphic record of the heart's electrical impulses. Using a Holter monitor, exercise stress tests, tilt table test and electrophysiologic studies (“mapping” the electrical system of your heart) are other ways to find where arrhythmias start. Treatment may include:
  •  Lifestyle changes
  •  Medicine to prevent and control arrhythmias
  •  Medicine to treat related conditions such as high blood pressure, coronary artery disease and heart failure
  •  Anticoagulants to reduce the risk of blood clots and stroke
  •  A pacemaker to help your heart beat more regularly
  •  Cardiac defibrillation and implanted cardioverter defibrillators (ICDs)
  •  Cardiac ablation
  •  Surgery
What is defibrillation?

It’s a way of returning an abnormal heartbeat to normal with a very brief electric shock.
  • An implantable cardioverter defibrillator (ICD) may be placed under the skin of the upper chest to give shocks and/or work as a pacemaker. It knows when the heartbeat isn’t normal and works 24 hours a day.
What is ablation?
It’s a way to fix an arrhythmia and get your heart to beat normally.
  • It’s done by putting a thin tube (a catheter) in your vein and guiding it to the heart muscle. The tip of the catheter delivers a burst of energy that destroys very small areas of heart tissue that cause abnormal electrical signals.
How can I learn more?
  1. Call 1-800-AHA-USA1 (1-800-242-8721), or visit heart.org to learn more about heart disease and stroke.
  2. Sign up to get Heart Insight, a free magazine for heart patients and their families, at heartinsight.org.
  3. Connect with others sharing similar journeys with heart disease and stroke by joining our Support Network at heart.org/supportnetwork.
We have many other fact sheets to help you make healthier choices to reduce your risk, manage disease or care for a loved one. Visit heart.org/answersbyheart to learn more.

Do you have questions or comments for your doctor or nurse?

Take a few minutes to write your own questions for the next time you see your healthcare provider. For example:

Can my arrhythmia be cured?

Will I have to keep taking medicine?

©2015, American Heart Association

Multi-language Fact Sheet Topics

Heart-related Conditions
What is Angina?
What is an Arrhythmia?
What Is Atrial Fibrillation?
What Do My Cholesterol Levels Mean?
How Can I Improve My Cholesterol?
What Are High Blood Cholesterol and Triglycerides?
What Is High Blood Pressure?
How Can I Reduce High Blood Pressure?
High Blood Pressure and Stroke
What Is Diabetes and How Can I Manage It?
How Can I Live With Heart Failure?
What Is Heart Failure?
What Is a Heart Attack?
How Will I Recover From My Heart Attack?
What Are the Warning Signs of Heart Attack?
What Are Heart Disease and Stroke?
What is Metabolic Syndrome?
What is Peripheral Artery Disease?

Stroke, Recovery and Caregiving
Hemorrhagic Stroke
Ischemic Stroke
Stroke, TIA and Warning Signs
What Are the Warning Signs of Stroke?
Stroke Risk Factors
Lifestyle Changes to Prevent Stroke
Stroke Diagnosis
Complications After Stroke
Changes Caused by Stroke
Emotional Changes After Stroke
Feeling Tired After a Stroke
Stroke and Aphasia
Stroke and Rehabilitation
Stroke Family Caregivers
How Should I Care for Myself as a Caregiver?

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What is High Blood Pressure Medicine?
What Are Anticoagulants and Antiplatelet Agents?
How Do I Manage My Medicines?
What Is an Implantable Cardioverter Defibrillator?
What Is a Pacemaker?
What Is Coronary Angioplasty?
What is a Stent?
What is Coronary Bypass Surgery?
What is a Coronary Angiogram?
How Can I Recover From Heart Surgery?
What is Carotid Endarterectomy?

Healthy Lifestyle and Risk Reduction
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How Can Physical Activity Become a Way of Life?
Why Should I Be Physically Active?
How Do I Follow a Healthy Diet?
How Can I Cook Healthfully?
Why Should I Limit Sodium?
How Do I Understand "Nutrition Facts" Labels?
How Can I Quit Smoking?
How Can I Manage Stress?
How Can I Make My Lifestyle Healthier?
How Can I Monitor My Cholesterol, Blood Pressure and Weight?