What Are Cardiac Arrhythmias?

In This Article
Table of Contents

When it's normal, your heartbeat is nice and regular and has just the right rate. But when your heartbeat is too fast, too slow, or beats in an irregular rhythm, it's known as a cardiac arrhythmia (abnormal heart rhythm), which is among the most common of the heart disorders. Most people, in fact, have occasional cardiac arrhythmias.

An arrhythmia is caused by a disruption of your heart’s normal electrical system, which regulates your heart rate and heart rhythm. The severity of cardiac arrhythmias can vary tremendously. Most arrhythmias are completely benign and inconsequential, while others are extremely dangerous and life-threatening. And many of them, while not particularly dangerous, produce symptoms that can be quite disruptive to your life.

Cardiac system without and with arrhythmia.

Types of Cardiac Arrhythmia

There are many kinds of cardiac arrhythmias and to treat an arrhythmia appropriately, it's important for your doctor to figure out which specific type you have. However, the arrhythmias all can be classified into three general types, including:

1. Extra heartbeats: Also known as premature heartbeats, when these extra beats generate in the atria of your heart, they're known as premature atrial complexes (PACs). They can also arise in the ventricles of your heart, called premature ventricular complexes (PVCs). PACs and PVCs are usually benign, but they can produce significant palpitations that some people find very disruptive.

2. Bradycardia: These are arrhythmias that make your heart rate too slow. While "officially," bradycardia is defined as a resting heart rate of fewer than 60 beats a minute, in practice a healthy person's resting heart rate will often be in the 50's, or even the 40's. Bradycardia is not considered a problem unless it is causing symptoms, or it indicates a serious problem with the heart's electrical system.There are two general causes of bradycardia, including:

  • Sinus bradycardia, which is caused by a disorder of the sinus node. Sinus bradycardia is the most common type of bradycardia, and when it produces symptoms, it's the most common reason to need a pacemaker. However, sinus bradycardia is rarely life-threatening.
  • Heart block, the more dangerous variety of bradycardia, occurs when some or all of the electrical impulses generated by the sinus node are blocked before they reach your ventricles. Heart block is most often accompanied by left bundle branch block or right bundle branch block.

3. Tachycardia: These are arrhythmias that make the heart rate too fast, which is defined as a resting heart rate of over 100 beats per minute. There are two general categories of tachycardia, including:

arrhythmia symptoms
© Verywell, 2018

Cardiac Arrhythmia Symptoms

Many arrhythmias cause no symptoms at all, so you may not even know you have one until your doctor tells you. Having symptoms doesn't necessarily mean that you're in any danger from the arrhythmia either. Despite the fact that there are many different kinds, the noticeable symptoms caused by arrhythmias generally fall into four major categories, including:

Depending on the type and severity of your arrhythmia, you may notice symptoms such as sweating, feeling like your heart is racing or fluttering, noticing extra heartbeats, feeling your heartbeat has slowed, chest pain, or shortness of breath.


There are many potential causes of heart arrhythmias, including:

  • A current heart attack
  • Scarring in your heart from a previous heart attack
  • Heart disease
  • Smoking
  • Abusing drugs
  • Exposure to too much alcohol or caffeine
  • Genetics
  • High blood pressure
  • Blocked arteries
  • Diabetes
  • Thyroid disorders, including hypothyroidism and hyperthyroidism
  • Stress
  • Certain medications and supplements, whether prescription or over-the-counter


Making the correct diagnosis of a cardiac arrhythmia generally requires capturing it on an electrocardiogram (ECG) or other heart-monitoring tests, along with a physical exam and complete medical history. If your doctor doesn't find an arrhythmia with a heart-monitoring test, he or she might use a stress test, a tilt table test, or do an electrophysiology study.


Just as there are many types of heart rhythm problems, many different treatment options are available. Deciding which treatment to use for which arrhythmia can be challenging even for cardiologists.

Arrhythmias Doctor Discussion Guide

Get our printable guide for your next doctor's appointment to help you ask the right questions.

Doctor Discussion Guide Old Man

The most common options for treating cardiac arrhythmias include:

If making the right diagnosis or deciding on the best therapy turns out to be difficult, you may be referred to a cardiac electrophysiologist—a cardiologist who specializes in heart rhythm disorders.

A Word From Verywell

Most heart arrhythmias aren't any cause for concern, even if they cause symptoms. If you do have symptoms of an arrhythmia, see your doctor but don't panic. You may need treatment to help control your symptoms, but the good news is that most people with arrhythmias have no trouble going about their daily activities and living normally. Treatment and implementing lifestyle changes like exercising, eating a heart-healthy diet, and watching your weight can help keep many symptomatic arrhythmias controlled and stop them from becoming dangerous.

Was this page helpful?
Article Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. National Heart, Lung, and Blood Institute. Arrhythmia

Additional Reading
  • Cleveland Clinic. Arrhythmia. Updated March 8, 2018.
  • Mayo Clinic Staff. Heart Arrhythmias. Mayo Clinic. Updated December 27, 2017.
  • National Heart, Lung, and Blood Institute. Arrhythmia. National Institutes of Health. U.S. Department of Health and Human Services.