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What Causes Abnormal Heart Rhythms?

What are Abnormal Heart Rhythms?

Have you ever felt your heart skip a beat? If you’re not a character in a romance novel, that may mean you have an abnormal heart rhythm (arrhythmia). Within the heart is a complex system of valves, nodes, and chambers that control how and when the blood is pumped. If the functions of this vital system are disrupted, damaged, or compromised, it can change the pattern with which your heart beats.

If you are diagnosed with an arrythmia, don’t panic. Not all arrhythmias are life threatening or cause health complications. However, to be on the safe side, any abnormal heart rhythm should be reported to your doctor.

The Types of Abnormal Heart Rhythms

The most common types of abnormal heart rhythms are:


Tachycardia means that your heart is beating too fast. For example, a normal heart beats 60-100 times per minute in adults. Tachycardia is any heart rate over 100 beats per minute. There are three sub-types of tachycardia:

  • Supraventricular tachycardia occurs in the upper chambers of your heart (the atria).
  • Ventricular tachycardia occurs in the lower chambers (the ventricles).
  • Sinus tachycardia is a normal increase in the heart rate that may occur when you are sick or excited. With sinus tachycardia, your heartbeat returns to normal once you get better or calm down.

Atrial Fibrillation (AF)

This disorganized heart rhythm occurs in the upper chambers of the heart. It is the most common arrhythmia. Atrial fibrillation occurs when many unstable electrical impulses misfire, or quiver out of control. AF can increase the heart rate to 200 or more beats per minute (BPM).

Atrial Flutter (AFL)

An atrial flutter typically occurs in the right atrium, but it may occur in the left atrium as well. The condition is caused by a single electrical impulse that travels rapidly in the affected atrium.


If you are bradycardic, it means you have a slow heart rate (less than 60 BPM). Bradycardia generally occurs when the electrical signals traveling from the atria to the ventricles become disrupted.

Ventricular Fibrillation (VF)

This type of abnormal rhythm can stop the heart from beating and cause cardiac arrest. It occurs in the ventricles, where blood is pumped out to the body and brain. VF is a serious condition that may cause death if it is not immediately treated.

Premature Contractions

With most premature contractions, the heart appears to skip a beat when the pulse is taken in the wrist or chest. The skipped beat is so faint or weak that it is not heard or felt.

Other types of premature contractions include extra beats and early beats. All three types may occur in the upper or lower heart chambers.

What Causes Abnormal Heart Rhythms?

A number of things may cause an abnormal heartbeat, including high blood pressure. Other common causes are:

Coronary Heart Disease

This serious heart problem occurs when the coronary arteries become blocked by cholesterol and other deposits.


Some medications or substances may cause your heart rate to change. Caffeine, amphetamines (drugs that stimulant the brain), and beta blockers (used to reduce high blood pressure) are examples.

Other Causes

A number of other factors can also cause alterations in your heart’s rhythm. These include:

  • changes in your heart’s muscle after illness or injury
  • healing after heart surgery
  • low potassium and other electrolytes
  • abnormalities of the heart
  • other health conditions

What are the Risk Factors for Abnormal Heart Rhythms?

The risks for arrhythmia include:

  • smoking
  • previous heart conditions, or a family history of heart conditions
  • diabetes
  • stress
  • being overweight
  • living a sedentary lifestyle, i.e. not exercising
  • eating a diet high in fats, cholesterol, and other unhealthy foods
  • having high blood pressure, diabetes, or other health problems

What Are the Symptoms of Abnormal Heart Rhythms?

If you have an abnormal heart rhythm you may experience some or all of these symptoms:

  • feeling faint, dizzy, or light-headed
  • shortness of breath
  • irregular pulse or heart palpitations
  • chest pain
  • pale skin
  • sweating

Diagnosing Abnormal Heart Rhythms

Your doctor may perform a physical examination to determine whether your heart rhythm is abnormal and try to identify the cause. He may use a stethoscope to listen to your heart. He may also use an EKG machine to examine the electrical impulses of your heart.

Other tools that can be used to diagnose an arrythmia include:

  • Echocardiogram: Also known as a cardiac echo, this test uses sound waves to take pictures of your heart.
  • Holter monitor: This monitor is worn for at least 24 hours while you go about your normal activities. It allows your doctor to track changes in your heart’s rhythm throughout the day.  
  • Stress test: For this test, your doctor will make you walk or jog on a treadmill to see how exercise affects your heart.

Treating Abnormal Heart Rhythms

The treatment for an arrythmia depends on its cause. You may need to stop smoking or change your diet, such as by limiting caffeine. You might also require medication to control or stop your abnormal heartbeat.

For serious abnormalities that do not go away with behavioral changes or medication, doctors can also implant a pacemaker, perform surgery to correct an abnormality, or try other procedures to correct your heart’s rhythm.

Prognosis: What Is to Be Expected in the Long Term?

Although arrythmia can be quite serious, many cases of arrhythmia can be controlled with treatment. Your doctor will probably want to monitor your condition with regular check-ups.


Once your arrythmia is under control, your doctor will discuss ways to keep it from coming back. In general, healthy lifestyle choices can go a long way towards helping you control your condition. Your doctor will probably recommend improving your diet, exercising more, and trying to limit other dangerous behaviors, such as smoking.

Content licensed from:

Written by: Brindles Lee Macon and Elizabeth Boskey, PhD
Published on: Jul 16, 2012
Medically reviewed on: Oct 09, 2017: Debra Sullivan, PhD, MSN, RN, CNE, COI

This feature is for informational purposes only and should not be used to replace the care and information received from your health care provider. Please consult a health care professional with any health concerns you may have.
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