Arrhythmias Causes and Triggers

Learn about how problems with your heart’s electrical signals can cause arrhythmias. Medical Illustration Copyright © 2021 Nucleus Medical Media, All rights reserved.

Arrhythmias are often caused by a problem with the electrical signals within the heart. Often, an arrhythmia is set off by a trigger. Sometimes the cause of an arrhythmia is not known. 

Problems with the heart’s electrical system

Your heart’s electrical signals control how fast your heart beats. A problem with these electrical signals can cause an irregular rhythm. This can happen when the nerve cells that produce electrical signals do not work properly or when the electrical signals do not travel normally through your heart. Also, another part of your heart could start to produce electrical signals, disrupting your normal heartbeat. 

Conditions that cause a slowing of your heart’s electrical signals are called conduction disorders

To understand arrhythmias, it helps to understand how your heart’s electrical system works.

What raises the risk of arrhythmia?


As we age, changes in our heart such as scarring and the effects of other chronic conditions can raise the risk of arrhythmias. Older adults are also more likely to have health conditions, such as high blood pressure, heart failure, diabetes, and thyroid disease, that can lead to arrhythmias. Arrhythmias caused by congenital heart defects or inherited conditions are more common in children and young adults.

Family history and genetics

Arrhythmias can run in families. You may have an increased risk of some types of arrhythmias if a parent or other close relative has an arrhythmia. 

Lifestyle habits

Your risk of arrhythmias may be higher if you:

  • Smoke
  • Use illegal drugs, such as cocaine or amphetamines
  • Drink alcohol more often and more than is recommended (no more than 2 drinks per day for men and 1 drink per day for women)


Sometimes, medicines your doctor prescribes for other health conditions can cause an arrhythmia. Talk to your doctor about your risk of an arrhythmia if you are taking medicine to treat high blood pressure or for a mental health condition. 

Certain antibiotics and over-the-counter allergy and cold medicines can also raise the risk of arrhythmias in some people.

Other health conditions

You may be more likely to have arrhythmias if you have:

Watch our video on how SARS-CoV-2, the virus responsible for COVID-19, may lead to or worsen arrhythmias. We also offer information and resources on how we are working hard to support necessary COVID-19 research. 


You may be at a higher risk of developing arrhythmias in the early days and weeks after surgery involving your heart, lungs, or throat.

What can trigger arrhythmias?

If you have any risk factors, certain situations may trigger an arrhythmia. These include any situations that make your heart work harder, raise your blood pressure, or cause your body to release stress hormones

Triggers include:

  • Blood sugar levels that are too low or too high
  • Caffeine, illegal drugs, and medicines that make you more alert or increase your energy
  • Dehydration
  • Low levels of electrolyte , such as potassium, magnesium, or calcium 
  • Physical activity
  • Strong emotional stress, anxiety, anger, pain, or a sudden surprise 
  • Vomiting or coughing

Talk to your doctor about your triggers and what you can do to avoid them. 

Research for your health

Learn about the current and future NHLBI efforts to improve health through research and scientific discovery on arrhythmias.

Can you prevent arrhythmias?

If you have a high risk of arrhythmias, your doctor may ask you to take some steps to help prevent them. 

  • Avoid triggers for arrhythmias. 
  • Get treatment for other health conditions that may cause arrhythmias.
  • Make heart-healthy lifestyle changes, such as choosing heart-healthy foods, being physically active, aiming for a healthy weight, quitting smoking, and managing stress.
  • Talk to your doctor if you need heart surgery. Your healthcare team may manage your electrolyte levels and use medicine during or after the procedure to prevent an arrhythmia.

If you have a child with a condition that raises their risk of an arrhythmia, talk to your child’s doctor about how to prevent arrhythmias. For example:

  • If you have a newborn, follow safe sleep recommendations to help lower the risk of sudden infant death syndrome (SIDS).
  • Your child may need regular checkups so the doctor can look for patterns or symptoms of arrhythmias that may develop over time.
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