Fast heart rate – tachycardia: MedlinePlus Medical Encyclopedia

Fast heart rate – tachycardia

URL of this page: //medlineplus.gov/ency/article/007855.htm

Tachycardia is when your heart beats faster than normal, above 100 beats per minute. Most adults have a normal resting heart rate from 60 to 100 beats per minute.

A fast heart rate can be a normal response to stress or exercise. Tachycardia can also be a sign of a more serious medical condition.

Normally, your heart works as a pump that sends blood to the lungs and the rest of the body.

To help this happen, your heart has an electrical system that makes sure it squeezes (contracts) in an orderly way. This process includes:

The electrical impulse that signals your heart to contract begins in an area of the heart called the sinoatrial node (also called the sinus node or SA node). This is your heart’s natural pacemaker.
The signal leaves the SA node and travels through the heart along a set electrical pathway.
Different nerve messages signal your heart to beat slower or faster.

If your heart beats too fast, its lower chambers (ventricles) don’t get enough time to fill up with blood between beats. As a result, the heart cannot pump enough blood and oxygen throughout your body.

There are many different ways to categorize tachycardias.

Causes of a fast heart rate range from harmless conditions to medical emergencies. They can include:

Symptoms of tachycardia can include:

Sometimes there may be no symptoms and a fast heart rate is detected by your health care provider or by a smartwatch or fitness tracker.

Your health care provider will ask about your medical history and the medicines you are taking. Your provider will do a physical exam and listen to your heart with a stethoscope for heart murmurs or other abnormal sounds. Your blood pressure and pulse rate will be measured.

Your provider may order the following tests:

Treatment depends upon the type of tachycardia you have, what’s causing it, and the severity of your symptoms. If your symptoms last only for a short time and are due to temporary reasons, such as strong emotions or exercise, you may not need treatment.

If you have an underlying medical condition, it will be diagnosed and treated by your provider. Your provider may tell you to avoid triggers such as tobacco and caffeine. If medicines are the cause of tachycardia, your provider may lower the dose or change the medicine.

Your provider may recommend the following treatments:

In case of emergency, you may need:

The outlook depends upon:

The type of tachycardia you have
Your heart function
The underlying cause

Once the trigger is removed or managed (such as medicine, caffeine, stress), your heart rate usually returns to normal. If an underlying disease is the cause, early diagnosis and treatment will help lower the risk for complications.

Untreated, regular episodes of tachycardia may lead to the following complications:

Contact your provider if:

You develop any of the symptoms of tachycardia that do not go away within a few minutes
You experience frequent episodes of tachycardia
You have been diagnosed with tachycardia and your symptoms get worse or do not improve with treatment

Call 911 or the local emergency number right away if you have:

Rapid, irregular pulse
Chest pain
Breathlessness
Very low blood pressure
Fainting

Not all cases of tachycardia can be prevented. Taking steps to prevent coronary artery disease may help reduce your chance of developing heart rate problems.

Tachyarrhythmia; Polycardia; Fast heart rate; Rapid heartbeat

American Heart Association website. Tachycardia: fast heart rate. www.heart.org/en/health-topics/arrhythmia/about-arrhythmia/tachycardia–fast-heart-rate. Updated September 24, 2024. Accessed July 22, 2026.

Kalman JM, Sanders P. Supraventricular tachycardias. In: Bonow RO, Mann DL, Tomaselli GF, et al, eds. Braunwald’s Heart Disease: A Textbook of Cardiovascular Medicine. 13th ed. Philadelphia, PA: Elsevier; 2026:chap 47.

Zimetbaum P, Goldman L. Supraventricular ectopy and tachyarrhythmias. In: Goldman L, Cooney KA, eds. Goldman-Cecil Medicine. 27th ed. Philadelphia, PA: Elsevier; 2024:chap 52.

Updated by: Michael A. Chen, MD, PhD, Associate Professor of Medicine, Division of Cardiology, Harborview Medical Center, University of Washington Medical School, Seattle, WA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.

The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Links to other sites are provided for information only — they do not constitute endorsements of those other sites. No warranty of any kind, either expressed or implied, is made as to the accuracy, reliability, timeliness, or correctness of any translations made by a third-party service of the information provided herein into any other language.
© 1997- 2026 A.D.A.M., a business unit of Ebix, Inc. Any duplication or distribution of the information contained herein is strictly prohibited.
All content on this site including text, images, graphics, audio, video, data, metadata, and compilations is protected by copyright and other intellectual property laws. You may view the content for personal, noncommercial use. Any other use requires prior written consent from Ebix. You may not copy, reproduce, distribute, transmit, display, publish, reverse-engineer, adapt, modify, store beyond ordinary browser caching, index, mine, scrape, or create derivative works from this content. You may not use automated tools to access or extract content, including to create embeddings, vectors, datasets, or indexes for retrieval systems. Use of any content for training, fine-tuning, calibrating, testing, evaluating, or improving AI systems of any kind is prohibited without express written consent. This includes large language models, machine learning models, neural networks, generative systems, retrieval-augmented systems, and any software that ingests content to produce outputs. Any unauthorized use of the content including AI-related use is a violation of our rights and may result in legal action, damages, and statutory penalties to the fullest extent permitted by law. Ebix reserves the right to enforce its rights through legal, technological, and contractual measures.