What Is Tachycardia? A Plain-Language Guide to the Fast Heartbeat, Its Causes, and Its Treatment
Updated: 3 days ago
Medically reviewed by Dr. Baraa Alnahhal, MD · Last reviewed: October 2026
Quick Answer
Tachycardia is the medical term for a heart rate over 100 beats a minute. A fast heart rate during exercise or stress is normal, but some types can lead to heart failure, stroke or sudden cardiac death if untreated. Types include atrial fibrillation, the most common, and ventricular fibrillation, a deadly emergency [1].
What is it? Tachycardia is the medical term for a heart rate over 100 beats a minute, when an irregular electrical impulse starts in the upper or lower chambers of the heart. [1]
Is it always dangerous? No — a fast heart rate during exercise or stress is normal — but sometimes it's a warning sign, and some types can lead to heart failure, stroke, or sudden cardiac death if not treated. [1]
What are the main types? Atrial fibrillation (AFib, the most common), atrial flutter, supraventricular tachycardia (SVT), ventricular tachycardia (V-tach), and ventricular fibrillation (VFib, a deadly emergency). [1]
How is it diagnosed? Through tests such as an ECG/EKG, Holter or event monitors, echocardiogram, heart MRI or CT, coronary angiogram, electrophysiological (EP) study, stress tests, and tilt table tests. [2]
How is it treated? Simple vagal maneuvers (coughing, bearing down, ice pack on face), medicines, cardioversion shocks, catheter ablation, pacemakers, implantable cardioverter-defibrillators (ICDs), the maze procedure, or surgery — plus heart-healthy lifestyle habits. [2]
What the research says
A small change in body position made a vagal maneuver much more effective. In a randomized trial of 433 adults with supraventricular tachycardia (excluding AFib and flutter) in emergency departments, 17% (37 of 214) of those who did a standard Valsalva maneuver returned to a normal rhythm at one minute, compared with 43% (93 of 214) of those who lay back and had their legs raised right after the strain (adjusted odds ratio 3.7, 95% CI 2.3 to 5.8). No serious adverse events were recorded. (Appelboam et al., Lancet, 2015) [3]
As a first treatment for symptomatic AFib, cryoballoon ablation reduced recurrence compared with drugs. A meta-analysis of three randomized trials (724 patients, mostly relatively young with paroxysmal AFib) found less recurrence of atrial arrhythmia with ablation (risk ratio 0.59, 95% CI 0.49 to 0.71) and less symptomatic recurrence (risk ratio 0.44, 95% CI 0.29 to 0.65), with a similar rate of serious adverse events (risk ratio 1.18, 95% CI 0.71 to 1.97). (Mao et al., Clin Cardiol, 2021) [4]
What Is Tachycardia, in Plain Language?
Tachycardia (tak-ih-KAHR-dee-uh) is the medical term for a heart rate over 100 beats a minute. [1] In tachycardia, an irregular electrical signal, called an impulse, starts in the upper or lower chambers of the heart. This causes the heart to beat faster. [1] Many types of irregular heartbeats, called arrhythmias, can cause tachycardia. [1]
A fast heart rate isn't always something to worry about. For instance, the heart may beat faster during exercise or when a person has a lot of stress. [1]
Tachycardia may not cause any symptoms or complications. But sometimes it's a warning of a condition that needs medical care. Some types of tachycardia can lead to serious health conditions if not treated. Examples are heart failure, stroke, or sudden cardiac death. [1]
Treatment for tachycardia may include specific actions or movements, medicine, a heart procedure called cardioversion, or surgery. [1]
How Does a Normal Heartbeat Work?
A normal heartbeat starts with an electrical signal from the sinus node that travels through the atria and AV node to the ventricles, which then pump blood. [1]
The heart has four chambers: the two upper chambers are called the atria, and the two lower chambers are called the ventricles. [1]
Inside the upper right heart chamber is a group of cells called the sinus node. These cells make the signals that start each heartbeat. [1] In a typical heartbeat, a tiny cluster of cells at the sinus node sends out an electrical signal, called an impulse. The signal then travels through the atria to the atrioventricular (AV) node and then passes into the lower heart chambers called the ventricles. This causes them to squeeze and pump out blood. [1]
In a healthy heart, this signaling process usually goes smoothly. The heart usually beats 60 to 100 times each minute when at rest. [1] But in tachycardia, something makes the heart beat faster than 100 beats a minute.
What Are the Different Types of Tachycardia?
Tachycardia has many types, grouped by their cause and the part of the heart causing the fast heart rate. Sinus tachycardia is a usual rise in the heart rate often caused by exercise or stress — it is a symptom, not a condition. [1]
Other types are grouped according to their cause and the part of the heart causing the fast heart rate. Common types include:
Type | Where It Starts | What Happens | Key Facts |
Atrial fibrillation (AFib) | Upper chambers (atria) | Chaotic, irregular electrical signals trigger a fast heartbeat | The most common type; may be short-lived, but sometimes treatment is needed [1] |
Atrial flutter | Upper chambers (atria) | Similar to AFib, but the heartbeats are more organized | May go away on its own, but some people need treatment; often occurs alongside AFib [1] |
Ventricular tachycardia (V-tach) | Lower chambers (ventricles) | The fast rate stops the lower chambers from filling and squeezing to pump enough blood | Brief episodes may cause no harm; lasting more than a few seconds can be life-threatening [1] |
Supraventricular tachycardia (SVT) | Above the lower chambers | A pounding heartbeat that starts and ends abruptly [1] | A broad term covering several irregular rhythms |
Ventricular fibrillation (VFib) | Lower chambers (ventricles) | Very fast, chaotic signals make the chambers quiver instead of squeezing in a coordinated way | Deadly if not fixed within minutes; most people with VFib have heart disease or a serious injury, such as being struck by lightning [1] |
What Does Tachycardia Feel Like?
Some people with tachycardia have no symptoms. The fast heartbeat may be found when a physical exam or heart tests are done for another reason. [1]
In general, tachycardia may cause these symptoms:
Symptom | Description |
Palpitations | Racing, pounding heartbeat or flopping in the chest [1] |
Chest pain | Pain or discomfort in the chest |
Fainting | Losing consciousness, or near fainting |
Lightheadedness | Feeling dizzy or unsteady |
Fast pulse | A noticeably rapid pulse |
Shortness of breath | Trouble catching your breath |
When Should I Get Medical Help?
Many things can cause tachycardia. If you feel like your heart is beating too fast, make an appointment for a health checkup. [1]
Get medical help right away if you have chest pain or discomfort, shortness of breath, weakness, dizziness or lightheadedness, or fainting or near fainting. [1]
Why Does the Heart Start Beating Too Fast?
Tachycardia is an increased heart rate for any reason. If a fast heart rate is caused by exercise or stress, it's called sinus tachycardia, which is a symptom, not a condition. [1]
Most heart conditions can lead to different forms of tachycardia. Irregular heart rhythms, called arrhythmias, are one cause — an example is atrial fibrillation (AFib). [1]
Health conditions and treatments that may lead to tachycardia include:
Cause | What It Is |
Anemia | A low number of red blood cells |
Electrolyte changes | Changes in the level of minerals in the body, such as potassium, sodium, calcium, and magnesium [1] |
Fever | An elevated body temperature |
Heart attack | Damage to the heart from a blocked blood supply |
High or low blood pressure | Blood pressure outside the healthy range |
Hyperthyroidism | An overactive thyroid gland |
Some medicines | Medications that can raise the heart rate |
Lifestyle habits and behaviors that may lead to tachycardia include:
Habit | Details |
Excessive alcohol use | If you choose to drink alcohol, limit how often you drink and keep the amount small — that often means less than two drinks a day on any specific day [1] |
Alcohol withdrawal | Stopping alcohol after heavy use |
Too much caffeine | High caffeine intake can drive up the heart rate |
Smoking or nicotine use | Tobacco and nicotine products |
Illicit drugs | Such as cocaine or methamphetamine |
Sometimes the exact cause of tachycardia is not known. [1]
Who Is at Higher Risk?
In general, things that may raise the risk of irregular heart rhythms that commonly cause tachycardia include older age, a family history of some heart rhythm disorders, and high blood pressure. [1] Lifestyle changes or treatment of heart conditions may lower the risk of tachycardia. [1]
What Happens if Tachycardia Is Left Untreated?
When the heart beats too fast, it may not pump enough blood to the body. As a result, the organs and tissues may not get enough oxygen. [1]
Complications of tachycardia depend on the type of tachycardia, how fast the heart is beating, how long the fast heartbeat lasts, and whether you have other heart conditions. [1]
Possible Complication | Notes |
Blood clots | Can cause a heart attack or stroke; blood-thinning medicine may be used to lower this risk [1] |
Frequent fainting | Fainting a lot or unconsciousness |
Heart failure | The heart can't pump enough blood over time |
Sudden cardiac death | Usually only associated with ventricular tachycardia or ventricular fibrillation [1] |
What should you do if someone collapses from a tachycardia emergency like VFib?
A type of tachycardia called ventricular fibrillation (VFib) is an emergency. It needs to be treated right away. During VFib, blood pressure drops dramatically. The person's breathing and pulse stop because the heart is not pumping any blood to the body. This is also called cardiac arrest. [1] The person usually falls down, or collapses.
If this happens, do the following:
Emergency Step | What to Do |
Call for help | Call 911 or the emergency number in your area |
Start CPR | CPR helps keep blood flowing to the organs until other treatments can start [1] |
Hands-only CPR | If you're not trained in CPR or worried about giving rescue breaths, provide hands-only CPR: push hard and fast on the center of the chest at a rate of 100 to 120 compressions a minute until paramedics arrive. [1] The American Heart Association suggests doing compressions to the beat of the song "Stayin' Alive" or another song that has 100 to 120 beats a minute. You don't need to do rescue breathing. [1] |
Get an AED | Have someone get an automated external defibrillator (AED) if one is nearby. An AED is a device that sends a shock to the heart to reset its rhythm. No training is needed to use it. The AED tells you what to do, and it's programmed to give a shock only when necessary. [1] |
How Is Tachycardia Diagnosed?
A thorough physical exam, medical history, and testing are needed to diagnose tachycardia. To diagnose tachycardia, a healthcare professional examines you and asks questions about your symptoms, health habits, and medical history. [2]
Tests may be done to confirm an unusually fast heartbeat and to look for the cause. Tests to diagnose tachycardia may include:
Test | How It Works |
Electrocardiogram (ECG or EKG) | A quick test that checks the heartbeat. Sticky patches with sensors, called electrodes, go on the chest and sometimes the arms or legs. An ECG shows how fast or how slow the heart is beating. Some personal devices, such as smartwatches, can do ECGs. [2] |
Holter monitor | A small, wearable device that records the heart's rhythm for a day or more while you do your daily activities. It can find irregular heartbeats that aren't seen on a regular ECG. [2] |
Event monitor | Like a Holter monitor, but it records only at certain times for a few minutes at a time. Typically worn for about 30 days. [2] You usually push a button when you feel symptoms; some devices automatically record when an irregular heart rhythm is noticed. |
Echocardiogram | Sound waves make images of the beating heart. Shows how blood flows through the heart and heart valves. [2] |
Chest X-ray | Shows the condition of the heart and lungs. [2] |
MRI scan of the heart (cardiac MRI) | Uses magnetic fields and radio waves to create detailed images of the heart. Most often done to find a cause of ventricular tachycardia or ventricular fibrillation. [2] |
CT scan of the heart (cardiac CT) | Takes several X-ray images to provide a more detailed look of the heart. May be done to find the cause of ventricular tachycardia. [2] |
Coronary angiogram | A flexible tube (catheter) is inserted into an artery, usually in the groin, arm, or neck, and guided to the heart. Dye flows through the tube to help the arteries show up on images. Checks for blocked or narrowed blood vessels; used in people with ventricular tachycardia or ventricular fibrillation. [2] |
Electrophysiological (EP) study | One or more flexible tubes are guided through a blood vessel, usually in the groin, to areas in the heart. Sensors on the tips record electrical signals. Confirms the diagnosis and helps find where the wrong signaling occurs. [2] |
Stress tests | Exercise can trigger or worsen some types of tachycardia. [2] Done on a treadmill or stationary bike while the heart is checked. If you can't exercise, you may get medicine that raises the heart rate like exercise does. Sometimes an echocardiogram is done during a stress test. |
Tilt table test | Checks heart rate, rhythm, and blood pressure while you lie flat; then the table is tilted to a standing position under careful supervision. Finds out if a fast heartbeat leads to fainting. [2] |
How Is Tachycardia Treated?
The goals of tachycardia treatment are to slow the fast heartbeat and prevent the fast heartbeat from happening again. [2] If another health condition is causing tachycardia, treating the condition may reduce or prevent the fast heartbeat. [2]
How Can a Fast Heartbeat Be Slowed?
A fast heartbeat may fix itself. But sometimes medicine or other treatments are needed to slow down the heartbeat. Ways to slow a fast heartbeat include:
Method | How It Works |
Vagal maneuvers | Simple but specific actions such as coughing, bearing down as if passing stool, or putting an ice pack on the face can help slow down the heartbeat. The actions affect the vagus nerve, which helps control the heartbeat. [2] |
Medicines | If vagal maneuvers don't stop the fast heartbeat, medicine may be needed to correct the heart rhythm. [2] |
Cardioversion | Paddles or patches on the chest electrically shock the heart and reset the heart rhythm. Generally used when emergency care is needed or when vagal maneuvers and medicines don't work. It's also possible to do cardioversion with medicines. [2] |
How Can a Fast Heartbeat Be Prevented?
Tachycardia treatment also involves taking steps to make sure the fast heartbeat doesn't come back. This may involve medicines, implanted devices, or heart surgeries or procedures.
Treatment | How It Works |
Medicines | Often used to slow or control the heartbeat [2] |
Catheter ablation | One or more thin, flexible tubes (catheters) are inserted through a blood vessel, usually in the groin. Sensors on the tip use heat or cold energy to create tiny scars in the heart. The scars block irregular electrical signals and help restore a typical heartbeat. Doesn't need surgery to reach the heart, but may be done at the same time as other heart surgeries. [2] |
Pacemaker | A small device placed under the skin near the collarbone that prevents the heart from beating too slowly. When the device finds an irregular heartbeat, it sends an electrical pulse that helps fix the heart's rhythm. [2] |
Implantable cardioverter-defibrillator (ICD) | A battery-powered device placed under the skin near the collarbone that continuously checks the heart rhythm. If it finds an irregular heartbeat, it sends out low- or high-energy shocks to reset the rhythm. May be suggested if you have a high risk of ventricular tachycardia or ventricular fibrillation. [2] |
Maze procedure | A surgeon makes tiny cuts in the upper chambers of the heart to create a pattern of scar tissue called a maze. The heart's signals can't pass through scar tissue, so the maze blocks stray heart signals that cause some types of tachycardia. [2] |
Surgery | Sometimes open-heart surgery is needed to destroy an extra heart-signaling pathway causing tachycardia. Usually done only when other treatment options don't work or when surgery is needed to treat another heart condition. [2] |
What Lifestyle Habits Help?
If you have tachycardia or any type of heart disease, it's important to take steps to keep your heart healthy. Eat healthy foods, get regular exercise, and don't smoke or use tobacco. Your care team also may suggest that you limit or do not use caffeine. [2]
Some stress-relief methods, such as meditation and yoga, might help slow the heartbeat. This can reduce tachycardia symptoms. [2]
If you have a plan to manage tachycardia, you may feel calmer and more in control when it happens. Ask your care team how to take your pulse, what heart rate is best for you, when and how to do vagal maneuvers if appropriate, and when to get emergency care. [2]
How Can Tachycardia Be Prevented?
The best way to prevent tachycardia is to keep the heart healthy. Have regular health checkups. If you have heart disease, follow your treatment plan. Take all medicines as told. [1]
Try these tips to prevent heart disease and keep the heart healthy:
Heart-Healthy Habit | Recommendation |
Don't smoke | Avoid tobacco in all forms |
Eat well | Choose foods that are low in salt and saturated fat [1] |
Exercise | At least 30 minutes a day on most days of the week [1] |
Keep a healthy weight | Maintain a weight that's right for your body |
Reduce and manage stress | Keep stress levels down |
Manage conditions | Control high blood pressure, high cholesterol, and diabetes [1] |
Get good sleep | Adults should try to get 7 to 9 hours daily [1] |
Talk to your healthcare team before using any medicines. Some cold and cough medicines have stimulants that may start a fast heartbeat. Illicit drugs such as cocaine and methamphetamine are other stimulants that can cause changes in the heartbeat. [1]
How Should I Prepare for My Appointment?
If you have tachycardia, you may see a doctor trained in heart conditions, called a cardiologist. You also might see a doctor trained in heart rhythm disorders, called an electrophysiologist. [2]
There's often a lot to discuss at a health checkup. Make a list ahead of time that you can share with your healthcare team. Your list should include any symptoms (including those that may seem unrelated to your heart), important personal information (including any major stresses or recent life changes), all medicines that you take (vitamins, supplements, and medicines bought with or without a prescription, with dosages), and questions to ask your healthcare professional.
Basic questions to ask your healthcare professional include: What is the likely cause of my fast heartbeat? What tests do I need? What's the most appropriate treatment? What are the risks of my heart condition? How do we check my heart? How often do I need checkups? I have other health conditions — how will they or their treatments affect my heart condition? What changes do I need to make to my activities or diet? Is there any information that I can take home with me? What websites do you recommend?
What your doctor may ask you:
Doctor's Question | What It Helps Reveal |
When did the symptoms start? | The timeline of the problem |
How often does your heart beat fast? | How frequent the episodes are |
How long does the fast heartbeat last? | The duration of episodes |
Does anything, such as exercise, stress, or caffeine, make your symptoms worse? | Triggers that worsen symptoms |
Does anyone in your family have heart disease or a history of irregular heartbeats? | Family risk patterns |
Has anyone in your family had cardiac arrest or died suddenly? | Family history of sudden cardiac events |
Do you smoke or have you ever smoked? | Tobacco exposure |
How much alcohol or caffeine do you use, if any? | Stimulant intake |
What medicines do you take? | Medications that may affect the heart |
Do you have conditions that may affect your heart health? | Such as being treated for high blood pressure or high cholesterol |
What is the bottom line on tachycardia?
Tachycardia is the medical word for a heart beating faster than 100 beats a minute, and it happens when an irregular electrical signal starts in the upper or lower chambers of the heart. A fast heart rate isn't always a problem — exercise and stress cause it all the time — but when it happens without an obvious reason, or comes with chest pain, fainting, or breathlessness, it deserves a doctor's attention. The good news is that modern medicine has a full toolbox: simple breathing-style maneuvers and medicines for mild cases, shocks (cardioversion), catheter ablation, pacemakers, implantable defibrillators, and surgery for more serious ones. And ventricular fibrillation, the most dangerous form, is treatable if acted on immediately — call 911, start CPR, and use an AED. Keeping your heart healthy through exercise, sleep, stress management, and avoiding tobacco and excess caffeine and alcohol is the best long-term protection.
Take the Next Step
If your heart is beating faster than 100 beats a minute and it doesn't have an obvious cause, see a doctor. If you ever experience chest pain, shortness of breath, fainting, or someone collapses, treat it as an emergency: call 911, start hands-only CPR, and use an AED if one is nearby.
Frequently Asked Questions
What is tachycardia?
Tachycardia (tak-ih-KAHR-dee-uh) is the medical term for a heart rate over 100 beats a minute. In tachycardia, an irregular electrical signal, called an impulse, starts in the upper or lower chambers of the heart, causing it to beat faster. Many types of irregular heartbeats, called arrhythmias, can cause tachycardia.
Is tachycardia always dangerous?
No. A fast heart rate isn't always something to worry about — the heart may beat faster during exercise or when a person has a lot of stress. But sometimes tachycardia is a warning of a condition that needs medical care, and some types can lead to serious health conditions such as heart failure, stroke, or sudden cardiac death if not treated.
What are the symptoms of tachycardia?
In general, tachycardia may cause a racing, pounding heartbeat or flopping in the chest (palpitations), chest pain, fainting, lightheadedness, a fast pulse, and shortness of breath. Some people have no symptoms at all. Get medical help right away for chest pain or discomfort, shortness of breath, weakness, dizziness, or fainting.
What are the types of tachycardia?
Common types include sinus tachycardia (a usual rise from exercise or stress), atrial fibrillation or AFib (the most common type), atrial flutter (more organized than AFib), supraventricular tachycardia or SVT (a pounding heartbeat that starts and ends abruptly), ventricular tachycardia or V-tach (life-threatening when it lasts more than a few seconds), and ventricular fibrillation or VFib (deadly if not fixed within minutes).
What causes tachycardia?
Causes include arrhythmias, anemia (low red blood cells), electrolyte changes, fever, heart attack, high or low blood pressure, an overactive thyroid, and some medicines. Lifestyle factors include excessive alcohol use, alcohol withdrawal, too much caffeine, smoking or nicotine use, and illicit drugs such as cocaine or methamphetamine. Sometimes the exact cause is not known.
How is tachycardia diagnosed?
Through a physical exam, medical history, and tests such as an ECG/EKG, Holter monitor (worn for a day or more), event monitor (worn about 30 days), echocardiogram, chest X-ray, cardiac MRI, cardiac CT, coronary angiogram, electrophysiological (EP) study, stress tests, and tilt table tests.
How is tachycardia treated?
A fast heartbeat may be slowed with vagal maneuvers (coughing, bearing down, ice pack on the face), medicines, or cardioversion (an electrical shock to reset the rhythm). Long-term prevention may involve medicines, catheter ablation, a pacemaker, an implantable cardioverter-defibrillator (ICD), the maze procedure, or open-heart surgery.
How can I prevent tachycardia?
Keep your heart healthy: don't smoke, choose foods low in salt and saturated fat, exercise at least 30 minutes a day on most days, keep a healthy weight, manage stress, control high blood pressure, high cholesterol, and diabetes, and get 7 to 9 hours of sleep daily. Talk to your healthcare team before using cold and cough medicines, which may contain stimulants.
When should I go to the ER for a fast heart rate?
Get medical help right away if a fast heartbeat comes with chest pain, shortness of breath, weakness, dizziness or fainting. If someone collapses and is not breathing, call 911 and start CPR.
Can anxiety cause tachycardia?
Yes. Stress and anxiety can raise your heart rate, which is called sinus tachycardia. A fast heartbeat with no clear cause should still be checked by a doctor.
Related Reading
Valsalva Maneuver: How to Do It and When It's Used explains a breathing technique that can stop a fast heartbeat.
Learn more in our guide to Holter Monitor: What It Detects, How It Works and Results.
Electrocardiogram (EKG or ECG): Why It's Done, How to Prepare, What Happens and Results explains how an EKG works and why a fast or fluttering heartbeat can lead to one.
Heart Rate Monitors: How They Work, Types, Accuracy and When to See a Doctor explains how heart rate monitors work, how accurate they are and when a reading needs a call to your doctor.
References
Mayo Clinic Staff. Tachycardia: Symptoms and causes. Mayo Clinic. Last updated August 7, 2026. Accessed October 14, 2026. https://www.mayoclinic.org/diseases-conditions/tachycardia/symptoms-causes/syc-20355127
Mayo Clinic Staff. Tachycardia: Diagnosis and treatment. Mayo Clinic. Last updated August 7, 2026. Accessed October 14, 2026. https://www.mayoclinic.org/diseases-conditions/tachycardia/diagnosis-treatment/drc-20355133
Appelboam A, Reuben A, Mann C, et al. Postural modification to the standard Valsalva manoeuvre for emergency treatment of supraventricular tachycardias (REVERT): a randomised controlled trial. Lancet. 2015;386(10005):1747-1753. PMID 26314489. https://doi.org/10.1016/S0140-6736(15)61485-4
Mao YJ, Feng WY, Huang QY, et al. Meta-analysis of cryoballoon ablation versus antiarrhythmic drugs as initial therapy for symptomatic atrial fibrillation. Clin Cardiol. 2021;44(10):1393-1401. PMID 34327708. https://doi.org/10.1002/clc.23695
Disclaimer: This guide is for general information only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of a physician or other qualified health provider with any questions about a medical condition. Never disregard professional medical advice or delay seeking it because of something you have read here.
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