Tachycardia is a heart rate that is faster than normal. For most adults at rest, that means more than 100 beats per minute. It is not a disease on its own. It is a sign — sometimes harmless, sometimes the first clue that something in the heart or body needs attention.
You have likely felt your heart race before. Climbing stairs, a scare, a strong coffee. That is normal. Tachycardia becomes a medical concern when the heart beats fast at rest, when it starts or stops suddenly, or when it comes with chest pain, shortness of breath, or fainting. This guide covers the symptoms, the main types, and how each is treated.
What Is Tachycardia?
Tachycardia is defined by a resting heart rate above 100 beats per minute in adults. A normal resting heart rate for adults is 60 to 100 beats per minute. In general, a lower resting rate reflects more efficient heart function and better cardiovascular fitness.
Your heart has its own electrical system. A small cluster of cells called the sinoatrial node, located in the upper right chamber, sets the pace. It sends an electrical signal that travels through the atria (upper chambers), down to the atrioventricular node, and into the ventricles (lower chambers). Each signal triggers a heartbeat.
Tachycardia happens when this system runs too fast. That can occur for a normal reason — your body needs more blood flow during exercise or stress — or because of a problem with the electrical signals themselves, a medical condition, or a medication effect.
One point that often gets lost: a fast heart rate is not automatically dangerous. A heart rate of 130 during a hard workout is expected. The same rate while sitting still is not. Context matters as much as the number.
What Are the Symptoms of Tachycardia?
Some people with tachycardia feel nothing at all. Others feel it clearly. Symptoms depend on how fast the heart is beating, how long it lasts, and whether the heart is pumping blood effectively.
Common symptoms include:
- A racing, pounding, or fluttering feeling in the chest (palpitations)
- Shortness of breath, especially with exertion
- Lightheadedness or dizziness
- Chest discomfort or pain
- Fainting or near-fainting
- Fatigue
- Confusion or difficulty concentrating, particularly in older adults
Some symptoms are warning signs that need urgent medical attention. Call emergency services if a fast heart rate comes with chest pain, fainting, severe shortness of breath, or signs of a stroke such as face drooping, arm weakness, or trouble speaking.
In older adults, tachycardia can sometimes show up mainly as confusion or a general feeling of being unwell rather than classic chest symptoms. That makes it easier to miss.
What Are the Main Types of Tachycardia?
Doctors group tachycardias by where in the heart they start. The two broad categories are supraventricular (above the ventricles) and ventricular (in the ventricles). Ventricular tachycardias are generally more dangerous.
Supraventricular Tachycardias
These begin in the atria or the atrioventricular node. They are common and often not immediately life-threatening, though they can be uncomfortable and sometimes serious.
- Atrial fibrillation. The most common sustained arrhythmia. The atria quiver instead of contracting in a coordinated way, producing an irregular, often fast pulse. It raises the risk of stroke and needs medical management.
- Atrial flutter. A fast, usually regular rhythm caused by a short-circuit in the right atrium.
- AV nodal reentrant tachycardia (AVNRT). The most common regular paroxysmal supraventricular tachycardia. It often starts and stops abruptly.
- Sinus tachycardia. A normal rhythm simply running fast, usually in response to exercise, fever, pain, anxiety, dehydration, or anemia. The underlying cause is the issue, not the rhythm itself.
Ventricular Tachycardias
These start in the ventricles and can be life-threatening, especially if they last more than a few seconds or occur in a damaged heart.
- Ventricular tachycardia (VT). A fast rhythm from the ventricles. Sustained VT can lead to cardiac arrest.
- Ventricular fibrillation (VF). Chaotic electrical activity. The heart cannot pump blood. This is a cardiac arrest emergency requiring immediate CPR and defibrillation.
What Causes Tachycardia?
Causes fall into two broad groups: those outside the heart and those inside it. Many fast heart rates have nothing to do with a heart problem at all.
Non-cardiac causes include fever, dehydration, anemia, an overactive thyroid, anxiety, pain, heavy alcohol use, and stimulants such as caffeine or certain medications. Exercise and emotional stress raise heart rate normally and are not causes for concern.
Cardiac causes include coronary artery disease, heart failure, heart valve problems, congenital heart defects, and problems with the heart’s electrical pathways. Some tachycardias are inherited.
Certain medications can trigger or worsen a fast heart rate. If you notice a racing heart after starting a new medicine, tell your doctor rather than stopping it on your own.
How Is Tachycardia Diagnosed?
Diagnosis starts with your history and a physical exam. A doctor will ask when the fast heart rate happens, how long it lasts, what triggers it, and whether it comes with other symptoms. Your pulse and blood pressure are checked.
An electrocardiogram (ECG) records the heart’s electrical activity and is the key test. It shows the rhythm and can reveal which type of tachycardia is present. Because many tachycardias come and go, a single ECG in the office may look normal.
When that happens, doctors use monitors that record your heart over time. A Holter monitor records continuously for 24 to 48 hours. Event monitors and wearable patches can record for days or weeks. Some people are given a small implantable monitor for longer periods.
Other tests may include blood work to check for anemia, thyroid problems, and electrolyte imbalances. An echocardiogram uses ultrasound to look at the heart’s structure and how well it pumps. A stress test checks the heart during exercise.
How Is Tachycardia Treated?
Treatment depends entirely on the type and cause. Some tachycardias need no treatment beyond addressing the trigger. Others need medication, a procedure, or emergency care.
When a fast heart rate is caused by something outside the heart, treating that cause usually resolves it. Rehydrating, treating a fever, correcting anemia or thyroid problems, and reducing stimulants can all slow the heart back to normal.
For many supraventricular tachycardias, doctors first try simple vagal maneuvers. These stimulate the vagus nerve and can slow the heart. Examples include bearing down as if having a bowel movement or splashing cold water on the face. These are often done under medical guidance the first time.
Medications can control rate or rhythm. Beta-blockers and calcium channel blockers are commonly used to slow the heart. Antiarrhythmic drugs help keep a normal rhythm. For atrial fibrillation, anticoagulant (blood-thinning) medication is often used to lower stroke risk, guided by a doctor’s assessment.
Catheter ablation is a procedure that uses radiofrequency energy to destroy the small area of heart tissue causing the abnormal rhythm. It can be highly effective for certain types of supraventricular tachycardia. Whether it is appropriate depends on the specific rhythm and the person.
For dangerous ventricular arrhythmias, an implantable cardioverter-defibrillator (ICD) may be placed. It monitors the heart and delivers a shock if a life-threatening rhythm occurs. This is a decision made with a cardiologist.
Ventricular fibrillation is a cardiac arrest emergency. It requires immediate CPR and defibrillation. Survival depends on fast action.
When Should You See a Doctor?
See a doctor if you have a fast resting heart rate that does not settle, if palpitations come and go, or if a racing heart is accompanied by dizziness, shortness of breath, or unusual fatigue. These symptoms deserve evaluation even when they are intermittent.
Call emergency services without delay for a fast heart rate with chest pain, fainting, severe breathlessness, or signs of a stroke. Do not drive yourself.
If you have a known heart condition or a family history of sudden cardiac death, tell your doctor. Some inherited rhythm disorders run in families, and that history can change how symptoms are evaluated.
Frequently Asked Questions
What heart rate is considered tachycardia?
In adults, a resting heart rate above 100 beats per minute is considered tachycardia. A normal resting rate is 60 to 100 beats per minute.
Is tachycardia always dangerous?
No. A fast heart rate during exercise or stress is normal and expected. Tachycardia is a concern when it happens at rest, starts and stops suddenly, or comes with chest pain, fainting, or severe shortness of breath.
Can tachycardia go away on its own?
Some types, such as sinus tachycardia from dehydration or fever, resolve once the cause is corrected. Others, like atrial fibrillation, usually need ongoing medical management and do not reliably resolve without treatment.
What is the difference between tachycardia and atrial fibrillation?
Atrial fibrillation is one specific type of tachycardia, marked by an irregular and often fast rhythm. Tachycardia is the general term for any heart rate above 100 beats per minute at rest.
