In tachycardia, an irregular electrical signal (impulse) starting in the upper or lower chambers of the heart causes the heart to beat faster.
Tachycardia (tak-ih-KAHR-dee-uh) is the medical term for a heart rate over 100 beats a minute. Many types of irregular heart rhythms (arrhythmias) can cause tachycardia.
A fast heart rate isn't always a concern. For instance, the heart rate typically rises during exercise or as a response to stress.
Tachycardia may not cause any symptoms or complications. But if left untreated, some forms of tachycardia can lead to serious health problems, including heart failure, stroke or sudden cardiac death.
Treatment for tachycardia may include specific maneuvers, medication, cardioversion or surgery to control a rapid heartbeat.
There are many different types of tachycardia. Sinus tachycardia refers to a typical increase in the heart rate often caused by exercise or stress.
Other types of tachycardia are grouped according to the part of the heart responsible for the fast heart rate and the cause. Common types of tachycardia caused by irregular heart rhythms (arrhythmias) include:
- Atrial fibrillation (A-fib). This is the most common type of tachycardia. Chaotic, irregular electrical signals in the upper chambers of the heart (atria) cause a fast heartbeat. A-fib may be temporary, but some episodes won't end unless treated.
- Atrial flutter. Atrial flutter is similar to A-fib, but heartbeats are more organized. Episodes of atrial flutter may go away themselves or may require treatment. People who have atrial flutter also often have atrial fibrillation at other times.
- Ventricular tachycardia. This type of arrhythmia starts in the lower heart chambers (ventricles). The rapid heart rate doesn't allow the ventricles to fill and squeeze (contract) to pump enough blood to the body. Ventricular tachycardia episodes may be brief and last only a couple of seconds without causing harm. But episodes lasting more than a few seconds can be life-threatening.
- Supraventricular tachycardia (SVT). Supraventricular tachycardia is a broad term that includes arrhythmias that start above the ventricles. Supraventricular tachycardia causes episodes of a pounding heartbeat (palpitations) that begin and end abruptly.
- Ventricular fibrillation. Rapid, chaotic electrical signals cause the ventricles to quiver instead of contracting in a coordinated way. This serious problem can lead to death if the heart rhythm isn't restored within minutes. Most people who have ventricular fibrillation have an underlying heart disease or have experienced serious trauma, such as being struck by lightning.
Mayo Clinic Minute: Identifying and treating atrial fibrillation
Mayo Clinic electrophysiologist Fred Kusumoto, M.D., explains what happens in the heart to create atrial fibrillation and what can be done to fix it.
MODERATOR: This is a normal heartbeat. [HEART BEATING] Atrial fibrillation interrupts this regular beat.
FRED KUSUMOTO, M.D.: "In atrial fibrillation, instead of the atria squeezing in a normal regular fashion, the atria beat irregularly and chaotically."
MODERATOR: Dr. Fred Kusumoto is an electrophysiologist at Mayo Clinic.
FRED KUSUMOTO, M.D.: "In some cases people feel their heart palpitating or beating very, very fast or a flip-flop in their heart or chest area. Other times, people just notice that they're more short of breath when they walk upstairs."
MODERATOR: Dr. Kusumoto says atrial fibrillation decreases the heart's blood pumping efficiency and puts a patient at higher risk for blood clots, heart failure, and stroke. In some cases, atrial fibrillation can be corrected with medication or by administering a shock to a sedated patient's heart. In other instances, a procedure called catheter ablation may be used to scar tissue that's creating the erratic signals--[HEART BEATING]-- in the hopes of getting back to that normal beat.
When the heart beats too fast, it may not pump enough blood to the rest of the body. As a result, the organs and tissues may not get enough oxygen.
In general, tachycardia may lead to the following signs and symptoms:
- Sensation of a racing, pounding heartbeat or flopping in the chest (palpitations)
- Chest pain
- Fainting (syncope)
- Rapid pulse rate
- Shortness of breath
Some people with tachycardia have no symptoms. The condition may be discovered when a physical exam or heart tests are done for another reason.
When to see a doctor
A number of things can cause a rapid heart rate (tachycardia). If you feel like your heart is beating too fast, make an appointment to see a health care provider.
Seek immediate medical help if you have shortness of breath, weakness, dizziness, lightheadedness, fainting or near fainting, and chest pain or discomfort.
A type of tachycardia called ventricular fibrillation can cause blood pressure to drop dramatically. Collapse can occur within seconds. Soon the affected person's breathing and pulse will stop. If this occurs, do the following:
- Call 911 or the emergency number in your area.
- If you or someone nearby is well trained in CPR, start CPR. CPR can help maintain blood flow to the organs until an electrical shock (defibrillation) can be given.
- If you're not trained in CPR or worried about giving rescue breaths, then 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. You don't need to do rescue breathing.
- If an automated external defibrillator (AED) is available nearby, have someone get the device for you, and then follow the instructions. An AED is a portable defibrillation device that can deliver a shock to reset the heart rhythm. No training is required to use the device. The AED will tell you what to do. It's programmed to give a shock only when appropriate.
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Tachycardia is an increased heart rate for any reason. It can be a usual rise in heart rate caused by exercise or a stress response (sinus tachycardia). Sinus tachycardia is considered a symptom, not a disease.
Tachycardia can also be caused by an irregular heart rhythm (arrhythmia).
Things that may lead to tachycardia include:
- Heavy alcohol use or alcohol withdrawal
- High levels of caffeine
- High or low blood pressure
- Imbalance of substances in the blood called electrolytes — such as potassium, sodium, calcium and magnesium
- Medication side effects
- Overactive thyroid (hyperthyroidism)
- Reduced volume of red blood cells (anemia), often caused by bleeding
- Use of illegal drugs, including stimulants such as cocaine or methamphetamine
Sometimes the exact cause of tachycardia can't be determined.
How does the heart beat?
In a typical heart rhythm, a tiny cluster of cells at the sinus node sends out an electrical signal. The signal then travels through the atria to the atrioventricular (AV) node and into the ventricles, causing them to contract and pump blood.
To understand the cause of tachycardia, it may be helpful to know how the heart typically works.
The heart is made of four chambers — two upper chambers (atria) and two lower chambers (ventricles).
The heart's rhythm is controlled by a natural pacemaker (the sinus node) in the right upper chamber (atrium). The sinus node sends electrical signals that normally start each heartbeat. These electrical signals move across the atria, causing the heart muscles to squeeze (contract) and pump blood into the ventricles.
Next, the signals arrive at a cluster of cells called the AV node, where they slow down. This slight delay allows the ventricles to fill with blood. When the electrical signals reach the ventricles, the chambers contract and pump blood to the lungs or to the rest of the body.
In a typical heart, this heart signaling process usually goes smoothly, resulting in a resting heart rate of 60 to 100 beats a minute.
In general, growing older or having a family history of certain heart rhythm problems (arrhythmias) may increase the risk of arrhythmias that commonly cause tachycardia.
Lifestyle changes or medical treatment for related heart or other health conditions may decrease the risk of tachycardia.
Complications of tachycardia depend on:
- The type of tachycardia
- How fast the heart is beating
- How long the rapid heart rate lasts
- If there are other heart conditions
Some people with tachycardia have an increased risk of developing a blood clot that could cause a stroke (risk is highest with atrial fibrillation) or heart attack. Your health care provider may prescribe a blood-thinning medication to help lower your risk.
Other potential complications of tachycardia include:
- Frequent fainting or unconsciousness
- Inability of the heart to pump enough blood (heart failure)
- Sudden death, usually only associated with ventricular tachycardia or ventricular fibrillation
The best ways to prevent tachycardia are to maintain a healthy heart and prevent heart disease. If you already have heart disease, monitor it and follow your treatment plan. Be sure you understand your treatment plan, and take all medications as prescribed.
Lifestyle changes to reduce the risk of heart disease may help prevent heart arrhythmias that can cause tachycardia. Take the following steps:
- Eat a healthy diet. Choose a diet rich in whole grains, lean meat, low-fat dairy, and fruits and vegetables. Limit salt, sugar, alcohol, and saturated fat and trans fats.
- Exercise regularly. Try to exercise for at least 30 minutes on most days.
- Maintain a healthy weight. Being overweight increases the risk of developing heart disease.
- Keep blood pressure and cholesterol levels under control. Make lifestyle changes and take medications as prescribed to control high blood pressure (hypertension) or high cholesterol.
- Stop smoking. If you smoke and can't quit on your own, talk to your health care provider about strategies or programs to help break the smoking habit.
- Drink in moderation. If you choose to drink alcohol, do so in moderation. For healthy adults, that means up to one drink a day for women and up to two drinks a day for men. For some health conditions, it's recommended that you completely avoid alcohol. Ask your health care provider for advice specific to your condition.
- Don't use illegal drugs or stimulants, such as cocaine. Talk to your health care provider about an appropriate program for you if you need help ending illegal drug use.
- Use medications with caution. Some cold and cough medications contain stimulants that may trigger a rapid heartbeat. Ask your health care provider which medications you need to avoid.
- Limit caffeine. If you drink caffeinated beverages, do so in moderation (no more than one to two beverages daily).
- Manage stress. Find ways to help reduce emotional stress. Getting more exercise, practicing mindfulness and connecting with others in support groups are some ways to reduce stress.
- Go to scheduled checkups. Have regular physical exams and report any changes in your heartbeat to your health care provider. If your symptoms change or get worse or you develop new ones, tell your health care provider immediately.