Ventricular tachycardia is a heart rhythm disorder (arrhythmia) caused by abnormal electrical signals in the lower chambers of the heart (ventricles).
Your heart rate is regulated by electrical signals sent across heart tissues. A healthy heart normally beats about 60 to 100 times a minute when at rest and is defined by signals that originate in the upper chambers of the heart (atria).
In ventricular tachycardia (V-tach or VT), abnormal electrical signals in the ventricles cause the heart to beat faster than normal, usually 100 or more beats a minute, out of sync with the upper chambers.
When that happens, your heart may not be able to pump enough blood to your body and lungs because the chambers are beating so fast or out of sync with each other that they don't have time to fill properly.
Ventricular tachycardia may be brief, lasting for only a few seconds, and perhaps not cause any symptoms. Or it can last for much longer and cause symptoms such as dizziness, lightheadedness, palpitations or even loss of consciousness.
In some cases, ventricular tachycardia can cause your heart to stop (sudden cardiac arrest), which is a life-threatening medical emergency. This condition usually occurs in people with other heart conditions, such as those who have had a previous heart attack or other structural heart disease (cardiomyopathy).
A dangerous condition related to ventricular tachycardia is ventricular fibrillation (V-fib). In V-fib, your lower heart chambers contract in a very rapid and uncoordinated manner.
Sometimes this rhythm may occur as a result of ventricular tachycardia degenerating into ventricular fibrillation, or it may originate from single ventricular beats. This abnormal rhythm happens most often in people with established heart disease or a prior heart attack. It may also occur due to electrolyte abnormalities (such as high or low potassium levels) or, rarely, in otherwise normal hearts.
Ventricular fibrillation may also cause sudden cardiac arrest and lead to death if not treated immediately.
In ventricular tachycardia, an abnormal electrical impulse originating in the lower chambers of the heart (ventricles) causes the heart to beat faster. The problem may involve either a small cluster of cells or a large area of scar tissue.
Brief episodes of ventricular tachycardia may not cause any symptoms in some people. Others may experience:
- Shortness of breath
- Feeling as if your heart is racing (palpitations)
- Chest pain (angina)
Sustained or more serious episodes of ventricular tachycardia may cause:
- Loss of consciousness or fainting
- Cardiac arrest (sudden death)
When to see a doctor
A number of conditions can cause ventricular tachycardia. It's important to get a prompt, accurate diagnosis and appropriate care. See your doctor if you or your child experiences any V-tach symptoms.
If you faint, have difficulty breathing or have chest pain lasting more than a few minutes, get emergency care, or call 911 or your local emergency number. Seek emergency care for anyone experiencing these symptoms.
V-tach is caused by a disruption in the normal electrical impulses that control the rate of your ventricles' pumping action.
Many things can cause or contribute to problems with the heart's electrical system. These include:
- Lack of oxygen to the heart due to tissue damage from heart disease
- Abnormal electrical pathways in the heart present at birth (congenital heart conditions, including long QT syndrome)
- Structural heart disease (cardiomyopathy)
- Medication side effects
- An inflammatory disease affecting skin or other tissues (sarcoidosis)
- Abuse of recreational drugs, such as cocaine
- Imbalance of electrolytes, mineral-related substances necessary for conducting electrical impulses
In some cases, the exact cause of ventricular tachycardia can't be determined (idiopathic ventricular tachycardia).
The heart's electrical system
To understand the causes of heart rate or rhythm problems such as ventricular tachycardia, it helps to understand how the heart's internal electrical system works.
Your heart is made up of four chambers — two upper chambers (atria) and two lower chambers (ventricles). The rhythm of your heart is normally controlled by a natural pacemaker called the sinus node, which is located in the right atrium. The sinus node produces electrical impulses that normally start each heartbeat.
From the sinus node, electrical impulses travel across the atria, causing the atria muscles to contract and pump blood into the ventricles.
The electrical impulses then arrive at a cluster of cells called the atrioventricular (AV) node — usually the only pathway for signals to travel from the atria to the ventricles.
The AV node slows down the electrical signal before sending it to the ventricles. This slight delay allows the ventricles to fill with blood. When electrical impulses reach the muscles of the ventricles, they contract, causing them to pump blood either to the lungs or to the rest of the body.
When anything disrupts this complex system, it can cause the heart to beat too fast (tachycardia), too slow (bradycardia) or with an irregular rhythm.
In a normal heart rhythm, a 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 then passes into the ventricles, causing them to contract and pump out blood.
Any condition that puts a strain on the heart or damages heart tissue can increase your risk of ventricular tachycardia. Lifestyle changes or medical treatment may decrease the risk associated with the following factors:
- Heart disease (for example, prior heart attack, hypertrophic cardiomyopathy, inflammatory diseases of the heart or genetic conditions)
- Use of recreational drugs
- Severe electrolyte abnormalities
- Medication side effects
Other risk factors
If you have a family history of ventricular tachycardia or other heart rhythm disorders, you may have an increased risk of ventricular tachycardia.
Complications of ventricular tachycardia vary in severity depending on such factors as the rate, and duration of a rapid heart rate, the frequency with which it happens, and the existence of other heart conditions. Possible complications include:
- Inability of the heart to pump enough blood (heart failure)
- Frequent fainting spells or unconsciousness
- Sudden death caused by cardiac arrest
The most effective way to prevent ventricular tachycardia is to reduce your risk of developing heart disease. If you already have heart disease, monitor it and follow your treatment plan to lower your ventricular tachycardia risk.
In some cases, ventricular tachycardia may occur in the absence of heart disease (idiopathic ventricular tachycardia).
Prevent heart disease
Treat or eliminate risk factors that may lead to heart disease. Take the following steps:
- Exercise and eat a healthy diet. Live a heart-healthy lifestyle by exercising regularly and eating a healthy, low-fat diet that's rich in fruits, vegetables and whole grains.
- Maintain a healthy weight. Being overweight increases your risk of developing heart disease.
- Keep blood pressure and cholesterol levels under control. Make lifestyle changes and take medications as prescribed to correct high blood pressure (hypertension) or high cholesterol.
- Stop smoking. If you smoke and can't quit on your own, talk to your doctor about strategies or programs to help you break a 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 of all ages and men older than age 65, and up to two drinks a day for men age 65 and younger. For some conditions it's recommended that you completely avoid alcohol.
Ask your doctor for advice specific to your condition. If you can't control your alcohol consumption, talk to your doctor about a program to quit drinking and manage other behaviors related to alcohol abuse.
- Don't use recreational drugs. Don't use stimulants, such as cocaine. Talk to your doctor about an appropriate program for you if you need help ending recreational drug use.
- Use over-the-counter medications with caution. Some cold and cough medications contain stimulants that may trigger a rapid heartbeat. Ask your doctor 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).
- Control stress. Avoid unnecessary stress and learn coping techniques to handle normal stress in a healthy way.
- Go to scheduled checkups. Have regular physical exams and report any signs or symptoms to your doctor.
Monitor and treat existing heart disease
If you already have heart disease, you can take steps to lower your risk of developing ventricular tachycardia or another arrhythmia:
- Follow the plan. Be sure you understand your treatment plan, and take all medications as prescribed.
- Report changes immediately. If your symptoms change or get worse or you develop new symptoms, tell your doctor immediately.
To diagnose ventricular tachycardia, your doctor may review your symptoms and your family and medical history and conduct a physical examination.
Your doctor may order several tests to diagnose your condition, determine the cause and severity of your condition, and determine the most appropriate treatment.
In some cases, ventricular tachycardia may be a medical emergency and require an urgent diagnosis and prompt treatment.
Several heart tests also may be necessary to diagnose ventricular tachycardia.
An electrocardiogram, also called an ECG or EKG, is the most common tool used to diagnose ventricular tachycardia. It's a painless test that detects and records your heart's electrical activity using small sensors (electrodes) attached to your chest and arms.
An ECG records the timing and strength of electrical signals as they travel through your heart. Your doctor can look for patterns among these signals to determine what kind of tachycardia you have and how abnormalities in the heart may be contributing to a fast heart rate.
Your doctor may also ask you to use portable ECG devices at home to provide more information about your heart rate. These devices include:
Holter monitor. This portable ECG device is carried in your pocket or worn on a belt or shoulder strap. It records your heart's activity for an entire 24-72 hour period, which provides your doctor with a prolonged look at your heart rhythms.
Your doctor will likely ask you to keep a diary during the same 24 hours. You'll describe any symptoms you experience and record the time they occur.
Event monitor. This portable ECG device is intended to monitor your heart activity over a few weeks to a few months. You wear it all day, but it records only at certain times for a few minutes at a time.
With many event monitors, you activate them by pushing a button when you experience symptoms of a fast heart rate. Other monitors automatically sense abnormal heart rhythms and then start recording. These monitors allow your doctor to look at your heart rhythm at the time of your symptoms.
- Transtelephonic monitor. This device provides continuous heart rhythm monitoring but must be worn continuously. It may or may not include wires.
- Implantable loop recorder. This is an implantable device that has no wires and can sit underneath your skin for up to three years to continuously monitor your heart rhythm.
Imaging of the heart may be performed to determine if structural abnormalities are affecting blood flow and contributing to ventricular tachycardia.
Types of cardiac imaging used to evaluate V-tach include:
- Echocardiogram (echo). An echocardiogram creates a moving picture of your heart using sound waves via a transducer placed on the chest that emits and detects these waves. An echo can identify abnormalities in the heart valves and heart muscle that contribute to poor blood flow.
- Magnetic resonance imaging (MRI). A cardiac MRI provides still or moving pictures of how the blood is flowing through the heart and detects irregularities. It is often used to evaluate potential causes of ventricular tachycardia.
- Computerized tomography (CT). CT scans combine several X-ray images to provide a more detailed cross-sectional view of the heart.
- Coronary angiogram. This may be used to study the flow of blood through your heart and blood vessels. Your doctor may use a coronary angiogram to reveal potential blockages or abnormalities. It uses a dye and special X-rays to show the inside of your coronary arteries.
- Chest X-ray. This painless test is used to take still pictures of your heart and lungs and can detect if your heart is enlarged.
Your doctor may recommend a stress test to see how your heart functions while it is working hard during exercise or when medication is given to make the heart beat faster.
In an exercise stress test, electrodes are placed on your chest to monitor heart function while you exercise, usually by walking on a treadmill. Other heart tests may be performed in conjunction with a stress test.
Your doctor may recommend an electrophysiological test to confirm the diagnosis or to pinpoint the location of problems in your heart's circuitry.
During this test, a doctor inserts thin, flexible tubes (catheters) tipped with electrodes into an access point, usually your groin or neck, and guides them through your blood vessels to various spots in your heart.
Your doctor may order additional tests as needed to diagnose an underlying condition that is contributing to ventricular tachycardia and judge the condition of your heart.
A thorough physical exam, medical history and testing is required to diagnose ventricular tachycardia.
An electrocardiogram monitors your heart rhythm for problems. Electrodes are taped to your chest to record your heart's electrical signals, which cause your heart to beat. The signals are shown as waves on an attached computer monitor or printer.
A Holter monitor uses electrodes and a recording device to track your heart's rhythm for 24 to 72 hours. Your doctor can print an electrocardiogram strip using the data on the recording device to see your heart's rhythm during the period you wore the monitor.
A wearable cardiac event monitor may be used to diagnose heart rhythm problems. This type of portable ECG device records heart activity only during episodes of abnormal heartbeat.
In an exercise stress test, electrodes are taped to your chest to detect your heart's rhythm. A nurse or technician will watch your heartbeat on a monitor while you exercise. If your doctor orders a nuclear stress test, you'll also receive a shot of radioactive dye that shows the blood flow to your heart muscle.
The goals of ventricular tachycardia treatment are to restore your normal heart rhythm, regulate your heart rate and prevent future episodes.
Treatment of V-tach depends largely on what is causing the arrhythmia and the type or severity of your ventricular tachycardia.
The two main types of ventricular tachycardia are those that resolve on their own within 30 seconds (nonsustained V-tach ) and those that last more than 30 seconds, interfere with normal blood flow or require medical intervention to resolve (sustained V-tach).
Urgent V-tach treatment
Sustained ventricular tachycardia may sometimes lead to sudden death and often requires urgent medical intervention.
Immediate treatment usually involves restoring a normal heart rate by delivering a jolt of electricity to the heart via defibrillation or cardioversion but can also involve providing medications orally or intravenously.
Defibrillation may be performed using an automated external defibrillator (AED) by a bystander who recognizes the signs of cardiac arrest, or by medical professionals using paddles in a hospital setting. Cardioversion is performed in a hospital setting using a cardioversion machine that monitors your heart rhythm before and after shocks are delivered.
An injection of an anti-arrhythmic medication, such as lidocaine, may also be used to treat sustained ventricular tachycardia and restore a normal heart rhythm.
Preventing episodes of a fast heart rate
People with nonsustained or sustained ventricular tachycardia may be treated in a variety of ways to prevent future episodes and related complications. Treatments for V-tach include:
Catheter ablation. This procedure is often used when a discrete electrical pathway is responsible for an increased heart rate.
In this procedure, a doctor inserts catheters into your groin or neck and guides them through the blood vessels to your heart. Electrodes at the catheter tips can use heat, extreme cold or radiofrequency energy to damage (ablate) the extra electrical pathway and prevent it from sending electrical signals.
- Medications. Anti-arrhythmic medications may prevent a fast heart rate when taken regularly.
Implantable cardioverter-defibrillator. If you're at risk of having a life-threatening ventricular tachycardia episode, your doctor may recommend an implantable cardioverter-defibrillator (ICD).
The device, about the size of a pager, is surgically implanted in your chest. The ICD continuously monitors your heartbeat, detects an increase in heart rate and delivers precisely calibrated electrical shocks, if needed, to restore a normal heart rhythm.
A new type of ICD called a subcutaneous implantable cardioverter-defibrillator (S-ICD) is less invasive but larger in size than an ICD. Your doctor implants the S-ICD under the skin at the side of the chest below the armpit. It’s attached to an electrode that runs along your breastbone. You may be a candidate for an S-ICD if you have structural defects in your heart that prevent advancing wires to the heart through your blood vessels, or if you have other reasons for wanting to avoid traditional ICDs.
- Surgery. Open-heart surgery may be needed in some cases to treat a process contributing to ventricular tachycardia (for example, if there are blockages in blood vessels). Surgery is usually used only when other treatment options don't work or when surgery is needed to treat another heart disorder.
Treating an underlying disease
If another medical condition is contributing to ventricular tachycardia, such as some form of heart disease, treating the underlying problem may prevent or minimize ventricular tachycardia episodes.
Mayo Clinic doctors deliver specialized care to treat ventricular tachycardia using advanced treatment technologies.
An ICD works to regulate your heartbeat by delivering shocks to your heart when it detects an abnormal heartbeat.
Coping and support
If you have a plan in place to deal with an episode of a fast heartbeat, you may feel calmer and more in control when one occurs. Talk to your doctor about:
- How to take your pulse and what a normal pulse rate is for you
- When and how to use a variety of maneuvers or take additional medications if they are appropriate for you
- When to call your doctor
- When to seek emergency care
Preparing for an appointment
Make a list ahead of time that you can share with your doctor. Your list should include:
- Symptoms you've experienced, including any that may seem unrelated to your heart
- Key personal information, including any major stresses or recent life changes
- Medications, including vitamins or supplements
- Questions to ask your doctor
List your questions from most important to least important in case time runs out. Basic questions to ask your doctor include:
- What is likely causing my fast heart rate?
- What kinds of tests do I need?
- What's the most appropriate treatment?
- What kind of risks does my heart condition create?
- How will we monitor my heart?
- How often will I need follow-up appointments?
- How will other conditions I have or medications I take affect my heart problem?
- Do I need to restrict my activities?
- Are there any brochures or other printed material that I can take home with me? What websites do you recommend visiting?
In addition to the questions that you've prepared to ask your doctor, don't hesitate to ask additional questions.
What to expect from your doctor
Your doctor is likely to ask you a number of questions. Being ready to answer them may reserve time to go over any points you want to spend more time on. Your doctor may ask:
- When did you first begin experiencing symptoms?
- How often have you had episodes of a fast heartbeat?
- How long have the episodes lasted?
- Does anything, such as exercise, stress or caffeine, seem to trigger or worsen episodes?
- Does anyone in your family have heart disease or a history of arrhythmias?
- Has anyone in your family experienced cardiac arrest or died suddenly?
- Do you smoke?
- How much alcohol or caffeine do you use?
- Do you use recreational drugs?
- Are you being treated for high blood pressure, high cholesterol or other conditions that may affect your circulatory system?
- What medications do you take for these conditions, and do you take them as prescribed?
Last updated: August 8th, 2017