Ventricular tachycardia is a heart rhythm disorder (arrhythmia) caused by abnormal electrical signals in the lower chambers of the heart (ventricles). This condition may also be called V-tach or VT.
A healthy heart normally beats about 60 to 100 times a minute at rest. In ventricular tachycardia, the heart beats faster than normal, usually 100 or more beats a minute.
The chaotic heartbeats prevent the heart chambers from properly filling with blood. As a result, your heart may not be able to pump enough blood to your body and lungs.
Ventricular tachycardia may last for only a few seconds, or it can last for much longer. You may feel dizzy or short of breath, or have chest pain. Sometimes, ventricular tachycardia can cause your heart to stop (sudden cardiac arrest), which is a life-threatening medical emergency.
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. Or you may have:
Sustained and more-serious episodes of ventricular tachycardia may cause:
Many different 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 has any problems with the heartbeat. In some cases, urgent care is needed.
Get emergency care, or call 911 or your local emergency number for anyone experiencing these symptoms:
Ventricular tachycardia is caused by a disruption in the normal electrical impulses that control the rate of your heart's pumping action.
Many things can cause or contribute to problems with the heart's electrical system. These include:
In some cases, the exact cause of ventricular tachycardia can't be determined (idiopathic ventricular tachycardia).
To understand the causes of heart rate or rhythm problems such as tachycardia, it helps to understand how the heart's electrical system works.
Your heart is made up of four chambers — two upper chambers (atria) and two lower chambers (ventricles). Your heartbeat 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 atrial muscles to contract and pump blood into the lower chambers of the heart (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:
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 and depend on how fast your heart is beating, how long the rapid heartbeat lasts, how often tachycardia occurs and your overall heart health. Possible complications include:
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.
This abnormal rhythm happens most often in people with heart disease or a prior heart attack. It may also occur due to electrolyte problems (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.
The best way to prevent ventricular tachycardia is to treat or eliminate risk factors that may lead to heart disease. If you already have heart disease, follow your treatment plan and a heart-healthy lifestyle.
Take the following steps:
Your doctor will evaluate your symptoms, perform a physical examination, and ask you about your health habits and medical history. In some cases, ventricular tachycardia may be a medical emergency that requires urgent diagnosis and treatment.
Several tests may be done to diagnose ventricular tachycardia.
An electrocardiogram (ECG or EKG) is the most common tool used to diagnose tachycardia. The painless test 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 the signals to determine what kind of tachycardia you have and how problems in the heart may be causing a fast heart rate.
Your doctor may also ask you to use a portable ECG device at home to obtain more information about your heart rate. These devices include:
Your doctor may recommend an electrophysiological test to confirm the diagnosis or to pinpoint the location of problems in your heart.
During this test, a doctor inserts thin, flexible tubes (catheters) tipped with electrodes into your groin, arm or neck and guides them through your blood vessels to various spots in your heart. Once in place, the electrodes can precisely map the spread of electrical impulses during each beat and identify abnormalities in your circuitry.
Your doctor may get images of your heart to determine if structural problems are affecting blood flow and causing your ventricular tachycardia.
Cardiac imaging tests used to diagnose ventricular tachycardia include:
Your doctor may recommend a stress test to see how your heart works when you are active 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 done along with a stress test.
This test is sometimes used to help your doctor better understand how your tachycardia contributes to fainting spells. Under careful monitoring, you'll receive a medication that causes a tachycardia episode. You lie flat on a special table, and then the table is tilted as if you were standing up. Your doctor notes how your heart and nervous system respond to these changes in position.
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.
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 tachycardia. 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 small amount of radioactive material (radiotracer) through an IV. The radiotracer shows the blood flow to your heart muscle.
The goals of ventricular tachycardia treatment are:
The specific treatment you receive depends on what is causing the arrhythmia and the type or severity of your ventricular tachycardia.
Ventricular tachycardia may go away on its own within 30 seconds (nonsustained V-tach) or last more than 30 seconds (sustained V-tach or VT ). Sustained VT can disrupt normal blood flow and requires immediate medical treatment.
Sustained ventricular tachycardia often requires urgent medical treatment, as this condition may sometimes lead to sudden cardiac death.
Treatment involves restoring a normal heart rate by delivering a jolt of electricity to the heart. This may be done using a defibrillator or with a treatment called cardioversion.
Defibrillation can be done using an automated external defibrillator (AED) by a bystander who recognizes the signs of cardiac arrest.
Cardioversion is done in a hospital setting using a machine that monitors your heart rhythm before and after shocks are delivered. In this procedure, medical professionals shock your heart using paddles, an automated external defibrillator (AED) or patches on your chest.
You may also be given medications by mouth or by IV (intravenously).
With treatment, it may be possible to prevent or manage episodes of ventricular tachycardia.
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 heart through the veins in your groin, arm or neck. Electrodes at the catheter tips can use extreme cold or radiofrequency energy to damage (ablate) the extra electrical pathway and prevent it from sending electrical signals.
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).
Tachycardia may also be treated with a maze procedure. During this procedure, a surgeon makes small incisions in heart tissue to create a pattern or maze of scar tissue. Because scar tissue doesn't conduct electricity, it interferes with stray electrical impulses that cause some types of tachycardia.
Surgery is usually used only when other treatment options don't work or when surgery is needed to treat another heart disorder.
If another medical condition is contributing to ventricular tachycardia, such as heart disease, treating the underlying problem may prevent or reduce ventricular tachycardia episodes.
Following your treatment plan is important. It can help lower your risk of future heart rhythm problems. If your symptoms change or get worse or you develop new symptoms, tell your doctor immediately.