It is a disorder of the cardiac rhythm (arrhythmia) caused by abnormal electrical signals in the lower chambers of the heart (ventricles).
Your heart rate is regulated by electrical signals sent through the tissues of the heart. A healthy heart normally beats 60 to 100 times per minute when it is at rest and is defined by signals that originate in the upper chambers of the heart (atria).
In ventricular tachycardia (V-tach or VT, for its acronym in English), abnormal electrical signals in the ventricles cause the heart to beat faster than normal, usually 100 or more beats per minute, without synchronizing with the upper chambers .
When that happens, your heart may not be able to pump enough blood to your body and lungs because the cameras are beating so fast or mismatched that they do not have time to fill properly.
Ventricular tachycardia can be brief, lasting only a few seconds, and may not cause any symptoms. Or it can last much longer and cause symptoms such as dizziness, lightheadedness, palpitations or even loss of consciousness.
In some cases, ventricular tachycardia can cause the heart to stop ( sudden cardiac arrest ), which is a potentially deadly 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 ).
Short episodes of ventricular tachycardia may not cause any symptoms in some people. Others may experience:
- Short of breath.
- Feeling as if your heart is accelerated (palpitations).
- Pain in the chest ( angina ).
Sustained or more severe episodes of ventricular tachycardia can cause:
- Loss of consciousness or fainting
- Cardiac arrest (sudden death).
When to see a Doctor
Several conditions can cause ventricular tachycardia. It is important to get a quick and accurate diagnosis and proper care. Consult your doctor if you or your child experience any V-tach symptoms.
If you faint, have trouble breathing, or have chest pain that lasts more than a few minutes, get emergency care. Seek emergency care for anyone who experiences these symptoms.
Ventricular tachycardia is caused by an interruption in the normal electrical impulses that control the pumping rate of your ventricles. Many things can cause or contribute to problems with the electrical system of the heart. These include:
- Lack of oxygen in the heart due to tissue damage caused by heart disease .
- Abnormal electrical pathways in the heart present at birth (congenital heart conditions, including prolonged QT syndrome).
- Structural heart disease (cardiomyopathy).
- Side effects of medications.
- An inflammatory disease that affects the skin or other tissues ( sarcoidosis ).
- Abuse of recreational drugs, such as cocaine.
- Imbalance of electrolytes, substances related to minerals necessary for the conduction of electrical impulses.
In some cases, the exact cause of ventricular tachycardia can not be determined.
The Electrical System of the Heart
To understand the causes of heart rate or rhythm problems, such as ventricular tachycardia, it helps to understand how the internal electrical system of the heart works.
Its heart is formed by four chambers: two upper chambers (atria) and two lower chambers (ventricles). The rhythm of your heart is usually 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 through the atria, causing the muscles of the atria to contract and pump blood to the ventricles.
The electrical impulses reach a group of cells called the atrioventricular (AV) node, usually the only way for signals to travel from the atria to the ventricles.
The atrioventricular node slows down the electrical signal before sending it to the ventricles. This slight delay allows the ventricles to fill with blood.
When the electrical impulses reach the muscles of the ventricles, they contract and cause them to pump blood to the lungs or the rest of the body.
When something interrupts this complex system, it can cause the heart to beat too fast ( tachycardia ), too slow ( bradycardia ) or with an irregular rhythm.
Any condition that puts pressure on the heart or damages the heart tissue can increase your risk of ventricular tachycardia. Changes in lifestyle or medical treatment may decrease the risk associated with the following factors:
- Heart disease (for example, previous heart attack, hypertrophic cardiomyopathy, inflammatory heart disease or genetic conditions).
- Use of recreational drugs.
- Severe electrolyte abnormalities.
- Side effects of medications.
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 factors such as a rapid heart rate, the frequency with which it occurs and the existence of other heart conditions. Possible complications include:
- Inability of the heart to pump enough blood (heart failure).
- Frequent fainting or unconsciousness.
- Sudden death caused by cardiac arrest.
The most effective way to prevent ventricular tachycardia is to reduce the risk of developing heart disease. If you already have heart disease, monitor and follow your treatment plan to decrease the risk of ventricular tachycardia.
In some cases, ventricular tachycardia can occur in the absence of heart disease (idiopathic ventricular tachycardia).
Prevention of Heart Disease
Treat or eliminate risk factors that can lead to heart disease. Follow the next steps:
Exercise and have a healthy diet : live a heart-healthy lifestyle by exercising regularly and eating a healthy low-fat diet 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 not stop smoking on your own, talk with your doctor about strategies or programs to help you break the habit of smoking.
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 over 65, and up to two drinks a day for men 65 and younger. For some conditions, it is recommended that you completely avoid alcohol.
Ask your doctor for advice about your condition : if you can not control your alcohol use, talk with your doctor about a program to stop drinking and control other behaviors related to alcohol abuse.
Do not use recreational drugs : do not use stimulants, such as cocaine. Talk to your doctor about a program that is right for you if you need help to end the use of recreational drugs.
Use over-the-counter medications with caution : some cold and cough medicines contain stimulants that can trigger an accelerated heart rate. Ask your doctor what medications you should avoid.
Limit caffeine : if you drink caffeinated beverages, do so in moderation (no more than one or two drinks a day).
Manage stress : avoid unnecessary stress and learn coping techniques to manage normal stress in a healthy way.
Go for scheduled check-ups : 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 reduce your risk of developing ventricular tachycardia or other arrhythmia:
- Follow the plan : make sure you understand your treatment plan and take all medications as prescribed.
- Report the changes immediately : if your symptoms change or get worse or if you develop new symptoms, tell your doctor immediately.
A dangerous condition related to ventricular tachycardia is ventricular fibrillation. In V-fib, the lower heart chambers contract in a very fast and uncoordinated way.
Sometimes, this rhythm may occur as a result of ventricular tachycardia degenerating into ventricular fibrillation, or may originate from single ventricular beats.
This abnormal rhythm occurs more frequently in people with established heart disease or a previous heart attack. It can also occur due to electrolyte abnormalities (such as high or low potassium levels) or, rarely, in normal hearts.
Ventricular fibrillation can also cause sudden cardiac arrest and cause death if not treated immediately.
- A complete physical examination, medical history, and tests are required to diagnose ventricular tachycardia.
- To diagnose ventricular tachycardia, your doctor can review your symptoms and your family and medical history, and perform 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 can be a medical emergency and requires an urgent diagnosis and rapid treatment.
- Several cardiac tests may also be necessary to diagnose ventricular tachycardia.
An electrocardiogram , also called ECG or EKG, is the most common tool used to diagnose ventricular tachycardia. It is a painless test that detects and records the electrical activity of your heart using small sensors (electrodes) attached to your chest and arms.
An electrocardiogram records the time and strength of electrical signals as they travel through your heart. Your doctor can look for patterns between these signals to determine what type of tachycardia you have and how abnormalities in the heart may be contributing to a rapid heart rate.
Your doctor may also ask you to use portable electrocardiogram devices at home to provide more information about your heart rate. These devices include:
Holter monitor : This portable electrocardiogram device is carried in your pocket or worn on a belt or shoulder strap. Record your heart activity for a full 24-72 hour period, which gives your doctor a long view of your heart rhythms.
Your doctor may ask you to keep a diary for the same 24 hours. Describe the symptoms you experience and record the moment they occur.
Event monitor : This portable electrocardiogram device is designed to monitor your heart activity in a few weeks or months. He uses it all day, but only records at certain times for a few minutes at a time.
With many event monitors, you activate them by pressing a button when you experience symptoms of an accelerated heart rate. Other monitors automatically detect abnormal heart rhythms and then start recording.
These monitors allow your doctor to observe your heart rate at the time of your symptoms.
Transtelephonic monitor : This device provides continuous monitoring of heart rate, but must be used continuously. It may or may not include cables.
Implantable loop recorder : This is an implantable device that has no wires and can sit under your skin for up to three years to continuously monitor your heart rate.
The heart can be imaged to determine if structural abnormalities affect blood flow and contribute to ventricular tachycardia. The types of cardiac images used to evaluate V-tach include:
Echocardiogram (echo) : an echocardiogram creates a moving image of your heart using sound waves through a transducer placed in 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 magnetic resonance image provides fixed or moving images of how blood flows through the heart and detects irregularities. It is often used to evaluate the possible causes of ventricular tachycardia.
Computed tomography (CT) scan : CT scans combine several X-ray images to provide a more detailed cross-sectional view of the heart.
Coronary angiogram : This can be used to study the flow of blood through your heart and blood vessels. Your doctor may use a coronary angiogram to reveal possible blockages or abnormalities. It uses a dye and special x-rays to show the inside of the coronary arteries.
Chest X-ray : This painless test is used to take a fixed picture of your heart and lungs and can detect if your heart is enlarged.
A cardiac MRI provides fixed or moving images of how blood flows through the heart and detects irregularities. It is often used to diagnose ventricular tachycardia.
Your doctor may recommend an exercise test to see how your heart works while you work hard during exercise or when medications are given so that your heart beats faster.
In a physical exertion test, electrodes are placed on the chest to monitor cardiac function while exercising, usually walking on a treadmill. Other heart tests can be done along with a stress test.
Your doctor may recommend an electrophysiological test to confirm the diagnosis or to identify the location of the problems in the circuits of your heart.
During this test, a doctor inserts thin, flexible tubes (catheters) with electrode tips into an access point, usually in the groin or neck, and guides them through the blood vessels to various points in the heart.
Your doctor may request additional tests as needed to diagnose an underlying condition that is contributing to the ventricular tachycardia and to judge the condition of your heart.
The objectives of the treatment of ventricular tachycardia are to restore the normal heart rate, regulate the heart rate and prevent future episodes.
The 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 themselves in 30 seconds (V-tach not sustained) and those that last more than 30 seconds, interfere with normal blood flow or require medical intervention to resolve (sustained V-tach) .
The pillars of the treatment for clinically stable ventricular tachycardia are the various antiarrhythmic drugs.
In the United States, intravenous antiarrhythmic drugs available for the suppression of acute monomorphic ventricular tachycardia are limited to procainamide, lidocaine, and amiodarone , along with the beta-adrenergic blocking agents metoprolol, esmolol, and propranolol. Bretylium is no longer available.
In view of the relatively narrow therapeutic windows with these agents, special attention must be paid to the pharmacokinetics of the drugs.
Most antiarrhythmic drugs can actually cause ventricular arrhythmias, and the risks generally increase with increasing serum drug levels.
The administration of intravenous antiarrhythmics of antiarrhythmics is used for the suppression of acute ventricular tachycardia. These agents alter the electrophysiological mechanisms that are responsible for the arrhythmia.
The amiodarone is the drug of choice for acute ventricular tachycardia refractory cardioversion shock. After recovery, oral medications are used for the long-term suppression of recurrent ventricular tachycardia.
Current evidence favors class III antiarrhythmic drugs compared to class I drugs.
Urgent treatment with V-tach
Sustained ventricular tachycardia can sometimes lead to sudden death and often requires urgent medical intervention.
Immediate treatment usually involves the restoration of a normal heart rate by administering an electrical shock to the heart by defibrillation or cardioversion, but it can also involve the administration of medications orally or intravenously.
Defibrillation can be performed using an automated external defibrillator by a bystander who recognizes the signs of cardiac arrest, or by medical professionals who use pallets in a hospital setting.
Cardioversion is performed in a hospital setting using a cardioversion machine that monitors the heart rate before and after administering the shocks.
An injection of an antiarrhythmic drug, such as lidocaine , can also be used to treat sustained ventricular tachycardia and restore normal heart rhythm.
Prevention of Rapid Heart Rate Episodes
People with sustained or non-sustained ventricular tachycardia can be treated in different 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 increase in heart rate.
In this procedure, a doctor inserts catheters in your groin or neck and guides them through the blood vessels to your heart. The electrodes on the catheter tips can use heat, extreme cold or radiofrequency energy to damage (eliminate) the additional electrical path and prevent it from sending electrical signals.
Medications : antiarrhythmic medications can prevent a rapid heart rate when taken regularly.
Implantable cardioverter defibrillator : If you run the risk of having a life-threatening episode of ventricular tachycardia, your doctor may recommend an implantable cardioverter defibrillator (ICD).
The device, the size of a pager, is surgically implanted in the chest. The DCI continuously monitors your heartbeat, detects an increase in heart rate and applies accurately calibrated electric shocks, if necessary, to restore a normal heart rhythm.
A new type of ICD called subcutaneous implantable cardioverter defibrillator (S-DCI) is less invasive but larger than an ICD. Your doctor places the S-DCI under the skin on the side of the chest below the armpit.
It is connected to an electrode that runs along your sternum. You may be a candidate for an S-DCI if you have structural defects in your heart that prevent the wires from advancing to the heart through your blood vessels, or if you have other reasons to want to avoid traditional ICDs.
Surgery : Open heart surgery may be necessary in some cases to treat a process that contributes to ventricular tachycardia (for example, if there are blockages in the blood vessels).
Surgery is usually used only when other treatment options do not work or when surgery is needed to treat another heart disorder.
Treatment of an Underlying Disease
If another medical condition contributes to ventricular tachycardia, such as some form of heart disease, treating the underlying problem can prevent or minimize episodes of ventricular tachycardia.
Coping and Support
If you have a plan to deal with an episode of an accelerated heartbeat, you may feel calmer and more in control when one occurs. Talk to your doctor about:
- How to take your pulse and what 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
Make a list in advance that you can share with your doctor. Your list should include:
- Symptoms you have experienced, including those that may seem unrelated to your heart.
- Key personal information, including any major stress or recent changes in life.
- Medications, including vitamins or supplements.
Questions to ask your doctor
Make a list of your questions from most important to least important in case the time runs out. The basic questions you should ask your doctor include:
- What is probably causing my rapid heartbeat?
- What kind of tests do I need?
- What is the most appropriate treatment?
- What kind of risks does my heart condition create?
- How are we going to control my heart?
- How often will I need follow-up appointments?
- How will other conditions I have or the medications I take in my heart problem affect?
- Should I restrict my activities?
- Are there brochures or other printed material that I can take home with me? What websites do you recommend to visit?
In addition to the questions you have prepared to consult your doctor, do not hesitate to ask additional questions.
What to expect from your Doctor
Your doctor will probably ask you a series of questions. Being prepared to answer them can set aside time to review any point where you want to spend more time. Your doctor can ask:
- When did you start experiencing symptoms for the first time?
- How often have you had episodes of an accelerated heartbeat?
- How long are the episodes?
- Does something, like exercise, stress or caffeine, seem to trigger or worsen the episodes?
- Does anyone in your family have a heart condition or a history of arrhythmias?
- Has anyone in your family suffered a cardiac arrest or died suddenly?
- Do you smoke?
- How much alcohol or caffeine do you use?
- Do you use recreational drugs?
- Are you receiving treatment for high blood pressure, high cholesterol or other conditions that can affect your circulatory system?
- What medications do you take for these conditions and take them as prescribed?