It is a problem with the electrical system of the heart that causes abnormal heart rhythms.
Ventricular arrhythmias begin in the two lower chambers of the heart, the ventricles.
Normally, your heartbeat begins in the atria (upper chambers of the heart) and travels throughout the heart through its electrical system.
Electrical impulses travel through the atria, causing them to contract and pump blood to the ventricles. The ventricles contract to pump blood to the body.
Ventricular arrhythmias occur when the normal pattern of electrical signals is disrupted, causing the heart to beat too fast.
These too-fast heart rates can prevent the heart from effectively pumping blood to the body. The reduced blood flow restricts oxygen supply to other organs, including the brain , which can cause fainting ( syncope ) and other serious symptoms.
The two most common types of ventricular arrhythmias, tachycardia and fibrillation, can be life-threatening and generally require immediate medical attention.
Types of ventricular arrhythmias
Arrhythmias that begin in the ventricles (lower chambers of the heart) can be life-threatening and require immediate medical attention. Ventricular tachycardia (VT) can lead to ventricular fibrillation (VFib).
This type of arrhythmia is a fast and regular heartbeat (more than 100 beats per minute) that can last a few seconds or more. VT prevents the ventricles from fully contracting, which means less blood is pumped into the body.
The longer the VT lasts, the greater the risk of it becoming VFib. Learn more about ventricular tachycardia.
This type of fast heartbeat is very abnormal and causes the ventricles to vibrate ineffectively. During VFib, the heart cannot pump blood, causing a lack of oxygen in the brain and body.
VFib can cause sudden cardiac arrest and death within minutes, without emergency care. Learn more about ventricular fibrillation.
Torsades de pointes
This type of VT develops in people with long QT syndrome, an electrical problem that causes the heart to take longer to recharge after each beat.
Torsades de pointes causes a rapid heart rate, which restricts oxygen-rich blood flow. Lack of oxygen can cause sudden fainting spells.
Short bouts of torsades de pointes (less than a minute) can often resolve on their own to bring you back to consciousness. If the episode lasts longer, it can lead to VFib and serious complications.
Symptoms of ventricular arrhythmia
The symptoms of ventricular tachycardia (VT) and ventricular fibrillation (VFib) are similar. On TV, you may experience few or no symptoms, or they may come and go. In VFib, symptoms can come on suddenly and get worse quickly.
Symptoms of both types of ventricular arrhythmias include:
- Chest discomfort or pain (angina pectoris).
- Fainting (syncope).
- Heart palpitations, a sensation of feeling your heart beat.
- Dizziness or vertigo
- Short of breath.
When ventricular fibrillation occurs, the person may experience one or more of these symptoms for up to an hour before suddenly fainting or collapsing. If you or someone else experiences any of these symptoms, it is essential to get medical help right away.
Complications of ventricular arrhythmias include:
- Organ damage : These arrhythmias can prevent enough oxygen-rich blood from reaching the body, which can damage the brain, kidneys, liver, lungs, and other organs.
- Sudden Cardiac Arrest (SCA): Rapid and irregular heartbeats in the ventricles can cause them to vibrate uselessly, unable to pump blood. SCA can lead to death in a matter of minutes without emergency medical attention.
Causes of ventricular arrhythmias
Ventricular arrhythmias occur due to problems with the electrical signals that control your heart rate and rhythm, such as:
- Delayed or blocked electrical signals.
- Electrical signals that travel erratically through the heart.
- Electrical signals that begin outside the atria.
- Causes of Ventricular Tachycardia.
- Damage to the heart muscle after a heart attack.
- Heart conditions including cardiomyopathy, congenital heart disease, heart failure, and valvular heart disease.
- Heart surgery.
- Lack of oxygen.
- Low levels of certain electrolytes, such as sodium or potassium.
- Medicines used to treat arrhythmias.
Causes of ventricular fibrillation
Ventricular fibrillation shares some of the same causes as ventricular tachycardia, but the most common cause is a heart attack. Additional causes and risk factors include:
- Certain medications
- Injury to the heart.
- Narrow coronary (heart) arteries.
Diagnostic tests for ventricular arrhythmias
With specialized experience in advanced diagnostic tools, our arrhythmia physicians are experts in interpreting our test results, including:
- Electrocardiogram (EKG) : This test measures the electrical activity of your heart for a short time, using a monitor with electrodes attached to your body. At Stanford, we offer different types of EKGs, depending on your individual symptoms and your overall health.
- Electrophysiology Study : This catheter-based test evaluates these serious ventricular arrhythmias by recording the electrical activity of the heart from inside the heart.
- Holter and event monitors : Portable ECG monitors record your heart’s electrical activity for longer to detect intermittent arrhythmias. Holter monitors record continuously for up to 48 hours. Event monitors record abnormal activity for several weeks, but only when it occurs.
- Implantable loop recorder: We implant a small device just under the skin in your chest to measure the electrical activity of your heart for up to two years.
Treatment for ventricular arrhythmia
Execution of advances in ablation for ventricular tachycardia and ventricular fibrillation, including endocardial, epicardial and hybrid surgical catheter ablation.
Performing a comprehensive evaluation to interpret images and other test results provides detailed information to determine your treatment options as each requires individual care and treatment depending on the causes.