Medically reviewed by Dr. Payal Kohli, M.D., FACC — Written by Adam Rowden on July 28, 2021
- Overview
- Types
- Causes
- Symptoms
- Contacting a doctor
- Complications
- Outlook
- Diagnosis
- Treatment
- Prevention
- Summary
Ventricular tachycardia (VT) is a heart condition that begins in the lower chambers of the heart. It causes the heart to beat very quickly at a rate of over 100 beats per minute. Symptoms of VT include heart palpitations, dizziness, chest pain, and shortness of breath.
The most common causeTrusted Source of VT is an underlying condition called ischemic heart disease (IHD). However, VT may also occur due to low levels of magnesium.
What is VT?
The human heart consists of four chambers. The two upper chambers are the atria, and the two lower ones are the ventricles.
These chambers work together to pump blood around the body. The heart beats around 100,000 times per day, and a regular heartbeat is usually between 60 and 100 beats per minute.
VT is a fast heart rate that begins in the ventricles.
Healthcare professionals categorize VT as a heart rate that is greater than 100 beats per minuteTrusted Source and has a characteristic appearance on an electrocardiogram (EKG).
While VT varies in severity, it is usually a medical emergency, whether a person is tolerating it or not.
This is because the condition can quickly turn into ventricular fibrillation, which is the most serious cardiac arrhythmia and can be life threatening.
Types
There are two main types of VT: non-sustained VT (NSVT) and sustained VT (SVT).
Experts define NSVT as three or more consecutive ventricular beats at a rate of over 100 beats per minute lasting less than 30 secondsTrusted Source.
SVT, on the other hand, is what experts define as three or more consecutive ventricular beats at a rate of over 100 beats per minute lasting more than 30 secondsTrusted Source.
Catecholaminergic polymorphic VT
Catecholaminergic polymorphic VT (CPVT) is an inherited condition that can cause an abnormally fast heartbeat.
It may lead to a loss of consciousness or even sudden death. This is because the heart is not pumping enough blood to the body.
This condition is more common in people who have a family history of fainting.
Idiopathic VT
Sometimes, VT can occur in people with no known heart disease.
This often happens due to an irritable focus, which is when cells outside the sinus node start creating an electrical impulse automatically on their own.
This type of VT is easier to treat.
Causes
There may be a link between VT and conditions that affect the heart’s electrical conduction system. However, it is not always clear what leads to VT.
The most common causeTrusted Source of VT is underlying IHD, but other heart conditions can also trigger it.
Common causes of VT include:
- a lack of blood flow to the heart, which deprives it of oxygen
- conditions of the heart muscle that affect its structure
- side effects of some medications
- use of illegal drugs, such as cocaine
- sarcoidosis, which is an inflammatory condition that affects the skin or body tissues
- structural heart disease
- damage to the heart due to a heart attack
- heart failure
Triggers
Some triggers of VT includeTrusted Source:
- low levels of potassium and magnesium
- high levels of potassium
- a lack of blood flow to the heart muscle
- stimulants or toxins
Symptoms
Common symptoms of VT include:
- heart rate that is higher than 100 beats per minute
- heart palpitations
- chest pain
- dizziness
- sweating
- shortness of breath
- nausea
- lightheadedness
In some cases, a person with VT may become unconscious or experience cardiac arrest.
When to contact a doctor
A person should contact a doctor immediately if they notice they have an abnormal heartbeat.
They should also seek medical attention if they experience the symptoms of VT. This way, a healthcare professional can make an early diagnosis and restore a normal heart rhythm.
Emergency care
If a person experiences any of the following symptoms, they should seek emergency care:
- chest pain that lasts for longer than a few minutes
- difficulty breathing
- fainting or nearly fainting
Complications
Possible complications of VT include:
- fainting
- heart failure
- pulmonary edema
- low blood pressure
- organ failure
For some people, untreated VT can lead to sudden cardiac arrest, which can be life threatening.
Outlook
VT typically requires treatment. The outlook for people with VT is usually good if they receive treatment quickly.
If a person does not seek treatment for VT, it may increase their risk of cardiac arrest and other serious conditions.
Diagnosis
A doctor will carry out a number of checks to diagnose VT.
They will start by performing a physical exam. During this exam, they will listen to the rhythm of a person’s heart with a stethoscope as well as check their pulse and blood pressure.
If the doctor suspects VT, they may use certain tests to confirm the diagnosis. These include:
- Echocardiogram: This test involves taking an ultrasound image of the heart.
- Stress test: A cardiac stress test allows doctors to analyze the heart during different levels of physical activity.
- EKG: This test measures and records a picture of the heart’s electrical activity. Doctors use EKG to spot abnormalities in the heart.
- Cardiac MRI: This imaging test uses strong magnets and radio waves to produce a clear, cross-sectional image of the heart, allowing a doctor to examine the heart in great detail.
Treatment
Seeking treatment for VT can improve a person’s outlook.
Antiarrhythmic drugs
Healthcare professionals may treat VT with a range of antiarrhythmic drugs. A person can take these drugs orally during long-term treatment or intravenously in an emergency.
Antiarrhythmic drugs may also help prevent heart attack and stroke. Additionally, they may prevent complications and slow the progression of coronary heart disease.
Implantable cardioverter-defibrillator
A healthcare professional may use an implantable cardioverter-defibrillator (ICD)Trusted Source to help prevent complications.
ICDs ensure that the heart can return to its normal rhythm and that it functions properly even if it goes into VT.
An ICD is a battery-powered device that sits under the skin and monitors a person’s heart rate. If it recognizes an abnormal heart rhythm, it emits an electric shock to reset the heart to a normal rhythm.
Catheter ablation
Healthcare professionals may decide to use catheter ablation to restore a regular rhythm to a person’s heart. Doctors sometimes refer to this procedure as radiofrequency ablation.
The procedure uses radiofrequency energy that is similar to microwave heat, to destroy small parts of the heart’s tissue.
During the procedure, a surgeon inserts long, thin tubes called catheters into blood vessels before guiding the tubes to the heart.
The surgeon then sends mild, painless radiofrequency energy to the tissue that is causing the irregular heartbeat. This destroys the cells in that exact area, restoring a regular heartbeat.
Treating cardiac arrest
If a person experiences cardiac arrest due to their VT and their heart stops beating, they will need immediate defibrillation, or electric shock treatment.
A healthcare professional may combine this with CPR in order to restart the person’s heart.
Prevention
Heart disease is a common cause of VT.
There are a number of behavioral changes a person can make to help lower their risk of heart disease. These includeTrusted Source:
- following a balanced diet
- eating less foods high in saturated fats and trans fats
- lowering alcohol consumption
- limiting sugar intake
- exercising regularly
- quitting smoking
Summary
VT causes the heart to beat very quickly at a rate of over 100 beats per minute. It begins in the ventricles of the heart and can cause a variety of symptoms, including heart palpitations, dizziness, chest pain, and shortness of breath.
A doctor may treat VT with antiarrhythmic drugs, an ICD, or a catheter ablation.
VT may cause no additional health complications. However, in some people, it may increase their risk of sudden cardiac arrest and death. Therefore, a workup and treatment are warranted in almost every case.
One of the main causes of VT is underlying IHD. A person can help prevent heart disease by eating a balanced diet, avoiding smoking and drinking alcohol, and exercising regularly.