Topic Overview
If you want to learn about supraventricular tachycardia (SVT), go to the topic Supraventricular Tachycardia.
What is ventricular tachycardia?
Ventricular tachycardia is a type of fast heart rhythm that starts in the lower part of the heart (ventricles). The heart might beat more than 100 beats per minute.
Some forms of ventricular tachycardia may get worse and lead to ventricular fibrillation, which can be life-threatening. With ventricular fibrillation, the heartbeats are very fast and irregular. Ventricular fibrillation may cause cardiac arrest. In cardiac arrest, the heart stops pumping blood to the body. Cardiac arrest can cause sudden cardiac death.
What causes ventricular tachycardia?
Sometimes it is not known what causes ventricular tachycardia, especially when it occurs in young people. But in most cases ventricular tachycardia is caused by heart disease, such as a previous heart attack, a congenital heart defect, hypertrophic or dilated cardiomyopathy, or myocarditis. Sometimes ventricular tachycardia occurs after heart surgery. Inherited heart rhythm problems, such as long QT syndrome or Brugada syndrome, are rare causes of ventricular tachycardia.
Some medicines can cause ventricular tachycardia. These include antiarrhythmic medicines, other heart medicines, and antibiotics. Less common causes include blood imbalances, such as low potassium levels and other electrolyte imbalances.
Natural health products that contain a banned substance called ephedra, also known as ma huang, can trigger ventricular tachycardia. Illegal drugs (such as stimulants, like cocaine) also may cause ventricular tachycardia.
What are the symptoms?
In ventricular tachycardia, the heart beats too rapidly and the ventricles cannot effectively pump oxygen-rich blood to the rest of the body. Ventricular tachycardia can be life-threatening.
Symptoms include:
Call
911
or other emergency services immediately if you have any of these symptoms.
This heart rhythm is dangerous for most people. Some types of ventricular tachycardia can turn into ventricular fibrillation, which can cause sudden death.
How is ventricular tachycardia diagnosed?
If an electrocardiogram (EKG, ECG) can be done while ventricular tachycardia is occurring, it often provides the most useful information. An electrocardiogram is a tracing of the electrical activity of your heart. It is usually done along with a history and physical examination, lab tests, and a chest X-ray.
Because ventricular tachycardia can occur intermittently and may not always be captured by an EKG at the doctor's office, you may be asked to use a portable EKG to record your heart rhythm on a continuous basis. This is referred to by several names, including ambulatory electrocardiography, ambulatory EKG, Holter monitoring, 24-hour EKG, or cardiac event monitoring.
Your doctor may recommend further tests, including an echocardiogram, to evaluate your heart's function, a stress test or coronary angiogram to determine whether a part of the heart is not getting enough blood, and/or an electrophysiology (EP) study. An EP study can locate specific areas of heart tissue that give rise to abnormal electrical impulses, which may be causing the ventricular tachycardia. This information is used to determine the best treatment.
Genetic tests may be done if you might have a heart problem that runs in families. The tests look for heart problems that can cause ventricular tachycardia. If you have one of these heart problems, a genetic test may be recommended for your close relatives.
How is it treated?
The goals for treating ventricular tachycardia are to:footnote 1
- Prevent an abnormal heartbeat.
- Improve your symptoms.
- Prevent cardiac arrest (the heart stops beating) and sudden death.
It is very important that any causes of ventricular tachycardia be identified and treated, if possible. For example, if the ventricular tachycardia results from a medicine, the medicine needs to be stopped.
To improve symptoms and prevent the arrhythmia from recurring, you might take antiarrhythmic medicines.
In some cases a procedure called catheter ablation is used to destroy small areas of heart tissue responsible for the arrhythmia. Catheter ablation might make the arrhythmia happen less often or stop the arrhythmia from happening again.
Your doctor may recommend a device that can detect a life-threatening abnormal heartbeat and help restore a normal rhythm. This device is typically implanted and called an ICD, or implantable cardioverter-defibrillator. Or it may be worn as a vest.
If you are having symptoms and are in a sustained tachycardia, it is a medical emergency. You will need immediate treatment. You may need CPR or a shock from an automatic defibrillator (also known as an AED). Paramedics or your doctor may try intravenous medicines or electrical cardioversion to return your heart to a normal rhythm.
