Ventricular Tachycardia

Ventricular tachycardia is a very fast heart rhythm that begins in the ventricles. The ventricles are the two lower chambers of the heart. They fill with blood from the atria, or top chambers of the heart, and send it to the rest of the body. Ventricular tachycardia is a pulse of more than 100 beats per minute with at least three irregular heartbeats in a row. It is caused by a malfunction in the heart’s electrical system.

Your heart rate is controlled by electrical impulses that trigger each contraction and determine the rhythm of the heart. When this process is disrupted and the electrical signals are sent too quickly, ventricular tachycardia can occur. The rapid heartbeat doesn’t give the ventricles enough to time to fill with blood before the heart contracts. As a result, the heart may not be able to pump enough blood to the rest of the body.

Ventricular tachycardia may only last for a few seconds or for much longer. It doesn’t always cause symptoms, but when symptoms do occur, they may include lightheadedness, dizziness, and fainting. The condition most commonly affects people who have heart disorders, such as coronary artery disease and cardiomyopathy.

Ventricular tachycardia may eventually lead to ventricular fibrillation, which is characterized by a rapid, inadequate heart rhythm. In this condition, the heartbeat is so fast and irregular that it causes the heart to stop working. To prevent this complication from occurring, it’s important to get immediate treatment for ventricular tachycardia.

Symptoms of ventricular tachycardia include:

• dizziness
• fainting
• fatigue
• chest pain
• shortness of breath

The exact cause of ventricular tachycardia isn’t always known. In most cases, however, it is triggered by another heart condition.

Known causes of ventricular tachycardia include:

• cardiomyopathy, which weakens the heart muscle
• structural heart disease, which can be the result of heart damage from a previous heart attack
• ischemic heart disease, which is caused by lack of blood flow to the heart
• heart failure, which is characterized by the heart’s inability to pump an adequate amount of blood

Certain forms of ventricular tachycardia are inherited, which means they’re passed down from a parent to a child. These include:

• catecholaminergic polymorphic ventricular tachycardia
• arrhythmogenic right ventricular dysplasia

In rare cases, ventricular tachycardia can be caused by certain medications, excessive caffeine or alcohol consumption, and intense exercise.

Classification of ventricular tachycardia is based on:

• duration, or the length of the episode
• morphology, or the heartbeat pattern
• hemodynamic effect, or the effect on the heart’s ability to pump blood

The types of ventricular tachycardia are as follows:

• nonsustained, which stops spontaneously without causing problems with blood flow
• sustained, which lasts longer than 30 seconds and causes decreased blood flow
• monomorphic, in which each heartbeat resembles the next one
• polymorphic, in which heartbeats vary

You may be more at risk for ventricular tachycardia if you:

• are an older adult
• have a heart condition
• have had a previous heart attack
• have a family history of ventricular tachycardia

Your doctor will make a diagnosis by performing a physical exam and running certain tests. During the exam, your doctor will listen to your heart and ask you about your symptoms. They’ll also check your pulse and blood pressure.

If ventricular tachycardia is suspected, your doctor will order certain tests. These may include:

• Electrocardiogram (ECG): This test measures the electrical activity of the heart. It records a picture of the heart’s electrical activity, allowing doctors to spot abnormalities.
• Cardiac MRI (CMRI): This imaging test uses strong magnets and radio waves to produce clear, cross-sectional images of the heart. This gives doctors the ability to look at the heart in more detail.
• Transesophageal echocardiography: In this procedure, an ultrasound probe is inserted into the esophagus. The probe uses high-frequency sound waves to create detailed images of the heart. These pictures give doctors a better view of the heart structures and valves.

The goal of treatment is to correct the heart rhythm immediately and to prevent future episodes. In an emergency, treatment for ventricular tachycardia may include:

• CPR
• electrical defibrillation
• electric shock
• antiarrhythmic medication

Long-term treatment may include oral antiarrhythmic medication. However, these drugs aren’t always prescribed because they can cause severe side effects. Other long-term treatment options include:

• Implantable cardioverter defibrillator: This device is placed in the chest or abdomen to correct abnormal heart rhythms.
• Radiofrequency ablation: In this procedure, an electrical current produced by a radio wave destroys abnormal tissues that are causing the heart to beat incorrectly.
• Cardiac-resynchronization therapy: This procedure involves the implantation of a device that helps regulate the heartbeat.

The outlook for people with ventricular tachycardia is usually good if treatment is received quickly. When the disorder goes untreated, however, people are at a greater risk for sudden cardiac arrest and other serious conditions. Implanted devices can help prevent complications from occurring. Once in place, these devices can keep the heart beating and functioning properly.