Ventricular Tachycardia

Overview

Ventricular tachycardia (VT) is a rapid and potentially life-threatening heart rhythm disorder that originates from the lower chambers of the heart (ventricles). Normally, the electrical signals that initiate the heartbeat come from the upper chambers (atria). In ventricular tachycardia, however, the electrical signals start from the ventricles themselves and the heart beats more than 100 times per minute, usually 120-250 beats.

Ventricular tachycardia is a serious condition because rapid and ineffective heartbeats cannot pump enough blood to the body. The brain, kidneys, and other organs may not receive enough oxygen. Brief ventricular tachycardia (less than 30 seconds) may cause no symptoms in some people. Prolonged ventricular tachycardia, however, can be life-threatening and can transform into ventricular fibrillation (completely irregular beating of the heart). If left untreated, ventricular fibrillation leads to death within minutes.

Ventricular tachycardia usually occurs in people with heart disease. The risk is higher in people who have had a heart attack, have heart failure, or have cardiomyopathy (heart muscle diseases). Rarely, however, it can also occur in people without structural heart disease.

Early diagnosis and treatment are very important. Treatment options such as implantable cardioverter defibrillators (ICD), medication, and catheter ablation are available.

Symptoms

The symptoms of ventricular tachycardia vary depending on how fast the rhythm is, how long it lasts, and the severity of any underlying heart disease.

The most common ventricular tachycardia symptoms are:

• Heart palpitations. Feeling the heart racing or fluttering in the chest is the most common symptom. Palpitations may be regular or irregular.
• Dizziness and lightheadedness. When the brain does not receive enough blood, dizziness and a sense of unsteadiness develop.
• Shortness of breath. When the ventricles do not pump effectively, blood pools in the lungs and breathing becomes difficult.
• Chest pain or discomfort. A feeling of pressure, tightness, or pain in the chest may be felt.
• Fainting (syncope). When blood flow to the brain is severely reduced, loss of consciousness occurs. This indicates that the ventricular tachycardia is serious.
• Absence of pulse. A pulse may not be detectable or may feel very weak.
• Sudden cardiac arrest. This is the most serious situation. The heart completely stops pumping and the person suddenly loses consciousness. Without emergency intervention it is fatal.

In some people, ventricular tachycardia is brief and stops on its own. In this case, symptoms may be mild or absent. Prolonged ventricular tachycardia, however, requires emergency medical intervention.

When to Call Emergency Services

Call emergency services immediately in the following situations:

• If chest pain, severe shortness of breath, or fainting develops together with palpitations, call for emergency help.
• If the person is unconscious and has no pulse, begin cardiopulmonary resuscitation (CPR) immediately and call emergency services.
• If your implantable cardioverter defibrillator (ICD) has delivered a shock, notify your doctor. If it has delivered multiple shocks, go to the emergency room.

Causes and Risk Factors

The most common cause of ventricular tachycardia is damage to the heart muscle. Damaged heart tissue causes electrical signals to deviate from their normal path.

The most important causes and risk factors are:

• Heart attack (myocardial infarction). Having had a previous heart attack is the most important risk factor for ventricular tachycardia. Heart tissue damaged during a heart attack can lead to ventricular tachycardia even years later.
• Cardiomyopathy. This is disease of the heart muscle. Dilated cardiomyopathy, hypertrophic cardiomyopathy, and arrhythmogenic right ventricular cardiomyopathy increase the risk of ventricular tachycardia.
• Heart failure. When the heart pumps weakly, the risk of ventricular tachycardia increases.
• Heart valve disease. Aortic valve stenosis and insufficiency in particular can set the stage for ventricular tachycardia.
• Electrolyte imbalance. Abnormal levels of potassium, magnesium, or calcium in the blood can lead to heart rhythm disorders.
• Medications and substances. Some medications (particularly some antiarrhythmic drugs, paradoxically), cocaine, amphetamines, and excessive alcohol use can trigger ventricular tachycardia.
• Inherited conditions. Genetic diseases such as long QT syndrome, Brugada syndrome, and catecholaminergic polymorphic ventricular tachycardia can cause ventricular tachycardia at a young age.
• VT without structural heart disease. Rarely, ventricular tachycardia can develop even in a completely healthy heart. This is usually less dangerous but still requires evaluation.

Complications

If left untreated, ventricular tachycardia can lead to serious complications.

Possible risks of ventricular tachycardia may include:

• Ventricular fibrillation. Ventricular tachycardia can transform into ventricular fibrillation. In this state, the heart beats completely irregularly and ineffectively. Pumping stops and sudden death occurs.
• Sudden cardiac arrest. The heart suddenly and unexpectedly stops pumping. Without intervention within minutes, it is fatal.
• Heart failure. Recurrent ventricular tachycardia can weaken the heart muscle and lead to heart failure or worsen existing heart failure.
• Stroke. Ineffective heartbeats can cause blood clot formation inside the heart. A clot can break loose and block blood vessels in the brain.
• Organ damage. Insufficient blood flow to the brain, kidneys, and other organs can lead to permanent damage.

Diagnosis

Ventricular tachycardia is diagnosed with an electrocardiogram (ECG) and other tests.

The diagnostic process typically includes:

• Electrocardiogram (ECG). This is the most important diagnostic tool. An ECG taken during VT shows wide QRS complexes and a rapid regular or irregular rhythm. The ECG helps distinguish ventricular tachycardia from supraventricular tachycardia.
• Holter monitor. This is a portable ECG device worn for twenty-four hours or longer. Brief episodes of ventricular tachycardia can be captured.
• Event recorder. This is a small device that can be worn for weeks or months. You activate it when you feel symptoms.
• Echocardiography. This assesses the structure of the heart and its pumping strength. Areas damaged by heart attack, heart failure, and cardiomyopathy are detected.
• Coronary angiography. This is imaging of the heart vessels. It shows whether coronary artery disease is present.
• Cardiac MRI. This shows scar tissue and inflammation in the heart muscle in detail. It is helpful in diagnosing cardiomyopathy.
• Electrophysiology study. This is performed via cardiac catheterization. The source of ventricular tachycardia is identified and treatment is planned. It can also be used for treatment purposes.
• Genetic testing. If there is a family history of sudden death or if VT has developed at a young age without structural heart disease, genetic testing may be performed.

Treatment

Treatment for ventricular tachycardia varies depending on the urgency of the situation and the underlying cause.

Treatment options include:

• Emergency treatment. Prolonged ventricular tachycardia requires emergency intervention. If the person has lost consciousness or has no pulse, cardiopulmonary resuscitation (CPR) is started. Electrical cardioversion (electric shock) is applied. Antiarrhythmic medications (amiodarone, lidocaine) are given intravenously.
• Implantable cardioverter defibrillator (ICD). This is a small device surgically placed below the chest in people at high risk for ventricular tachycardia. It continuously monitors heart rhythm. When it detects a dangerous rhythm disorder, it automatically delivers an electrical shock to restore the heart to normal. The ICD is very effective at preventing sudden death and is life-saving in high-risk patients.
• Medication. Antiarrhythmic medications help prevent episodes of ventricular tachycardia. Medications such as beta blockers, amiodarone, sotalol, and mexiletine may be used. These medications have side effects, however, and can paradoxically cause rhythm disorders in some cases. They therefore need to be carefully monitored.
• Catheter ablation. A thin catheter is advanced to the heart through a vessel in the groin. The abnormal heart tissue that is the source of ventricular tachycardia is destroyed with radiofrequency energy. This is very successful in some types of VT without structural heart disease. It can also be used for VT after heart attack, but the success rate is lower. It is preferred in patients who do not respond to medication or who experience frequent ICD shocks.
• Treatment of the underlying cause. If coronary artery disease is present, stent placement or bypass surgery may be needed. Electrolyte imbalances are corrected. Heart failure treatment is optimized. Triggering medications are stopped.

Living with Ventricular Tachycardia

Most people diagnosed with ventricular tachycardia can lead normal lives with treatment. Certain important points should be kept in mind, however.

If you have been diagnosed with ventricular tachycardia, pay attention to the following:

• If you have an ICD, keep it maintained. Attend regular cardiology appointments. The ICD battery will need to be replaced after years. If your ICD delivers a shock, be sure to notify your doctor.
• Use your medications regularly. Antiarrhythmic medications or heart failure medications should be used regularly without interruption.
• Avoid triggers. Stay away from alcohol, caffeine, and stimulant substances. Learn stress management techniques.
• Maintain your electrolyte balance. Your potassium and magnesium levels should be checked regularly. Your doctor may recommend supplements if needed.
• Consult about exercise. Light to moderate exercise is safe for most people. An exercise program should be started with cardiology approval, however. Intense and competitive sports may be restricted.
• Family screening. If genetic VT syndromes are present, family members may also need to be evaluated.
• Educate those close to you. Have your family and those around you receive CPR (chest compressions and rescue breathing) training. Knowing what to do in an emergency can save lives.
• Driving restrictions. After ventricular tachycardia or an ICD shock, driving may be restricted for a certain period. This period varies by country and regulations. Discuss with your doctor.

Preparing for Your Appointment

What you can do:

• When did palpitation or fainting episodes start and how often do they occur?
• Have you had a heart attack before?
• Is there a family history of sudden death?
• List all medications and supplements you are taking.
• If you have an ICD, has it delivered shocks? When?
• Write your questions down in advance.

Questions you can ask your doctor:

• Is the diagnosis of ventricular tachycardia certain?
• Do I need an ICD?
• Is catheter ablation appropriate for me?
• What is my risk of sudden death?
• Can I exercise?
• Can I drive?
• Should my family be screened?

Your doctor may ask you:

• Have you experienced palpitations or fainting?
• Have you had a heart attack before?
• Do you have heart failure?
• Is there a family history of sudden death?
• What medications are you taking?
• Is there any drug use?