Ventricular Tachycardia
What is Ventricular Tachycardia?
Frequent, sudden chest tightness and palpitations may be a sign of ventricular tachycardia (VT), a regular but abnormally fast heart rhythm that starts in the lower chambers of the heart, called the ventricles. Occasionally occurring in people with normal hearts, VT usually is seen in patients who have other serious heart problems.
Ventricular tachycardia (VT) is considered a serious condition that warrants aggressive monitoring and treatment, because some forms of VT may get worse if left untreated and lead to life-threatening ventricular fibrillation, an uncontrolled irregular heartbeat that can cause death. Ventricular fibrillation (VF) is the type of irregular heartbeat that is the leading cause of sudden cardiac death. In VF, the heartbeat is rapid and chaotic, which prevents the ventricles from pumping blood to the brain or body. During VF, the blood pressure falls to zero, and the person falls unconscious.
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 an early or late complication of a heart attack. It may also occur in patients with:
- Cardiomyopathy, a disease that weakens and enlarges the heart muscle
- Heart failure
- Heart surgery
- Myocarditis, or inflammation of the heart muscle
- Valvular heart disease
Ventricular tachycardia can occur in others who are exposed to
- Anti-arrhythmic medications
- Changes in blood chemistry (such as a low potassium level)
- Changes in the body's pH levels (acid-base)
- Lack of enough oxygen due to medical condition (e.g. sleep apnea) or injury
"Torsade de pointes" is a form of ventricular tachycardia that is often due to congenital heart disease or the use of certain medications.
Ventricular tachycardia is defined as a resting pulse rate of more than 100 beats per minute, with at least 3 irregular heartbeats in a row.
Symptoms include:
- Heart palpitations (or, feeling like your heart is racing, pounding or fluttering)
- Dizziness or lightheadedness
- Shortness of breath
- Chest tightness, pain, or angina
- Near-fainting or fainting , also called syncope
- Weak pulse or no pulse
Untreated VT may get worse and lead to ventricular fibrillation, the leading cause of sudden cardiac death.
If you are having symptoms and are in a sustained tachycardia, it is a medical emergency. You will require immediate treatment. Paramedics or your doctor may try intravenous medicines or electrical cardioversion to return your heart to a normal rhythm.
It is very important that any causes of ventricular tachycardia be identified and treated, if possible. For example, if a low potassium level is causing ventricular tachycardia, it needs to be corrected to prevent a recurrence. If the ventricular tachycardia results from a medicine, the medicine needs to be stopped. If heart disease is causing the ventricular tachycardia, the heart disease needs to be treated. Treating coronary artery disease provides the best treatment for ventricular tachycardia caused by a heart attack.
Long-term treatment of ventricular tachycardia may require the use of oral anti-arrhythmic medications. However, anti-arrhythmic medications may have severe side effects. Their use is decreasing in favor of other treatments.
A common treatment for many chronic (long-term) ventricular tachycardias consists of implanting a device called implantable cardioverter defibrillator (ICD). This device is placed under the skin in your chest, like a pacemaker, and continuously monitors your heart's rhythm. If ventricular tachycardia occurs, the ICD applies an electrical shock to the heart to restore a normal rhythm. After a normal rhythm is restored, the device goes back to continuous monitoring mode.
More ventricular tachycardias are being treated with cardiac ablation procedures. This is due to the availability of sophisticated tools that can navigate the heart's anatomy and reach the otherwise very remote ventricle, enabling a higher rate of efficacy than what is possible via manual catheter navigation techniques, with a greater degree of safety and less exposure to x-ray radiation.
Radiofrequency catheter ablation can also minimize the need for ICD rescue therapy, possibly reduce the number of electrical shocks experienced by patients with ICDs and, in certain cases, cure tachycardias.
Arrhythmia Quiz: Questions to Ask Your Doctor about Ventricular Tachycardia.
- What is causing the arrhythmia?
- How serious is the problem?
- What are the treatment options?
- Should I have an angiogram done to look for blocked arteries?
- Is it possible to ablate this arrhythmia?
- Would drug therapy be helpful in this case?
- Is an implantable defibrillator needed?
