Ventricular tachycardia

Ventricular tachycardia is a type of abnormal heartbeat (arrhythmia) in which your heart beats too fast. Most people who get ventricular tachycardia have already had some problems with their heart, such as a previous heart attack or heart muscle disease (cardiomyopathy). 

What happens in ventricular tachycardia?

Your heartbeat is controlled by electrical signals (impulses) that travel through your heart and make it contract. In ventricular tachycardia, faulty electrical signals in your ventricles (the lower chambers of your heart) cause your heart to beat faster than normal.

Normally, at rest, your heart will beat between 60 and 100 times a minute. If you have ventricular tachycardia, it beats over 100 times per minute – often more than 120 times per minute. However, although your heart might be beating faster, it’s not pumping blood so efficiently. Because your ventricles are beating too quickly, they might not have enough time to fill up with blood between beats. Your heart then can’t pump enough blood to the rest of your body.

Attacks of ventricular tachycardia can sometimes stop on their own after a few seconds (non-sustained). But if it carries on for longer than 30 seconds (sustained ventricular tachycardia), it will usually cause symptoms and you may need treatment to stop it.

Watch our animation to see how your heart beats normally and what happens in ventricular tachycardia.

Symptoms of ventricular tachycardia

Symptoms of ventricular tachycardia can include:

• palpitations (a thumping or fluttering feeling in your chest)
• chest pain or discomfort
• difficulty breathing
• feeling sick
• sweating a lot
• feeling light-headed or passing out

If you just have brief episodes of ventricular tachycardia that stop on their own, you may not get any symptoms at all.

If you do get any of these symptoms and they’re relatively mild, see your Doctor. If the symptoms are severe and come on suddenly, you should go to your nearest accident and emergency department.

Complications of ventricular tachycardia

It’s important to get prompt treatment for ventricular tachycardia. If it lasts for a long time or is very fast and not treated quickly, it can be fatal, causing ‘sudden cardiac death’.

Ventricular tachycardia can sometimes lead to another type of arrhythmia called ventricular fibrillation. This is when electrical signals fire off in different areas of your ventricles at the same time and cause an extremely fast, life-threatening heart rhythm. It results in your heart being unable to beat properly which means little or no blood is pumped out. Ventricular fibrillation is more likely to lead to sudden cardiac death, but it can be reversed if you get treatment straight away.

Watch our animation to see what happens in ventricular fibrillation.

https://youtu.be/IFIu0QBwM0I 

Diagnosis of ventricular tachycardia

If you see your Doctor with symptoms of an arrhythmia, they’ll want to ask about your symptoms and examine you. They’ll also ask about your medical history. Your doctor will check your pulse and blood pressure, and listen to your heartbeat.

You’ll need to have a test called an electrocardiogram (ECG). An ECG records the electrical activity of your heart to see how well it's working.

You may need to have an ambulatory ECG. This records your heartbeat over a period of 24 hours or more while you go about your normal daily activities. If it’s not been possible to record the abnormal heartbeat using external monitors, you might need to have an implantable loop recorder. This is a small device which is implanted under your skin and is programmed to record abnormal rhythms. Your GP will need to refer you to a cardiologist (a doctor specialising in diagnosing and treating heart conditions) to have this.

If your ECG test shows you have ventricular tachycardia, your doctor will ask you to have some more tests, which may include the following.

• Blood tests. These will check for certain substances in your blood that can be associated with ventricular tachycardia or other conditions that may be causing your symptoms.
• Echocardiogram. This is a type of scan that uses ultrasound (sound waves) to produce a clear image of your heart muscles and valves to see how well it’s working.
• Chest X-ray. This allows your doctor to look for any changes in your heart or lungs that might be causing the problem.
• An exercise ECG (cardiac stress test). This is when you have an ECG while you exercise on a treadmill to see if it triggers an arrhythmia. 
• Coronary angiography. This is a type of X-ray that uses a dye to show your coronary arteries. It can show if they’re narrowed or blocked.
• An MRI scan of your heart. This is to check if you have any problem with your heart muscle.

Treatment for ventricular tachycardia

Treatment for ventricular tachycardia aims to stop the attack and get your heart back to a normal rhythm, and then prevent you getting further attacks. Sometimes episodes of ventricular tachycardia stop on their own.

The type of treatment you have will depend on how serious your ventricular tachycardia is, and what’s causing it. If it’s caused by an underlying health condition, your doctor will also treat that. 

Stopping an attack

If your heart stops due to ventricular tachycardia (a cardiac arrest), you’ll need immediate defibrillation (electric shock treatment), along with cardiopulmonary resuscitation (CPR) to re-start your heart.

If defibrillation isn’t needed, but your ventricular tachycardia has been going on for some time, you may have one or more of the following to stop it.

• Electrical cardioversion. This uses an electric shock to restore your rapid heartbeat back to normal. It’s similar to defibrillation, but the electrical burst can be timed. 
• Antiarrhythmic medicine, such as amiodarone through a drip in your arm. 
• Overdrive pacing. This is where a thin tube is placed on your skin or gently guided through a vein to your heart. It gives electrical impulses to control your heartbeat.

Long-term treatment

If your doctor thinks you may be at ongoing risk of ventricular tachycardia attacks, they’ll offer you treatment aimed at preventing or stopping any further attacks. What treatment you are offered will depend on your own individual circumstances. Your doctor will discuss your options with you. They may include one or more of the following. 

Implantable cardioverter defibrillator (ICD)

Most people who have previously had a ventricular tachycardia attack for which there isn’t a treatable cause, have an implantable cardioverter defibrillator (ICD) fitted. An ICD is a device that’s put under your skin or muscle, usually near your collarbone, and has leads into your heart. It can detect an attack of ventricular tachycardia starting and then deliver electrical pulses or shocks to restore your heartbeat to normal. For more information, see our FAQ: What happens when my ICD delivers a shock?

You’ll usually have check-ups about every three months to check how well your ICD is working. Some types of ICD allow your clinic to monitor its effect remotely using software installed in your home.

Medicines

You might be prescribed medicines instead of or in addition to an ICD to help control your heart rate and rhythm. Medicines you may have include:

• beta-blockers
• calcium-channel blockers
• other antiarrhythmic medicines such as amiodarone

Always read the patient information leaflet that comes with your medicine and ask your doctor if you have any questions.

Radiofrequency ablation

Depending on what’s causing your ventricular tachycardia, you may be given the option of having radiofrequency ablation to stop future attacks. These procedures use radiofrequency energy to destroy the tissue in your heart that's disrupting or causing abnormal electrical signals.

You might have catheter ablation, in which a thin tube (an electrode catheter) is passed up to your heart via a vein in your groin. Or you might have epicardial ablation, in which the catheter is passed through the skin of your chest and into the outer layer of your heart wall.

Lifestyle changes

In addition to the treatments outlined above, your doctor may advise you to make some lifestyle changes to reduce your risk of further attacks. These may include making some changes to your diet, or avoiding caffeine if this seems to set off your symptoms. In certain situations, you may be advised to avoid strenuous physical activity, at least until your symptoms are under control.

If you smoke, it’s always advisable to give up – and this is particularly so if you have ventricular tachycardia. Giving up smoking can reduce your risk of sudden cardiac death from ventricular tachycardia.

Causes of ventricular tachycardia

Ventricular tachycardia usually happens in people who have already had significant problems with their heart. These are most often:

• a previous heart attack
• coronary heart disease 
• heart muscle disease (cardiomyopathy)

Other problems affecting the structure of your heart may also lead to ventricular tachycardia. These include problems that you’re born with (congenital heart disease) such as the conditions called long QT syndrome and Brugada syndrome.

It’s also possible to get ventricular tachycardia if you don’t have any underlying problems with your heart. Certain things can trigger ventricular tachycardia, if you’re already at risk. These may include:

• some types of medicine
• physical or mental stress
• having too much caffeine
• illegal drugs such as cocaine
• imbalances of certain chemicals in your blood (for example, too low a level of potassium, calcium or magnesium)