Ventricular tachycardia

The different types of arrhythmia

About ventricular tachycardia

Tachycardia means a rapid heart rate, usually of more than 100 beats per minute. Ventricular means that the problem starts in the lower chambers of your heart (the ventricles).

Ventricular tachycardia can be life-threatening, especially if other heart problems already exist, such as heart disease or a history of heart attack. However, ventricular tachycardia can occur with an apparently normal heart. This is usually a less serious condition.

What happens in ventricular tachycardia?

Your heartbeat is controlled by electrical signals (impulses), which start in a part of your heart wall called the sinus node and travel through your heart making it contract. The signals travel from your atria (the upper chambers of your heart) to your ventricles (the lower chambers of your heart) through an area called the atrioventricular (AV) node. The AV node helps to synchronise the pumping action of your atria and ventricles.

Ventricular tachycardia occurs when the electrical signals in your ventricles become disorganised, overriding your heart's normal rate and rhythm. This causes your ventricles to contract faster than normal. Your heart then pumps out blood quicker than normal and your ventricles may not have enough time to fill up properly with blood.


Symptoms of ventricular tachycardia

You will generally feel well in between attacks. Symptoms during an attack of ventricular tachycardia may include:

  • palpitations – you're aware of your heart beating faster or more forcefully
  • chest pain or discomfort
  • shortness of breath
  • severe dizziness
  • fainting

If you get these symptoms, this is known as ventricular tachycardia with a pulse. There is another form of ventricular tachycardia where your heart stops pumping blood around your body (pulseless ventricular tachycardia). This is an emergency situation.

These symptoms may be caused by problems other than ventricular tachycardia, however, if you have them, seek urgent medical advice.

Complications of ventricular tachycardia

If you have heart disease or have had a heart attack in the past, ventricular tachycardia can lead to a life-threatening condition called ventricular fibrillation, which causes cardiac arrest. Cardiac arrest is when your heart stops pumping blood around your body. This is life-threatening and usually fatal unless corrected within a minute or two.

Causes of ventricular tachycardia

Many conditions that affect your heart or blood circulation can cause ventricular tachycardia. These include:

  • heart valve disease
  • heart muscle disease (cardiomyopathy)
  • coronary artery disease
  • heart problems since birth (congenital heart disease)

Certain factors can trigger ventricular tachycardia, such as:

  • certain medicines or illegal drugs
  • emotional or physical stress (including exercise)

You may develop ventricular tachycardia without having any apparent underlying cause or risk factor.

Diagnosis of ventricular tachycardia

Ventricular tachycardia is diagnosed with an electrocardiogram (ECG). An ECG is a test that records the electrical activity of your heart. An ECG will be done if you have had a heart attack, have suddenly become unwell with symptoms, such as chest pain and fainting, or if there is anything else to suggest a heart problem.

If you have symptoms, such as palpitations or fainting episodes, your GP or cardiologist (a doctor that specialises in heart conditions) will ask you about your medical history and may suggest you have an ECG. If your ECG test suggests you have ventricular tachycardia, you will need to go to hospital immediately for the following tests.

  • Blood tests.
  • Echocardiogram. An ultrasound scan of your heart providing a clear image of your heart muscles and valves that shows how well your heart is working.
  • Ambulatory ECG. This takes a recording of your heartbeat while you go about your normal daily activities, over 24 hours or longer.
  • Electrophysiological study. This uses electrode catheters to record and stimulate your heart, allowing your doctor to check your heart's electrical activity in greater detail than an ECG.
  • Angiogram. A dye visible on X-rays is injected into your coronary arteries to show up any narrowing or blockages.

Treatment of ventricular tachycardia

Treatment of ventricular tachycardia is aimed at stopping attacks, treating symptoms and preventing future attacks.

Emergency treatment

A ventricular tachycardia attack can sometimes stop by itself. However, if the attack is sustained (lasts for longer than 30 seconds) you may need hospital treatment to stop it.

If your symptoms aren't severe, you may be given an antiarrhythmic medicine, such as amiodarone, through a drip in your arm to get your heart rhythm back to normal. This is known as pharmacological cardioversion.

If you're having symptoms, such as low blood pressure, breathlessness, dizziness and chest pain, or are falling unconscious, it means that there may be an immediate risk of your condition getting worse and your heart going into ventricular fibrillation. This can be fatal. You will need to have an emergency procedure called electrical (DC) cardioversion. In this procedure, a controlled electrical current is applied to your chest via a machine called a defibrillator to help restore your heart to its normal rhythm. You will have a general anaesthetic for DC cardioversion, which means you will be asleep during the procedure.

Medicines

There are several different types of medicine that can help control your heart rate and rhythm, including beta-blockers, calcium-channel blockers and antiarrhythmic medicines.

If your symptoms aren't severe, your doctor may prescribe a combination of any of these medicines. You may have to take them for just a short period of time until you have another treatment to restore your heart rhythm, such as DC cardioversion. Alternatively, you may be given medicine to take just when you get symptoms.

Always ask your doctor for advice and read the patient information leaflet that comes with your medicine.

Surgery

Catheter ablation is now a preferred option for many people with ventricular tachycardia. This is when small tubes called electrode catheters are passed into the veins in your groin and threaded up to your heart. Abnormal tissue that is disrupting the electrical signals in your heart is burnt or frozen away.

Implantable cardioverter defibrillator (ICD) treatment

You may need to have an implantable cardioverter defibrillator (ICD) fitted to detect ventricular tachycardia and restore your heart to a regular, slower rhythm in the event of future attacks.

An ICD is a device implanted under your skin, usually near your collarbone on your left side. It monitors your heartbeat and when it detects that your heart rate is too fast, it will carry out at least one of three treatments described below.

  • Pacing. Your ICD stimulates your heart electrically to correct attacks of ventricular tachycardia. This is known as override pacing.
  • DC cardioversion. If ventricular tachycardia continues despite the pacing treatment, your ICD will deliver an internal shock to correct it.
  • Defibrillation. If the rhythm problem continues even after the DC cardioversion, the ICD will deliver a larger internal shock, called defibrillation.

Can I drive if I have ventricular tachycardia?

Answer

There are some circumstances in which you will not be allowed to drive. You must follow your doctor's advice and check with the Driver and Vehicle Licensing Agency (DVLA) before you continue to drive any vehicle.

Explanation

The DVLA advice states that you must not drive if you have an arrhythmia (an abnormal heartbeat) that has caused, or is likely to cause, incapacity (an inability to drive, for example, because you faint at the wheel). However, you can drive again if an underlying cause for your arrhythmia has been identified and it has been controlled for at least four weeks.

If you have catheter ablation, you must not drive a small vehicle (car or motorbike) for at least two days after the procedure, but you need to follow your doctor’s advice about when to drive again. However, if you hold a licence for large goods vehicles (LGVs) or passenger-carrying vehicles (PCVs), you must not drive these for at least two weeks and possibly up to six weeks, depending on your individual circumstances. Discuss this with your doctor so that you can plan ahead if you won’t be allowed to drive soon after the procedure.

If you have an implantable cardioverter defibrillator (ICD) fitted, you might need to tell the DVLA. Depending on your individual circumstances, you may not be allowed to drive for six months after having the ICD fitted. In some cases, this time period may be extended. You will be offered regular check-ups after the ICD is fitted and you can discuss with your doctor when you will be allowed to drive again. Not having your ICD regularly reviewed may slow your return to driving.

If you hold a driving licence that allows you to drive LGVs or PCVs, you will no longer be allowed to hold this licence after you have your ICD fitted.

Why do I need an implantable cardioverter defibrillator (ICD) if I haven't had any symptoms of tachycardia?

Answer

An implantable cardioverter defibrillator (ICD) can be used if your doctor thinks that you’re at a high risk of developing ventricular tachycardia or fibrillation, even if you haven't had symptoms yet. The device acts as a safeguard by giving you immediate treatment if you have an episode of arrhythmia.

Explanation

An ICD is a device that can monitor your heart rhythm and restore your heartbeat to a normal rate if you have an episode of ventricular tachycardia.

Getting you to have prompt treatment for ventricular tachycardia is important, especially if it develops into ventricular fibrillation, which can be more serious. Without it, your heart may stop beating altogether (cardiac arrest). If your doctor thinks that you’re at high risk for ventricular tachycardia or fibrillation, your doctor may suggest you have an ICD fitted. This ensures that if you ever have an episode of arrhythmia, the device can provide you with immediate treatment.

You may be at high risk if you have:

  • previously had a heart attack
  • disease of the heart muscle
  • an inherited condition of the heart

Not everyone who has one of these conditions will need an ICD. Talk to your doctor before you have the procedure to make sure you understand the risks, benefits and possible alternatives.

What is torsades de pointes?

Answer

Torsades de pointes is a form of ventricular tachycardia. It occurs typically in people who have a condition known as long QT syndrome.

Explanation

Your heartbeat is controlled by electrical signals (impulses). In long QT syndrome, the time it takes for your heart to recharge after each heartbeat is longer than normal. This can cause sudden, uncontrollable arrhythmias in response to exercise or stress.

There are several factors that can also cause long QT syndrome.

  • An inherited heart condition.
  • Certain medicines, such as antiarrhythmic medicines or antidepressants.
  • Lack of calcium or magnesium.
  • Poisoning with insecticides or heavy metals.
  • A major loss of potassium or sodium ions from your bloodstream because of severe diarrhoea or vomiting.
  • Eating disorders, such as anorexia nervosa and bulimia, and some thyroid disorders.

If you have long QT syndrome, you're more likely to get torsades de pointes. Episodes of torsades de pointes can be triggered by stress, physical exercise or when something makes you jump, such as an alarm going off. It often stops by itself, but can sometimes lead to cardiac arrest (your heart stops pumping blood around your body).

Treatment for torsades de pointes depends on what is causing your condition and includes the following options.

  • Medicines called beta-blockers.
  • A pacemaker implanted to regulate your heartbeat.
  • An implantable cardioverter defibrillator (ICD) if you have a family history of sudden death. This is a device, similar to a pacemaker, which is implanted near your collarbone. It can monitor your heart rhythm and return your heartbeat to normal when you have an attack of ventricular tachycardia.

What do I need to tell my family and friends about having an implantable cardioverter defibrillator (ICD)?

Answer

Getting treatment for your arrhythmia by having an implantable cardioverter defibrillator (ICD) fitted will allow you to continue with most activities as you did before you had the device. Most of the time, you won’t be aware of your ICD and people around you wouldn’t know you have it. However, the effects of your ICD treating you with a shock may seem frightening at first to you and those around you, so you may want to talk to your family and friends about this.

Explanation

If you explain more about your ICD to people who know you, they will know what to do to help and reassure you when your ICD is triggered to give your heart a larger shock (defibrillation).

You may have warning symptoms that the ICD is about to be triggered. You may feel dizzy or have palpitations. If you do get warning symptoms, sit or lie down because your symptoms could cause you to collapse before the ICD delivers the shock. Tell anyone you’re with what is happening. If your ICD does give you a shock, you may cry out or jump, and if anyone is touching you at the time, they may feel a tingling sensation. This isn’t dangerous for them. Ask your family and friends to stay calm and to stay with you if you have been shocked by your ICD.

You can provide your family and friends with useful phone numbers relating to your heart condition and ICD. Explain to them what to do to help you if your ICD is triggered.

If you have a single shock some time after the device has been implanted, this may just be its normal function treating ventricular tachycardia. However, if you have several shocks, you should go to an accident and emergency department. If you experience a shock within the first week of having the device implanted, seek immediate medical advice, as a lead may have become displaced or there may be a problem with the device.

If you or your family and friends have any concerns about you living with your ICD, there are support groups you can contact. Your doctor and ICD clinic will able to offer you further advice and support on any aspect of having an ICD.