Overview
Ventricular tachycardia (VT) is a potentially life-threatening abnormal heart rhythm from the lower chambers of the heart (ventricles) most often caused by scarring in the muscle, although it can occur in a completely normal heart.
VT needs emergency assessment and treatment.
Symptoms
The main symptoms of ventricular tachycardia are:
- sudden feeling of your heart pounding or racing (heart palpitations) – this may last for a few seconds up to a few minutes
- heart rate faster than 100 beats per minute
- light-headedness
- loss of consciousness (syncope)
- chest pain or tightness
- breathlessness
- seizure or fit
- cardiac arrest
VT may start and stop on its own or persist until it is treated. If persistent you will likely need treatment in hospital.
Cardiac arrest
If the VT causes the heart to stop beating effectively, then this is known as a cardiac arrest, and it is important to restore normal heart rhythm as soon as possible.
If cardiac arrest is suspected (loss of consciousness and no pulse), then the priority is to seek help, call 999.
If you are familiar with cardio-pulmonary resuscitation (CPR), then this can be started after help has been sought.
An automatic external defibrillator (AED) can be used if available prior to professional help arriving.
Causes
Ventricular tachycardia is most commonly caused by scarring in the bottom chambers of your heart which disrupt the electrical signals.
Conditions that cause scarring and can lead to VT and cardiac arrest include:
- previous heart attack
- heart muscle disease (cardiomyopathy)
- inflammation of the heart muscle (myocarditis)
VT can occur in structurally normal hearts due to the presence of a short circuit or as a result of an inherited condition such as long QT syndrome (LQTS) or Brugada Syndrome (BRS).
Diagnosis
Sustained ventricular tachycardia can be confirmed on an ECG. Intermittent short episodes can also be detected on an ambulatory ECG.
Once VT is confirmed and treated, further investigations are needed to look for reversible or treatable causes.
Tests may include:
- echocardiogram
- cardiac MRI
- coronary angiography
- genetic testing
Treatment
The priority, once VT has been confirmed, is to restore normal heart rhythm. This is best achieved by external defibrillation (applying an electrical shock), although sometimes medications are needed as well.
In a cardiac arrest situation, defibrillation should be performed as soon as equipment is available.
If the VT is being tolerated, then it may be more appropriate to wait for emergency anaesthesia first, before defibrillation.
Once normal rhythm has been restored and any underlying reversible conditions have been treated, you will likely need to start medications to prevent recurrence.
If the risk of recurrence is high, then it may be necessary to consider an implantable cardioverter defibrillator.
If you continue to have episodes of VT despite medications, then a procedure called an VT ablation can be performed to reduce the risk of further occurrences.