Ventricular tachycardia: symptoms, causes, treatment and when it is an emergency

The NHS explains that heart rhythm problems (arrhythmias) happen when there is a fault with the electrical system that makes your heart beat. GOSH describes ventricular tachycardia as an arrhythmia in which the electrical signals start in a different place and travel a different way through the heart.

Because of the speed and origin of the beat, GOSH says the heart may not have time to fully fill with blood before pumping. If the rhythm stays in VT, the heart cannot pump blood effectively around the body, which can cause a drop in blood pressure, fainting (syncope), or cardiac arrest. Other people do not have this and their blood pressure stays stable.

GOSH says that if symptoms are present they can include the following, and some people with VT do not notice symptoms. VT is sometimes found by accident on an ECG done as part of a general check-up.

GOSH adds that in babies and young children, who cannot say how they feel, signs may include reduced feeding or breathlessness, and lists changes in behaviour, lethargy, colour change, clamminess, breathing difficulty, dizziness and collapse as red flags.

• Dizziness or feeling faint (pre-syncope).

• Palpitations.

• Tiredness.

• Shortness of breath.

• Fainting (syncope) or collapse.

The NHS says to call 999 or go to A&E if you currently have heart palpitations with chest pain, shortness of breath, feeling dizzy or lightheaded, or fainting or feeling like you might faint, and not to drive yourself. If you have had these symptoms but they have stopped, ask your GP surgery for an urgent appointment or call 111.

The BHF says that if someone collapses suddenly, is unconscious and unresponsive and not breathing or not breathing normally, it is a cardiac arrest: call 999 and start CPR.

GOSH describes four ways VT is classified, which help the team decide how serious it is and how to treat it.

The NHS lists conditions that can cause heart rhythm problems, including high blood pressure, coronary heart disease, heart valve disease and heart attack, and says abnormal heartbeats can also come from medicines, viruses, caffeine, alcohol, smoking or drugs.

The BHF says rhythms such as ventricular tachycardia can be caused by cardiomyopathies (diseases of the heart muscle), inherited heart conditions such as Brugada syndrome, congenital heart disease, heart failure, heart valve disease, severe or untreated myocarditis and heart attack. GOSH says in some people there is a structurally normal heart and the VT is considered safe, which the medical team decides on tests.

GOSH says VT is picked up on an ECG. Tests used to check how the heart's electrical system and function are working include those listed below. Although GOSH describes children's services, similar tests are used in adults.

• ECG, which records the electrical signal and takes a few minutes.

• Echocardiogram, an ultrasound scan of the heart.

• Exercise test, to see rhythm when the heart works harder.

• MRI scan of the heart.

• 24 to 48 hour ECG recording (Holter monitor).

• Blood tests for electrolytes and markers of heart muscle disease.

Treatment depends on the type and cause (NHS). GOSH says if the heart structure is normal and the VT is safe, you continue to be monitored and treated if you have symptoms or very frequent VT. If there is underlying disease and a risk of a life-threatening event, an implantable cardioverter defibrillator (ICD) is offered.

GOSH says conditions can progress, so ongoing monitoring at hospital is important. It says tea and coffee can be consumed within recommended guidelines unless you have been advised otherwise, energy drinks contain high levels of caffeine and should be avoided, and exercise limits will be discussed in clinic. Tell your doctor if you have episodes of fainting or collapse.

The Arrhythmia Alliance and British Heart Foundation, which GOSH lists, offer helplines and support for people with heart rhythm conditions.

On the NHS, VT is usually assessed by cardiology and an electrophysiology or inherited cardiac conditions service, with ablation and ICD fitting in specialist centres. Private cardiology can offer quicker ECG or echocardiogram access or a second opinion, but ICD and ablation decisions are generally coordinated with specialist NHS services, with results shared with your GP.