Ventricular Tachyarrhythmia

Ventricular Tachycardia (VT)

Ventricular tachycardia is a rapid heart rhythm that starts in the ventricles. It ranges from brief episodes to rhythms that need prompt assessment, and each patient is assessed individually.

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Understanding VT

What Is Ventricular Tachycardia?

The ventricles are the main pumping chambers of the heart. In ventricular tachycardia (VT), an abnormal electrical signal starts in the ventricles and drives them at a fast rate.

When the ventricles beat very fast, they have less time to fill, which can reduce the amount of blood pumped with each beat. This can affect how a person feels.

The clinical significance varies. It depends on how long the rhythm lasts, how fast it is, the symptoms and whether there is underlying heart disease.

Origin of the rhythm in the ventricles

Mechanisms

How VT Can Develop

VT can start in different ways. Understanding the mechanism helps to guide the assessment and the choice of treatment.

Focal ventricular origin

A small area of the ventricle fires repeatedly and drives the rhythm.

Re-entry

An electrical signal travels around a circuit and re-excites the tissue again and again.

Scar-related circuits

In some patients, areas of scarring from earlier heart conditions can form pathways for abnormal circuits.

Conceptual illustration of ventricular re-entry

Clinical context

Types of VT

Doctors describe VT using a few terms. They help to describe how the rhythm behaves.

Non-sustained

A short run that stops on its own.

Sustained

A longer run, or one that needs treatment to stop.

Monomorphic

The beats look the same on the ECG, which can suggest a single focus or circuit.

Polymorphic

The beats change shape on the ECG and need individual assessment.

The type of VT is established by ECG and rhythm recordings and interpreted in clinical context.

What patients may notice

Symptoms

Symptoms and their severity vary. Some episodes are brief and noticed only as a few fast beats, while others cause more marked symptoms.

Palpitations

Awareness of a pounding or racing heart.

Rapid heartbeat

A heartbeat that suddenly speeds up.

Dizziness

Feeling light-headed or unsteady.

Weakness

A feeling of tiredness or lack of strength.

Shortness of breath

Feeling breathless during an episode.

Chest discomfort

Pressure or discomfort in the chest.

Fainting

Needs urgent medical assessment.

Fainting, chest pain or severe breathlessness need urgent medical care.

ECG

VT on an ECG

  • Shows a run of fast beats starting in the ventricles
  • The beats are often wide compared with normal beats
  • Helps to describe whether the beats look the same or change shape

An ECG recorded during an episode is the most informative. Interpretation needs clinical context.

About ECG

Looking at the heart

Structural Heart Disease

Heart structure assessment

VT assessment often includes looking at the structure and function of the heart, where clinically appropriate, because the findings influence the overall picture.

This does not mean every patient with VT has structural heart disease. VT can also occur in a heart with normal structure.

  • Heart structure and pumping function
  • Previous heart conditions or scarring
  • Family history

Assessment

How VT Is Assessed

Assessment documents the rhythm and puts it in context.

ECG

Records the rhythm and describes its pattern.

Rhythm monitoring

Used to record episodes over time.

Cardiac imaging

Assesses structure and function.

Clinical assessment

History, symptoms and examination.

Electrophysiology study

Considered in selected situations.

Electrophysiology study

The Role of an Electrophysiology Study

An EPS records electrical signals from inside the heart. In selected patients with VT it may help to evaluate the mechanism of the rhythm and support treatment planning.

Whether an EPS is appropriate depends on the type of VT, the clinical presentation and the overall assessment.

Electrophysiology Study

Intracardiac recording during an electrophysiology study

Technical mapping

3D Mapping in VT

Three-dimensional electroanatomical mapping builds an electrical picture of the ventricle. It can help to understand where VT starts or which tissue supports a circuit.

Ventricular geometry

A three-dimensional model of the chamber is created.

Electrical signal collection

Signals are recorded from points across the ventricle.

Activation mapping

The timing of activation shows where a rhythm starts or travels.

Voltage and substrate

Where relevant, voltage information can show areas of abnormal tissue.

Target localisation

The information helps to select the area to treat.

Not every VT case uses the same mapping strategy. The approach depends on the rhythm and the patient.

3D Electroanatomical Mapping

Treatment approach

Treatment

Treatment depends on the type of VT, the clinical presentation, any underlying heart disease, individual risk and the overall assessment. More than one approach may be used.

Observation and follow-up

Where appropriate, with monitoring over time.

Contributing factors

Other conditions and triggers are reviewed.

Medication

May be used in selected cases. The choice is individual.

Catheter ablation

Considered in selected patients.

In selected patients, a defibrillator may also be considered. See the page on the implantable cardioverter-defibrillator for more information.

Implantable Cardioverter-Defibrillator

This page does not replace medical advice. Fainting, chest pain or severe breathlessness need urgent medical care.

Catheter ablation

Catheter Ablation for VT

Catheter ablation treats the part of the ventricle that starts or sustains the rhythm. Whether it is appropriate depends on clinical assessment.

EPS

The rhythm is studied from inside the heart.

Ventricular mapping

The ventricle is mapped.

Mechanism and target

The mechanism and area to treat are identified.

Catheter ablation

Energy is delivered to the target.

Reassessment

The result is checked.

Catheter Ablation
Electrophysiology Study

After assessment or treatment

Follow-up

Follow-up depends on the findings and on the treatment given. It may include:

  • Reassessment of the rhythm
  • Clinical follow-up and review of symptoms
  • Device follow-up, where a device is used
  • Additional monitoring where required

Patients are told which symptoms need urgent medical care.

Before Your Procedure
After Your Procedure

Questions

Frequently Asked Questions

VT is a rapid heart rhythm that starts in the ventricles, the lower chambers of the heart. It can be brief or longer lasting, and its significance depends on the clinical context.
No. Some episodes are brief and stop on their own, while others are longer and need prompt medical attention. Fainting, chest pain or severe breathlessness need urgent medical care.
Non-sustained VT is a short run that stops by itself. Sustained VT lasts longer or needs treatment to stop.
Not necessarily. VT can occur in a structurally normal heart, but assessment usually includes looking at heart structure and function, because it influences management.
In selected patients an EPS can help to evaluate the mechanism of the rhythm and support treatment planning.
Mapping builds an electrical picture of the ventricle, which can show where a rhythm starts or which tissue supports a circuit. The strategy differs between patients.
In selected patients, ablation may be considered depending on the type of VT, the clinical presentation and the overall assessment.
Not for everyone. A device is considered in selected patients based on the overall assessment and individual risk. This is decided individually.

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