Stereotactic Ablative Radiotherapy for the Treatment of Refractory Ventricular Tachycardia

NCT ID: NCT05696522

Last Updated: 2025-06-19

Basic Information

• Recruitment Status: RECRUITING
• Clinical Phase: NA
• Total Enrollment: 6 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2023-01-12
• Study Completion Date: 2026-05-02

Brief Summary

Ventricular tachycardia (VT) is an abnormal rhythm arising from the bottom chambers (ventricles) of the heart. The hearts of most patients who develop VT have been previously damaged by a myocardial infarction (heart attack) or other heart muscle diseases (cardiomyopathies). The damage produces scar or fatty deposits that conduct electrical impulses slowly allowing VT to occur. Recurrent episodes of VT can compromise heart function and increase mortality.

VT is prevented by special drugs but these are not always effective and can have many side effects. Most patients with VT will also have a specialised device called an implantable defibrillator (ICD) implanted. The ICD treats VT by either stimulating the heart rapidly or delivering a shock to it. ICDs are very effective but the shocks are painful and have a big impact on quality of life. If VT occurs despite optimal drug treatment, patients undergo an invasive procedure called catheter ablation. Here, wires are passed into the heart from the blood vessels in the leg and the damaged heart muscle causing the VT is identified whilst the heart is in VT. An electrical current is passed down the wire making its tip heat up allowing discrete burns (ablation) to be placed inside the heart. The ablated heart muscle doesn't conduct electricity which stops the VT and prevents it recurring.

Some patients are so frail that ablation cannot be performed safely. A recent clinical trial has shown that VT can be treated in such patients using radiotherapy, which is usually used to treat tumours with high energy radiation. This approach is non-invasive, painless and requires no sedation or anaesthesia.

This study will test whether VT can be successfully treated using stereotactic ablative radiotherapy. This can deliver high dose radiotherapy very precisely, whilst minimising the risk of damage to healthy tissues.

Detailed Description

Principal objectives:

1. To determine the safety and efficacy of stereotactic ablative radiotherapy (SABR) for the treatment of VT refractory to conventional therapies.

Background:

VT is an abnormal heart rhythm arising from either of the bottom chambers of the heart (ventricles). Most patients with VT have scarring or fatty deposits in the heart muscle caused by a previous heart attack or a heart muscle problem called a cardiomyopathy. The abnormal heart muscle conducts electricity slowly allowing VT to occur. Most patients with VT have a device called an implantable defibrillator (ICD) fitted to treat VT. The ICD has wires going into the heart from a small generator that is inserted under the skin below the left collar bone. ICDs stop VT by stimulating the heart rapidly or by shocking the heart which is very painful and can stun the heart temporarily, weakening its pumping function. Patients who experience a lot of VT can have more admissions to hospital, worsening heart failure and a poorer quality of life, as well as a higher risk of dying. Consequently, all patients are treated with drugs to prevent VT but these are not always effective. If VT keeps recurring, many patients undergo an invasive procedure called catheter ablation where wires are passed into the heart from the leg and the part of the ventricles causing the VT identified. A high frequency electrical current is then passed down one of the wires making its tip heat up allowing discrete burns (ablation) to be placed on the culprit area, which stops the VT and prevents it from recurring. Performing catheter ablation in such patients is a high risk procedure and the overall complication rate is between 5 - 15% in experienced centres. Some patients have recurrent VT despite catheter ablation or the VT cannot be ablated because the patient is too frail, or the VT causes a significant fall in the blood pressure resulting in cardiac arrest (heart stops beating).

In the last 6 years, several case reports and series have been published showing that radiotherapy using different types of linear accelerator machines (including the Cyberknife) can successfully and safely ablate VT. Most recently, a prospective, randomised trial (ENCORE-VT) has reported a dramatic reduction in VT following radioablation.

This study will therefore assess our ability to perform stereotactic radioablation for VT at St Bartholomew's Hospital. We will determine procedural success and safety. Patients will be assessed 3, 6 and 12 months after the treatment and their burden of VT determined by checking the ICD.

Conditions

Radiotherapy; Complications; Ventricular Tachycardia; Structural Heart Abnormality; Heart Failure

Study Design

• Allocation Method: NA
• Intervention Model: SINGLE_GROUP
• Primary Study Purpose: TREATMENT
• Blinding Strategy: NONE

Study Groups

Treatment arm

Treatment with stereotactic ablative radiotherapy

Group Type: EXPERIMENTAL

Stereotactic ablative radiotherapy

Intervention Type: RADIATION

Stereotactic ablative radiotherapy will be delivered to a volume of ventricular myocardium responsible for the clinical ventricular tachycardia.

Interventions

Stereotactic ablative radiotherapy

Stereotactic ablative radiotherapy will be delivered to a volume of ventricular myocardium responsible for the clinical ventricular tachycardia.

Intervention Type: RADIATION

Eligibility Criteria

Inclusion Criteria

1. They are at least 18-85 years old.

2. They have recurrent VT (at least three episodes in the preceding six months) requiring therapy from an ICD, that is refractory to conventional treatments - both maximally tolerated doses of anti- arrhythmic drugs and/or conventional catheter ablation.

3. They are too frail or do not wish to undergo conventional catheter ablation.

4. They have not had previous radiotherapy to the anticipated treatment field.

Exclusion Criteria

1. They have polymorphic VT or ventricular fibrillation (VF).

2. They have inotrope-dependent heart failure or a left ventricular assist device (LVAD) in situ.

3. They are unlikely to live more than 12 months irrespective of the VT.

4. There is a potentially reversible cause for the VT e.g. critical coronary artery disease or a metabolic problem such as an overactive thyroid gland.

5. They are unable to provide informed consent.

6. They have had previous radiotherapy to the anticipated treatment field.

7. The patient weighs in excess of 170kg (maximum weight capacity of the tables in the imaging department).

• Minimum Eligible Age: 18 Years
• Maximum Eligible Age: 85 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: No

Sponsors

Barts & The London NHS Trust

OTHER

Sponsor Role: lead

Responsible Party

Responsibility Role: SPONSOR

Locations

St Bartholomew's Hospital

London, , United Kingdom

Site Status: RECRUITING

Countries

United Kingdom

Central Contacts

Hakam Abbas, MSc

Role: CONTACT

Hakam.abbass@nhs.net

020 37658635

Facility Contacts

MEHUL DHINOJA, FRCP

Role: primary

mehul.dhinoja@nhs.net

02073777000

Other Identifiers

262246

Identifier Type: -

Identifier Source: org_study_id