Cardiac RADIoablation Versus Repeat Catheter Ablation: a Pivotal Randomized Clinical Trial Evaluating Safety and Efficacy for Patients With High-risk Refractory Ventricular Tachycardia (RADIATE-VT) (RADIATE-VT)

April 17, 2026 updated by: Varian, a Siemens Healthineers Company

Cardiac RADIoablation Versus Repeat Catheter Ablation: a Pivotal Randomized Clinical Trial Evaluating Safety and Efficacy for Patients With High-risk Refractory Ventricular Tachycardia

RADIATE-VT is a pivotal, multicenter, randomized trial comparing safety and efficacy between cardiac radioablation (CRA) using the Varian CRA System and repeat catheter ablation (CA), for patients with high-risk refractory ventricular tachycardia (VT) who have experienced VT recurrence after CA and are candidates for additional CA.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

380

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact Backup

Study Locations

  • United States
    • California
      • Los Angeles, California, United States, 90048
        • Recruiting
        • Cedars-Sinai Medical Center
        • Contact:
        • Contact:
        • Principal Investigator:
          • Ashkan Ehdaie, MD
    • Connecticut
      • Hartford, Connecticut, United States, 06102
    • Massachusetts
      • Boston, Massachusetts, United States, 02115
    • Minnesota
      • Rochester, Minnesota, United States, 55905
        • Recruiting
        • Mayo Clinic
        • Principal Investigator:
          • Kenneth Merrell, MD
        • Contact:
        • Contact:
          • Study Team Heart Rhythm Services
          • Phone Number: 5072550774
        • Sub-Investigator:
          • Konstantinos Siontis, MD
    • Missouri
      • Columbia, Missouri, United States, 65211
        • Recruiting
        • University of Missouri
        • Contact:
        • Principal Investigator:
          • Rahul Jain, MD
      • St Louis, Missouri, United States, 63110
        • Recruiting
        • Washington University
        • Contact:
        • Principal Investigator:
          • Daniel Cooper, MD
    • Ohio
    • Pennsylvania
      • Philadelphia, Pennsylvania, United States, 19104
      • Pittsburgh, Pennsylvania, United States, 15260
        • Recruiting
        • University of Pittsburgh Medical Center
        • Contact:
        • Principal Investigator:
          • Krishna Kancharla, MD
    • South Carolina
      • Charleston, South Carolina, United States, 29425
        • Recruiting
        • Medical University of South Carolina
        • Principal Investigator:
          • Jeffrey Winterfield, MD
        • Contact:
          • Phone Number: 843-792-5998
    • Tennessee
      • Nashville, Tennessee, United States, 37232
        • Recruiting
        • Vanderbilt University Medical Center
        • Contact:
        • Principal Investigator:
          • William G Stevenson, MD

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  1. High-risk refractory VT, defined as:

    1. Ischemic and/or nonischemic cardiomyopathy, and

    2. Recurrent sustained monomorphic VT, defined as at least one of the following below, documented by ICD interrogation or ECG in the prior 6 months, and having occurred after the last VT ablation:

      A: ≥3 episodes of monomorphic VT treated with anti-tachycardia pacing (ATP) at least one of which is symptomatic

      B: ≥1 appropriate ICD shock

      C: ≥3 episodes of sustained monomorphic VT within 24 hours treated with ICD shock or ATP

      D: sustained monomorphic VT below detection rate of ICD documented by ECG, and

    3. Left ventricular ejection fraction (LVEF) ≤49% and
    4. Previously underwent at least one standard of care CA for VT.
  2. Presence of a clinical indication for a repeat CA procedure for scar-mediated VT in the judgement of the treating investigator.

  3. Has failed amiodarone therapy or is intolerant to amiodarone:

    • Failed amiodarone therapy is defined as: appropriate ICD therapy or sustained monomorphic VT having occurred while the patient was taking amiodarone (minimum cumulative dose of 10 g).
    • Intolerant to amiodarone is defined as: previously tried or taken amiodarone but stopped due to medication related side effects or toxicities.
  4. Deemed to be medically and technically a candidate for further CA by the electrophysiologist investigator.
  5. Presence of an ICD.
  6. At least 18 years of age (or meets local age of majority).
  7. Ability to understand and willingness to sign an IRB approved written informed consent document.

Exclusion Criteria:

  1. Contraindication to a CA procedure for VT (e.g., presence of mobile LV thrombus, active systemic infection, active ischemic or other reversible causes of VT).
  2. Patients with expected, right ventricular scar only.
  3. Any prior radiation to the thorax region of the body.
  4. Known medical conditions associated with higher risk of radiotherapy complications in the judgement of the radiation oncologist (i.e., active connective tissue disorders, interstitial lung disease, etc.) that would preclude safe delivery of CRA.
  5. Current use of inotropes.
  6. Presence of a left-ventricular assist device (LVAD).
  7. Scheduled for LVAD or heart transplant procedures.
  8. Presence of a systemic illness likely to limit survival to < 1 year.
  9. VT ablation procedure performed within the prior 2 weeks.
  10. Polymorphic VT or ventricular fibrillation (VF) as the primary clinical heart rhythm, as indicated by 12-lead ECG and/or ICD interrogation.
  11. >3 distinct clinical monomorphic VT morphologies on ICD interrogation since the prior CA, or >5 induced monomorphic VT morphologies during NIPS testing.
  12. Incessant VT that is hemodynamically unstable.
  13. Bundle branch reentry (BBR) VT.
  14. Pregnant and/or breastfeeding. (Patient denial is sufficient for enrollment).

  15. Patients of childbearing potential who:

    • are not on a medically effective means of birth control at the time of screening or do not start a medically effective means of birth control prior to randomization; or
    • do not agree to continue medically effective means of birth control until they have completed their assigned therapy; or
    • do not agree to be on a medically effective means of birth control if they are treated with CRA after their index CA procedure.
  16. Patients enrolled in another clinical study the investigator believes to be in conflict with this clinical investigation.
  17. Patients enrolled or planned to be enrolled in another cardiac radioablation clinical study or registry.
  18. Patients with any other medical condition or laboratory value that would, at the discretion of the investigator, preclude the patient from participation in this clinical investigation.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Active Comparator: Repeat catheter ablation (CA)
Procedure: Catheter Ablation (CA)
Subjects randomized to the CA arm will be treated according to a uniform CA protocol.
Experimental: Varian Cardiac Radioablation (CRA)
Device: Varian Cardiac Radioablation (CRA)
Subjects randomized to CRA will be treated with the Varian CRA system according to a uniform CRA protocol. A dose of 25 Gy in a single fraction is prescribed to the planning target volume (PTV), and delivered using a stereotactic body radiotherapy (SBRT) technique.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Co-primary safety endpoint: freedom from treatment-attributed (i.e., probably or definitely related) serious adverse events (SAEs)
Time Frame: Treatment through 12 months post-treatment
Freedom from treatment-attributed (i.e., probably or definitely related) serious adverse events (SAEs), evaluated from treatment through 12 months post-treatment.
Treatment through 12 months post-treatment
Co-primary efficacy endpoint: Freedom from death, and appropriate ICD shock, and VT storm.
Time Frame: Death will be counted from randomization through 12 months, and shock and storm will be counted starting after a 30-day period immediately post-randomization and continuing through 12 months post randomization
Freedom from death, and appropriate ICD shock, and VT storm, where death will be counted from randomization through 12 months, and shock and storm will be counted starting after a 30-day period immediately post-randomization and continuing through 12 months post randomization.
Death will be counted from randomization through 12 months, and shock and storm will be counted starting after a 30-day period immediately post-randomization and continuing through 12 months post randomization

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in quality of life at 6 weeks post treatment:
Time Frame: From baseline through 6 weeks post treatment
Change in quality of life at 6 weeks post treatment measured by the Short Form Health Survey 36 (SF-36) Health Change Question. This item asks the subject to rate their health in general compared to one year ago in a 5-point scale of 1 (much better), 2 (somewhat better), 3 (about the same), 4 (somewhat worse), 5 (much worse).
From baseline through 6 weeks post treatment
VT burden reduction
Time Frame: From 6 months before randomization through to a 6 month period starting after a 30-day period immediately post-randomization
VT burden reduction measured as a ≥75% reduction in appropriate ICD therapies (ATP, shock), comparing a 6-month period before randomization and a 6-month period starting after a 30-day period immediately post-randomization.
From 6 months before randomization through to a 6 month period starting after a 30-day period immediately post-randomization
Change in quality of life (Social Functioning) at 6 weeks post treatment
Time Frame: From baseline through 6 weeks post treatment
Change in quality of life (Social Functioning) measured by the Short Form Health Survey 36 (SF-36) Social Functioning item (social activities in past 4 weeks). This item asks the subject to rate how much of the time their physical health or emotional problems interfered with their social activities in the past 4 weeks in a 5-point scale of 1 (All of the time), 2 (Most of the time), 3 (Some of the time), 4 (A little bit of the time), 5 (None of the time).
From baseline through 6 weeks post treatment

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Varian, a Siemens Healthineers Company

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

April 21, 2023

Primary Completion (Estimated)

May 1, 2026

Study Completion (Estimated)

May 1, 2030

Study Registration Dates

First Submitted

February 15, 2023

First Submitted That Met QC Criteria

February 28, 2023

First Posted (Actual)

March 13, 2023

Study Record Updates

Last Update Posted (Actual)

April 22, 2026

Last Update Submitted That Met QC Criteria

April 17, 2026

Last Verified

April 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • VAR-2022-01

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

Yes

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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