Proton Particle Therapy for Cardiac Arrhythmia


Researchers are gathering information on the safety and effectiveness of proton radiation therapy in reducing the number of ventricular tachycardia (VT) episodes in subjects who continue to experience VT despite treatment with an implantable cardioverter defibrillator (ICD) and undergoing a previous catheter ablation.

Full Title of Study: “Proton Particle Therapy for Cardiac Arrhythmia Extracorporeal Energy Source Ablation of Cardiac Tissue: A First Stage Early Feasibility Study”

Study Type

  • Study Type: Interventional
  • Study Design
    • Allocation: N/A
    • Intervention Model: Single Group Assignment
    • Primary Purpose: Treatment
    • Masking: None (Open Label)
  • Study Primary Completion Date: July 1, 2022

Detailed Description

Proton therapy has been approved by the U.S. Food and Drug Administration (FDA) for cancer patients, including tumors in the heart, but not for treating heart rhythm disorders. The use of proton radiation therapy to treat heart rhythm disorders including VT and ventricular fibrillation (VF) is new and investigational; however, the FDA has approved proton therapy to treat abnormal rhythm disorders for this study. The development of a proton radiation therapy approach could be of substantial value in providing alternative therapy to either drug therapy or catheter-based ablation. With appropriate development, this therapy may be successful in the primary or secondary elimination of arrhythmias.

Participants will be followed at 1 and 2 weeks, 1, 3, 6, 12 and 24-month intervals following treatment throughout the trial.

Participant involvement will last approximately two years from the time of the proton radiation therapy procedure or until the last subject enrolled completes a 24 month follow-up.


  • Radiation: Proton Particle Therapy
    • Proton therapy will be delivered in a single fraction using the Probeat-V system

Arms, Groups and Cohorts

  • Experimental: Proton Particle Therapy for Cardiac Arrhythmia
    • Subjects who have an ICD with recurrent VT, VF, or VT storm who have failed one prior standard catheter-based ablation after device implantation, will subsequently undergo particle-based extracorporeal ablation.

Clinical Trial Outcome Measures

Primary Measures

  • Mortality
    • Time Frame: 2 years
    • Total number of subject deaths
  • Implantable Cardioverter Defibrillator (ICD) Shocks
    • Time Frame: 2 years
    • Total number of recurrent ICD shocks
  • Recurrent Ventricular Tachycardia (VT)
    • Time Frame: 2 years
    • Total number of recurrent VT requiring repetitive antitachycardia pacing (ATP) device therapy
  • Cardiac Arrest
    • Time Frame: 2 years
    • Total number of cardiac arrests

Participating in This Clinical Trial

Inclusion Criteria

  • Prior myocardial infarction or non-ischemic disease resulting in myocardial dysfunction
  • A left ventricular ejection fraction (EF) <50%
  • An implanted ICD device as secondary prevention for monomorphic VT/VF. This includes patients who receive a device for primary prevention and then have recurrent sustained monomorphic VT or VT
  • Have failed a prior catheter-based ablation for VT/VF after device implantation or have a contraindication to repeat ablation and and have failed reasonable drug options over the 3 months prior to consideration of particle therapy
  • Repeat ablation from an epicardial venue in the absence of prior cardiac surgery, or where such an ablation if felt to be inappropriate in the view of the primary investigator
  • Electrocardiographic documentation of 2 additional episodes of recurrent, sustained monomorphic ventricular tachycardia (MMVT) and/or pre-ventricular contraction (PVC) induced VT or VF that are terminated by ATP or ICD shocks by device interrogation over the past 3 months, since the sentinel ablation (see criteria #4).
  • Age ≤ 80 yrs.

Exclusion Criteria

  • VT in the absence of cardiomyopathy
  • Reversible causes of VT including thyroid disorders, acute alcohol intoxication, recent major surgical procedures, trauma, or VT clearly produced by recurrent ischemia
  • Multiple (e.g. >3) clinical VT morphologies, that are thought to originate from widely disparate right ventricular (RV) or left ventricular (LV) areas.
  • Recent cardiac events including myocardial infarction (MI), percutaneous coronary intervention (PCI), or valve or bypass surgery in the preceding 3 months, or anticipated in the next 3 months
  • Hypertrophic obstructive cardiomyopathy > Class IV
  • Progressive Class IV angina or Class IV congestive heart failure (CHF) (including past or planned heart transplantation)
  • Heritable arrhythmias or increased risk for torsade de pointes with class I or III drugs
  • Prior surgical interventions for VT such as an encircling ventriculotomy procedure
  • Contraindication to appropriate anti-coagulation therapy after ablation
  • Renal failure requiring dialysis
  • Prior therapeutic radiation therapy to the left chest that would preclude safe ablation of the cardiac target in the judgment of the radiation oncologist
  • Medical conditions limiting expected survival to <1 year
  • Women of childbearing potential (unless post-menopausal or surgically sterile)
  • Participation in any other clinical mortality trial (Participation in other non-mortality trials should be reviewed with the clinical trial management center)
  • Unable to give informed consent

Gender Eligibility: All

Minimum Age: 18 Years

Maximum Age: 80 Years

Are Healthy Volunteers Accepted: No

Investigator Details

  • Lead Sponsor
    • Douglas L. Packer
  • Provider of Information About this Clinical Study
    • Sponsor-Investigator: Douglas L. Packer, Principal Investigator – Mayo Clinic
  • Overall Official(s)
    • Douglas L Packer, MD, Principal Investigator, Mayo Clinic
  • Overall Contact(s)
    • Kristi H Monahan, RN, 507-255-6676,

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