Cohort Study - SBRT for VT Radioablation

Noninvasive Cardiac Radioablation for Ventricular Tachycardia

Ventricular tachycardia (VT) contributes to over 350,000 sudden deaths each year in the US. Malignant VTs involve an electrical "short circuit" in the heart, formed by narrow channels of surviving tissue inside myocardial scar. Current treatment for VT consists of either implantable defibrillators (ICDs), suppressive drug therapy, catheter ablation or a combination of all 3.

Implantable Defibrillators (ICDs) reduce sudden death and can terminate some ventricular tachycardia (VT) without shocks, but they don't prevent VT. The occurrence of ≥1 ICD shock is associated with reductions in mental well-being and physical functioning, and increases in anxiety and sometimes depression. Further, ICD shocks have been consistently associated with adverse outcomes, including heart failure and death. Furthermore, the most important predictor of ICD shocks is a history of prior ICD shocks.

Therapies to suppress VT include antiarrhythmic drug therapy and catheter ablation, neither however is universally effective. When VT recurs despite antiarrhythmic drug therapy and catheter ablation, novel yet invasive, approaches may be required. Such invasive procedures carry consequent risks of cardiac and extra-cardiac injury.

Stereotactic body radiotherapy (SBRT) is a non-invasive technique that delivers high doses of radiation precisely to specified regions in the body, while minimizing exposure to adjacent tissue. This technique is currently, and commonly used in the treatment of cancer. Conventional application of SBRT has made use of its ability to spare non-target tissue, including for treatment of tumors near the heart. More recently, clinicians have changed the paradigm, by focusing radioablative energy on ventricular scar responsible for ventricular tachycardia. Pre-clinical studies have supported the concept and were followed by first-in-human VT therapeutic experience in 2017. Subsequent studies have had encouraging results for patients who failed or were unable to tolerate conventional treatment.

Study Overview

• Status: Recruiting
• Conditions: Myocardial Infarction; Ventricular Tachycardia; Heart Disease Structural Disorder
• Intervention / Treatment: Radiation: Stereotactic Body Radiotherapy (SBRT) ablation of VT

Detailed Description

This will be a single centre single arm prospective cohort study. 12 patients with ventricular tachycardia will be recruited from those who have failed or were unable to tolerate conventional therapy. These patients will be recruited from the cardiology clinic where they will already be under the care of a heart rhythm/heart function specialist. Clinical imaging data, medical history and previous ablation data will be collected and use towards planning their treatment with SBRT. Patients will undergo further imaging (unless recently done clinically), including: 4D cardiac CT (cCT), cardiac MRI (cMRI) and a planning CT (pCT). MRIs will only be performed on patients with ICDs for whom it is considered safe to do so. Using the imaging and electroanatomic substrate mapping data collected from a previous ablation attempt, a volumetric modulated arc therapy (VMAT) treatment plan will be established. This treatment plan will be generated in consultation between the cardiac electrophysiologist, radiation oncologist and medical physicist; and will define the target volume (TV) of myocardial tissue to be treated.

Once a TV has been established and verified, patients will be set up on a TrueBeam 1 linear accelerator where the treatment will be administered. The actual time for treatment administration is approximately 30 minutes.

After the procedure, at 6 & 12 weeks, 7.5 months then every 6 months, a follow-up will occur as a part of standard care where outcome data regarding the chronic success of the ablation procedure will be collected and ICD interrogation will be performed. No imaging or mapping is planned at the follow-up. Patients will be followed for a minimum of 7.5 months to a maximum of 2 years depending on when they are enrolled.

• Study Type: Interventional
• Enrollment (Estimated): 12
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: John Sapp, MD FRCPC; Phone Number: 902.473.4474; Email: John.Sapp@nshealth.ca
• Study Contact Backup: Name: Karen Giddens; Phone Number: 902 237-5551; Email: karen.giddensl@nshealth.ca

Study Locations

• Canada
  • Nova Scotia
    • Halifax, Nova Scotia, Canada, B3H 3A7
      • Recruiting
      • Nova Scotia Health Authority
      • Contact: Gillian Schraefel, RN; Phone Number: 902 473 7733; Email: Gillian.Schraefel@nshealth.ca
      • Principal Investigator: John L Sapp, MD FRCPC

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child; Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Structural heart disease: ischemic or non-ischemic cardiomyopathy diagnosed with cardiac imaging demonstrating either segmental myocardial dysfunction, or presence of scar, AND
• One of the following monomorphic VT events despite prior attempted catheter ablation (or contraindication for ablation), AND despite treatment with a class III antiarrhythmic drug (contraindicated, ineffective or not tolerated): A: Documented sustained monomorphic VT terminated by pharmacologic means, DC cardioversion or manual ICD Therapy. B: ≥3 episodes of monomorphic VT treated with antitachycardia pacing (ATP), at least one of which was symptomatic C: ≥ 5 episodes of monomorphic VT treated with antitachycardia pacing (ATP) regardless of symptoms D: ≥1 appropriate ICD shocks, E: ≥3 monomorphic VT episodes within 24 hours ** VT events must be confirmed by ECG/monitor or ICD download.

Exclusion Criteria:

• Unable or unwilling to provide informed consent
• Have received prior radiotherapy to the likely treatment field
• Inotrope-dependent heart failure or an anticipated life-expectancy of < 1 year in the absence of VT
• Presenting arrhythmia: polymorphic VT or ventricular fibrillation (VF)
• Pregnancy
• Active ischemia (acute thrombus diagnosed by coronary angiography, or dynamic ST segment changes demonstrated on ECG) or another reversible cause of VT (e.g. drug-induced arrhythmia), had recent acute coronary syndrome within 30 days thought to be due to acute coronary arterial thrombosis, or have CCS functional class IV angina. Note that biomarker level elevation alone after ventricular arrhythmias does not denote acute coronary syndrome or active ischemia.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm

Intervention / Treatment

Experimental: Imaging & SBRT Treatment for Ventricular Tachycardia

Radiation: Stereotactic Body Radiotherapy (SBRT) ablation of VT; Additional imaging for SBRT planning and implementation: Planning CT (pCT) - CT simulator that utilizes a respiratory positioning monitoring (RPM) optical tracking system and SBRT immobilization setup to provide necessary data to allow for monitoring of the patient's deep inspiration breath-hold (DIGH) maneuver during treatment delivery.; SBRT treatment - 30 min procedure on a TrueBeam 1 linear accelerator using SBRT fixation. Patient alignment and DIBH maneuver from the pCT will be replicated using the on-board cone-beam CT (CBCT) guidance and RPM systems.; Other Names: VT Radioablation

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Comparative analysis of ventricular arrhythmia events	Number of patients with a reduction in the absolute number of ventricular arrhythmia events following ablation and blanking period, in comparison with those prior to treatment.	During the first 6 months post blanking period vs. 6 months prior to treatment.
Comparative analysis of targeting methods assessed by volume of sparred healthy tissue	Effectiveness of different myocardial substrate targeting methods on sparing non-target tissue. Delivered treatment approach as compared to a proposed calculated treatment plan using a single phase of the 4DcCT. Measured differences between 2 target-method volumes will equate to the volume of sparred tissue.	From time of enrollment to 7.5 ,months post treatment.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Number of patients with procedural complications, including: all cause mortality, pericarditis, pneumonitis, heart failure hospitalization and extra-cardiac injury	Composite of; all cause mortality, pericarditis, pneumonitis, heart failure hospitalization and extra-cardiac injury.	Through study completion,min of 7.5 months to max of 2 years.
Time to Recurrent Arrhythmia Outcomes	Composite of; appropriate ICD shock, VT storm, incessant VT, sustained VT below ICD detection and appropriate antitachycardia pacing.	Through study completion,min of 7.5 months to max of 2 years
Ventricular arrhythmia Burden	Composite of; number of appropriate shocks, number of inappropriate shocks, number of antitachycardia pacing events.	During 6 months prior vs. 6 months following treatment.

Collaborators and Investigators

• Sponsor: John Sapp
• Investigators: Principal Investigator: John Sapp, MD FRCPC, Nova Scotia Health Authority; Study Director: James Clarke, MD FRCPC, Nova Scotia Health Authority; Study Director: James Robar, Phd FCCPM, Nova Scotia Health Authority; Study Director: Jean-Philippe Pignol, MD FRCPC, Nova Scotia Health Authority

Study record dates

Study Major Dates

• Study Start (Actual): June 1, 2021
• Primary Completion (Estimated): June 1, 2027
• Study Completion (Estimated): September 1, 2027

Study Registration Dates

• First Submitted: October 29, 2019
• First Submitted That Met QC Criteria: November 11, 2019
• First Posted (Actual): November 14, 2019

Study Record Updates

• Last Update Posted (Actual): March 18, 2026
• Last Update Submitted That Met QC Criteria: March 16, 2026
• Last Verified: March 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Cardiac Conduction System Disease; Vascular Diseases; Cardiovascular Diseases; Pathologic Processes; Heart Diseases; Arrhythmias, Cardiac; Infarction; Necrosis; Myocardial Ischemia; Ischemia; Tachycardia; Pathological Conditions, Signs and Symptoms; Myocardial Infarction; Tachycardia, Ventricular; Investigative Techniques; Therapeutics; Surgical Procedures, Operative; Radiotherapy; Stereotaxic Techniques; Neurosurgical Procedures; Radiosurgery
• Other Study ID Numbers: Sapp007

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: No
• product manufactured in and exported from the U.S.: No