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Cohort Study - SBRT for VT Radioablation

Myocardial Infarction | Ventricular Tachycardia | Heart Disease Structural Disorder

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.

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Participation Requirements

  • Sex:

    ALL

  • Eligible Ages:

    0 and up

Participation Criteria

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 Location

Nova Scotia Health Authority
Nova Scotia Health Authority
Halifax, Nova Scotia
Canada

Contact Study Team

Primary Contact

Gillian Schraefel, RN

[email protected]
902 473 7733
Study Sponsored By
Nova Scotia Health Authority
Participants Required
More Information
Study ID: NCT04162171