The objective of this clinical investigation is to evaluate:

1. the safety and efficacy of the CyberHeart System, CardioPlan™ Software and Laptop, in treating patients with refractory ventricular tachycardia (VT) using the CyberKnife® Radiosurgical System.
2. The CyberHeart System performance with respect to the ability to contour myocardial targets that are transferred to the Multi-plan® Treatment Planning Software of the CyberKnife® system for the production and delivery of a safe radiosurgical treatment plan.

Cardiac radiosurgery is a minimally-non invasive, painless, procedure. Tissue ablation can be accomplished precisely.

This study is a prospective, multi-center (2), single arm, open label US-based feasibility study.

The clinical hypothesis for the study is that the CyberHeart treatment approach will be safe and with further study will not be shown to be inferior to current treatment options, may lead to a survival benefit and improved quality of life.

The ablation to be performed with the CyberHeart System will be targeting the anatomical site of the clinically presenting VT. The application site will be determined by morphological criteria on the 12 lead ECG along with anatomical data from MRI or CT scan imaging. Ablation will be performed at the designated location with the intention to produce substrate modification.

The Study will enroll a maximum of 10 patients.

Inclusion Criteria:

• Presence of an implantable cardioverter-defibrillator (ICD)
• Patients with ischemic or non-ischemic cardiomyopathy who have had recurrent symptomatic VT that induced ICD shock(s) following catheter ablation and/or antiarrhythmic drug (AAD) therapy.
• 60 years of age or greater.
• Left ventricular ejection fraction ≥ 20%.
• Failure of or ineligible for catheter ablation.

Exclusion Criteria:

• Unable or unwilling to provide informed consent
• Patients with idiopathic VT
• Women who are pregnant
• Prior radiation therapy to the thorax
• Active ischemia or other reversible causes of VT
• Active non-cardiovascular illness or systemic infection
• Presence of thrombus in the right atrium or right ventricle on pre-procedure echocardiogram
• Cardiogenic shock
• NYHA (New York Heart Association) Class IV Heart Failure.
• Presence of incessant VT that is hemodynamically unstable.
• Acute heart failure exacerbation.
• Revascularization in the past 90 days.
• Other disease process that is likely to limit survival to less than 12 months