Saline Enhanced Radiofrequency (SERF) Needle Ablation for Refractory VT

Inclusion Criteria: 1. Subject has structural heart disease 2. Subject has recurrent symptomatic sustained (\> 30 seconds) monomorphic ventricular tachycardia (MMVT) within 180 days prior to planned study ablation that meets the following criteria: 1. At least 3 episodes of the MMVT have been treated with ATP and/or shock, OR at least 2 episodes were treated with shock AND 2. Documentation of the presumed recurrent MMVT was treated with prior catheter ablation AND 3. Occurred despite treatment with at least one Class III antiarrhythmic after last ablation or treatment with a Class III antiarrhythmic is not tolerated or is contraindicated AND 4. VT has recurred despite VT ablation at one of the investigational centers UORU the investigator documents the reason that the subject is unlikely to benefit from a repeat ablation using a conventional, approved catheter. 3. Subject is at least 18 years old 4. Subject has an implantable cardioverter-defibrillator (ICD) with a full 6-month (prior to planned study ablation) ICD interrogation history documenting incidences of VT 5. Subject is able to provide informed consent Exclusion Criteria: 1. Idiopathic VT (VT occurring in subjects without structural heart disease \[including the absence of LGE on MRI, if performed\], metabolic abnormalities or long QT syndrome) 2. Suspected area of ablation of target clinical VT includes aortic root, aortic cusp or any area outside left ventricle except the ventricular septum 3. Subject with a prior ablation within 4 weeks of planned study ablation 4. Subject's VT is not amenable to treatment with the study device at the time of mapping for the study ablation 5. Only PVCs are induced during mapping for the study ablation 6. No clinical VT induced during mapping for the study ablation 7. Planned use of a non-study ablation catheter 8. Subject has an LVEF \< 20% reported on pre-ablation imaging (CT, MRI or echocardiogram within 48 hours of the study procedure) 9. Subject with evidence of any right- or left-sided (including left atrium, left atrial appendage and left ventricle) intracardiac thrombus OR pericardial effusion (except chronic trivial) reported on required pre-ablation imaging (CT, MRI, or echocardiography) or seen on required procedural intracardiac echocardiography (ICE) prior to study ablation catheter insertion. 10. Subjects with atrial fibrillation/flutter (paroxysmal, persistent, or permanent) without uninterrupted anticoagulation for at least 3 weeks immediately prior to the date of ablation procedure. (Interruption of anticoagulation in the day(s) just prior to ablation will be left to physician decision based upon subject's risk of stroke, anticoagulation agent, renal status, and bleed/embolic risk status with recommendation to consider bridging for high-risk subjects. 11. Subjects with NYHA Class IV heart failure 12. Renal dysfunction with eGFR \<30 ml/min/1.73mP2 13. Subject with known coagulopathy or other condition likely to increase risk of periprocedural bleeding 14. Subject with known coagulopathy or other condition likely to increase risk of a thrombotic event 15. Subject with a mechanical aortic valve, mechanical mitral valve, or MitraClip 16. Subject with flail mitral leaflet or severe aortic stenosis 17. Subject with LAA occlusion device 18. Subject with a congenital heart defect except patent foramen ovale (PFO) 19. Subject with suspected life expectancy of less than 1 year 20. Subject with myocardial infarction (MI) or unstable angina (UA) within previous 90 days 21. Subject with cardiac surgery or percutaneous coronary intervention (PCI) within previous 90 days 22. Subject with known untreated significant ischemic coronary artery disease, acute illness (unrelated to VT or its origin) or active systemic infection. 23. Subject with left ventricular assist device planned or required for the procedure 24. Females who are or may potentially be pregnant (must be post-menopausal or have a negative pregnancy test) 25. Allergy or contraindications to the medications/agents used during a standard ablation/EP intervention including heparin and ionic contrast media 26. Contraindication to cardiac CT 27. Subject concurrently enrolled in any other investigational drug or device study that the investigator deems would interfere with study results 28. Subject with a condition (including a chronic illness) or circumstance that the investigator feels puts the subject at an unacceptable risk for participation in the study or may interfere with quality data collection or study results 29. Subject is not willing or is unable to participate in all study procedures and follow-up requirements \-