Safety and Effectiveness of the Sphere-9™ Catheter and Affera™ Ablation System for the Treatment of Ventricular Tachycardia (Sphere VT)

Inclusion criteria

• Prior myocardial infarction (MI).
• At least one episode of sustained (continuous for \>30 seconds or requiring ICD intervention for termination) monomorphic ventricular tachycardia within the 6 months prior to enrollment.
• Recurrence of sustained ventricular tachycardia despite Class I or III antiarrhythmic drug therapy or ICD intervention.
• Implanted with an implantable cardiac defibrillator (ICD) or CRT-D for at least 2 months prior to the ablation procedure.
• Age 18 through 85 years old.
• Willing and able to provide informed consent.
• Willing and able to comply with all pre-, post-, and follow-up testing requirements.

Exclusion criteria

• Incessant VT necessitating hemodynamic support prior to the ablation procedure.
• Unstable polymorphic VT or ventricular fibrillation (VF).
• Idiopathic VT or VT of non-ischemic cardiomyopathy.
• VT secondary to electrolyte imbalance, active thyroid disease, or any other reversible or non-cardiac cause (e.g., drug-induced arrhythmia).
• VT or VF thought to be from channelopathies.
• More than two prior VT ablations at any time, more than one prior VT ablation within 12 months prior to the ablation procedure, or any VT ablation within 4 weeks prior to the ablation procedure.
• Sarcoidosis.
• Hypertrophic cardiomyopathy, except when due to an apical aneurysm.
• Unstable angina.
• Active myocardial ischemia.
• Type 1 myocardial infarction within 2 months (60 days) prior to the ablation procedure.
• Any percutaneous coronary intervention performed in a setting of unstable angina or acute MI (STEMI or non-STEMI) within 2 months (60 days) prior to the ablation procedure. Note: elective PCI performed during elective angiogram would be excluded only if occurring within 30 days prior to the ablation procedure.
• Any cardiac surgery within 2 months (60 days) prior to the ablation procedure. Note: ICD lead implant/replacement falls under this exclusion, but ICD generator-only replacement does not.
• Left ventricular ejection fraction (LVEF) \<15%.
• NYHA Class IV heart failure.
• Decompensated heart failure.
• Extravascular ICD (EV-ICD) or subcutaneous ICD (S-ICD)
• Currently receiving support, or anticipated to receive support prior to the index ablation procedure, via extracorporeal membrane oxygenation (ECMO).
• Circulatory/ventricular assist device (VAD; surgical or percutaneous) implanted, planned or required for the procedure.
• Severe aortic or mitral stenosis, or severe aortic or mitral regurgitation.
• Presence of prosthetic valve in the aortic or mitral valve.
• Patients with advanced COPD (on home oxygen).
• Presence of intracardiac tumor or other abnormality that precludes vascular access, catheter introduction, or manipulation.
• Thromboembolic event (stroke or transient ischemic attack) within 6 months (180 days) prior to the index ablation procedure or with neurologic deficit.
• Left atrium (LA) or left ventricle (LV) intracardiac thrombus on imaging.
• Severe bleeding, clotting or thrombotic disorder, or thrombocytopenia (defined as platelet count \<80,000).
• Contraindication to anticoagulation.
• End-stage renal disease (requiring dialysis).
• Acute illness, active infection, or sepsis.
• Life expectancy less than 12 months.
• Any woman known to be pregnant or breastfeeding, or any woman of childbearing potential who is not on a reliable form of birth regulation method or abstinence.
• Body mass index \>45 kg/m2.
• Known ongoing drug or alcohol dependency.
• Current or anticipated participation in any other ongoing study of a drug, device, or biologic during the duration of the study not pre-approved by the Sponsor.
• Vulnerable subjects (such as a prisoner, handicapped or mentally disabled person, or person under tutelage or guardianship).
• Any other condition that, in the opinion of the investigator, would preclude enrollment in this study or compliance with follow-up requirements or would pose a significant hazard to the subject if an ablation procedure were performed.