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

Sphere VT is a prospective, multi-center, single-arm, unblinded pivotal clinical study. Adult subjects with recurrent, sustained, monomorphic ventricular tachycardia (MMVT) due to prior myocardial infarction (MI) will be enrolled and treated with the Sphere-9 Catheter and Affera Ablation System.

Inclusion Criteria: 1. Prior myocardial infarction (MI). 2. 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. 3. Recurrence of sustained ventricular tachycardia despite Class I or III antiarrhythmic drug therapy or ICD intervention. 4. Implanted with an implantable cardiac defibrillator (ICD) or CRT-D for at least 2 months prior to the ablation procedure. 5. Age 18 through 85 years old. 6. Willing and able to provide informed consent. 7. Willing and able to comply with all pre-, post-, and follow-up testing requirements. Exclusion Criteria: 1. Incessant VT necessitating hemodynamic support prior to the ablation procedure. 2. Unstable polymorphic VT or ventricular fibrillation (VF). 3. Idiopathic VT or VT of non-ischemic cardiomyopathy. 4. VT secondary to electrolyte imbalance, active thyroid disease, or any other reversible or non-cardiac cause (e.g., drug-induced arrhythmia). 5. VT or VF thought to be from channelopathies. 6. 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. 7. Sarcoidosis. 8. Hypertrophic cardiomyopathy, except when due to an apical aneurysm. 9. Unstable angina. 10. Active myocardial ischemia. 11. Type 1 myocardial infarction within 2 months (60 days) prior to the ablation procedure. 12. 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. 13. 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. 14. Left ventricular ejection fraction (LVEF) \