Ventricular Catheter Ablation Study (VCAS)

INCLUSION: 1. Signed patient informed consent form (ICF). 2. Female and male participants between 18 and 80 years. 3. For VCAS-I group, patients with VT meeting class II-a/b indications in European guideline for catheter ablation, with a clinical VT event detected by an implanted ICD 4. For VCAS-II group, patients with frequent premature ventricular complexes (PVCs) meeting class II-a/b indications based on European guidelines for catheter ablation. 5. For VCAS-II, documentation of frequent PVCs by 24 hours Holter with \>15% PVC burden for asymptomatic patients and \>5% PVC burden for symptomatic patients within the last 60 days. EXCLUSION: 1. Body Mass Index \> 40. 2. Pacemaker dependence. 3. Ineligible for ablation according to Physician judgement (including but not limited to known to have protruding left ventricular thrombus or have implanted mechanical aortic and mitral valves). 4. Recent MI (less than 90 days) or another reversible cause of VT (e.g., electrolyte abnormalities, drug-induced arrhythmia). 5. The presence of inferior vena cava embolic protection filter devices. 6. Recent cardiac surgery (less than 2 months) 7. NYHA Class IV. 8. Hemodynamically severe valvular disease that precludes ablation. Severity will be evaluated by using echocardiography, according to AHA and European guidelines. 9. Uncontrolled abnormal bleeding and/or clotting disorder. 10. Contraindication to systemic or oral anticoagulation. 11. Serious or untreated medical conditions that would prevent participation in the study, interfere with assessment or therapy, or confound data or its interpretation, including but not limited to solid organ or hematologic transplant, or currently being evaluated for an organ transplant. 12. Severe lung disease, pulmonary hypertension, or any lung disease involving abnormal blood gases or significant dyspnea. 13. Chronic renal insufficiency of eGFR\< 30 mL/min/1.73 m2. 14. Active malignancy 15. Untreated clinically significant infection. 16. Life expectancy is less than one year. 17. Clinically significant psychological condition that in the investigator's opinion would prohibit the subject's ability to meet the study requirements. 18. Prohibitively distorted cardiac anatomy due to congenital heart disease. 19. Had a recent percutaneous coronary intervention (\<1 month). 20. Participation in another investigational study or treatment with any investigational drug within the previous 30 days that would interfere with this study. 21. Patient is not able to understand the nature of this study or is unwilling or unable to attend the study procedures. 22. Pregnancy or breastfeeding