Safety and Performance of Electrodes Implanted in the Left Ventricle

Inclusion Criteria: Patients with standard indications for CRT based upon the most recent ESC/EHRA guidelines AND meeting criteria for one of these two categories: 1. Patients with previously implanted pacemakers or ICD's and meeting standard indications for CRT but in whom standard CRT is not advisable due to known high risk - referred to as "upgrades". Justifications for not using standard CRT must be documented in a CRF. 2. Patients in whom coronary sinus lead implantation or attempted implantation for CRT has failed to provide demonstrable therapy benefit - referred to as "untreated" Exclusion Criteria: 1. Inability to comply with the study follow-up or other study requirements 2. History of chronic alcohol/drug abuse and currently using alcohol/drugs 3. Non-ambulatory (or unstable) NYHA class 4 4. Contraindication to heparin 5. Contraindication to both chronic anticoagulants and antiplatelet agents 6. Triple anticoagulation therapy (warfarin, clopidogrel, ASA, and other agents) 7. Thrombocytopenia (platelet count \<150,000) 8. Contraindication to iodinated contrast agents 9. Intracardiac thrombus by transesophageal echocardiography 10. Age less than 18 years or greater than 75 11. Attempted IPG implant within 3 days 12. Life expectancy of less than 12 months 13. Chronic hemodialysis 14. Stage 4 or 5 renal dysfunction defined as GFR \<30 15. Grade 4 mitral valve regurgitation 16. Myocardial infarction within one month 17. Major cardiac surgery within one month 18. History of a pericardial effusion in prior procedures 19. Female of childbearing potential, pregnant, or breastfeeding (a pregnancy test will be obtained where applicable) 20. Non-cardiac implanted electrical stimulation therapy devices