Safety and Effectiveness of Left Bundle Branch Area Pacing Versus Conventional Cardiac Resynchronization Therapy in Heart Failure

Inclusion Criteria:

1. Patient is age 18 years or above, or of legal age to give informed consent specificto state and national law

2. Patient meets a guideline-based indication for a de novo CRT-D device

3. Primary prevention indication for ICD therapy

4. Ischemic or nonischemic cardiomyopathy with LVEF ≤ 35% within 6 months of enrollment (LVEF must be assessed after the subject has been on GDMT for a minimum of 3 months)using an appropriate method of assessment (i.e. Echo, MRI, etc)

5. NYHA class II-IV despite maximally tolerated guideline directed medical therapy (GDMT)* for at least 3 months

*GDMT is defined as all four drug classes listed below for at least 3 months priorto enrollment unless the investigator provides justification (e.g., contraindicated,not tolerated or cost): Renin Angiotensin System Inhibitors (ACE, ARB, or ARNI)Evidence based betablockers (metoprolol succinate, carvedilol, bisoprolol)Mineralocorticoid antagonists SGLT2 Inhibitor medications

6. Sinus rhythm with left bundle branch block (LBBB) defined as a QRS ≥ 140 ms in menand ≥ 130 ms in women with a predominantly negative deflection (QS or rS in lead V1and mid QRS notching or slurring in at least two of the following leads: 1, aVL, V1,V2, V5, V6) within 3 months of enrollment

7. Patient is willing to participate in LATITUDE™ NXT remote patient monitoring

8. Patient is willing and capable of providing informed consent and participating inall testing associated with this investigation at an approved study site and at theprotocol defined intervals (Note: Use of a legally authorized representative (LAR)is not allowed)

9. Patient plans to remain geographically stable (not permanently moving to anotherlocation) and can commit to all study participation requirements (procedure,follow-up visits and testing requirements)

Exclusion Criteria:

1. Persistent or permanent atrial fibrillation (AF) within 3 months prior to enrollmentand documented in the medical record

2. Frequent premature ventricular contractions (PVCs), atrial arrhythmias, and/or othercauses of expected percentage of cardiac physiologic pacing (CPP) delivery below 95%at the time of enrollment

3. Non-LBBB conduction abnormalities (including right bundle branch block (RBB) orintraventricular conduction delay (IVCD)) within 3 months prior to enrollment

4. Complete, second degree or high degree atrioventricular (AV) block, that requirespacing at the time of enrollment

5. Current or prior pacemaker, ICD or CRT implant (Also includes non-transvenous ICDtechnology and leadless pacemakers)

6. Prior or planned mechanical or bioprosthetic tricuspid valve replacement

7. Currently receiving or previously received positive inotrope therapy within 3 monthsprior to enrollment

8. Unstable angina, acute myocardial infarction, coronary artery bypass grafting, orpercutaneous coronary intervention within 3 months prior to enrollment

9. History of heart transplantation or left ventricular assist device (LVAD)implantation

10. Less than 1 year of life expectancy at the time of enrollment

11. Anticipated heart transplantation or LVAD implantation within 1 year of enrollment

12. History of ventricular septal defect (VSD)

13. Complex congenital heart disease

14. Documented diagnosis of cardiac amyloidosis

15. Known occlusion or other reason limiting central venous access for transvenous leads

16. Women of childbearing potential who are, or plan to become, pregnant during thecourse of the study (assessment per investigator's discretion)

17. Patient currently requiring dialysis

18. Patient with known or suspected sensitivity to Dexamethasone Acetate (DXA)

19. Patient with contrast dye allergy or unwilling/able to undergo pre-treatment withsteroids and/or diphenhydramine

20. Inability or refusal to comply with the follow-up schedule including subject livingat such a distance from the investigational site that attending follow-up visitswould be unusually difficult or burdensome

21. Patient is enrolled in any other concurrent study. Co-enrollment into other studiessuch as observational studies/registries needs prior written approval by BSC. Localmandatory governmental registries are accepted for co-enrollment without approval byBSC.