CLINICAL TRIAL / NCT05650658

Inclusion Criteria: - Men and women 18 years of age or older. - A LVEF ≤ 50% within 6 months prior to enrollment. - Resting QRS duration ≥130 ms as evidenced by a historical 12-lead ECG prior to enrollment OR anticipated right ventricular pacing >40% OR device in place with right ventricular pacing > 40%. - Are optimized on HF guideline directed medical therapy according to current HF published guidelines. Exclusion Criteria: - Women who are pregnant, lactating, or plan to become pregnant during the course of the trial. - Participants with angiographic evidence of coronary disease who are candidates for coronary revascularization and are likely to undergo coronary artery bypass graft surgery or percutaneous coronary, intervention in the next three (3) months. - Enzyme-positive myocardial infarction within the past three (3) months prior to enrollment. - Coronary artery bypass graft surgery or percutaneous coronary intervention (balloon and/or stent angioplasty) within the past three (3) months prior to enrollment. - Reversible non-ischemic cardiomyopathy (e.g., acute viral myocarditis). - Participants with Chagas disease, cardiac sarcoidosis or amyloidosis. - Expected to receive left ventricular assist device or heart transplantation within 6 months. - Participants with severe valvular disease (e.g., aortic stenosis). - Have a life expectancy of less than 12 months. - Participants with irreversible brain damage from preexisting cerebral disease. - Participants with a contrast dye allergy unable or unwilling to undergo pretreatment with steroids and/or diphenhydramine. - Participants participating in any other interventional cardiovascular clinical trial. - Participants who would be unable to return for follow-up visits due to the distance from the clinic. - Participants who do not anticipate being a resident of the area for the scheduled duration of the trial.