Could two pacing leads be better than one for failing hearts?

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * Subject meets current ACC/AHA/HRS guidelines for implantation of a CRT-D device. * Subject has documented LVEF ≤ 35% within 60 days of enrollment. * Subject meets the criteria for presence of Strauss-defined LBBB. * Subject meets NYHA classification II or III. * Subject is willing and able to provide written consent. * Subject is at least 18 years of age at the time of consent. * Subject is geographically stable and willing and able to complete study procedures, including follow-up visits. * The subject's medical records must be accessible by the enrolling site over the follow-up period. Exclusion Criteria: * Subject has documented myocardial infarction before enrollment. * Subject has non-LBBB conduction patterns such as Right Bundle Branch Block (RBBB) or non-specific IVCD. * Subject has 2nd or 3rd degree AV block. * Subject has persistent or permanent atrial fibrillation (AF) or atrial flutter (AFL). * Subject has intrinsic (non-paced) QRS duration ≤ 120ms. * Subject with previous or existing pacemaker (including transvenous and transcatheter pacing system), Implantable Cardioverter Defibrillator (ICD, transvenous) or CRT-D (transvenous) device or leads. * Subject has contraindications for screw-in transvenous lead placement (e.g., mechanical right heart valve). * Subject underwent valve surgery within 90 days prior to enrollment. * Subject is unable or unwilling to undergo baseline CMR imaging, if previously collected CMR images are unavailable or do not meet minimum acceptable criteria. * Subject is post-heart transplantation or is actively listed on the transplantation list. * Subject is implanted with a left ventricular assist device (LVAD). * Subject has severe renal disease. * Subject is on continuous or uninterrupted infusion (inotropic) therapy for heart failure. * Subject has complex and uncorrected congenital heart disease. * Subject has life expectancy of less than 12 months. * Subject is pregnant or breastfeeding. * Subject is enrolled or planning to enroll in a concurrent clinical study that may confound the results of this study, without documented pre-approval from a Medtronic study manager.