Dual Site Left Ventricular (LV) Pacing (DIVA)

Inclusion Criteria:

• Moderate or severe heart failure, defined as NYHA Class III-IV despite optimal pharmacological heart failure therapy
• On heart failure medical regimen (beta blockers and ACE-I or ARB's) for at least one month before randomization
• A 12-lead electrocardiogram (ECG) obtained no more than 90 days prior to enrollment documenting a QRS duration > 120 ms
• Left ventricular ejection fraction (LVEF) < 35% or equal
• Willing and capable of undergoing the device implant procedure and participating in all testing associated with this clinical study
• Have a life expectancy of more than 180 days, per physician discretion
• Age 40 or above, ensuring of legal age to give informed consent specific to state and national law

Exclusion Criteria:

• Have had previous cardiac resynchronization therapy or a previous coronary venous lead
• Unable to perform a Six-Minute Hall Walk (6MHW) Test
• Have an atrial tachyarrhythmia that is permanent (i.e., does not terminate spontaneously and cannot be terminated with medical intervention)without CHB or planned AVJ ablation prior to randomization
• Have an atrial tachyarrhythmia that is persistent (i.e. can be terminated with medical intervention, but does not terminate spontaneously) without planned and successful cardioversion prior to randomization (patients with unsuccessful cardioversions and no AVJ Ablation will be exited.)
• Have hypertrophic obstructive cardiomyopathy or infiltrative cardiomyopathy (e.g., amyloidosis, sarcoidosis)
• Have a mechanical tricuspid prosthesis
• Has severe aortic or mitral stenosis
• Enrolled in any concurrent study that may confound the results of this study
• Patients who are or suspect they may be pregnant or plan to become pregnant