Clinical Study of the EASYTRAK 3 Spiral Fixation Coronary Venous Bipolar Pace/Sense Lead

Inclusion Criteria: Moderate to severe heart failure (NYHA Class III/IV) including left ventricular dysfunction (EF <= 35%) and QRS duration >= 120 ms remaining symptomatic despite stable, optimal heart failure drug therapy. Creatinine < 2.5 mg/dL obtained no more than two weeks prior to enrollment. Age 18 or above, or of legal age to give informed consent specific to state and national law. Willing and capable of providing informed consent, undergoing a device implant, participating in all testing associated with this clinical investigation at an approved clinical investigational center and at the intervals defined by this protocol. Exclusion Criteria: A known hypersensitivity to a 1.0 mg (0.5 mg per electrode) dose of dexamethasone acetate. Previous cardiac resynchronization therapy, a coronary venous pace/sense lead or attempted LV lead placement. Pre-existing cardioversion/defibrillation leads other than those specified in this investigational plan (unless the investigator intends to replace them with permitted cardioversion/defibrillation leads). Requiring dialysis. A myocardial infarct, unstable angina, percutaneous coronary intervention, or coronary artery bypass graft during the preceding 30 days prior to enrollment. Hypertrophic obstructive cardiomyopathy or infiltrative cardiomyopathy (e.g., amyloidosis, sarcoidosis). A documented life expectancy of less than 6 months or expected to undergo heart transplant within 6 months. Enrolled in any concurrent study, without prior Guidant written approval, that may confound the results of this study. Have a mechanical tricuspid heart valve.