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.