Device Evaluation of Contak Renewal 2and Easytrak 2 - DECREASE-HF

Inclusion Criteria: * Meet the general indications for a CRT-D device * Moderate or severe heart failure, defined as NYHA Class III-IV despite optimal pharmacological heart failure therapy. * A 12-lead electrocardiogram (ECG) obtained no more than 90 days prior to enrollment documenting a sinus rate \> 50 bpm, QRS duration ³ 150 ms, and PR interval £ 320 ms measured from any two leads, and a P-wave duration \< 150 ms measured from lead V1 * Creatinine £ 2.5 mg/dL obtained no more than 14 days prior to enrollment * Left ventricular ejection fraction £ 35% \[measured by echo, multiple gated acquisition (MUGA) scan, cardiac catheterization, etc.\] no more than 14 days prior to enrollment * Willing and capable of undergoing a device implant and participating in all testing associated with this clinical investigation * Have a life expectancy of more than 180 days, per physician discretion * Age 18 or above, or of legal age to give informed consent specific to state and national law Exclusion Criteria: * Right bundle branch block morphology (per World Health Organization Guidelines) on a 12-lead ECG obtained no more than 90 days prior to enrollment. * Have had previous cardiac resynchronization therapy, a previous coronary venous lead, or meet the general indications for antibradycardia pacing * Have a neuromuscular, orthopedic, or other non-cardiac condition that prevents normal, unsupported walking * Have an atrial tachyarrhythmia that is permanent (i.e., does not terminate spontaneously and cannot be terminated with medical intervention) or persistent (i.e., can be terminated with medical intervention, but does not terminate spontaneously) within 180 days prior to enrollment * Have a hypersensitivity to a 0.7 mg dose of dexamethasone acetate * Have surgically uncorrected primary valvular heart disease * Currently requiring dialysis * Have chronic obstructive pulmonary disease (COPD), defined as FEV1/FVC \< 60% * Have had a myocardial infarct, unstable angina, percutaneous coronary intervention, or coronary artery bypass graft during the 30 days prior to enrollment * Have hypertrophic obstructive cardiomyopathy or infiltrative cardiomyopathy (e.g., amyloidosis, sarcoidosis) * Have a mechanical tricuspid prosthesis * Enrolled in any concurrent study, without Guidant written approval, that may confound the results of this study.