The purpose of this post-approval study is to evaluate the acute and chronic performance of a Quadripolar CRT-D device system in a patient population indicated for cardiac resynchronization therapy (CRT).

Quad PAS is a multi-center, post-approval study. Patients who meet inclusion/exclusion criteria will have an attempted implant of a Quadripolar CRT-D device system (device and left ventricular (LV) lead). Patients who have an unsuccessful implant will be followed for 30 days for any adverse events and then withdrawn from the study, or may have an implant reattempted if the physician chooses to do so. Patients enrolled in the study will be followed at 6 months, and every 6 months thereafter, for 60 months of follow up (5 years). After patients complete 60 months of follow-up, their participation in the study will be terminated.

Inclusion Criteria:

1. Approved indication per current American College of Cardiology/American Heart Association/Heart Rhythm Society guidelines for implantation of a CRT-D system for treatment of heart failure or life threatening ventricular tachyarrhythmia(s).
2. Participated in the Promote® Q CRT-D and Quartet™ Left Ventricular Heart Lead Study (Investigational Device Exemption (IDE) study), or are receiving a new Quadripolar CRT-D device system implant or are undergoing an upgrade from an existing implantable cardioverter-defibrillator or pacemaker implant with no prior LV lead placement.
3. Have the ability to provide informed consent for study participation and be willing and able to comply with the prescribed follow-up tests and schedule of evaluations

Exclusion Criteria:

1. Have a hypersensitivity to a single 1.0mg dose of dexamethasone sodium phosphate
2. Have a life expectancy of less than 5 years due to any condition
3. Be less than 18 years of age

Patients indicated for CRT.