This study will collect data, from an implanted Cardiac Resynchronization Therapy-Defibrillator (CRT-D) device, to further evaluate a new feature for future heart failure devices.

ELEVATE 2.0 is an acute, prospective, multi-center, feasibility study randomized within patient test sequence and pulse width, designed to characterize the performance of the Left Ventricular Auto Threshold (LVAT) feature.

Inclusion Criteria:

• Patients who have a COGNIS CRT-D device implanted for at least 24 hours, with or without a right atrial lead
• Patients who have an active LV bipolar lead
• Patients who have an active right ventricular (RV) defibrillation lead
• Patients who are willing and capable of participating in all testing associated with this Clinical Investigation
• Patients who are age 18 or above, or of legal age to give informed consent specific to state and national law

Exclusion Criteria:

• Patients who have a COGNIS CRT-D that has less than or equal to one year of battery life remaining
• Patients who are pacemaker-dependent
• Patients who will not tolerate a pacing pause of up to 6 seconds
• Patients who have a unipolar LV pace/sense lead, unless the patient has any commercially available epicardial leads with at least two electrodes (from one or more leads)
• Patients with pre-existing leads other than those specified in this investigational plan
• Patients with a pre-existing unipolar pacemaker
• Patients who are unable or unwilling to maintain a supine or sitting position for 40-50 minutes
• Patients enrolled in any concurrent study, without Boston Scientific written approval
• Women who are pregnant

The study population will be a sample of patients with COGNIS CRT-D devices and bipolar LV leads.