The purpose of this clinical investigation is to evaluate the safety and hemodynamic performance of the MSLV Pacing feature in a clinical setting.

To evaluate the hemodynamic impact of different pacing MSLV configurations.

Inclusion Criteria:

• Patients who have a recognised indication to receive a CRT-D device or an upgrade from a pacemaker or ICD to a CRT-D system.
• Patients have signed an informed consent form indicating their willingness to participate to this study.

Exclusion Criteria:

• Patients who are unable to comply with the follow-up schedule based on their geographic location or for any reason.
• Patients with second or third degree AV Block
• Patients with intrinsic atrial rhythm < 40 bpm
• Patients with a previously implanted left ventricular pacing lead.
• Patients who are pregnant.
• Patients currently participating in a clinical investigation that includes an active treatment arm.
• Patients under 18 years of age.
• Patients with a life expectancy of less then 6 months.

Patients with standard CRT-D indications