Strategic Management to Improve CRT Using Multi-Site Pacing Post Approval Study (Reference # C1918)

Evaluate the effectiveness of Boston Scientific (BSC)'s LV MSP (Left Ventricular MultiSite Pacing) feature in the Resonate family of CRT-D devices and confirm safety in a post approval study when used in accordance with its approved labeling.

Inclusion criteria

• Subjects who received de novo implantation of BSC's Resonate family of CRT-D devices with the LV MSP feature4 and BSC's ACUITYTM X4 LV Quadripolar leads. A Resonate family of CRT-D device upgrade from previous single or dual chamber pacemaker or ICD implantation is allowed.
• Subjects must meet BSC labeled indication for CRT-D implantation.
• Subjects must have a functional RA lead and RV lead implanted
• Subjects who are willing and capable of providing informed consent
• Subjects who are willing and capable of participating in all testing/visits associated with this clinical study at an approved clinical study center and at the intervals defined by this protocol
• Subjects who are age 18 and above, or of legal age to give informed consent specific to state and national law

Exclusion criteria

• Subjects who received LV pacing prior to receiving the Resonate family of CRT-D system implantation.
• Subjects who received the LV MSP therapy post CRT-D implantation but prior to enrollment
• Subjects with documented history of permanent AF
• Subjects with documented permanent complete AV block
• Subjects who are expected to receive a heart transplant during the 12 months course of the study
• Subjects with documented life expectancy of less than 12 months
• Subjects who enrolled in any other concurrent study or registry, with the exception of mandatory national or governmental registry, without prior written approval from BSC