Assessment of HDAH 1 year prior to 3 years following index implantation.

Change in NYHA Functional Class from baseline to 1-, 2-, 3-, 4-, and 5-years following the index procedure.

Change in 6-minute walk test (6MWT) from baseline to 1 year following the index procedure.

Change in KCCQ score from baseline to 6 months and 1 year after the index procedure. Scores range from 0 to 100, with higher scores showing better health status and lower scores showing worsen health status.

Change in LVEF, LVESV, LVEDV from baseline to 1-, 2-, 3-, 4-, and 5-years following the index procedure.

Change in QRS duration from baseline to 1-, 2-, 3-, 4-, and 5-years following the index procedure.

Change in eGFR and BNP from baseline to 1-, 2-, 3-, 4-, and 5-years following the index procedure.

An assessment of the incidence of CCM device-related serious complications and non-serious CCM-device-related observations occurring during the 5-year period following the index procedure.

Correlation of CCM % and milliamp (mA) delivered with clinical outcomes and health status

Assess overall battery charging compliance defined as 60 minutes of charging per 10-day period between charging sessions (Expressed as percentage of compliant charging periods per subject over time e.g., number of compliant charging cycles ÷ total expected cycles × 100%).

Impact of ancillary equipment on clinical outcomes at 1- 2-, 3-, 4-, and 5-years following the index procedure. Including but not limited to:

Lead type: style-driven lead, lumenless lead

Guiding sheath/catheter

Assess CCM effectiveness at various timepoints in sub-groups of interest, including but not limited to:

Male vs female <65 vs ≥ 65-year-old Ischemic vs non-ischemic CRT non-responders Patients with concomitant devices (e.g. CRT, pacemaker, LBBP) Patients with wide, intermediate, narrow QRS Patients with cardiac amyloidosis