The CCS has 4 components: New York Heart Association (NYHA) functional classification, Patient Global Assessment (PGA), heart failure (HF) events, cardiovascular death. NYHA Class ranges from Class I (least severe) to Class IV (most severe); possible PGA responses are "markedly worse", "moderately worse", "slightly worse", "no change", "slightly better", "moderately better, "markedly better". CCS components were used to classify or score subjects as "IMPROVED" (at least one-class improvement in NYHA Class or improvement by PGA "moderately" or "markedly" better AND no HF events AND no cardiovascular death), or "WORSENED" (worsening in NYHA Class OR worsening by PGA "moderately" or "markedly" worse OR presence of HF events OR Cardiovascular death, or "UNCHANGED" (neither "improved" or "worsened"). Note CCS is not a numeric score. A responder is defined as improved or unchanged from baseline and non-responder is defined as worsened from baseline.

The analysis population includes any subjects whose device is programmed with MPP.

The change in the Minnesota Living with Heart Failure (MLWHF) questionnaire score between baseline and 12 months (12 months - baseline).

MLWHF score: the total scale is from 0 to 105, with higher scores indicating worse health status.

The analysis population includes any subjects whose device is programmed with MPP.

The duration of MPP programming in months in the treatment groups.

The analysis population includes any subjects whose device is programmed with MPP.

The number of MPP programming optimizations per subject

The analysis population includes any subjects whose device is programmed with MPP.

HF event is defined as any one of the following when the subject has symptoms and/or signs consistent with congestive heart failure:

• Hospitalization for HF ≥ 24 hours
• Clinic or hospital visit for HF<24 hours (i.e. outpatient treatment, observational care, ER, Urgent Care and physician's office visit) requiring administration of IV diuretics, inotropes, and/or vasodilators

The analysis population includes any subjects whose device is programmed with MPP.

Number of subjects with cardiovascular hospitalization as reported by the sites

The analysis population includes any subjects whose device is programmed with MPP.

Number of subjects with heart failure 30-day hospitalization as reported by the sites

The analysis population includes any subjects whose device is programmed with MPP.

Overall mortality rate for all subjects who started the trial is summarized.

The analysis population includes any subjects who started the trial.

Change in left ventricular ejection fraction between baseline and 12 months (12 months - baseline)

The analysis population includes any subjects whose device is programmed with MPP. LVEF was optional data point in the study. Results were available from a very small number of subjects.

Change in left ventricular end systolic volume between baseline and 12 months (Baseline - 12 months)

The analysis population includes any subjects whose device is programmed with MPP. LVESV was optional data point in the study. Results were available from a very small number of subjects.