Effects of CCM-therapy in Patients With Heart Failure

Inclusion Criteria (treatment group): * Any subject who receives an OPTIMIZER system implant and provides informed consent Exclusion Criteria (treatment group): * None Inclusion Criteria (control group): * Symptomatic heart failure (NYHA Class 2, 3 or 4) despite receiving optimal medical therapy with doses of medications that are stable (no more than 50 % variation) for at least 7 days. * EF ≤ 45% * Signed informed consent Exclusion Criteria (control group): * Heart failure due to a potentially correctible cause ( e. g. valvular disease, congenital disease) * Idiopathic hypertrophic cardiomyopathy, restrictive or constrictive cardiomyopathy, or heart failure on the basis of a known inflammatory or infiltrative disease (e. g. amyloidosis, sarcoidosis) or constrictive disease * Active ischemia or exercise tolerance limited by angina * Hospitalizations for heart failure which required the use of inotropic support within 14 days of enrollment * Chronic (permanent or persistent) atrial fibrillation or atrial flutter * Scheduled for a CABG or a PCI procedure, or has undergone a CABG procedure within 90 days or a PCI procedure within 30 days of enrollment * Myocardial infarction within 90 days of enrollment * Hemodialysis or peritoneal dialysis * Prior heart transplant * Participating in another study