The primary objective of the protocol was to allow ongoing access to treatment of patients suffering from moderate to severe heart failure at selected investigational sites until the PMA was approved by the FDA for the OPTIMIZER System.

This is a multicenter, prospective, single-arm Continued Access study of the Optimizer Smart System with CCM therapy.

The Continued Access study is a prospective, non-randomized, multi-center study designed to allow controlled access to the Optimizer Smart System until the PMA order has been issued by the FDA.

Inclusion Criteria:

1. Subjects who are 18 years of age or older
2. Subjects who have a baseline ejection fraction greater than or equal to 25% and less than or equal to 45% by echocardiography.
3. Subjects who, in the opinion of the Investigator (based on the current guidelines for clinical practice), have been treated for heart failure for at least 90 days and are currently receiving appropriate, stable medical therapy during the 30 days prior to enrollment for treatment of heart failure.
4. Subjects who are in New York Heart Association functional Class III and IV at the time of enrollment.
5. Subjects who are willing and able to return for all follow-up visits.

Exclusion Criteria:

1. Subjects who have a potentially correctible cause of heart failure, such as valvular heart disease or congenital heart disease.
2. Subjects receiving any form of inotropic support within 30 days before enrollment, including subjects on continuous IV inotrope therapy.
3. Subjects hospitalized for decompensated heart failure requiring acute treatment with intravenous loop diuretics, IV inotropes or hemofiltration within 30 days before enrollment and baseline testing.
4. Subjects who have a clinically significant amount of ambient ectopy, defined as more than 8,900 PVCs per 24 hours on baseline Holter monitoring.
5. Subjects having a PR interval greater than 375ms.
6. Subjects who are scheduled for a CABG or a PTCA procedure, or who have undergone a CABG procedure within 90 days or a PTCA procedure within 30 days of enrollment.
7. Subjects who have a biventricular pacing system, an accepted indication for such a device, or a QRS width of 130ms or greater.
8. Subjects who have had a myocardial infarction within 90 days of enrollment.
9. Subjects who have mechanical tricuspid valve.
10. Subjects who have a Left Ventricular Assist Device or prior heart transplant.
11. Subjects on dialysis.
12. Subjects who are participating in another experimental protocol.
13. Subjects who are unable to provide informed consent.

The Publication Committee shall consist of the National PIs and Impulse Dynamics representatives. All abstracts and papers of the multi-center publications will be reviewed by members of the publication committee and all authors. When appropriate, the publication committee will collect comments and resolve final draft issues. If a paper is rejected, the publication committee and its authors will decide the next course of action.