INcrease Of VAgal TonE in CHF

Prospective, Randomized (3:2 active:control), Open Label, Event-driven Interventional Study. All subjects undergo the following: Baseline, Randomization, (Implantation \& Optimization for subjects randomized to the active therapy), and Follow-up Period, followed by an Extension period, which lasts until the end of the study. The Clinical Events Committee (CEC) and Data Monitoring and Safety Board (DSMB) will conduct scheduled independent reviews of the data at the following time-points in order to ensure that an ongoing acceptable safety profile is being achieved.