Implantable pulse generator system and method for vagal nerve stimulation

An implantable pulse generator system (10) including:

• a. a nerve stimulation unit (80) configured to deliver vagal nerve stimulation pulses,
• b. an autonomic tone sensor (82) configured to generate an autonomic status signal representing a patient's autonomic status, and
• c. a control unit (62):
• (1) connected to the nerve stimulation unit (80) and the autonomic tone sensor (82), and
• (2) configured to control the nerve stimulation unit (80) to deliver vagal nerve stimulation (VNS) having intensity dependent on the autonomic status signal, the intensity of the delivered vagal nerve stimulation (VNS):
• (a) increasing along a first pathway when the autonomic status signal indicates an autonomic tone that is shifting toward greater sympathetic dominance, and
• (b) decreasing along a second pathway when the autonomic status signal indicates an autonomic tone that is shifting toward greater parasympathetic dominance,
• wherein the first and second pathways differ.