An implantable device (11) for evaluating autonomic cardiovascular drive in a patient (10) suffering from chronic cardiac dysfunction is provided. A stimulation therapy lead (13) includes helical electrodes (14) configured to conform to an outer diameter of a cervical vagus nerve sheath, and a set of connector pins (28) electrically connected to the helical electrodes (14). A neurostimulator (12) includes an electrical receptacle (25) into which the connector pins (28) are securely and electrically coupled. The neurostimulator (12) also includes a pulse generator configured to therapeutically stimulate the vagus nerve through the helical electrodes (14) in alternating cycles of stimuli application and stimuli inhibition (90) that are tuned to both efferently activate the heart's intrinsic nervous system and afferently activate the patient's central reflexes by triggering bi-directional action potentials. The neurostimulator (12) includes a recordable memory (29) storing a baseline heart rate.
