1. A method of treating a medical condition in a patient having a brain, a vagus nerve, and a heart that generates a cardiac signal having a QRS wave portion, the method comprising: identifying a select portion of the QRS wave portion of the patient's cardiac signal; after identifying the select portion of the QRS wave portion and before identifying a select portion of a next sequential QRS wave portion, generating at least one microburst, the-at least one microburst being patterned and comprising 2 to 20 electrical pulses, adjacent ones of the electrical pulses being separated from one another by an interpulse interval of less than about 40 milliseconds; and delivering the at least one microburst directly to a selected location on the vagus nerve of the patient, the at least one microburst delivered to the vagus nerve evoking a response in the brain of the patient, wherein the pulses of the at least one microburst are spaced apart to simulate endogenous afferent activity occurring at a particular time in the cardiac signal and enhance a vagal evoked potential evoked in the brain.