A system for treating a medical condition in a patient who has a vagus nerve and a heart that generates a cardiac signal that has a portion of the QRS wave (174), the system comprising: - a sensor (210A or 210B) configured to detect at least a portion of the portion of the QRS wave of the heart signal； - an electric signal generator (200) capable of identifying the portion of the R wave of at least a portion of the QRS wave portion of the heart signal； - the cardiac signal, where each portion of the R wave is separated from a portion of the successive R wave by an R-R interval, each R-R interval has a duration and a previous R-R interval that precedes it； and - an electrode (220A or 220B) in electrical communication with the vagus nerve, the electrode that is configured to deliver the pulsed electrical signal to the patient's vagus nerve, the pulsed electrical signal that lasts less than about a second, where The pulsed electrical signal is generated in a series of microbursts that have one last pulse, each pulse different from the last pulse in the series that is separated from a successor pulse in the series by an interpulse interval, each interpulse interval that is less than approximately 40 milliseconds, where in a series of microbursts, each microburst (170) comprising 2 to 20 electrical pulses, and each of the microbursts that occur after a portion of the selected R wave of the cardiac cycle, where each of the microbursts are delayed relative to the portion of the R wave selected to simulate the endogenous afferent activity that occurs at a particular time in the cardiac cycle, characterized in that the electric signal generator is further configured to generate a pulsed electrical signal in the shortening RR intervals during heart rate variability (HRV), so that a signal is generated only in an R wave that has a RR interval less than the preceding RR interval, or less than a moving average during several RR intervals.Un sistema para tratar una condición médi
