Various system embodiments comprise a myocardial stimulator, at least one sensor adapted for use in detecting heart rate to determine heart rate turbulence (HRT), and a controller connected to the myocardial stimulator and the at least one sensor. The myocardial stimulator is adapted to deliver pacing pulses through at least one electrode to provide cardiac pacing. The controller is adapted to intermittently deliver a sequence of stress-inducing pacing pulses adapted to increase sympathetic tone during the stress-inducing pacing. The controller is further adapted to determine HRT from the detected heart rate to assess cardiac stress to the stress-inducing pacing pulses, and adjust at least one parameter of the stress-inducing pacing pulses to adjust cardiac stress if the cardiac stress to the stress-inducing pacing pulses is undesirable.