In some examples, this disclosure describes techniques for assessing hemodynamic intolerance of ventricular pacing. A method comprises sensing a parameter indicative of autonomic tone during a first period in which a medical device delivers ventricular pacing to a patient, sensing the parameter indicative of autonomic tone during a second period in which the medical device does not deliver ventricular pacing to the patient, and assessing a level of change in autonomic tone in the patient induced by ventricular pacing based on values of the sensed parameter during the first and second periods.
