Abstract: The activity sensing pacemaker comprises: a heart pulse sensing device for sensing heart pulses; pulse generating circuitry for generating pacing pulses; activity sensing structure and circuitry for sensing activity/movement of a patient wearing the pacemaker in one or more of three directions/dimensions, x, y, z, and for causing the pulse generating circuitry to generate pacing pulses at a rate/frequency related to the movements sensed; and, control circuitry coupled to the heart pulse sensing device, to the pulse generating circuitry and to the activity sensing structure and circuitry for controlling the pulse generating circuitry in response to the heart pulses sensed or in response to the patient movements sensed, the activity sensing structure and circuitry causing generation of control pulses related to the movements of the patient and the control circuitry including frequency sensing circuitry for sensing the frequency of the control pulses generated and for controlling the rate/frequency of the pacing