Patent ID: 6334071
Filing Date: 2001-12-25
Classification: A61N

Abstract:
An implantable cardiac stimulator comprising:a housing having two external electrodes formed thereon;a unipolar lead electrically isolated from the housing but extending therefrom and terminating at a distal electrode adapted for location in the heart of a patient;a pulse generator disposed within the housing and generating stimulation pulses on the lead in response to trigger signals;a metabolic demand detector that detects the metabolic demand of the patient and generates a metabolic demand parameter, the metabolic demand detector including a test pulse generator that generates a test pulse between one of the two external electrodes and the distal electrode, and a test sensor that senses voltage developed in response to the test pulse between the second of the two external electrodes and the distal electrode, the metabolic demand parameter being dependent on the sensed voltage; anda control and timing circuit that generates the trigger signals at a rate determined by the magnitude of the metabolic demand parameter.