Patent ID: 7164948

Claim:
An implantable medical device comprising: a pulse generator that delivers a first pacing pulse to a left ventricle and a second pacing pulse to a right ventricle following a pacing interval; an oxygen saturation monitor that monitors a first blood oxygen saturation level in the left ventricle and a second blood oxygen saturation level in the right ventricle; a processor that adjusts the pacing interval as a function of the first and second blood oxygen saturation levels; a memory storing oxygen consumption data for the patient, wherein the processor computes cardiac output according to the Fick method based on the first and second blood oxygen saturation levels and the oxygen consumption data, and the hemoglobin data, and adjusts the pacing interval as a function of the computed cardiac output; and an activity level sensor that senses an activity level of the patient, wherein the memory stores oxygen consumption data for different activity levels of the patient, and the processor computes the cardiac output based on oxygen consumption data in the memory that corresponds to the sensed activity level.