System for determining the physical activity of a patient by measuring the blood oxygen saturation.

摘要

A and system for determining the physical activity of a patient senses the minimum blood oxygen saturation in the right atrium (38) of the patient's heart (36) and uses such minimum blood oxygen saturation as a control parameter for indicating the muscular activity of the patient. Because the oxygen content of the venous blood in the right atrium varies significantly as venous blood from all parts of the body is introduced therein, evidencing differing levels of oxygen demand throughout the patient's body, the minimum oxygen content of the venous blood provides an accurate and reliable measure of those portions of the patient's body experiencing the greatest oxygen demand, i.e., experiencing muscular activity. The determined minimum blood oxygen saturation can be used to control the stimulating rate of a pacemaker. <IMAGE>