Oxygen pressure as biosensor for rate adaptive cardiac pacing

A new carbon based oxygen sensor for rate adaptive cardiac pacing has been developed. It measures oxygen partial pressure In mixed venous blood. The system was implanted in six sheep with a mean follow-up time of 261 days after implant. The sensor reacted in a physiological manner when the animals were at rest as well as during exercise. Long-term sensor stability and sensitivity were satisfactory, and we found excellent correlation with spontaneous heart rate variations and with oxygen saturation measurements. The sensor shows great promise although our experience is still limited and further development on the concept is on-going.