An algorithm for determining pacemaker rate based on temperature variations

Rate-modulating pacemakers sense one of several biological quantities to determine the appropriate heart rate. The authors investigate the use of the temperature of blood in the right ventricle of the heart, which is metabolically based and not voluntarily controllable, as the determining parameter. Using telemetered blood temperature recordings, a novel algorithm to control pacing rate was evaluated. The evaluation was based on the algorithm´s ability to respond to the variations in temperature which occurred during exercise, as compared to the normal heart rate response and the response time of the algorithm. The algorithm was sufficiently sensitive to provide appropriate pacing rate increases for 25 exercising patients and provided a rapid response time of 16 s from the time of exercise onset.<>