Current status of dual-sensor pacemaker systems for correction of chronotropic incompetence

Rate-adaptive pacing has been shown to improve exercise capacity in patient s with chronotropic incompetence. However, all sensors used to adapt the pa cing rate to meet metabolic demands show typical limitations. To overcome t hese, concepts using 2 sensors for rate adaptation have been developed, com bining an unspecific but fast-reacting sensor with a specific but stower-re acting one. Clinical performance of these dual-sensor pacemaker systems is related to 3 factors: (1) choice of sensors, (2) mode of sensor integration , and (3) algorithms for automatic optimization of the integrated sensor re sponse. Clinical studies using dual-sensor rate-adaptive pacing systems hav e demonstrated their ability to mimic normal sinus rate during different fo rms of exercise, avoiding inadequate or delayed rate response, However, to avoid combining the disadvantages of both single sensors, dual-sensor rate- adaptive systems need effective automatic algorithms. Sensor cross-check sh ould be quick and combine fast reactivity and high specificity, particularl y so as to prevent overpacing, Programmable rate response-related parameter s should continuously be optimized. The pacemaker should provide diagnostic facilities during exercise to simulate short-term sensor performance at di fferent settings and memory functions to evaluate long-term sensor performa nce. Assessment and eventually deactivation of all automatic functions shou ld be possible. Finally, even with automatic algorithms for sensor optimiza tion, maximal benefit from a dual-sensor system can only be achieved if the physician is able to identify and correct pitfalls of each system. (C) 200 0 by Excerpta Medica, Inc.