Next generation rate adaptive algorithm using activity

An automatic and easy-to-program algorithm was developed to provide circadian modulation of pacing rate. It also improved rate response during exercise and recovery. We developed the algorithm using data collected from a ''taped-on'' accelerometer sensor. The algorithm uses activity variance. It is a long-term average of changes in activity. The algorithm could be viewed as a dual sensor algorithm. Activity variance modulates the slow-responding circadian base rate and activity establishes the fast-responding rate response. The algorithm creates a patient-specific rate histogram that closely mimics the normal sinus rate histogram. The algorithm paces patients with a higher daytime mean rate while pacing with a lower rate at night. Activity variance also provides a secondary rate response with a more natural long-term decay in pacing rate following sustained exercise.