Implantable cardiac stimulation device and method for varying pacing parameters to mimic circadian cycles

摘要

Provided herein are methods and apparatus for automatically adjusting pacing parameters in implantable programmable stimulation devices, such as rate-responsive pacemakers and cardioverter defibrillators. The methods and apparatus provide a circadian varying pacing parameter (e.g., pacing rate, AV Delay, etc.) that very closely mimics the natural diurnal fluctuations of a patient's heart. Using physiological parameters that vary diurnally (e.g., minute ventilation and/or activity variance, etc.), a circadian-base value is derived. In the preferred embodiments, the physiological measurements are used to derive a histogram from which certain characteristic values are determined. These physiological characteristic values, along with the predetermined characteristic rates, automatically and periodically determine a transfer function from which the patient's appropriate circadian base rate is derived. Further contemplated herein are the use of more than one physiological parameter to derive a final circadian base rate, and stimulation devices employing these methods.