The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 19, 1999
Filed:
Feb. 14, 1997
Gustaaf A Stoop, Dieren, NL;
Vitatron Medical, B.V., Dieren, NL;
Abstract
There is provided an implanted pacemaker having a system and method for determining a measure of the circadian rhythm of a patient and adjusting the pacemaker nighttime setting of lower rate limit to correspond to the determined circadian rhythm. In a preferred embodiment, the circadian rhythm is determined by examining daily variations in QT interval. In a first QT embodiment of the invention, when QT interval becomes longer than a parameter QT.sub.-- sleep, which represents a value associated with patient nighttime, the LRL is dropped to a night value and maintained at such value for a predetermined duration. In another embodiment, the start of night LRL is determined as a function of when QT interval becomes longer than a sleep value for a predetermined elapsed time, and LRL is changed back to a day value when QT interval drops back down to a shorter value than the sleep value and stays there for an elapsed period of time. In yet another algorithm in accordance with this invention, the sleep value of QT interval is adapted so that the night period when QT interval is longer than the sleep value more closely corresponds to desired time of sleep, and the start of night LRL and the start of Day LRL are shifted to correspond to the detected night period. Additionally, other pacing parameters such as the escape interval hysteresis value may be varied based on determinations of the circadian rhythm.