Resources Contact Us Home
Browse by: INVENTOR PATENT HOLDER PATENT NUMBER DATE
 
 
Dual chamber pacemaker system and method with improved switching between synchronous and asyncrhonous behavior










Image Number 4 for United States Patent #5531771.

A dual chamber pacemaker system having a dynamic tracking limit, as well as a dynamic pacing limit (flywheel rate), the two dynamic limits being normally coupled to a measure of the sensed atrial rate as long as such rate is physiological. When the atrial signal is lost, i.e., cannot be tracked, the pacemaker responds with asynchronous pacing and normally decrements both dynamic limits, taking the flywheel rate down toward a lower pacing limit. The pacemaker of this invention provides a freeze function whereby the dynamic pacing limit and dynamic tracking limit are maintained constant for a plurality of cycles following asynchronous operation, to improve the possibility of regaining tracking if an underlying physiological atrial signal reappears at about the rate prior to being lost. The freeze function may be timed out for a predetermined number of cycles, e.g., eight, or may have a reduced duration if a series of consecutive synchronous cycles is detected. In a second embodiment, the dynamic tracking limit is decreased without any freeze when the pacer goes into asynchronous operation, but the dynamic tracking limit which existed just before the switch to asynchronous operation is remembered; if the atrial rate reappears below this remembered dynamic tracking limit, the dynamic tracking limit is ramped upward to achieve quick tracking of the reappeared sinus rate. A further embodiment may incorporate the features of the first two embodiments, i.e., a short freeze followed by a period of remembering the value of DTL when async mode was initiated.








 
 
  Recently Added Patents
Electronic time stamping apparatus for use with an inground transmitter
Mechanism for visible users and groups
Molecular sieve
System and method for producing statistically valid assay means and ranges for quality control materials
Nonvolatile semiconductor memory device and method for manufacturing the same
Power converter with a variable reference voltage and inrush current limiting
Multichannel device utilizing a centralized out-of-band authentication system (COBAS)
  Randomly Featured Patents
Mitigation of plating stub resonance by controlling surface roughness
Offset-compensated active load and method
Pet toy
Cooler box with handle round
Human antibodies that bind human TNF.alpha.
Male/female abrasive disk/wheel mounting member and subsequent abrasive mounting systems
Table assembly for patient transfer device
Air dispersing head for air heaters
Brake controlled modulating clutch valves
Apparatus and method for preventing access to SMRAM space through AGP addressing