Resources Contact Us Home
Dual chamber pacemaker system and method with improved switching between synchronous and asyncrhonous behavior

Image Number 7 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
Polynucleotide capture materials, and methods of using same
Universal handle extension for unloading butterfly valve for tank trailer or other vehicle
Semiconductor device and manufacturing method thereof
Randomly accessible visual information recording medium and recording method, and reproducing device and reproducing method
AC/DC converter
Tool bag with removable tool wall
Polyolefin and composition for pipe systems and sheets
  Randomly Featured Patents
Ball drop and electrical readout rotating receptacle having a vacuum conduit ball return
Reducing coupling effect on reference voltages when output buffers implemented with low voltage transistors generate high voltage output signals
Filtering container for fryer
Gradient coil arrangement comprising dampening of inner mechanical vibrations
Process for preparing purified 2,6-naphthalenedicarboxylic acid
Castor oil based polyurethane for underbody coatings and the like
Combined cycle air/air heat pump
Axial-force-detective fastening tool, bolt, and method of manufacturing bolt
Process for preparation of 1,2-diamino-cyclohexane-platinum (II) complexes
Use of cytokine receptors as biomarkers and therapeutic targets in human cancer