Resources Contact Us Home
Method and device for optimally altering stimulation energy to maintain capture of cardiac tissue

Image Number 10 for United States Patent #6456879.

An improved system and method for performing automatic capture/threshold detection in an implantable cardiac stimulation device or any device capable of stimulating some body organ or tissue. Prior art systems determine the cardiac tissue's stimulation threshold by detecting an evoked response to a fixed duration stimulation pulse and then increasing the stimulation pulse's amplitude by a predetermined safety margin value. Such systems are inherently based upon a belief that the chronaxie of a particular patient's strength-duration curve is essentially fixed and that the rheobase is variable. While this may be true at some times during the patient's life, e.g., during the acute phase after lead implantation absent drug effects, it is reported that drugs alone may alter the chronaxie and it is believed that other factors may also affect the chronaxie either alone or in combination with the rheobase. Accordingly, the present invention compares the present stimulation pulse to at least two pulse duration regions and, if a loss-of capture criteria is met, alters the amplitude aid/or the duration of the stimulation pulse accordingly in order to take into account a rheobase and/or chronaxie shift. The decision of whether to increase amplitude and/or duration is dependent on the current operating point. For example, in an embodiment having two pulse duration regions, the amplitude and duration of the stimulation pulse may be increased in the first duration region below the chronaxie while, in the second duration region above the chronaxie, only the amplitude may be increased.

  Recently Added Patents
Multicolored light converting LED with minimal absorption
Electronic document reading devices
Pyroelectric detector, pyroelectric detection device, and electronic instrument
Flexible organic light emitting device and manufacturing method thereof
System, method, and computer program product for identifying unwanted data communicated via a session initiation protocol
High-voltage AC light-emitting diode structure
Quinazoline compounds and their use in perfume compositions
  Randomly Featured Patents
Expansion joints for roads
Quick sealing glass-lidded package fabrication method
Bonding method and bonding apparatus
Trophinin, trophinin-assisting proteins and methods to inhibit implantation
Method for treating a magnetic recording medium
Signal encoding apparatus, signal decoding apparatus, signal processing system, signal encoding process method, signal decoding process method, and program
Methods of and apparatuses for maintenance, diagnosis, and optimization of processes
Process for forming bottom anti-reflection coating for semiconductor fabrication photolithography which inhibits photoresist footing
Device for identifying an information particularly an electronic lock/key combination
Plumbing fitting