US 5,350,410 A · Autocapture system for implantable pulse generator

Abstract

An autocapture system within an implantable pulse generator automatically maintains the energy of a stimulation pulse at a level just above that which is needed to effectuate capture. The electrical post-stimulus signal of the heart following delivery of a stimulation pulse is compared to a polarization template, determined during a capture verification test. A prescribed difference between the polarization template and the post-stimulus signal indicates capture has occurred. Otherwise, loss of capture is presumed, and a loss-of-capture routine is invoked that increases the energy a prescribed amount to obtain capture. Periodically, and/or at programmed intervals or events, the capture verification test is performed. During the capture verification test, the pulse generator determines a polarization template for a particular stimulation energy and for each of a plurality of sensitivity or threshold settings. A determination is also made as to which sensitivity settings yield capture. An autocapture routine extends the capture verification test data to a wide range of stimulation energies. An autothreshold routine automatically sets the energy of the stimulation pulse a specified level above the energy at which capture is first lost.

Claims34

Dependent claims

A system for detecting capture in an implantable pulse generator on a beat-by-beat basis, the implantable pulse generator being coupled to an implantable stimulation lead in contact with the heart, the system comprising:

pulse generating means for generating stimulation pulses at a desired stimulation pulse energy;
sensing means, coupled to the stimulation lead, for sensing cardiac signals and for sensing post-stimulation signals which occur following each stimulation pulse, the sensing means including means for sensing first and second post-stimulation signals at each of a plurality of sensitivities, the first post-stimulation signals corresponding to polarization signals sensed at each of a plurality of sensitivities;
means for comparing the first and second post-stimulation signals at each respective sensitivity and producing as an output a plurality of difference signals, presence of a prescribed difference signal indicating that the heart was captured by the stimulation pulse;
means for determining an optimum sensitivity setting based on the prescribed difference signal, and for biasing the sensing means to the optimum sensitivity setting for stimulation pulses subsequently generated at the desired stimulation pulse energy;
and
processing means for comparing post-stimulation signals sensed by the sensing means at the optimum setting with the respective polarization signal, whereby a prescribed difference signal sensed by the sensing means at the optimum sensitivity setting is used for capture detection on a beat-by-beat basis.

3 more elements

An autocapture system for use within an implantable pulse generator, comprising:

means for stimulating the heart with a stimulation pulse at each of a plurality of stimulation energies;
sensing means for sensing cardiac signals and for sensing post-stimulation signals which occur following each stimulation pulse, the post-stimulation signals being sensed at each of a plurality of sensitivity settings for each of the plurality of stimulation energies;
means for defining a plurality of polarization templates corresponding to the plurality of post-stimulation signals;
processing means for comparing the plurality of post-stimulation signals with the corresponding polarization template and indicating capture if a prescribed difference exists therebetween, and for determining an optimal sensitivity setting for the sensing means for each of the plurality of stimulation energies based on the existence of the prescribed difference signal;
means for biasing the sensing means at the optimum sensitivity setting for stimulation pulses subsequently generated at a desired stimulation pulse energy;
and
wherein the processing means compares the post-stimulation signal sensed by the sensing means at the optimum sensitivity setting to the corresponding polarization template for beat-by-beat capture detection, whereby the presence of the prescribed difference signal at the optimum sensitivity setting indicates whether capture has occurred.

4 more elements

A method for detecting capture in an implantable pulse generator, the method comprising the steps of:

generating stimulation pulses at a desired stimulation pulse energy;
sensing cardiac signals and post-stimulation signals which occur following each stimulation pulse with a sense amplifier, the post-stimulation signals including first and second post-stimulation signals at each of a plurality of sensitivities, the first post-stimulation signals corresponding to polarization signals sensed at each of a plurality of sensitivities;
comparing the first and second post-stimulation signals at each respective sensitivity and producing as an output a plurality of difference signals, presence of a prescribed difference signal indicating that the heart was captured by the stimulation pulse;
determining an optimum sensitivity setting based on the prescribed difference signal;
biasing the sense amplifier to the optimum sensitivity setting for stimulation pulses subsequently generated at the desired stimulation pulse energy;
and
comparing post-stimulation signals sensed at the optimum setting with the respective polarization signal, whereby a prescribed difference signal sensed by the sensing means at the optimum sensitivity setting is used for capture detection on a beat-by-beat basis.

4 more elements

A method for determining capture within an implantable pulse generator, the implantable pulse generator including stimulation means for generating a stimulation pulse at a selectable stimulation energy and delivering the stimulation pulse to a heart, and sensing means for sensing a post-stimulus signal from the heart at a selectable sensitivity following delivery of the stimulation pulse, the method comprising the steps of:

(a) defining a plurality of polarization templates for a selected stimulation energy of the stimulation means and for a plurality of sensitivity settings of the sensing means;
(b) stimulating the heart with a stimulation pulse having the selected stimulation energy;
(c) sensing a plurality of post-stimulus signals at the selected stimulation energy with the sensing means at each of the plurality of sensitivity settings;
(d) comparing the polarization template with the post-stimulus signal and indicating capture if a prescribed difference signal exists therebetween;
and
(e) determining an optimum sensitivity setting for the sensing means based on the prescribed difference signal.

3 more elements

Dependencies are inferred from the claim text.

Autocapture system for implantable pulse generator

Life of this patent

Autocapture system for implantable pulse generator

Life of this patent

Abstract

Claims34