US 5,843,136 A · Pacing output circuitry for automatic capture threshold detection in cardiac pacing systems

Abstract

A method and apparatus for attenuating polarization voltages or "afterpotentials" which develop at the heart tissue/electrode interface following the delivery of a pacing stimulus to the heart tissue such that the evoked response of the heart may be accurately detected to determine whether each pacing stimulus resulted in heart capture or contraction, thereby facilitating improved tracking of the capture threshold for minimizing power consumption while assuring therapeutic efficacy. The conventional large capacitance coupling capacitor used to suppress DC components of the pacing spike has a second, much lower capacitance capacitor connector in series with it, the second capacitor being shunted by a switch so that its value can be selectively inserted in series with the coupling capacitor to effectively lower the overall capacitance of the coupling capacitor following delivery of the pacing spike.

Claims9

Dependent claims

An improved pacing output circuit for use in a cardiac pacemaker, comprising:

(a) power supply means;
(b) first capacitor means cooperatively operable with said power supply means for selectively storing a pacing charge to be delivered to myocardial tissue in a heart via an electrode;
(c) first switching means for selectively delivering said pacing charge from said first capacitor means to said myocardial tissue within said heart;
(d) second capacitor means coupled to said electrode and cooperatively operable with said first capacitor means for blocking DC components from said heart during pacing;
and
(e) afterpotential attenuation means for selectively attenuating afterpotentials which result due to the application of said pacing charge to said heart, said afterpotential attenuation means including third capacitor means coupled to said second capacitor means and second switching means for selectively coupling said second capacitor means in series with said third capacitor means so as to reduce the effective capacitance of said second capacitor means.

3 more elements

An improved cardiac pacemaker, comprising:

pulse generation means for selectively generating stimulus pulses;
lead means coupled to said pulse generation means and adapted to deliver said stimulus pulses to a patient's heart;
said pulse generation means including power supply means, first capacitor means cooperatively operable with said power supply means for selectively storing a pacing charge to be delivered to said heart via said lead means, first switching means for selectively delivering said pacing charge from said first capacitor means to said heart via said lead means, second capacitor means coupled to said lead means and cooperatively operable with said first capacitor means for blocking DC components from said heart during pacing, and afterpotential attenuation means for selectively attenuating afterpotentials which result due to the application of said pacing charge to said heart;
and
said afterpotential attenuation means including third capacitor means coupled to said second capacitor means and a second switching means for selectively coupling said second capacitor means in series with said third capacitor means so as to reduce the effective capacitance of said second capacitor means.

2 more elements

Dependencies are inferred from the claim text.

Pacing output circuitry for automatic capture threshold detection in cardiac pacing systems

Life of this patent

Pacing output circuitry for automatic capture threshold detection in cardiac pacing systems

Life of this patent

Abstract

Claims9