Sensor for detecting cardiac depolarizations particularly adapted for use in a cardiac pacemaker
First Claim
Patent Images
1. Cardiac interface apparatus, for detecting the passage of a cardiac depolarization wavefront in the myocardium, and generating a sense event signal;
- and for providing stimulating energy in response to a pace event signal, to the myocardium to provoke a contraction of the myocardium, comprising;
a first, probe electrode for location proximate said myocardium;
a second, reference electrode;
a virtual load connected to said first electrode;
charge supplying means coupled to said virtual load and to said second electrode for maintaining said first electrode at a steady state of electrical potential relative to said second electrode;
monitoring means for monitoring the current through said virtual load means required to maintain said steady state during the occurrence of a cardiac depolarizationand for generating a sense detect signal when said current exceeds a threshold; and
pulse generator means coupled to at least one of first and second electrodes for delivering pacing energy in response to said pace event signal.
0 Assignments
0 Petitions
Accused Products
Abstract
A pacemaker sense amplifier which includes active circuitry which establishes and maintains a constant field density between two electrode poles, effectively clamping them together at a substantially fixed potential difference. The amount of current or power required to maintain this condition in the steady state is monitored and forms the basis of detection of the passing depolarization wavefront.
-
Citations
28 Claims
-
1. Cardiac interface apparatus, for detecting the passage of a cardiac depolarization wavefront in the myocardium, and generating a sense event signal;
- and for providing stimulating energy in response to a pace event signal, to the myocardium to provoke a contraction of the myocardium, comprising;
a first, probe electrode for location proximate said myocardium; a second, reference electrode; a virtual load connected to said first electrode; charge supplying means coupled to said virtual load and to said second electrode for maintaining said first electrode at a steady state of electrical potential relative to said second electrode; monitoring means for monitoring the current through said virtual load means required to maintain said steady state during the occurrence of a cardiac depolarization and for generating a sense detect signal when said current exceeds a threshold; and pulse generator means coupled to at least one of first and second electrodes for delivering pacing energy in response to said pace event signal. - View Dependent Claims (2, 3, 4, 5)
- and for providing stimulating energy in response to a pace event signal, to the myocardium to provoke a contraction of the myocardium, comprising;
-
6. Cardiac interface apparatus, for detecting the passage of a cardiac depolarization wavefront in the myocardium, and generating a sense event signal;
- and for providing stimulating energy in response to a pace event signal, to the myocardium to provoke a contraction of the myocardium, comprising;
a first, probe electrode for location proximate said myocardium; a second, reference electrode for location proximate said myocardium; a virtual load connected to said first electrode; charge supplying means coupled to said virtual load and said second electrode for maintaining said first electrode at a steady state potential with respect to said second electrode; monitoring means for monitoring the current through said virtual load required to maintain said steady state potential during the occurrence of a cardiac depolarization and for generating a sense detect signal when the transduced value of said current exceeds a threshold; third, stimulating electrode for location proximate said myocardium; forth, stimulating electrode for location proximate said myocardium; pulse generator means coupled to third and fourth electrodes for delivering pacing energy to said myocardium in response to said pace event signal.
- and for providing stimulating energy in response to a pace event signal, to the myocardium to provoke a contraction of the myocardium, comprising;
-
7. Apparatus for detecting the passage of a cardiac depolarization wavefront in the myocardium comprising:
-
a first electrode for location inside the heart; a second electrode for location outside the heart; a virtual load connected to said first electrode; charge supplying means coupled to said virtual load and said second electrode for maintaining said first electrode at a steady state potential relative to said second electrode; monitoring means for monitoring the current through said virtual load means and for generating a sense detect signal for indicating the occurrence of said cardiac depolarization. - View Dependent Claims (8)
-
-
9. In a cardiac stimulation apparatus comprising means for generating cardiac stimulating pulses for application to a patient'"'"'s heart and means detecting depolarizations of said patient'"'"'s heart, the improvement wherein said detector means comprises:
-
first and second electrodes for sensing cardiac signals; a virtual load connected to said first electrode; an active circuit, coupled to said second electrode and said virtual load, for providing electrical energy to said first electrode through said virtual load in response to the occurrence of a cardiac depolarization to counteract depolarization induced variation in the relative electrical potentials of said first and second electrodes; a monitoring circuit, coupled to said active circuit, for monitoring electrical current provided through said virtual load, for detecting the occurrence of a cardiac depolarization. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
-
-
20. Apparatus for detecting depolarization of cardiac tissue, comprising:
-
first and second electrodes, said first electrode for location adjacent cardiac tissue; first and second electrodes, said first electrode for location adjacent cardiac tissue; an active circuit means coupled to said first and second electrodes for providing electrical energy to said first electrode in response to the occurrence of a cardiac depolarization to counteract depolarization induced variation in the relative electrical potentials of said first and second electrodes; wherein said active circuit means comprises an operational amplifier having first and second inputs, an output and means for providing an electrical output signal, said active circuit means further comprising a feedback impedance connected between said second input to said operational amplifier and said output, said apparatus further comprising a virtual load impedance connected between said first electrode and said first input and means for connecting said second electrode to said second input; and a monitoring circuit coupled to said output of said operational amplifier for detecting the occurrence of cardiac depolarizations. - View Dependent Claims (21, 22, 23, 24, 25, 26, 27, 28)
-
Specification