Automatic gain control and method for enabling detection of low and high amplitude depolarization activation waves of the heart and atrial defibrillator utilizing the same
First Claim
1. A method for reliably detecting a depolarization activation wave of a heart, the method including the steps of:
- providing a detection system having a gain and a threshold;
sensing activity of the heart in at least one chamber of the heart and producing an input signal corresponding to said sensed activity, said input signal having an input amplitude;
amplifying said input signal according to said gain to produce an amplified input signal having an amplified input amplitude;
producing an output when said amplified input signal exceeds said threshold, said output indicating an occurrence of said depolarization activation wave; and
varying at least one of said gain and said threshold to maintain a predetermined sense margin between said input amplitude and said gain and said threshold.
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Accused Products
Abstract
An apparatus reliably detects a depolarization activation wave of the heart. The apparatus includes a sensor in electrical contact with the heart for sensing electrical activity of the heart and including an amplifier for amplifying the sensed electrical activity according to a variable gain and providing a signal corresponding to the depolarization activation wave. The apparatus further includes an output circuit coupled to the sensor for producing an electrical output corresponding to the depolarization activation wave sensed by the sensor when the signal exceeds a threshold. The apparatus still further includes a control circuit coupled to the sensor and the output circuit for varying at least one of the gain and the threshold to maintain a predetermined sense margin between the sensed electrical activity and the gain and the threshold.
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Citations
17 Claims
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1. A method for reliably detecting a depolarization activation wave of a heart, the method including the steps of:
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providing a detection system having a gain and a threshold; sensing activity of the heart in at least one chamber of the heart and producing an input signal corresponding to said sensed activity, said input signal having an input amplitude; amplifying said input signal according to said gain to produce an amplified input signal having an amplified input amplitude; producing an output when said amplified input signal exceeds said threshold, said output indicating an occurrence of said depolarization activation wave; and varying at least one of said gain and said threshold to maintain a predetermined sense margin between said input amplitude and said gain and said threshold. - View Dependent Claims (2, 3, 4, 5)
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6. An apparatus for reliably detecting a depolarization activation wave of a heart, the apparatus comprising:
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sensing means in electrical contact with the heart for sensing electrical activity of the heart and including amplifying means for amplifying said sensed electrical activity by a gain and providing a signal; threshold means coupled to said amplifying means for producing an electrical output when said signal exceeds a threshold; and control means coupled to said sensing means and said threshold means for varying at least one of said gain and said threshold to maintain a predetermined sense margin between said sensed electrical activity and said gain and said threshold. - View Dependent Claims (7, 8, 9, 10)
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11. An implantable atrial defibrillator for applying cardioverting electrical energy to the atria of a heart in synchronism with a detected depolarization activation wave, the atrial defibrillator comprising:
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detecting means for sensing activity of the heart in at least one of the atria of the heart; atrial fibrillation detecting means responsive to activity of the heart sensed by said detecting means for determining when the atria of the heart are in need of cardioversion; an apparatus for detecting a depolarization activation wave of the heart, said apparatus including sensing means in electrical contact with the heart for sensing electrical activity of the heart and including amplifying means for amplifying said sensed electrical activity by a gain and providing a signal, threshold means coupled to said amplifying means for producing an electrical output when said signal exceeds a threshold, and control means coupled to said sensing means and said threshold means for varying at least one of said gain and said threshold to maintain a predetermined sense margin between said sensed electrical activity and said gain and said threshold; and cardioverting means for applying cardioverting electrical energy to the atria of the heart when the atria of the heart are in need of cardioversion and responsive to said electrical output.
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- 12. An atrial defibrillator as defined in claim further comprising conversion means coupled to said sensing means for converting said signal to digital data and memory means for storing said data.
Specification