Implantable cardiac stimulator with automatic gain control
First Claim
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1. An implantable cardiac stimulator for detecting cardiac cycles by analyzing electrical signals produced by the heart, comprising:
- means for detecting electrical signals produced by the heart; and
amplifier means responsive to the detected signals and having dual signal paths for said detected signals, one of said paths having a feedback loop with means for automatically adjusting the gain of the amplifier means, the other said signal paths enables the determination of a sensing level, said means for automatically controlling the gain including an algorithm controlling gain requiring a ratio of greater than 1 to 1, said algorithm controlling gain requiring sensing of two lows in a row to increase gain and sensing one high to decrease gain whereby the gain and threshold relationships between said dual signal paths maybe altered to produce variable sensing margins.
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Abstract
An implantable cardiac stimulator for detecting and treating bradycardias includes a sense amplifier responsive to sensed cardiac signals for detecting cardiac activity. The sense amplifier includes an automatic gain control amplifier, a filter and quad comparator having a pair of signal channels to establish sensing thresholds, margins and signal gain. The sense amplifier has a feedback loop containing a microprocessor which implements preselected algorithms in conjunction with the outputs of the quad comparator to variably adjust the amplifier gain and to programmably control the sensing margin.
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3 Claims
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1. An implantable cardiac stimulator for detecting cardiac cycles by analyzing electrical signals produced by the heart, comprising:
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means for detecting electrical signals produced by the heart; and amplifier means responsive to the detected signals and having dual signal paths for said detected signals, one of said paths having a feedback loop with means for automatically adjusting the gain of the amplifier means, the other said signal paths enables the determination of a sensing level, said means for automatically controlling the gain including an algorithm controlling gain requiring a ratio of greater than 1 to 1, said algorithm controlling gain requiring sensing of two lows in a row to increase gain and sensing one high to decrease gain whereby the gain and threshold relationships between said dual signal paths maybe altered to produce variable sensing margins. - View Dependent Claims (2, 3)
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Specification