Method and apparatus to remove data outliers, produced by external disturbance, in internally measured signals in an implantable cardiac stimulator
First Claim
1. A method for removing an effect produced by an external disturbance on an internally obtained signal in an implantable cardiac stimulator, comprising the steps of:
- intracorporeally acquiring an intracorporeally-produced physiological signal from a subject, said physiological signal representing data susceptible to a corrupting effect by an extracorporeally-produced disturbance resulting in a corrupted signal;
substantially removing said corrupting effect on said data in said corrupted signal while substantially preserving said data in said corrupted signal by median filtering said corrupted signal; and
controlling intracorporeal administration of a medical therapy dependent on said data after median filtering said corrupted signal.
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Abstract
In a method and apparatus for removing data outliers in measured signals in an implanted medical apparatus, such as data outliers produced by GSM disturbance picked up by an implanted cardiac stimulator lead and superimposed on the sensed cardiac activity signal, the signal from the implanted lead is subjected to median filtering. The median filtering minimizes, or eliminates, the effect of highly aberrational data points in the incoming signal, without the necessity of actually removing the components in the signal produced by the disturbance from the incoming signal itself. Since no portion of the actual incoming signal is removed by the median filtering, the data integrity of the sensed cardiac signal is preserved. The signal processed by median filtering, possibly subjected to subsequent post filtering, is then supplied to a detector within the implanted stimulator, which performs the desired detection on the filtered signal, with the result of the detection then being used to control operation of the implanted stimulator.
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Citations
19 Claims
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1. A method for removing an effect produced by an external disturbance on an internally obtained signal in an implantable cardiac stimulator, comprising the steps of:
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intracorporeally acquiring an intracorporeally-produced physiological signal from a subject, said physiological signal representing data susceptible to a corrupting effect by an extracorporeally-produced disturbance resulting in a corrupted signal; substantially removing said corrupting effect on said data in said corrupted signal while substantially preserving said data in said corrupted signal by median filtering said corrupted signal; and controlling intracorporeal administration of a medical therapy dependent on said data after median filtering said corrupted signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. An implantable cardiac stimulator comprising:
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pulse generator means for emitting stimulation pulses having an amplitude and a rate; a sensing amplifier; an electrode lead, adapted for implantation in a subject, connected to said pulse generator means and to said sensing amplifier for delivering said stimulation pulses to cardiac tissue and for acquiring an electrical signal containing data representing cardiac activity, said electrical signal and the data contained therein being susceptible to a corrupting effect by an extracorporeally-produced disturbance resulting in a corrupted signal, said corrupted signal being supplied to said sense amplifier and said sense amplifier producing an amplifier output signal containing said data; median filter means, supplied with said amplifier output signal, for substantially removing said corrupting effect on said data while substantially preserving said data by median filtering said amplifier output signal; means, supplied with said data from said median filter means, for controlling intracorporeal administration of a medical therapy dependent on the data with said corrupting effect substantially removed therefrom after median filtering; and a housing adapted for implantation in a subject, said housing containing said pulse generator means, said sense amplifier, said median filter means and said means for controlling intracorporeal administration of a medical therapy. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19)
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Specification