Low amplitude pacing artifact detection amplifier circuit with driven right leg for filtering high frequency noise caused by multiple noise sources

• US 5,435,316 A
• Filed: 10/07/1993
• Issued: 07/25/1995
• Est. Priority Date: 10/07/1993
• Status: Expired due to Term

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Kruse, John M.
• Primary Examiner(s): MANUEL, GEORGE C
• Application Number:
  US08/133,539
• Time in Patent Office: 656 Days
• Field of Search: 128/696, 128/697, 128/901, 607/9, 607/27, 318/801, 307/87
• US Class Current: 600/510
• CPC Class Codes: A61N 1/3702 Physiological parameters A61N1/365 takes precedence; evoked response A61N1/371
• CPC Class Codes: B60K 15/03177 made of non-metallic material, e.g. plastics, or of a combination of non-metallic and metallic material B60K15/03006 takes precedence

Abstract

A pacing artifact detection apparatus and method uses high speed operational amplifiers configured as an instrumentation amplifier to sense common mode noise signals at frequencies up to and above 10 MHz. The common mode noise signals are eliminated from a patient'"'"'s pacing artifact signal by driving the noise signals back onto the body of the patient.

Claims

1. An apparatus for filtering high frequency noise signals having frequencies up to 10 MHz generated by a plurality of noise sources from EKG signals having high frequency, (RF) pacing artifacts, said apparatus comprising:

means for sensing said EKG signals having said pacing artifacts;

means coupled to said sensing means for amplifying frequencies up to 10 MHz within said EKG signals to produce amplified EKG signals;

means coupled to said amplifying means for generating common-mode noise signals including frequencies of up to 10 MHz, said common-mode noise signals comprising a portion of said amplified EKG signals.; and

means coupled to said generating means for inverting said common-mode noise signals and means for driving said inverted common-mode noise signals back onto a body of a patient, whereby said pacing artifacts are preserved and said high frequency noise signals are canceled.

2. The apparatus of claim 1 wherein said means for amplifying said EKG signals comprises a plurality of high speed operational amplifiers.

3. The apparatus of claim 1 wherein said means for inverting said common mode noise signals comprises at least one high speed operational amplifier.

4. An apparatus for protecting high speed biopotential amplifiers from ESD and defibrillation energies without distorting EKG signal having a pacing artifact, said apparatus comprising:

(a) at least one high speed biopotential amplifier having at least one input and one output; and

(b) at least one SCR array coupled to said input, said SCR array adding no more than about 3 pico-farads of parasitic capacitance to said input.

5. A method for filtering high frequency noise signals having frequencies up to 10 MHz generated by a plurality of noise sources from EKG signals having high frequency, (RF), pacing artifacts, said method comprising the steps of:

sensing said EKG signals having said pacing artifacts from a patient'"'"'s body.;

amplifying frequencies up to 10 MHz within said EKG signals to produce amplified EKG signals;

generating common-mode noise signals including frequencies of up to 10 MHz from said amplified EKG signals;

inverting said common-mode noise signals; and

driving said inverted common-mode noise signals back onto said patient'"'"'s body, whereby said high frequency noise signals are canceled and said pacing artifacts are preserved.