Wrist-worn ECG monitor

• US 5,333,616 A
• Filed: 01/07/1993
• Issued: 08/02/1994
• Est. Priority Date: 12/26/1991
• Status: Expired due to Term

• Current Assignee: Card Guard Technologies Inc.
• Original Assignee: Instromedix, Inc. (Koninklijke Philips N.V.)
• Inventors: Homayoun, Habib, Mills, Gary N.
• Primary Examiner(s): Cohen, Lee S.
• Assistant Examiner(s): Jastrzab, Jeffrey R.
• Application Number:
  US08/002,161
• Time in Patent Office: 572 Days
• Field of Search: 128/696, 128/670, 128/710, 128/903, 128/904, 128/690
• US Class Current: 600/508
• CPC Class Codes: A61B 5/332 Portable devices specially adapted therefor
• CPC Class Codes: A61B 5/7203 for noise prevention, reduction or removal
• CPC Class Codes: A61B 5/7207 of noise induced by motion artifacts
• CPC Class Codes: Y10S 128/901 Suppression of noise in electric signal
• CPC Class Codes: Y10S 128/904 Telephone telemetry

Abstract

A compact, lightweight wrist-worn cardiac data and event monitor having dry skin electrodes integral with the monitor'"'"'s housing is disclosed. Preferably, the skin electrodes are made of titanium nitride-plated stainless steel and form inner, wrist-contacting, and outer, other hand'"'"'s palm-contactable regions of the housing. Chronometric and other multiple functions are provided to increase the functional density of the monitor by partitioning and very-large-scale-integrating the circuitry, which includes signal detection; data conversion, storage, display and telecommunication; and external pushbutton controls operable by the patient'"'"'s other hand. In accordance with the preferred embodiment, a telephonic transmitter is integrally included within the housing for remote diagnostic purposes without the need for external connections. By a preferred method of the invention, a simplified digital filter implemented in firmware ensures that only ECG and event data are recorded at the exclusion of noise and motion artifacts. By another preferred method of the invention, a battery life prediction method is used to extend the useful life of the battery and to indicate to the patient when the battery should be replaced. Event data that may be recorded and tele-transmitted along with the ECG data include time-of-day or elapsed time markers, as well as markers or indications of the detection of any pulses produced, for example, by an implanted pacemaker or an implanted cardio-verter/defibrillator monitor (ICDM).

Claims

1. A high functional-density cardiac monitoring system comprising:

a pair of dry skin electrodes for contacting the skin surface or a cardiac patient;

an ECG signal amplifier coupled with said electrodes for producing an analog signal representative of an electrical field therebetween;

analog-to-digital signal conversion means connected with said amplifier for producing digital data representing the patient'"'"'s ECG waveform over a defined interval of time;

memory means for recording said digital data;

means for wirelessly communicating said data recorded in said memory means by producing a modulated ECG data carrier for telephonic transmission to a remote site; and

a housing containing said electrodes, said amplifier, said conversion means, said memory means and said communicating means;

said housing having an exterior predetermined volume not exceeding approximately 1.5 inches³.

3. The monitoring system of claim 1 or 2, wherein said predetermined volume further contains controller means for interpreting such ECG waveform to produce ECG activity indicia and display means enabling visual ECG activity monitoring by the cardiac patient.

2. A high functional-density cardiac monitoring system comprising:

a pair of dry skin electrodes for contacting the skin surface of a cardiac patient;

an ECG signal amplifier coupled with said electrodes for producing an analog signal representative of an electrical field therebetween;

analog-to-digital signal conversion means connected with said amplifier for producing digital data representing the patient'"'"'s ECG waveform over a defined interval of time;

memory means for recording said digital data;

means for wirelessly communicating said data recorded in said memory means by producing a modulated ECG data carrier for telephonic transmission to a remote site; and

a housing integrally including said electrodes defining an interior predetermined volume containing said amplifier, said conversion means, said memory means and said communicating means;

said interior volume not exceeding approximately 0.75 inches³.