Cardiac monitoring apparatus

• US 4,230,127 A
• Filed: 05/24/1978
• Issued: 10/28/1980
• Est. Priority Date: 05/24/1978
• Status: Expired due to Term

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Larson, Lary R.
• Primary Examiner(s): Michell, Robert W.
• Assistant Examiner(s): Jaworski, Francis J.
• Application Number:
  US05/909,230
• Time in Patent Office: 888 Days
• Field of Search: 128/2.05 T, 128/2.06 F, 128/2.06 R, 128/2.06 E, 128/2.1 E, 128/706, 128/690, 128/639-644
• US Class Current: 600/519
• CPC Class Codes: A61B 5/332 Portable devices specially adapted therefor

Abstract

There is disclosed herein a wristwatch size cardiac monitoring apparatus which is worn on the wrist of one arm. A conductive material housing acts as one electrode when held firmly in contact with the wrist of the arm on which it is worn. A finger of the other limb is placed on a receiving electrode of the casing which acts as the second electrode. Together, these two electrodes provide a Lead I electrocardiac signal to electronics within the housing. The second electrode consists of a metal layer on which is placed a dielectric material and when the finger is placed on top of the dielectric material, a capacitor is formed and the electric signal on the finger is transferred to the metal layer. Additionally, there is described circuitry which is used to operate the rate monitor. This circuitry includes means for detecting a QRS complex and for causing a count in beats per minute to be displayed, manifesting the heartbeat rate. The circuitry includes means for updating the heartbeat rate displayed every two seconds and for automatically turning the system off when no heartbeats are detected for a six second interval.

Claims

1. In a portable cardiac rate monitor adapted to be worn on one wrist including case means for housing electrical means capable of detecting a Lead I electrocardiac signal in response to the electrical signals taken between two upper limbs, said case means including a conductive back, which is adapted to be in physical contact with one of said limbs and receiving one of said electrical signals for provision to said electrical means, the improvement of receiving means on said case for providing said other electrical signal to said electrical means comprising:

a conductive layer insulated from said backing;

a dielectric layer affixed to said conductive layer on the side thereof remote from said case, and adapted to have a part of said other limb placed in physical contact therewith; and

a conductive rubber means connecting said conductive layer and said electrical means.

2. The invention according to claim 1 and further comprising substrate means to which said conductive layer is affixed, and wherein said conductive layer has at least a portion of its surface exposed on two opposing sides of said substrate means and said conductive rubber means is in contact with said surface of said conductive layer which is exposed in the direction away from said dielectric layer.

3. The invention according to claim 1 wherein said conductive rubber means is held in compressed contact between said conductive layer and said electrical means.

4. The invention according to claim 3 wherein said conductive rubber means is a conductive rubber cylinder.