CARDIAC MONITOR

• US 3,742,937 A
• Filed: 01/20/1971
• Issued: 07/03/1973
• Est. Priority Date: 01/20/1971
• Status: Expired due to Term

• Current Assignee: Barry Manuel, Harvey L. Pastan
• Original Assignee: Barry Manuel, Harvey L. Pastan
• Inventors: Manuel, Barry, Pastan, Harvey L.
• Primary Examiner(s): Kamm, William E.
• Application Number:
  US05/107,959
• Time in Patent Office: 895 Days
• Field of Search: 128/2.5E,2.5P,2.5R,2.5T,2.6A,2.6F,2.6R,2R
• US Class Current: 600/503
• CPC Class Codes: A61B 5/024 Detecting, measuring or recording pulse rate or heart rate A61B5/0205, A61B5/021 take precedence
• CPC Class Codes: A61B 5/02438 with portable devices, e.g. worn by the patient
• CPC Class Codes: A61B 5/02444 Details of sensor A61B5/02427 takes precedence

Abstract

The monitoring device is self-contained, compact and is preferably strapped about the wrist over the region where a radial pulse is normally detected. Heart rate and abnormalities in the heart beat rate are sensed by the device. Because no external connections are necessary to a power source, for example, the device is particularly useful for ambulatory patients suffering from various types of heart ailments. A pressure sensitive diaphragm sensor is held against the skin over the radial pulse region to sense the pulse wave transmitted from the heart. This pressure sensor couples to a mechanoelectrical transducer which converts the pressure pulse into an electrical analog pulse. A multivibrator, or the like, couples from the transducer and is used to square (digitize) the analog pulse. Logic circuitry receives a digital heart pulse from the multivibrator and is adapted to detect when the heart rate is either below a minimum predetermined rate or above a maximum predetermined rate. When either of these conditions exists an alarm signal is generated. Circuitry may also be included for those patients who may be expected to experience irregularities of the heart beat. This circuitry determines when heart beats have been dropped, for example.

Claims

1. A cardiac monitor adapted to be attached to the body comprising:

a pressure sensor;

means for holding the pressure sensor against the body at an area Where a pressure pulse transmitted from the heart can be detected;

means for converting a detected pressure pulse into a representative electrical pulse; and

circuit means for establishing an alarm condition when an abnormal pattern of successive electrical pulses is detected comprising;

a binary counter coupled from said means for converting for counting heart pulses during a predetermined time interval, decode logic means coupled from said binary counter and including a first logic gate responsive to a minimum predetermined count and a second logic gate responsive to a maximum predetermined count, and means coupled from the logic gates of the decode logic means for generating an alarm condition after the predetermined time interval when the minimum predetermined count has not been attained and also when the maximum predetermined count has been exceeded.

2. A cardiac monitor adapted to be attached to the body comprising:

a pressure sensor;

means for holding the pressure sensor against the body at an area where a pressure pulse transmitted from the heart can be detected;

means for converting a detected pressure pulse into a representative electrical pulse; and

circuit means for establishing an alarm condition when an abnormal pattern of successive electrical pulses is detected comprising;

a bistable device that is set to its alternate states by successive electrical pulses and has first and second output terminals, first and second resistive means each having one end coupled, respectively, to said first and second output terminals, a capacitor coupled between the other ends of said first and second resistive means, difference circuit means coupled from said capacitor, and means for generating an alarm when the difference circuit means detects a voltage of greater than a predetermined voltage level across said capacitor.

3. The cardiac monitor of claim 2 comprising third and fourth resistive means coupling from said capacitor to respective inputs of said difference circuit means.

4. The cardiac monitor of claim 3 comprising a filter circuit coupled across said difference circuit means.