Left ventricular ejection meter

• US 3,881,481 A
• Filed: 02/08/1973
• Issued: 05/06/1975
• Est. Priority Date: 02/08/1973
• Status: Expired due to Term

• Current Assignee: James E. Heule, Richard C. Gaard
• Original Assignee: James E. Heule, Richard C. Gaard
• Inventors: Heule, James E., Gaard, Richard C.
• Primary Examiner(s): Kamm, William E.
• Application Number:
  US05/330,746
• Time in Patent Office: 817 Days
• Field of Search: 128/2.5A,2.5D,2.5E,2.5F,2.5G,2.5M,2.5N,2.5P,2.5Q,2.5R
• US Class Current: 600/479
• CPC Class Codes: A61B 5/02416 using photoplethysmograph signals, e.g. generated by infrared radiation A61B5/14552 takes precedence

Abstract

A meter for measuring the heart left ventricular ejection characteristic. The meter includes a circuit for emphasizing the left ventricular ejection phase preferentially to the other heart beat phases. According to a preferred embodiment, a circuit is provided which emphasizes signals of a blood volume waveform sensed by a pulsed light, source, photoelectric probe in a range of about 3.75 to 6.75 hertz.

Claims

1. An apparatus for measuring and indicating the left ventricular output of the heart by monitoring light reflective characteristics of blood flow in blood vessels and capillaries, comprising:

a. a pulsating light source placed in proximity to said blood vessels and capillaries;

b. a light responsive element placed in reflective relationship to said light source and said blood vessels and capillaries, and having means for converting received light into electrical signals;

c. circuit means, connected to said light responsive element, for receiving said electrical signals and attenuating frequency components of said signals below about 0.6 Hz. and above about 40 Hz.; and

d. indicator means, connected to said circuit means, for providing an observable indication of said nonattenuated electrical signals.

2. The apparatus of claim 1 wherein said circuit means further comprises a band pass circuit portion for emphasizing signal frequencies in the range of 3.75 Hz. to 6.75 Hz.

3. The apparatus of claim 2 wherein said band pass circuit further comprises a first capacitor in series connection with said light responsive element and a second capacitor in shunt connection with said light responsive element.

4. The apparatus of claim 2 wherein said band pass circuit portion further comprises means for attenuating signals outside the frequency range about 0.6-40 Hz. by at least 3 decibels.

5. The apparatus of claim 1 wherein said indicator means further comprises a current mEter.

6. The apparatus of claim 1 wherein said pulsating light source is pulsated at a frequency of about 1000 Hz. and having a light pulse duration of about 100 micro-seconds.