Method and apparatus for determining systolic time intervals

• US 4,446,872 A
• Filed: 08/29/1978
• Issued: 05/08/1984
• Est. Priority Date: 09/08/1977
• Status: Expired due to Term

• Current Assignee: Avl Medical Instruments AG (Roche Holding AG)
• Original Assignee: AVL AG
• Inventors: Marsoner, Hermann J., Savora, Gunther
• Primary Examiner(s): Howell, Kyle L.
• Assistant Examiner(s): Jaworski, Francis J.
• Application Number:
  US05/937,886
• Time in Patent Office: 2,079 Days
• Field of Search: 128/695-706, 128/687-688, 128/715
• US Class Current: 600/513
• CPC Class Codes: A61B 5/024 Detecting, measuring or recording pulse rate or heart rate A61B5/0205, A61B5/021 take precedence

Abstract

A method and apparatus for determining the systolic time intervals from the electrocardiogram (ECG) wherein initially there is detected at least the point in time of the Q-wave in the ECG. Thereafter there is determined the time point for the start of the second cardiac sound and then there is determined the start of the ascent of the pulse curve as well as the position as a function of time of the dicrotic depression. Then there is checked the timewise correlation of the signals with respect to one another, and finally, there is checked whether the timewise spacing of characteristic points of the signals are within predetermined tolerances. The apparatus for performance of the method contains analogue signal processing means for ECG-signals, analogue signal processing means for cardiac sound signals, analogue signal processing means with which there is operatively associated a computer and output device.

Claims

1. An apparatus for determining systolic time intervals from an electrocardiogram, the heart sound and the pluse pressure curve of a patient, comprising:

analogue signal processing means for electrocardiogram signals;

analogue signal processing means for heart sound signals;

analogue signal processing means for pulse pressure signals; and

process control means containing a computer means and display device;

each analogue signal processing means having a respective output connected to said computer means;

said analogue processing means for electrocardiogram signals having a second output connected to an amplitude and trigger control input of said analogue signal processing means for heart sound signals and having a third output connected to an amplitude control input of said analogue signal processing means for pulse pressure signals.

2. The apparatus as defined in claim 1, wherein:

said analogue signal processing means for the electrocardiogram signals comprises an amplifier;

said amplifier having an input which can be connected by means of electrodes with a patient;

said amplifier having an output;

a signal separator;

a clamping circuit having an input and output and connecting the output of the amplifier with the signal separator;

said signal separator having a positive output;

a control stage and two trigger stages;

the positive output of the signal separator being connected with the control stage and the two trigger stages;

regulator means connected with the output of the clamping circuit;

the control stage controlling by means of the regulator means the amplifier;

a third trigger stage;

the signal separator having a negative output connected with said third trigger stage;

one of said two trigger stages having an output connected with the clamping circuit.

3. The apparatus as defined in claim 1, wherein:

said analogue signal processing means for heart sound signals comprises;

a pre-amplifier having an output;

a non-linear circuit having an output;

a bandpass connecting the output of the preamplifier with the non-linear circuit;

a trigger circuit and an amplitude-regulation circuit;

the output of the non-linear circuit being connected with the trigger circuit and the amplitude regulation circuit;

a control stage controlling the trigger circuit and the amplitude-regulating circuit;

the output of the amplitude-regulating circuit regulating the gain of the pre-amplifier.

4. The apparatus as defined in claim 1, wherein:

the analogue signal processing means for the pulse pressure signals comprises;

a pre-amplifier having an output;

a clamping stage having an input and an output;

the output of the pre-amplifier being connected with the input of the clamping stage;

a first trigger circuit and a second trigger circuit;

a differentiation stage for connecting the output of the clamping stage with the first trigger circuit;

the output of said clamping stage being further connected with said second trigger circuit;

a regulation stage;

the output of the clamping stage controlling the regulation stage;

a control stage for controlling said regulation stage; and

the regulation stage having an output which controls the pre-amplifier.

5. The apparatus as defined in claim 1, wherein:

the respective means for analogue signal processing of the electrocardiogram signals, heart sound signals and pulse pressure signals each have a respective output side connected with the computer means of the process control means;

the computer means having an output; and

the output of the computer means being connected with said display device.