METHOD AND APPARATUS FOR DIAGNOSING MYOCARDIAL INFARCTION IN HUMAN HEART

• US 3,799,147 A
• Filed: 03/23/1972
• Issued: 03/26/1974
• Est. Priority Date: 03/23/1972
• Status: Expired due to Term

• Current Assignee: John F. Stephens III, Robert J. Adolph
• Original Assignee: John F. Stephens III, Robert J. Adolph
• Inventors: Adolph, Robert J., Stephens, John F. III
• Primary Examiner(s): Kamm, William E.
• Application Number:
  US05/237,442
• Time in Patent Office: 733 Days
• Field of Search: 128/2.5Q,2.5R,2.5S,2.6R,2.1R,2K 179/1ST 181/24
• US Class Current: 600/513
• CPC Class Codes: A61B 5/336 Magnetic recording apparatus
• CPC Class Codes: A61B 7/00 Instruments for auscultation

Abstract

Apparatus and method for diagnosing myocardial infarction predicated on analysis of the acoustical frequency spectrum of the human heart during the isovolumic contraction phase of the cardiac cycle for the purpose of detecting a shift in the predominant frequency component of the spectrum from a 30-50 cps frequency band, typical of a noninfarcted heart, to a 20-40 cps frequency band, indicative of an infarcted heart.

Claims

1. A method of diagnosing the condition of a living human heart to determine the probable existence of a myocardial infarction comprising the steps of:

monitoring the multiple frequency component sound emanating from the living heart in components centered approximately at 30 cps and 40 cps, detecting the frequency component of said monitored components which predominates, and indicating the probable existence of a myocardial infarction when the frequency of said predominant component is centered at approximately 30 cps.

2. A method of diagnosing the condition of a living human heart to determine the probable existence of a myocardial infarction comprising the steps of:

monitoring the multiple frequency sound emanating from the living heart in at least the range of frequencies lying below approximately 50 cps, determining the occurrence of the isovolumic contraction phase of the cardiac cycle, detecting the frequency component of said monitored sounds which predominates, in the range of frequencies below approximately 50 cps, during said isovolumic contraction phase of the cardiac cycle, and indicating the probable existence of a myocardial infarction based on the frequency of said predominant component.

3. The method of claim 1 further including the step of determining the occurrence of the isovolumic contraction phase of the cardiac cycle, and wherein said detecting step includes detecting which of said components occurring during the isovolumic contraction phase of the cardiac cycle is predominant.

4. A method of diagnosing the condition of a living human heart to determine the probable existence of a myocardial infarction comprising the steps of:

monitoring the sounds emanating from the living heart, measuring (a) the magnitude of said sound energy over a first specified frequency range including substantially all frequencies between approximately 20 cps and 220 cps, (b) the magnitude of sound energy at a first frequency band within said range and associated with an infarcted heart, said first frequency band including the frequency of approximately 30 cps, and (c) the magnitude of sound energy at a second frequency band within said range and associated with a noninfarcted heart, said second frequency band including the frequency of approximately 40 cps, adjusting said second third mentioned magnitudes with said first mentioned magnitude to normalize said second and third mentioned magnitudes, comparing said normalized magnitudes to determine which is predominant, and indicating the probable existence of a myocardial infarction when said normalized second magnitude exceeds said normalized third magnitude.

5. The method of claim 4 wherein said measuring step includes measuring the magnitude of said sound in the range of at least 20 cps - 50 cps, the magnitude of said sound in a band centered at approximately 30 cps, and the magnitude of said sound in a band centered at approximately 40 cps, and wherein said indicating step includes indicating the probable existence of a myocardial infarction when the normalized magnitude associated with said 30 cps band exceeds said normalized magnitude associated with said 40 cps band.

6. A method of diagnosing the condition of a living human heart to determine the probable existence of a myocardial infarction comprising the steps of:

transducing sounds emanating from The living heart, concurrently recording on the same record member (a) transduced sounds emanating from the heart in at least the range of frequencies lying below approximately 50 cps and (b) electrocardiographic signals, concurrently reproducing the recorded sound signals and electrocardiographic signals, determining reproduced sound signals associated with the isovolumic contraction phase of the cardiac cycle using the reproduced electrocardiographic signals as a cardiac cycle phase reference, measuring the predominant frequency component of the reproduced sound signals associated with the isovolumic contraction phase, and indicating the probable existence of a myocardial infarction based on the frequency of said predominant component.

7. Apparatus for diagnosing the condition of a living human heart to determine the probable existence of a myocardial infarction comprising:

a transducer positionable in use in sound receiving relation to a living human heart for producing signals correlated to sounds emanating from the heart, electrocardiographic means for producing an electrocardiographic signal, and means responsive to said heart sound signals for measuring the relative magnitudes of said sound signals in frequency bands centered at approximately 30 cps and 40 cps and responsive to said electrocardiographic means for measuring the relative magnitudes of said 30 cps and 40 cps centered sound signal bands during the isovolumic contraction phase of the cardiac cycle for indicating the existence of a myocardial infarction based on the frequency of the predominant component band occurring during the isovolumic contraction phase of the cardiac cycle.

8. The apparatus of claim 7 wherein said measuring means includes recording means for producing a visually perceptive indication of the magnitude of said 30 cps and 40 cps centered sound signal bands during said isovolumic contraction phase.

9. Apparatus for diagnosing the condition of a living human heart to determine the probable existence of a myocardial infarction comprising:

a transducer positionable in use in sound receiving relation to the living human heart for producing signals correlated to sounds emanating from the heart, electrocardiographic electrodes positionable in use to produce electrical signals correlated to electrical activity of the heart, recording means for concurrently recording said sound and electrocardiographic signals, reproducing means associated with said recording said sound and electrocardiographic signals, reproducing means associated with said recording means for reproducing said recorded sound and electrocardiographic signals, indicating means responsive to said reproduced electrocardiographic signal to provide an indication of the isovolumic contraction phase of the cardiac cycle, and means responsive to said indicating means and to said reproduced sound signals for detecting the predominant frequency component below approximately 50 cps of said sound signals occurring during the isovolumic contraction phase of the cardiac cycle.

10. Apparatus for diagnosing the condition of a living human heart to determine the probable existence of a myocardial infarction comprising:

a transducer positionable in use in sound receiving relation to the living human heart for producing signals correlated to multicomponent sounds emanating from the heart in a range at least including sounds below approximately 50 cps, means for determining the isovolumic contraction phase of the cardiac cycle, frequency selective means jointly responsive to said heart sound signals and to said isovolumic contraction phase determining means for measuring the relative magnitudes of said sound signals occurring during the isovolumic contraction phase of the cardiac cycle in a first frequency band which includes a first frequency below approximately 50 cps and in a second frequency Band which includes a second frequency below said first frequency, and indicating means for indicating the probable existence of a myocardial infarction when the signal magnitude associated with said second band exceeds the signal magnitude associated with said first band.