Estimation of cardiac death risk

• US 7,330,750 B2
• Filed: 04/25/2003
• Issued: 02/12/2008
• Est. Priority Date: 04/25/2003
• Status: Active Grant

• Current Assignee: Instrumentarium Dental Incorporated (Envista Holdings Corporation)
• Original Assignee: Instrumentarium Dental Incorporated (Envista Holdings Corporation)
• Inventors: Kaski, Mikko, Erkkilä, Jouni, Takala, Panu
• Primary Examiner(s): Getzow; Scott M.
• Application Number:
  US10/423,474
• Publication Number:
  US 20040215090A1
• Time in Patent Office: 1,754 Days
• Field of Search: 600509-519
• US Class Current: 600/509
• CPC Class Codes: A61B 5/02405 Determining heart rate variability
• CPC Class Codes: A61B 5/349 Detecting specific parameters of the electrocardiograph cycle
• CPC Class Codes: A61B 5/7275 Determining trends in physiological measurement data; Predicting development of a medical condition based on physiological measurements, e.g. determining a risk factor
• CPC Class Codes: G16H 50/30 for calculating health indices; for individual health risk assessment

Abstract

The invention relates to a method and apparatus for predicting a sudden heart abnormality for an individual patient. In order to provide a prediction mechanism that is suitable for acute care, three sub-indices are determined based on medical data obtained from the patient. The first sub-index indicates the level of deterministic chaos in the heart rate variability of the patient, the second sub-index indicates the energy level in the myocardium of the patient, and the third sub-index indicates the degree of ventricular arrhythmia of the patient. Based on the first, second, and third sub-indices, at least one overall risk index is then determined, the overall risk index indicating the risk level of a sudden heart abnormality for the patient.

Claims

1. A method providing a composite, multiple component index for assessing a current state of a patient'"'"'s heart to evaluate associated cardiac health risks, the method comprising the steps of:

determining a first sub-index indicating the current level of chaos in heart rate variability of a patient;

determining a second sub-index indicating the current energy level in the myocardium of the patient;

determining a third sub-index indicating the current degree of arrhythmia of the patient; and

combining the first, second, and third sub-indices to compile at least one composite index from the sub-indices indicative of a current state of the patient'"'"'s heart and suitable for use in evaluating cardiac health risks in the patient.

2. A method according to claim 1, further comprising the step of measuring ECG data from the patient, wherein the first, second and third sub-indices are determined based on the EGG data.

3. A method according to claim 1, wherein the step of determining said first sub-index is further defined as determining the level of non-linear behavior found in the heart rate variability of the patient.

4. A method according to claim 1, wherein the step of determining the second sub-index includes the steps of:

analyzing the repolarisation phase of the physiological functioning of the heart of the patient;

determining a set of repolarisation parameters based on the analyzing step; and

providing the second sub-index from the set of repolarization parameters.

5. A method according to claim 4, wherein the step of determining the second sub-index further includes the step of calculating the second sub-index as a weighted sum of at least some of the repolarisation parameters.

6. A method according to claim 1, wherein the third sub-index is determined based on the current extent of ventricular arrhythmia occurring in the heart of the patient.

7. A method according to claim 1, wherein the third sub-index is determined based on the current extent of ventricular arrhythmia occurring in the heart of the patient and an analysis of the electrical conduction functioning of the heart.

8. A method according to claim 1, wherein the composite index is determined as a weighted sum of the first, second, and third sub-indices.

9. A method according to claim 1, further defined as repeating the steps of the method to provide a plurality of sequentially obtained composite indices.

10. A method according to claim 9, further comprising the steps of

carrying out a comparison of composite indices;

and

giving an alarm when the comparison of composite indices fulfills a predetermined condition.

11. A method according to claim 1, further comprising the steps of

determining at least one parameter relating to the arterial blood pressure of the patient;

and

utilizing said at least one parameter in determining the second sub-index.

12. A method according to claim 1, further comprising the steps of

determining a value for the arterial blood oxyhemoglobin saturation of the patient;

and

utilizing said value in determining the second sub-index.

13. A system providing a composite, multiple component index for assessing a current state of a patient'"'"'s heart to evaluate associated cardiac health risks, the system comprising:

measurement means for obtaining ECG data from the patient;

first calculation means for determining a first sub-index from the medical data, the first sub-index indicating the current level of chaos in heart rate variability of the patient;

second calculation means for determining a second sub-index from the medical data, the second sub-index indicating the current energy level in the myocardium of the patient;

third calculation means for determining a third sub-index from the medical data, the third sub-index indicating the current degree of arrhythmia of the patient; and

fourth calculation means for combining the first, second, and third sub-indices to compile at least one composite index from the sub-indices.

14. A system according to claim 13, wherein the measurement means are configured to provide, in addition to the ECG data, blood pressure data related to the patient.

15. A system according to claim 13, wherein the system further comprises a communication interface operatively connected to said fourth calculation means, for connecting the system to an external device.

16. A system according to claim 13, wherein the first, second, third, and fourth calculation means reside in a single processor unit.