Estimation of cardiac death risk

• US 20040215090A1
• Filed: 04/25/2003
• Published: 10/28/2004
• 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, Takala, Panu, Erkkila, Jouni
• Granted Patent: US 7,330,750 B2
• Time in Patent Office: Days
• US Class Current: 600/515
• 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 for predicting cardiovascular disorders for an individual patient, 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

based on the first, second, and third sub-indices, determining at least one overall risk index, the overall risk index indicating a risk level of a cardiovascular disorder for 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 ECG data.

3. A method according to claim 1, wherein the first sub-index is determined based on an HRV analysis.

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 heart of the patient; and

determining a set of repolarisation parameters based on the analyzing step.

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 an arrhythmia analysis.

7. A method according to claim 1, wherein the third sub-index is determined based on an arrhythmia analysis and a conduction analysis.

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

9. A method according to claim 1, wherein said at least one overall risk index is determined repeatedly.

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

comparing subsequent overall risk indices with each other;

and

giving an alarm when the subsequent overall risk indices fulfill a predetermined condition.

11. A method according to claim 10, 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 10, 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 for predicting a cardiovascular disorder for an individual patient, the system comprising:

measurement means for obtaining medical data from an individual patient, the medical data including ECG data;

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

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

fourth calculation means for determining at least one overall risk index based on the first, second, and third sub-indices, the overall risk index indicating a risk level of a cardiovascular disorder for the patient.

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. An apparatus for predicting a cardiovascular disorder for an individual patient, the apparatus comprising:

a measurement interface for receiving at least one physiological signal originated from an individual patient;

first calculation means for determining a first sub-index based on said at least one physiological signal, the first sub-index indicating the current level of chaos in heart rate variability of a patient;

second calculation means for determining a second sub-index based on said at least one physiological signal, the second sub-index indicating the current energy level in the myocardium of the patient;

third calculation means for determining a third sub-index based on said at least one physiological signal, the third sub-index indicating the current degree of arrhythmia of the patient; and

fourth calculation means for determining at least one overall risk index based on the first, second, and third sub-indices, the at least one overall risk index indicating a risk level of a cardiovascular disorder for the patient.

16. An apparatus according to claim 15, wherein said at least one physiological signal includes an ECG signal.

17. An apparatus according to claim 16, wherein the apparatus further comprises a communication interface operatively connected to said fourth calculation means, for connecting the apparatus to an external device.

18. An apparatus according to claim 15, wherein the first, second, third, and fourth calculation means reside in a single processor unit.