Cardiac arrhythmia detection using interdependent multiple parameter settings

• US 5,458,620 A
• Filed: 02/14/1994
• Issued: 10/17/1995
• Est. Priority Date: 02/20/1992
• Status: Expired due to Term

• Current Assignee: Ela Medical S.A. (LivaNova Plc)
• Original Assignee: Angeion Corporation (Niterra Co., Ltd.)
• Inventors: Kroll, Mark W., Adams, Theodore P.
• Primary Examiner(s): Cohen, Lee S.
• Assistant Examiner(s): Jastrzab, Jeffrey R.
• Application Number:
  US08/195,557
• Time in Patent Office: 610 Days
• Field of Search: 607/5, 607/18, 607/19, 128/705
• US Class Current: 607/5
• CPC Class Codes: A61N 1/3621 for treating or preventing abnormally high heart rate
• CPC Class Codes: A61N 1/36585 controlled by two or more physical parameters
• CPC Class Codes: A61N 1/3956 Implantable devices for applying electric shocks to the heart, e.g. for cardioversion
• CPC Class Codes: Y10S 128/925 Neural network

Abstract

A programmable implantable cardioverter defibrillator (ICD) provides signals from a plurality of cardiac sensing modalities to a control circuit within the ICD that analyzes the signals and determines whether to deliver an electrical countershock therapy. An interdependent detection parameter threshold is programmably established for each of a programmably selectable combination of two or more cardiac sensing modalities by selecting at least two corner points that will define a boundary condition for a given cardiac dysrhythmia. Whenever the threshold is exceeded, the control circuit automatically diagnoses a cardiac dysrhythmia and delivers a preprogrammed electrical countershock therapy regimen for the diagnosed dysrhythmia. Multiple interdependent detection parameter thresholds may be combined in a variety of ways. More than one combination of two or more cardiac sensing modalities may be used to define a multivariant boundary condition for the given cardiac dysrhythmia. Alternatively, more than one set of corner points for a particular combination of cardiac sensing modalities may be used so as to create multiple detection envelopes, one for each different type of cardiac dysrhythmia. Finally, both of these options may be programmed together so as to allow for the definition of multivariant performance envelopes for different cardiac dysrhythmias.

Claims

1. A method for detecting and treating a plurality of cardiac dysrhythmias in an ailing human heart using an implantable programmable automatic cardioverter defibrillator electrically connected to a plurality of implantable electrodes placed proximate the human heart, the method comprising the device-implanted steps of:

a) providing a plurality of cardiac sensing modalites;

b) selecting from the plurality of sensing modalites a set of two or more corner point values for each sensing modality provided;

c) programming at least two sets of corner point values into the cardioverter defibrillator;

d) combining the selected sets of corner point values within the programming as interdependent detection parameter thresholds defining a plurality of cardioverter defibrillator detection envelopes;

e) detecting a cardiac dysrhythmia falling within the detection envelopes;

f) diagnosing a cardiac dysrhythmia from results of the detected cardiac dysrhythmia based on the detection envelopes; and

g) providing a cardioverter defibrillator treatment regimen consistent with the diagnosed cardiac dysrhythmia.

2. The method of claim 1 in which the step of providing a plurality of cardiac sensing modalities comprises providing a range of modalities selected from a list of modalities consisting of:

cardiac electrical cycle rates;

ventricular beat to beat intervals;

ventricular interval instability;

duration periods during which cardiac cycle rates are measured; and

acceleration of cardiac electrical cycle rates.

3. The method of claim 1 in which step d defines at least three combined detection envelopes, one each for ventricular fibrillation, high rate ventricular tachycardia and low rate ventricular tachycardia.

4. The method of claim 1 further comprising the step of modifying at least one of the selected sets of corner point values to include a rate ruling zone.

5. A cardiac dysrhythmia detection system for a programmable implantable cardioverter defibrillator that determines whether one or more preprogrammed electrical countershock therapies should be delivered through a plurality of implantable electrodes placed proximate a human heart, the detection system comprising:

means for providing electrical signals representative of a plurality of cardiac sensing modalities; and

control means for analyzing the electrical signals and, in response, determining whether a preprogrammed electrical countershock therapy should be delivered by the implantable cardioverter defibrillator, the control means including;

memory means for storing values defining one or more interdependent detection parameter thresholds, each threshold being established for a programmably selectable combination of two or more of the plurality of cardiac sensing modalities by selecting at least two corner points as a set of corner points that define a boundary condition for the particular combination of the plurality of cardiac sensing modalities for a given cardiac dysrhythmia;

means for comparing the electrical signals to the one or more interdependent detection parameter thresholds and automatically diagnosing a cardiac dysrhythmia whenever the interdependent detection parameter thresholds are exceeded by the electrical signals for the particular combination of cardiac sensing modalities; and

means for selecting one or move preprogrammed electrical countershock therapies to be delivered in response to the means for comparing.

6. The detection system of claim 5 in which the means for comparing uses combination of two or more cardiac sensing modalities to define a multivariant boundary condition for the given cardiac dysrhythmia.

7. The detection system of claim 5 in which the plurality of cardiac sensing modalities comprises providing a range of modalities selected from a list of modalities consisting of:

cardiac electrical cycle rates;

ventricular beat to beat intervals;

ventricular interval instability;

duration periods during which cardiac cycle rates are measured; and

acceleration of cardiac electrical cycle rates.

8. The detection system of claim 5 in which the memory means defines more than one set of corner points for a particular combination of cardiac sensing modalities so as to create a detection envelope for each of a different type of cardiac dysrhythmia.

9. The detection system of claim 8 in which the memory means uses more than one set of corner points for a particular combination of cardiac sensing modalities to define at least three combined performance envelopes, one each for ventricular fibrillation, high rate ventricular tachycardia and low rate ventricular tachycardia.

10. The detection system of claim 5 further comprising means for modifying at least one or more interdependent detection parameter thresholds to include a rate ruling zone.