Method and apparatus for preventing heart tachyarrhythmia
View Patent ↗The invention is for a method for predicting an imminent episode of ventricular tachyarrhythmia by an analysis of the variations in the heart beat frequency during otherwise normal appearing sinus rhythm in the normal beat frequency range. The analysis is based on detecting a prolonged pattern of increasing heart beat rate. When the method is implemented by hardware it can initiate, or cause to be initiated, preventive therapies. A further implementation can cause the patient or attendant to be notified of imminent ventricular tachyarrhythmia. Both implantable and external devices are considered.
1. A method for predicting an imminent tachyarrhythmia that
detects a prolonged heart rhythm acceleration, even if and when the heart is driven at normal sinus rates;
applies a filter on the heart beat interval data to remove the effects of premature beats;
computes the long term average of heart beat intervals based on the filtered heart beat intervals; and
uses the difference signal between the filtered heart beat intervals and the long term average of heart beat intervals to predict imminent tachyarrhythmia.
2. The method of claim 1 that
compares the difference signal between the filtered heart beat intervals and the long term average of heart beat intervals to a programmable percentage of the long term average of heart beat intervals to determine a heart rhythm acceleration,
upon such a heart rhythm acceleration, counts the number of heart beats until the difference signal returns to zero or changes sign, and
upon the count exceeding a programmable number,
causes a signal which signified imminent ventricular tachyarrhythmia to be issued.
3. The method of claim 1 that
compares the difference signal between the filtered heart beat intervals and the long term average of heart beat intervals to a programmable percentage of the long term average of heart beat intervals to determine a heart rhythm acceleration,
upon such a heart rhythm acceleration, tracks the amount of time until the difference signal returns to zero or changes sign, and
upon the amount of time exceeding a programmable value,
causes a signal which signified imminent ventricular tachyarrhythmia to be issued.
4. A cardiac device, which comprises the method of claim 1 or 2 or 3 , which can generate a signal which signifies imminent tachyarrhythmia.
5. The device of claim 4 which is an implantable cardioverter defibrillator.
6. The implantable defibrillator of claim 5 which generates a signal which can be perceived by the patient as notification of imminent tachyarrhythmia.
7. The implantable cardioverter defibrillator of claim 6 which can initiate preventive therapy upon a signal which signifies imminent tachyarrhythmia.
8. The implantable cardioverter defibrillator of claim 7 , which delays anti tachyarrhythmic therapy for a programmable time duration, when no signal indicating imminent tachyarrhythmia has been generated within a previous specified time period, and a tachyarrhythmia has been detected.
9. The device of claim 4 , which is a pacemaker.
10. The pacemaker of claim 9 which generates a signal which can be perceived by the patient as notification of imminent tachyarrhythmia.
11. The pacemaker of claim 10 , which can initiate preventive therapy upon a signal which signifies imminent tachyarrhythmia.
12. The device of claim 4 ,
which is an implantable drug delivery system and
which can deliver a preventive drug therapy upon a signal which signifies imminent tachyarrhythmia.
13. The device of claim 4 , which is an external cardiac monitor.
14. The cardiac monitor of claim 13 that can convert the signal that signifies imminent tachyarrhythmia to an audible signal.
15. The cardiac monitor of claim 14 that can convert the signal that signifies imminent tachyarrhythmia into an electronic notification to be sent out over a network.
16. The cardiac monitor of claim 15 that can initiate preventive drug therapy through a drug delivery subsystem upon the signal that signifies imminent tachyarrhythmia.
17. The cardiac monitor of claim 15 that can initiate preventive drug therapy through an external device.
18. The implantable cardioverter defibrillator of claim 6 , which delays anti tachyarrhythmic therapy for a programmable time duration, when no signal indicating imminent tachyarrhythmia has been generated within a previous specified time period, and a tachyarrhythmia has been detected.
19. The implantable cardioverter defibrillator of claim 5 which can initiate preventive therapy upon a signal which signifies imminent tachyarrhythmia.
20. The implantable card ioverter defibrillator of claim 19 , which delays anti tachyarrhythmic therapy for a programmable time duration, when no signal indicating imminent tachyarrhythmia has been generated within a previous specified time period, and a tachyarrhythmia has been detected.
21. The pacemaker of claim 9 , which can initiate preventive therapy upon a signal which signifies imminent tachyarrhythmia.
22. The cardiac monitor of claim 13 that can convert the signal that signifies imminent tachyarrhythmia into an electronic notification to be sent out over a network.
23. The cardiac monitor of claim 22 that can initiate preventive drug therapy through a drug delivery subsystem upon the signal that signifies imminent tachyarrhythmia.
24. The cardiac monitor of claim 22 that can initiate preventive drug therapy through an external device.