Device and method for automatically adjusting tachycardia recognition criteria based on detected parameter
First Claim
1. An implantable medical interventional device for generating electrical therapies for delivery to the heart of the implant patient to treat pathological tachycardia, comprising:
- first sensor means adapted to produce a signal indicative of the patient'"'"'s ECG,second sensor means adapted to produce a signal representative of the current status of physical exercise by the patient,evaluation means for establishing criteria for recognizing pathological tachycardias, including means for applying said criteria against the ECG signal produced by the first sensor means to recognize pathological tachycardia and distinguish it from physiological tachycardia experienced by the patient,control means for automatically modifying at least one of said criteria according to the nature of the signal produced by the second sensor means, for application against said ECG signal to enhance the recognition and distinction of pathological tachycardia, andgenerator means for generating an appropriate one of said electrical therapies to be delivered to the patient'"'"'s heart for treating the recognized pathological tachycardia.
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Accused Products
Abstract
An implantable medical interventional device delivers electrical therapies to the heart of the implant patient to treat pathological tachycardia. A first sensor of the device generates a signal indicative of the patient'"'"'s ECG, and a second sensor in the form of an activity sensor such as an accelerometer generates a signal representative of the current status of physical exercise by the patient. An evaluation system of the device establishes heart rate criteria for recognizing pathological tachycardias, to be applied against the ECG signal to recognize pathological tachycardia and distinguish it from physiological tachycardia experienced by the patient. A control system of the device modifies the criteria according to the nature of the exercise status signal, to enhance recognition and distinction. In an embodiment, the criteria of heart rate at the boundary between physiological and pathological tachycardia for the particular implant patient is modified by shifting it to a different rate. The boundary rate is shifted to a higher rate when the exercise status signal indicates a change from patient rest to patient exercise, and to a lower rate when that signal indicates a change from patient exercise to patient rest. Bipolar floating electrodes sense atrial ECG status, and solely atrial defibrillation is applied when ventricular tachycardia is found attributable to primary atrial fibrillation. Such a situation may be determined by measuring the R-R interval of the beats to detect irregularity. The modification of the tachycardia recognition criteria is disabled when primary atrial fibrillation is detected.
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Citations
54 Claims
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1. An implantable medical interventional device for generating electrical therapies for delivery to the heart of the implant patient to treat pathological tachycardia, comprising:
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first sensor means adapted to produce a signal indicative of the patient'"'"'s ECG, second sensor means adapted to produce a signal representative of the current status of physical exercise by the patient, evaluation means for establishing criteria for recognizing pathological tachycardias, including means for applying said criteria against the ECG signal produced by the first sensor means to recognize pathological tachycardia and distinguish it from physiological tachycardia experienced by the patient, control means for automatically modifying at least one of said criteria according to the nature of the signal produced by the second sensor means, for application against said ECG signal to enhance the recognition and distinction of pathological tachycardia, and generator means for generating an appropriate one of said electrical therapies to be delivered to the patient'"'"'s heart for treating the recognized pathological tachycardia. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. In an implantable defibrillator for detecting and treating abnormal tachycardias experienced by the implant patient and including means for distinguishing abnormal tachycardias from normal elevated heart rates of the patient by the application of distinction criteria, the improvement comprising:
means responsive to changes in a physiological parameter which signify a basis for normal elevation of heart rate of the patient, for modifying the distinction criteria to enhance the capability of the defibrillator to make the distinction. - View Dependent Claims (12, 13, 14, 15, 16, 17)
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18. A method for detecting pathological tachycardia by means of a medical interventional device implanted in a patient, to determine when to deliver electrical therapy from the device to the patient'"'"'s heart to treat the pathological tachycardia, comprising the device-implemented steps of:
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sensing the patient'"'"'s cardiac activity and status of physical exercise and producing an ECG signal and an exercise status signal respectively representative thereof, setting criteria for evaluating the ECG signal to recognize onset and continuation of pathological tachycardia, modifying at least one of the criteria according to a change in the status of rest or exercise of the patient as determined from the exercise status signal, applying the at least one modified criterion to the ECG signal to recognize pathological tachycardia in the changed status, and selecting and generating an electrical therapy for delivery to the patient'"'"'s heart to treat a recognized pathological tachycardia. - View Dependent Claims (19, 20, 21, 22, 23, 24)
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- 25. A method for determining which therapy in a tier of electrical therapies is to be applied to the heart of a cardiac patient to treat pathological tachycardia detected in different zones of recognition from criteria applied to evaluation of the patient'"'"'s ECG, including shifting the different zones and the consequent therapies to be applied upwardly or downwardly in response to the status of a physiological parameter of the patient other than the ECG.
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27. In a method to detect pathological tachycardia in a patient having an automatic implantable defibrillator, in which the patient'"'"'s ECG is detected and an ECG-based heart rate is selected as a threshold for distinguishing pathological and physiological tachycardias experienced by the patient at least according to whether the heart rate exceeds or does not exceed the selected threshold rate, respectively, the improvement comprising the additional steps of:
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employing a non-ECG sensor to generate an output signal in response to detection of a parameter indicative of status of physiological tachycardia of the patient, and modifying the selected threshold rate depending upon the output signal of the non-ECG sensor. - View Dependent Claims (28, 29, 30, 31, 32, 33, 34, 35, 36)
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37. An implantable medical interventional device for delivering electrical therapies to the heart of an implant patient to treat pathological ventricular tachycardia, comprising:
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first sensor means adapted to generate a signal indicative of the patient'"'"'s ventricular ECG status, second sensor means adapted to generate a signal indicative of the patient'"'"'s atrial ECG status, evaluation means for establishing criteria to distinguish physiological and pathological tachycardia in the ventricles from an evaluation of the signal generated by Mid first sensor means and adapted to apply an appropriate therapy in response to an evaluation that a pathological tachycardia is present, said evaluation means including therapy delivering means responsive to the signal generated by said second sensor means indicative of atrial fibrillation or other atrial dysrhythmias for limiting the therapy to an atrial response. - View Dependent Claims (38, 39, 40, 41)
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42. The method of controlling pathological tachycardia whether in the atrium or the ventricles of the heart, including:
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sensing atrial and ventricular dysrhythmias, providing tiered electrical therapies for application to the heart to treat the sensed dysrhythmia, and responding to a sensed dysrhythmia in the right ventricle and to a sensed atrial dysrhythmia in the right atrium while the patient is substantially at rest, by treating both the ventricular dysrhythmia and the atrial dysrhythmia with one of the tiered therapies applied solely to the atrium. - View Dependent Claims (43)
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44. An implantable medical interventional device for delivering electrical therapies to the heart of an implant patient to treat pathological ventricular tachycardia, comprising:
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first sensor means adapted to be positioned in the patient'"'"'s right ventricle to sense ventricular electrical activity, second sensor means adapted to be positioned in the patient'"'"'s right atrium to sense atrial electrical activity, and defibrillation electrode means adapted to be positioned in the patient'"'"'s right ventricle to electrically stimulate excitable myocardial tissue thereof; evaluation means establishing criteria to distinguish ventricular tachycardia of physiological origin and of pathological origin, and responsive to said first and second sensor means for determining whether a pathological ventricular tachycardia is primary, originating from ventricular dysfunction, or secondary, originating from atrial dysfunction; and control means responsive to said evaluation means for selecting an electrical therapy for delivery to the patient'"'"'s heart; all of said first and second sensor means and said defibrillation electrode means being disposed on the same electrode structure. - View Dependent Claims (45, 46)
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47. A method of controlling both atrial and ventricular pathological dysrhythmias, including:
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sensing atrial and ventricular dysrhythmias utilizing respective recognition criteria, normally modifying the recognition criteria for ventricular dysrhythmias if it is determined that the patient is undergoing exercise and removing the modification when the patient returns to a state of rest, providing tiered electrical therapies for application to the heart to treat the sensed dysrhythmia, responding to a sensed dysrhythmia in the right ventricle and to a sensed atrial dysrhythmia in the right atrium as indicative that the atrial dysrhythmia is primary, by treating both the ventricular dysrhythmia and the atrial dysrhythmia with one of the tiered therapies applied solely to the atrium, while avoiding modification of the recognition criteria. - View Dependent Claims (48, 49, 50)
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51. An implantable medical interventional device for distinguishing pathologic tachycardia from physiologic tachycardia of a patient, and for promptly generating a selected electrical therapy for delivery to the heart of the patient to treat a detected pathologic tachycardia, comprising:
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means for detecting a tachycardia in the patient, means for establishing at least one criterion by which to distinguish whether a detected tachycardia is pathologic or physiologic based on the patient'"'"'s cardiac activity, sensor means for generating an electrical signal indicative of the patient'"'"'s cardiac activity, complementary sensor means for generating an electrical signal representative of the state of physical exercise of the patient, means responsive to said electrical signal representative of the state of physical exercise of the patient for selectively modifying said at least one criterion according to the nature of the physical exercise, and for applying said at least one criterion as modified against said electrical signal indicative of the patient'"'"'s cardiac activity to assess whether a detected tachycardia is pathologic, and means for generating one of a plurality of available electrical therapies of the device if the assessment is that a pathologic tachycardia is in progress. - View Dependent Claims (52, 53, 54)
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Specification