Implantable medical device with automatic tachycardia detection and control in MRI environments
First Claim
1. An implantable medical device (IMD) comprising:
- one or more leads configured to sense cardiac signals and deliver therapy signals;
a sensor configured to detect the presence of static and time-varying scan fields in a magnetic resonance imaging (MRI) environment; and
a controller configured to process detect cardiac event based on the cardiac signals, compare the sensed static and time-varying scan fields to static and time-varying scan field thresholds, and control delivery of a first type of stimulation therapy and a second type of stimulation therapy as a function of the detection of the cardiac events, the comparison of the sensed static scan field to the static scan field threshold, and the comparison of the time-varying scan fields to the time-varying scan field thresholds such that;
when the static and time-varying scan field thresholds are exceeded, the controller disqualifies the cardiac events to inhibit delivery of the first type of stimulation therapy and the second type of stimulation therapy, andwhen the static scan field threshold is exceeded and the time-varying scan field threshold is not exceeded, the controller processes sensed cardiac events, causes the IMD to deliver the first type of stimulation therapy upon detection of the cardiac events, and inhibits delivery of the second type of stimulation therapy.
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Abstract
An implantable medical device (IMD) includes a lead having one or more sensing electrodes and one or more therapy delivery electrodes, and a sensor configured to detect the presence of static and time-varying scan fields in a magnetic resonance imaging (MRI) environment. A controller, in electrical communication with the lead and the sensor, is configured to process signals related to tachycardia events sensed via the one or more sensing electrodes and to deliver pacing and shock therapy signals via the one or more therapy delivery electrodes. The controller compares the sensed static and time-varying scan fields to static and time-varying scan field thresholds. The controller controls delivery of anti-tachycardia pacing and shock therapy signals as a function of the detected tachycardia events, the comparison of the sensed static scan field to the static scan field threshold, and the comparison of the time-varying scan fields to the time-varying scan field thresholds.
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Citations
20 Claims
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1. An implantable medical device (IMD) comprising:
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one or more leads configured to sense cardiac signals and deliver therapy signals; a sensor configured to detect the presence of static and time-varying scan fields in a magnetic resonance imaging (MRI) environment; and a controller configured to process detect cardiac event based on the cardiac signals, compare the sensed static and time-varying scan fields to static and time-varying scan field thresholds, and control delivery of a first type of stimulation therapy and a second type of stimulation therapy as a function of the detection of the cardiac events, the comparison of the sensed static scan field to the static scan field threshold, and the comparison of the time-varying scan fields to the time-varying scan field thresholds such that; when the static and time-varying scan field thresholds are exceeded, the controller disqualifies the cardiac events to inhibit delivery of the first type of stimulation therapy and the second type of stimulation therapy, and when the static scan field threshold is exceeded and the time-varying scan field threshold is not exceeded, the controller processes sensed cardiac events, causes the IMD to deliver the first type of stimulation therapy upon detection of the cardiac events, and inhibits delivery of the second type of stimulation therapy. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method for operating an implantable medical device (IMD), the method comprising:
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sensing for static and time-varying scan fields associated with a magnetic resonance imaging (MRI) environment; comparing the sensed static and time-varying scan fields to static and time-varying scan field thresholds; detecting cardiac events; and controlling delivery of a first type of stimulation therapy and a second type of stimulation therapy as a function of the detected cardiac events, the comparison of the sensed state electromagnetic field to the static scan field threshold, and the comparison of the time-varying scan fields to the time-varying scan field thresholds, wherein the controlling step comprises causing the IMD to deliver the first type of stimulation therapy and inhibiting the second type of stimulation therapy when a cardiac event is detected, the static scan field threshold is exceeded, and the time-varying scan field threshold is not exceeded, and wherein the controlling step comprises inhibiting delivery of both of the first type of stimulation therapy and the second type of stimulation therapy when both of the static and time-varying scan field thresholds are exceeded. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15)
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16. An implantable medical device (IMD) comprising:
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one or more leads configured to sense cardiac signals and deliver therapy signals; a sensor configured to detect the presence of static and time-varying scan fields in a magnetic resonance imaging (MRI) environment; and a controller configured to detect cardiac events based on the cardiac signals, compare the sensed static and time-varying scan fields to static and time-varying scan field thresholds, and control delivery of a first type of stimulation therapy and a second type of stimulation therapy as a function of the detection of the cardiac events, the comparison of the sensed static scan field to the static scan field threshold, and the comparison of the time-varying scan fields to the time-varying scan field thresholds such that; when the static and time-varying scan field thresholds are exceeded, the first type of stimulation therapy and the second type of stimulation therapy are both inhibited, and when the static scan field threshold is exceeded and the time-varying scan field threshold is not exceeded, the second type of stimulation therapy is inhibited and the first type of stimulation therapy is delivered based on detection of the cardiac events. - View Dependent Claims (17, 18, 19, 20)
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Specification