Abstract: A system for accessing implantable medical device (IMD) data is provided including an interrogation appliance to retrieve data from an IMD and transfer the data to a processor. The processor converts the device data to a viewable form that is transferred by the processor to a data destination. The data destination may be an electronic mail address, a secure web site, a facsimile number or the interrogation appliance. The data is presented in a viewable form at the data destination either on a display or by printing. Any number of interrogation appliances may be communicatively coupled to the processor for converting IMD data and providing the IMD data back to a data destination in a viewable form for use by a clinician.

Abstract: Undersensing of an evoked response during an automatically initiated search of the stimulation threshold in a stimulation channel of an IMD, e.g., the pacing threshold in a pacing channel of a pacing system, is minimized by repeating the search using the sense amplifier of the stimulation channel configured in bipolar and unipolar sensing configurations. A failure to sense an evoked response in the search in one sensing configuration can be confirmed, and stimulation energy set to a high output, if an evoked response is not sensed in an alternate sensing configuration or refuted if an evoked response is sensed in the alternate sensing configuration. If the failure is refuted, the alternate sensing configuration is employed until the next search.

Abstract: A capture detection algorithm detects and distinguishes atrial capture. Atrial chamber reset (ACR) and AV conduction (AVC) algorithms are implemented to measure an atrial pacing threshold The data that is used to choose between ACR and AVC methods is used to determine the progression of the patient's disease state. Some of the significant aspects of the invention include enablement of accurate threshold measurements, including calculation of stability criteria, precise interval measurements and the use of reference interval to determine capture and loss of capture.

Abstract: In an implantable medical device having an electrical lead coupled to tissue of a user and a circuit for measuring the impedance of the lead, a method and apparatus for responding to impedance variations in the lead which includes measuring the impedance of the lead while monitoring physiologic parameters of the user, detecting the presence or absence of electromagnetic interference, and if the impedance of the lead is out-of-range, determining whether the electromagnetic interference exceeds a predetermined value, and if the electromagnetic interference exceeds a predetermined value, administering a therapy to the tissue of the user.

Abstract: A capture detection algorithm in which atrial capture is detected and distinguished. Further, an immediate measurement of the capture threshold is implemented when a pacemaker switches a lead's polarity from bipolar to unipolar in response to a detected lead failure, in either one or both chambers. Atrial chamber reset (ACR) and AV conduction (AVC), implemented to measure an atrial pacing threshold, are comparatively measured to enable measurement of the atrial pacing threshold. The data that is used to choose between ACR and AVC methods is used to determine the progression of the patient's disease state. Some of the significant aspects of the invention include enablement of accurate threshold measurements, including calculation of stability criteria, precise interval measurements and the use of reference interval to determine capture and loss of capture.

Abstract: In an implantable medical device having an electrical lead coupled to tissue of a user and a circuit for measuring the impedance of the lead, a method and apparatus for responding to impedance variations in the lead which includes measuring the impedance of the lead while monitoring physiologic parameters of the user, detecting the presence or absence of electromagnetic interference, and if the impedance of the lead is out-of-range, determining whether the electromagnetic interference exceeds a predetermined value, and if the electromagnetic interference exceeds a predetermined value, administering a therapy to the tissue of the user.

Abstract: Undersensing of an evoked response during an automatically initiated search of the stimulation threshold in a stimulation channel of an IMD, e.g., the pacing threshold in a pacing channel of a pacing system, is minimized by repeating the search using the sense amplifier of the stimulation channel configured in bipolar and unipolar sensing configurations. A failure to sense an evoked response in the search in one sensing configuration can be confirmed, and stimulation energy set to a high output, if an evoked response is not sensed in an alternate sensing configuration or refuted if an evoked response is sensed in the alternate sensing configuration. If the failure is refuted, the alternate sensing configuration is employed until the next search.

Abstract: A capture detection algorithm detects and distinguishes atrial capture. Atrial chamber reset (ACR) and AV conduction (AVC) algorithms are implemented to measure an atrial pacing threshold The data that is used to choose between ACR and AVC methods is used to determine the progression of the patient's disease state. Some of the significant aspects of the invention include enablement of accurate threshold measurements, including calculation of stability criteria, precise interval measurements and the use of reference interval to determine capture and loss of capture.

Abstract: A capture detection algorithm in which atrial capture is detected and distinguished. Further, an immediate measurement of the capture threshold is implemented when a pacemaker switches a lead's polarity from bipolar to unipolar in response to a detected lead failure, in either one or both chambers. Atrial chamber reset (ACR) and AV conduction (AVC), implemented to measure an atrial pacing threshold, are comparatively measured to enable measurement of the atrial pacing threshold. The data that is used to choose between ACR and AVC methods is used to determine the progression of the patient's disease state. Some of the significant aspects of the invention include enablement of accurate threshold measurements, including calculation of stability criteria, precise interval measurements and the use of reference interval to determine capture and loss of capture.

Abstract: An apparatus and method for detecting micro-dislodgment at a heart tissue/pacing lead electrode interface involves measuring a first pacing threshold parameter at a first time in a patient's cardiac cycle and measuring a second pacing threshold parameter at a second time in the patient's cardiac cycle. Micro-dislodgment occurring at the heart tissue/pacing lead electrode interface is detected using the first and second pacing threshold parameters. Micro-dislodgment may be detected by comparing a difference between, or a ratio of, the first and second pacing threshold parameters to a preestablished maximum allowable deviation value. A difference between the first and second pacing threshold parameters or a ratio in excess of the preestablished maximum allowable deviation value indicates a problem at the heart tissue/pacing lead interface.