Abstract: A method and device for detecting a cardiac event that includes sensing cardiac electrical signals representative of electrical activity of a heart of a patient, detecting the cardiac event in response to the sensed cardiac signals, determining an indication of signal reliability corresponding to the sensed cardiac signals as being one of a reliable signal and a not reliable signal, and switching operation of the device between a first mode of determining whether the sensed signal is one of treatable and not treatable and a second mode of determining whether the sensed signal is one of treatable and not treatable in response to the determined indication of signal reliability.

Abstract: An implantable medical device and method are provided for determining if a patient is in a substantially horizontal position and delaying a programmed cardioversion/defibrillation shock therapy in response to determining the patient is in a substantially horizontal position. In various embodiments, the shock therapy may be delayed by adjusting tachycardia detection criteria or scheduling the shock therapy after a maximum tachycardia episode duration.

Abstract: System and method for assessing a likelihood of a patient to experience a cardiac arrhythmia. A biological sensor is configured to sense biological parameters of the patient. A processor is coupled to the biological sensor and is configured to determine the likelihood of the patient experiencing a cardiac arrhythmia based, at least in part, on a combination of the biological parameters, the combination dynamically weighting each of the plurality of biological parameters based on another one of the plurality of biological parameters.

Abstract: A method of delivering phrenic nerve stimulation in a medical device system that includes detecting an activation event, delivering phrenic nerve stimulation therapy in response to the detected activation event, sensing a heart sound signal, in response to the delivered phrenic nerve stimulation therapy, monitoring a portion of the sensed heart sound signal, the portion defined by a predetermined window ocurring after the delivered phrenic nerve stimulation therapy, and determining whether the delivered phrenic nerve stimulation therapy was successful in response to the monitoring.

Abstract: A method and system of detecting phrenic nerve stimulation in a patient that includes detecting an activation event, obtaining a heart sound signal of a patient from an implanted heart sound sensor, determining that an electrical stimulation has been applied to the patient, in response to detecting the activation event, monitoring a portion of the heart sound signal, the portion defined by a predetermined window after the application of the electrical stimulation, and determining whether phrenic nerve stimulation occurred based on the portion of the heart sound signal.

Abstract: An apparatus and method to discriminate cardiac events by sensing atrial and ventricular depolarizations having associated refractory periods thereafter. A fast ventricular rate is detected in response to the sensed ventricular depolarizations. Responsive to detecting the fast ventricular rate, at least one stimulus pulse is delivered to atrial tissue within the associated refractory period of the ventricle but outside of an associated refractory period of the stimulated atrial tissue. A ventricular response to the atrial tissue stimulus pulse is determined, and the cardiac event is discriminated based on the ventricular response to the atrial tissue stimulus pulse.

Abstract: An apparatus and method to discriminate cardiac events by sensing atrial and ventricular depolarizations having associated refractory periods thereafter. A fast ventricular rate is detected in response to the sensed ventricular depolarizations. Responsive to detecting the fast ventricular rate, at least one stimulus pulse is delivered to atrial tissue within the associated refractory period of the ventricle but outside of an associated refractory period of the stimulated atrial tissue. A ventricular response to the atrial tissue stimulus pulse is determined, and the cardiac event is discriminated based on the ventricular response to the atrial tissue stimulus pulse.

Abstract: A system and method for delivering both anti-tachy pacing (ATP) therapy and high-voltage shock therapy in response to detection of abnormal cardiac rhythms is disclosed. The system controls the time between delivering ATP therapy and the charging of high-voltage capacitors in preparation for shock delivery based on a predetermined set of criteria. In one embodiment, the inventive system operates in an ATP During Capacitor Charging (ATP-DCC) mode wherein all, or substantially all, of the ATP therapy is delivered during charging of the high-voltage capacitors. Based on evaluation of the predetermined set of criteria, the system may switch to an additional ATP Before Capacitor Charging (ATP-BCC) mode, wherein substantially all of the ATP therapy is delivered prior to charging of the high-voltage capacitor. According to one aspect of the invention, the predetermined set of criteria is based, at least in part, on the effectiveness of previously-delivered ATP therapy.

Abstract: System and method for assessing a likelihood of a patient to experience a cardiac arrhythmia using dynamic changes in a biological parameter. A biological sensor is configured to sense a biological parameter of the patient. A processor is coupled to the biological sensor and is configured to determine a dynamic change of the biological parameter and determine the likelihood of the patient experiencing a cardiac arrhythmia based, at least in part, on the dynamic change of the biological parameter.

Abstract: System and method for assessing a likelihood of a patient to experience a cardiac arrhythmia. A biological sensor is configured to sense biological parameters of the patient. A processor is coupled to the biological sensor and is configured to determine the likelihood of the patient experiencing a cardiac arrhythmia based, at least in part, on a combination of the biological parameters, the combination dynamically weighting each of the plurality of biological parameters based on another one of the plurality of biological parameters.

Abstract: Techniques for activating an alternative operating mode in an implantable medical device based on a determination that the device is within a relatively high noise environment or otherwise exposed to relatively high noise. The implantable medical device can automatically detect its presence in a high noise environment and automatically revert to the alternative operating mode, the device may be manually switched to alternative operating mode, or a hybrid manual/automatic approach may be used to switch the device to alternative operating mode.

Abstract: A medical electrical system includes a device including a connector port and an external electrically active surface and an auxiliary lead including a supplemental electrode and a connector end. The external electrically active surface of the device is adapted to receive the auxiliary lead connector end, thereby electrically coupling the supplemental electrode to the device via contact between the connector end and the external surface.

Abstract: A medical electrical system includes a device including a connector port and an external electrically active surface and an auxiliary lead including a supplemental electrode and a connector end. The external electrically active surface of the device is adapted to receive the auxiliary lead connector end, thereby electrically coupling the supplemental electrode to the device via contact between the connector end and the external surface.

Abstract: A device and method to detect slow ventricular tachycardia, deliver anti-tachycardia pacing therapies, and delay a scheduled shock therapy if the ventricular tachycardia is not terminated or accelerated. Preferably, a shock therapy is delayed after verifying hemodynamic stability based on a hemodynamic sensor. After a shock is delayed, the device operates in a high alert mode for redetecting an accelerated tachycardia. Anti-tachycardia pacing therapies are repeated during the shock delay. A number of conditions can trigger delivery of the delayed shock therapy including a specified period of elapsed time; determination that the patient is likely to be asleep; detection of myocardial ischemia; detection of compromised hemodynamics, or detection of a substantially prone position or sudden change in position.

Abstract: The present invention outlines structures and methods for delivering a controllable amount of energy to a patient by automatically compensating for the load impedance detected by an implantable-cardioverter defibrillator (ICD). The invention employs high speed, switching power converter technology for the efficient generation of high energy, arbitrarywaveforms. Unlike a linear amplifier, switching power converters deliver high-energy waveforms with an efficiency that is independent of the size and amplitude of the desired waveform. An ICD that uses a switching power converter to deliver the desired energy to the patient stores the energy to be delivered in a storage capacitor. The converter then transforms this energy into an arbitrarily shaped output voltage-controlled or current-controlled waveform by switching the storage capacitor in and out of the output circuit at a high rate of speed. Preferably, the waveform comprises a ramp-type waveform.

Abstract: An implantable medical device (IMD) provides for adaptive timing of the delivery of cardioversion shocks. In particular, the invention IMD provides for an adaptive cardioversion synchronization delay with respect to a cardiac event, such as a sensed P-wave or R-wave. When cardioversion with a first synchronization delay fails to terminate a tachycardia, for example, cardioversion may be attempted again with a second synchronization delay. The IMD may keep track of whether each synchronization delay is effective in terminating the tachycardia, and may employ a historically effective synchronization delay when applying cardioversion therapy to treat a subsequent tachycardia episode.

Abstract: The present invention provides structures and methods for delivering a complex slow-rise defibrillation waveform wherein in lieu of the simple truncation of prior art defibrillation waveforms, when a predetermined amplitude is reached for an ascending waveform (e.g., a ramp waveform), the waveform transitions to an exponential decay portion for a period of time and at the expiration of the period of time, a truncation occurs. In the event that a first complex bi-phasic ramp wave form is implemented, a second opposite polarity waveform may be delivered. Said second waveform is preferably of similar shape to the first waveform, but of a less magnitude amplitude, although the second waveform may comprise a traditional waveform. The implementation and feasibility of the waveforms according to the present invention in an ICD or an AED is relatively simple while providing significant advantages not previously known or used in the prior art.

Abstract: The present invention outlines structures and methods for delivering a controllable amount of energy to a patient by automatically compensating for the load impedance detected by an implantable-cardioverter defibrillator (ICD). The invention employs high speed, switching power converter technology for the efficient generation of high energy, arbitrary waveforms. Unlike a linear amplifier, switching power converters deliver high-energy waveforms with an efficiency that is independent of the size and amplitude of the desired waveform. An ICD that uses a switching power converter to deliver the desired energy to the patient stores the energy to be delivered in a storage capacitor. The converter then transforms this energy into an arbitrarily shaped output voltage-controlled or current-controlled waveform by switching the storage capacitor in and out of the output circuit at a high rate of speed. Preferably, the waveform comprises a ramp-type waveform.

Abstract: An apparatus for discriminating between cardiac events that includes an input circuit receiving signals indicative of the cardiac events, a first output circuit generating pulses in response to the received signals, and a microprocessor determining whether a signal received by the input circuit subsequent to the generated pacing pulses corresponds to a predetermined cardiac event in response to an elapsed time period between the generated pulses and the subsequently received signal and a predetermined discrimination threshold.

Abstract: An implantable medical device may be programmed by a programmer to apply a variety of ventricular fibrillation (VF) and ventricular tachycardia (VT) therapies, such as antitachycardia pacing (ATP) and cardioversion shocks. In general, the invention is directed to automatic activation of VF- and VT-related functions upon a single command. When a clinician interacts with the programmer to set VF therapies to active status, for example, VT therapies are automatically set to active status as well. Activation of several VF- and VT-related functions with a single command may save considerable time and may be beneficial to the patient. The invention further provides the freedom to customize the functions to the particular needs of a single patient or a group of patients.