Abstract: A biocompatible inductor for an implantable medical lead is disclosed herein. In one embodiment the biocompatible inductor may include a biocompatible bobbin and a wire wound about a barrel of the biocompatible bobbin to form a coil. The wire may include an electrically conductive core, an electrically conductive biocompatible jacket extending over the core, and a coating of high dielectric strength insulation material extending over the jacket. Additionally, the biocompatible inductor may include medical adhesive located in gaps within the coil and a polyester shrink tube covering the coil.

Abstract: A filtering scheme for an implantable medical device mitigates potentially adverse effects that may be caused by MRI-induced signals. In some aspects filtering is provided to attenuate MRI-induced signals on an implanted cardiac lead that is coupled to an implanted device. In some aspects the filter may be configured to complement a capacitor circuit (e.g., a feedthrough capacitor) that reduces the amount of EMI that enters the implanted device via the cardiac lead. In some implementations the filter consists of a LC tank circuit and a series LC circuit, where the LC tank circuit is in series with the cardiac lead and a cardiac stimulation circuit and the series LC circuit is in a shunt configuration across the cardiac stimulation circuit.

Abstract: An implantable medical device (IMD) is provided which is capable of sensing and determining its orientation, and of determining whether the IMD has been displaced over time away from its original or optimal position. Electronic components of the IMD, including a processor, digital memory, signal conditioning components, and a power supply, are preferably hermetically sealed within a biocompatible housing. At least three subcutaneous electrodes have fixed relative spacing for sensing electrical cardiac activity for various combinations of two electrodes, forming sensing vectors. Amplitude ratios and sign indicators associated with the sensing vectors are compared with a reference to determine an orientation of the device. In one embodiment, a telemetry unit transmits orientation data as a function of time to a remote device, and the remote device compares different stored orientations to detect displacement over time.

Abstract: A system, method and computer-readable storage medium are configured for the detection of electrical signals originating from a human or animal heart. In particular, for monitoring devices, it is desired to obtain electrical signals from a human or animal heart with electrical contacts at the body of an implantable medical device, hence without the need to implant electrical leads to the hearts. Hence, a method, a system and a computer-readable storage medium for detecting electrical signals originating from a human or animal heart is proposed. The method includes the steps of receiving electrical signals in at least two sensing channels, combining the electrical signals for forming a combined channel, extracting a template from the signals of the combined channel, comparing incoming electrical signals with the template, and depending from the result of the comparison, performing at least one of controlling one or more devices and signaling the result.

Abstract: An implanted cardioverter defibrillator (ICD) delivers an electrical therapy signal to the heart of a patient. When ventricular fibrillation or another condition of the heart requiring high voltage therapy is sensed, the therapy signal is delivered to the heart. When a partial short-circuit or other low impedance condition occurs, an over-current protection circuit will stop delivery of a shocking pulse. The ICD will then reduce the voltage of the shocking pulse and try again to deliver electrical therapy. This process is repeated until a voltage level is found that is able to deliver the electrical therapy without causing an over-voltage condition. Alternate lead configurations may also be tried in an attempt to find a signal path that is not affected by the low impedance or short-circuit condition.

Abstract: An implantable medical lead for coupling to an implantable pulse generator may be configured for improved safety. The lead may include: a first electrode; a second electrode in electrical communication with the first electrode; and an active circuit element in electrical communication with the first electrode and the second electrode. The active circuit element may be configured to change an impedance of the lead. The active circuit element may be configured to change the impedance of the lead in response to a pacing signal or a signal having opposite polarity to a pacing signal. A method of using an implantable medical lead for improved safety may include changing an impedance of an implantable medical lead from a relatively high impedance to a relatively low impedance and/or changing an impedance of an implantable medical lead from a relatively low impedance to a relatively high impedance.

Abstract: An implanted cardioverter defibrillator (ICD) delivers an electrical therapy signal to the heart of a patient. When ventricular fibrillation or another condition of the heart requiring high voltage therapy is sensed, the therapy signal is delivered to the heart. When a partial short-circuit or other low impedance condition occurs, an over-current protection circuit will stop delivery of a shocking pulse. The ICD will then reduce the voltage of the shocking pulse and try again to deliver electrical therapy. This process is repeated until a voltage level is found that is able to deliver the electrical therapy without causing an over-voltage condition. Alternate lead configurations may also be tried in an attempt to find a signal path that is not affected by the low impedance or short-circuit condition.

Abstract: An implantable medical lead is disclosed herein. In one embodiment, the lead includes a body and an electrical pathway. The body may include a distal portion with an electrode and a proximal portion with a lead connector end. The electrical pathway may extend between the electrode and lead connector end and include a coiled inductor including a first portion and a second portion at least partially magnetically decoupled from the first portion. The first portion may include a first configuration having a first SRF. The second portion may include a second configuration different from the first configuration. The second configuration may have a second SRF different from the first SRF. For example, the first SRF may be near 64 MHz and the second SRF may be near 128 MHz.

Abstract: Systems and methods are provided for reducing heating within pacing/sensing leads of a pacemaker or implantable cardioverter-defibrillator that occurs due to induced loop currents during a magnetic resonance imaging (MRI) procedure, or in the presence of other sources of strong radio frequency (RF) fields. For example, bipolar coaxial leads are described herein wherein the ring conductor of the lead is disconnected from the ring electrode in response to detection of MRI fields so as to convert the ring conductor into an RF shield for shielding the inner tip conductor of the lead so as to reduce the strength of loop currents induced therein and hence reduce tip heating. Techniques are also described herein for selectively disconnecting the tip electrode of the lead during an MRI procedure, except during actual delivery of pacing pulses, so as to permit delivery of individual pacing pulses to pacemaker dependent patients during the MRI.

Abstract: An implantable cardiac device to induce fibrillation in the heart of a patient to allow testing of the defibrillation capability of the device. The device induces fibrillation using a direct current across the heart. The shock to the heart may be applied in a method to minimize discomfort to the patient. The heart is monitored during application of the shock. The voltage of shock at the heart is gradually increased until fibrillation is induced. Once the fibrillation is detected the shock may be stopped. This results in a minimized voltage level and duration for the shock to the heart, thereby diminishing pain and discomfort to the patient.

Abstract: Disclosed herein is an implantable medical lead. In one embodiment, the lead includes a ring electrode, a tip electrode, first and second helically wound coaxial conductor coils, and a distal coil transition. The coils extend between the proximal and distal ends of the lead. The distal coil transition is proximal to the ring electrode and near the distal end and is where the first coil transitions from being outside the second coil proximal of the distal coil transition to being inside the second coil distal of the distal coil transition.

Abstract: Techniques are provided for generating plateau-shaped cardioversion shocks having reduced lead edge voltages. The reduced leading edge voltages are provided primarily to reduce the likelihood that any cardiac pain receptors will fire twice during a single cardioversion shock. Other techniques described herein relate to the generation of plateau-shaped shocks without reduced leading edge voltages. Still other techniques pertain to the generation of pre-pulse pain inhibition (PPI) pulses, particularly PPI pulses having chevron-shaped waveforms.

Abstract: An output circuit for use in an implantable cardiac defibrillation provides an output pulse having a waveform of virtually any desired shape. The device includes a sensing circuit that senses cardiac activity. An arrhythmia detector detects fibrillation responsive to the cardiac activity signal. The device further includes an output circuit that provides a stimulation output pulse when the arrhythmia detector detects a cardiac arrhythmia. The output circuit includes an H-bridge having a pair of switching devices which control the output pulse waveform with pulse-width modulation and a second pair of switching devices that control the output pulse polarity.

Abstract: Methods and systems for increasing capacitor reformation efficiency in an implantable cardiac device (ICD) are presented. In one embodiment, a method and system provide for: (1) fully charging a first capacitor, (2) transferring energy from the first capacitor to an inductor, (3) transferring energy from the inductor to the second capacitor, and (4) completing charging of the second capacitor. In another embodiment, a method and system provide for: (1) fully charging a first capacitor, (2) sharing energy from the first capacitor with a second capacitor, and (3) completing charging of the second capacitor. In yet another embodiment, a method and system provide for: (1) fully charging a first capacitor, (2) sharing energy from the first capacitor with a second capacitor, (3) transferring remaining energy from the first capacitor to an inductor, (4) transferring energy from the inductor to the second capacitor, and (5) completing charging of the second capacitor.

Abstract: An implantable cardiac stimulation device and method provides reliable sensing of cardiac events to support cardiac pacing or fibrillation detection. The device comprises a sensing circuit that senses the cardiac events in accordance with a plurality of threshold characterizing parameters. A parameter control adjusts the threshold parameters responsive to the rate of the sensed cardiac events in a manner which precludes positive feedback to prevent continued oversensing, undersensing, or noise sensing.

Abstract: An implantable cardiac stimulation device and method provides reliable sensing of cardiac events to support cardiac pacing or fibrillation detection. The device comprises a sensing circuit that senses the cardiac events in accordance with a plurality of threshold characterizing parameters. A parameter control adjusts the threshold parameters responsive to the rate of the sensed cardiac events in a manner which precludes positive feedback to prevent continued oversensing, undersensing, or noise sensing.

Abstract: The present invention relates to a percutaneous-point determination device for determining a location of a point associated with a surface of an animal organ. The device comprises an ultrasound device configured to emit a focused ultrasound beam along an ultrasound beam axis having a known orientation with respect to the ultrasound device. The ultrasound device is configured to output ultrasound data indicative of a distance from the ultrasound device to the point. A position measurement device is configured to output position data indicative of a location of the ultrasound device. The device includes a computer configured to process the ultrasound data and position data to thereby determine a location of the point.

Abstract: The present invention relates to a percutaneous-point determination device for determining a location of a point associated with a surface of an animal organ. The device comprises an ultrasound device configured to emit a focused ultrasound beam along an ultrasound beam axis having a known orientation with respect to the ultrasound device. The ultrasound device is configured to output ultrasound data indicative of a distance from the ultrasound device to the point. A position measurement device is configured to output position data indicative of a location of the ultrasound device. The device includes a computer configured to process the ultrasound data and position data to thereby determine a location of the point.