Cardiac Pacemakers, Inc.

Micromotion Gmbh

Masoud Ameri

Yingbo Li

G Shantanu Reddy

Arthur J Foster

Lisa B Schmalhurst

James Gregory Bentsen

Michael J Root

Michael J Lyden

Joseph Walker

Kurt E Koshiol

Greg Paul Carpenter

David C Olson

Daniel Joseph Landherr

Brian D Allen

Keith R Maile

Gregory J Sherwood

Devon N Arnholt

Scot Ronald Foss

David A Chizek

David P Stieper

Jared James Dreier

James Blilie

Niharika Varanasi

A magnetic flowmeter for measuring a fluid flow includes flow tube assembly receiving the flow having a coil with first and second coil wires for receiving a coil current to produce a magnetic field in the fluid. This generates an EMF in the fluid representative of the flow. An EMF sensor is arranged to sense the EMF and generate an output related to the flow rate. Current supply circuitry provides the coil current to the first and second wires of the coil in response to a command signal. A digital control circuit provides the command signal to the current supply circuitry as a function of a control algorithm. In one aspect, the control algorithm is adapted to changes in electrical parameters of the coil. A method of implementing the magnetic flowmeter is also provided.

Continuously adaptive digital coil driver for magnetic flowmeter

A magnetic flowmeter includes a flow tube assembly and a programmable bi-directional current generator. The flow tube assembly receives the fluid flow and includes a coil and an electromotive force (EMF) sensor. The coil is configured to produce a magnetic field across the fluid flow in response to a coil current. The EMF sensor is arranged to sense an EMF across the fluid flow that is proportional to the flow rate, and generate an output indicating the induced EMF. The current generator includes a profile generator that issues profile commands, a power amplifier and a controller. The controller is configured to control the power amplifier to generate coil current pulses forming the coil current that travel through the coil in alternating directions. Each coil current pulse has a current profile that is based on a corresponding profile command.

Magnetic flowmeter having a programmable bi-directional current generator

A magnetic flowmeter includes a flow tube assembly, an electromotive force (EMF) sensor, a power amplifier, a current sampling circuit, and a controller. The flow tube assembly receives the fluid flow, and includes a coil configured to receive a coil current and induce an EMF in the fluid flow that is proportional to the flow rate. The EMF sensor generates an output indicating the induced EMF. The power amplifier is configured to generate unfiltered current pulses at a first frequency. The power amplifier includes a low pass filter that attenuates the unfiltered current pulses to form coil current pulses at a second frequency that form the coil current. The current sampling circuit samples the coil current pulses at a sampling frequency. The controller is configured to change a relationship between the sampling frequency and the first frequency, and adjust the coil current based on the samples.

Magnetic flowmeter with a current sampling circuit sampling coil current pulses at a sampling frequency

An implantable device, such as a pacer, defibrillator, or other cardiac rhythm management device, can include one or more MRI Safe components. In an example, the implantable device includes a battery including a first electrode and a second electrode separate from the first electrode. The second electrode includes a first surface and a second surface. The second electrode includes a slot through the second electrode from the first surface toward the second surface. The slot extends from a perimeter of the second electrode to an interior of the second electrode. The slot is configured to at least partially segment a surface area of the second electrode to reduce a radial current loop size in the second electrode.

Implantable medical device including eddy current reducing battery

An implantable medical device can include a device housing including a circuitry module and a header including a header core defining a bore configured to receive a distal end of a lead, an antenna, and a header shell disposed around the header core and the antenna. The antenna can be a closed loop antenna and arranged such that the antenna is positioned within two planes to maximize the area within the closed loop to increase the radiation characteristics of the antenna.

Bent loop antenna for implantable medical devices

In general, techniques are described for wirelessly transferring information using an implantable antenna. In one example, an apparatus includes an implantable medical device that includes a housing including an implantable telemetry circuit. The apparatus includes a dielectric compartment, mechanically coupled to the housing and including first and second substantially parallel face portions, and a third face portion extending between the first and second face portions, and an antenna assembly configured to be mechanically attached to the dielectric compartment and configured to be electrically coupled to the implantable telemetry circuit, the antenna assembly includes a spiral conductor comprising first, second, and third spiral conductor portions that extend adjacent the first, second, and third face portions, respectively, of the dielectric compartment, where the first, second, and third spiral conductor portions define an interior region, and where at least a portion of the third spiral conductor portion extends inwardly into the interior region.

Antennas for implantable medical devices

A medical device lead includes a tubular conductive element disposed over a lead body. The tubular conductive element includes at least one segment having one or more kerfs formed radially therethrough in a predetermined configuration so as to affect at least one electrical property, e.g., electrical impedance, of the segment. The segment may form a shocking conductor of the medical device lead. The tubular conductive element may alternatively include proximal, intermediate and distal segments each having one or more kerfs formed radially therethrough, where the one or more kerfs in each of the proximal and intermediate segments are configured so that these segments each have a higher electrical impedance than the distal segment. A layer of insulative material is disposed over the proximal and intermediate segments, so that the proximal and intermediate segments of the tubular conductive element are operable to filter electromagnetic energy from an external source.

Construction of an MRI-safe tachycardia lead

A medical device lead includes a proximal connector configured to couple the lead to a pulse generator, an insulative lead body extending distally from the proximal connector, and a conductor assembly extending distally from the proximal connector within the lead body. The conductor assembly includes a conductor having a proximal end electrically coupled to the connector and a distal end electrically coupled to a defibrillation coil. A first portion of the defibrillation coil is exposed at an outer surface of the medical device lead and a second portion of the defibrillation coil is insulated at the outer surface of the medical device lead.

MRI compatible tachycardia lead

Various embodiments concern leads having low peak MRI heating for improved MRI compatibility. Various leads include a lead body having at least one lumen, a proximal end configured to interface with an implantable medical device, and a distal end. Such leads can further include a conductor extending along at least a portion of the lead body within the at least one lumen and a defibrillation coil extending along an exterior portion of the lead body and in electrical connection with the conductor, wherein at least a section of the defibrillation coil is under longitudinal compression. The longitudinal compression can lower peak MRI heating along the defibrillation coil. The longitudinal compression may maintain circumferential contact between adjacent turns of the section of the defibrillation coil.

MRI compatible lead coil

A medical device includes a pulse generator and an electrode configured to contact tissue in a body vessel. The medical device includes a lead that includes a lead connector. The lead connector connects a pulse generator with an electrode via a conductive path. An electrode switch is electrically connected between the lead conductor and the electrode. The electrode switch includes an open state preventing the conductive path between the lead and the electrode. The electrode switch includes a closed state establishing the conductive path between the lead and the electrode when a voltage is applied across the electrode switch that exceeds a threshold voltage. The electrode switch in the open state electrically shields the electrode from electromagnetic radiation and induced voltages during magnetic resonance imaging.

Selectively connecting the tip electrode during therapy for MRI shielding

Implantable medical leads having resistance characteristics adapted to dissipate radio frequency (RF) electromagnetic energy during medical procedures such as magnetic resonance imaging (MRI) are disclosed. An illustrative medical device includes a lead having an inner electrical conductor operatively coupled to an electrode and a pulse generator, and one or more outer resistive shields that radially surround the inner conductor and dissipate RF energy into the surrounding body tissue along the length of the lead.

Leads with high surface resistance

An implantable medical device lead includes an inner conductor coil comprising one or more generally cylindrically wound filars. The inner conductor coil is configured to have a first inductance value greater than or equal to 0.2 &#x3bc;H/inch when the inner conductor coil is subjected to a range of radio frequencies. The implantable medical device lead also includes a multi-filar outer coil comprising two or more generally cylindrically wound filars. The multi-filar outer coil is configured to have a second inductance value greater than or equal to 0.1 &#x3bc;H/inch when the multi-filar outer coil is subjected to the range of radio frequencies.

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Maple Plain, MN, United States of America

Masoud Ameri