Medtronic, Inc.

Kendra K Gealow

David E Francischelli

Johann J Neisz

Pierre Andre Grandjean

John Hammargren

Koen J Weijand

Robert Leinders

David K Peterson

Philip H Lee

Michael A Colson

Martinus A G M Bakx

There is provided a system and method for continually monitoring the occurrence of contraction during stimulation of skeletal muscle which is employed in a cardiac assist-type system. During delivery of a periodic burst, or train of stimulus pulses, the impedance of the muscle between the electrodes through which the pulses are delivered is monitored, and evaluated to determine whether or not stimulation has been achieved. In a particular embodiment, the impedance and impedance derivative values are accumulated throughout the burst, and assessed to determine whether the impedance change corresponded to a full muscle contraction. In the event of failure to stimulate the muscle to contraction, the system can automatically adjust the pulse output parameters to achieve reliable contraction.

System and method of determining skeletal muscle contraction by serial lead impedance measurements

A cardiac assist device having circadian muscle stimulation. In particular the present invention operates in one of two states, either day mode or night mode. During the day mode, muscle stimulation and conditioning are performed according to a first schedule. During the night mode, muscle stimulation and conditioning are performed according to a second schedule. In addition, the night mode is only reached if the night mode is permitted, a set number of sensed beats are less than the night mode rate, and the time of day is nighttime. The night mode is interrupted if the night mode is turned off, the time of day is daytime, or a set number of beats are greater than the night rate. In short, the present invention provides for skeletal muscle stimulation at a less fatiguing level during the night than during the day.

Cardiac assist device having circadian muscle simulation

A device and algorithm for a combined cardiomyostimulator and a cardiac pacer-cardioverter-defibrillator. In particular the present device operates, in a first embodiment, to deliver stimulation to a skeletal muscle grafted about a heart; sense depolarizations of a patient's heart; measure the intervals separating successive depolarizations of the patient's heart; define first and second interval ranges; determine the number of the measured intervals falling within the first and second interval ranges; inhibit the delivery of stimulation to a skeletal muscle grafted about a heart upon the sensing of a depolarization within the first or second interval range; detect the occurrence of a first type of arrhythmia when the number of the measured intervals falling within the first interval range equals a first predetermined value; detect the occurrence of a second type of an arrhythmia when the number of the intervals falling within the second interval range equals a second predetermined value; deliver a first type of arrhythmia therapy in response to the detection of the first arrhythmia; and deliver a second type of arrhythmia therapy in response to the detection of the second arrhythmia, the second type of arrhythmia therapy having a cardiac stimulation component and a skeletal muscle component.

Device and algorithm for a combined cardiomyostimulator and a cardiac

A linear motion, muscle-actuated cardiac assist device novelly uses a powering muscle whose contractions and relaxations are made in a substantially linear fashion, as opposed to the curvilinear muscle motions associated with prior art muscle-actuated cardiac assist devices. As a result, collateral circulation of the powering muscle need not be cut, theoretically leading to prevention of ischemia in the powering muscle. Other benefits include: greater energy efficiency of the powering muscle; greater available choice of powering muscles (i.e., not limited to the latissimus dorsi as the powering muscle); and reduced profile height of the cardiac assist device to reduce protrusion from the implanted area of the body.

Linear motion, muscle-actuated cardiac assist device

An implantable heart-assist device including extra-aortic balloon pump (EAB pump) for use in cooperation with a fluid pump is disclosed. The extra-aortic balloon pump includes a rigid, generally cylindrical housing and a flexible, generally cylindrical diaphragm residing generally within a longitudinal passageway in the rigid housing and secured to the rigid housing so as to create a plurality of separate expansion chambers. A plurality of fluid communication ports are provided for passing fluid into and out of the respective expansion chambers. The rigid housing includes interior and exterior surfaces, proximal and distal ends, and a longitudinal passageway. The diaphragm has an inner surface which defines a longitudinal lumen within the longitudinal passageway. The longitudinal lumen has a longitudinal axis and the respective expansion chambers and corresponding fluid communication ports are oriented axisymmetrically in respect to the longitudinal axis. In preferred embodiments, the fluid pump is a fluid filled bladder within an innervated skeletal muscle pouch. The skeletal muscle pouch is preferably created surgically from a latissimus dorsi muscle flap which is preferably generated during a prior surgical procedure. The fluid filled bladder communicates with the EAB pump via fluid communication conduits and the fluid communication ports. Contraction of the skeletal muscle pouch is stimulated by an implantable pulse train generator which is synchronized with the beating of the active heart. Methods of assisting an active heart using the disclosed implantable heart assist device are also disclosed.

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Plymouth, MN, United States of America

Kendra K Gealow