Medtronic, Inc.

John Hammargren

Johann J Neisz

David E Francischelli

David K Peterson

Kendra K Gealow

Mark A Christopherson

Koen J Weijand

Pierre Andre Grandjean

A method of predicting critical points in patient respiration includes monitoring at least one characteristic of a respiratory effort waveform of a patient to detect a respiratory event. A refractory period is defined that includes a hard refractory period during which time the respiratory event cannot be responded to and a soft refractory period following the hard refractory period. The respiratory event outside of the refractory period is detected as a function of a first set of predetermined parameters for the monitored at least one characteristic and the respiratory event within the soft refractory period is detected as a function of a second set of predetermined parameters for the monitored at least one characteristic. The respiratory event may be inspiration onset and the characteristic of the respiratory effort waveform monitored is at least one of slope and amplitude. The refractory period may be defined based on detection of inspiration offset and further may be defined based on inspiration offset, an average respiratory period, and an average time of inspiration. Further, stimulation may be provided in response to a detected inspiration onset. Another method of predicting critical points includes sampling the amplitude of the respiratory effort waveform of a patient. A sample signal is generated representative of at least one characteristic of the respiratory effort waveform based on each amplitude sample. The sample signals representative of the at least one characteristic of the respiratory effort waveform are monitored and a respiratory event is detected as a function of at least two sample signals. Apparatus and systems for use with such methods are also described.

Respiratory effort detection method and apparatus

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 cardiac assist device having muscle augmentation after a confirmed arrhythmia. In particular the present invention operates, in a first embodiment, to sense a cardiac event, next it determines whether the cardiac event is a cardiac arrhythmia, if the event is not a cardiac arrhythmia the devices delivers stimulation to a skeletal muscle grafted about a heart, but if the event is a cardiac arrhythmia the device inhibits delivery of skeletal muscle stimulation and once the arrhythmia is confirmed, then delivers therapeutic stimulation to the heart. In a second embodiment the present invention operates to re-initiate skeletal muscle stimulation once the arrhythmia is confirmed but prior to the delivery of the therapeutic stimulation to the heart.

Cardiac assist device having muscle augementation after confirmed

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.

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Medina, MN, United States of America

John Hammargren