Implantable medical systems, devices, and methods for affecting cardiac function through diaphragm stimulation, and for monitoring diaphragmatic health

Inventors

Bauer, Peter T. • Wheeler, Timothy

Assignees

Viscardia Inc

Abstract

Devices, systems and methods provide forms of asymptomatic diaphragmatic stimulation (ADS) therapy that affect pressures within the intrathoracic cavity, including: 1) dual-pulse ADS therapy, during which a first ADS pulse is delivered during a diastolic phase of a cardiac cycle and a second ADS pulse is delivered during a systolic phase, 2) paired-pulse ADS therapy, during which a first ADS pulse is delivered, closely followed by a second ADS pulse, with the second ADS pulse functioning to extend or enhance a phase of a transient, partial contraction of the diaphragm, and 3) multiple-pulse ADS therapy, during which a stream of ADS pulses is delivered, wherein the time between pulses is based on heart rate. Devices, systems and methods also monitor electromyography (EMG) activity of the diaphragm relative to baseline activity to assess the health of a diaphragm subject to ADS therapy and to adjust ADS therapy parameters or sensing parameters.

Core Innovation

The disclosed invention relates to an apparatus having one or more electrodes configured for placement on or near a diaphragm and a controller with a therapy module coupled to the electrodes. The controller delivers asymptomatic diaphragm stimulation (ADS) therapy and switches between a deactivated state in which the ADS therapy is prevented from being delivered and an activated state in which the ADS therapy can be delivered.

The ADS therapy includes at least one of dual-pulse therapy, paired-pulse therapy, and multiple-pulse therapy. The dual-pulse therapy includes a single diastolic ADS pulse delivered during a diastolic phase of a cardiac cycle and a single systolic ADS pulse delivered during a systolic phase of the cardiac cycle, while the paired-pulse therapy includes first and second ADS pulses delivered during a time duration of a transient, partial contraction of the diaphragm induced by the first ADS pulse.

The multiple-pulse therapy includes ADS pulses delivered at a rate based on a heart rate and a time duration of a transient, partial contraction induced by previously delivered ADS pulses. The controller periodically senses electromyography (EMG) electrical activity produced by one or more skeletal muscles of the diaphragm and determines whether the EMG electrical activity satisfies a criterion relative to baseline EMG electrical activity, where the criterion corresponds to a threshold increase in a characteristic of the EMG activity relative to the same characteristic of baseline EMG activity, indicative of a decline in diaphragmatic health.

In response to the EMG electrical activity satisfying the criterion, the controller switches the therapy module from the deactivated state to the activated state. The sensing and evaluation can support assessment of diaphragmatic or phrenic health and decompensation based on composite ECG/EMG sensing and baseline-relative criterion evaluation.

Claims Coverage

The claim coverage identifies one independent claim with three alternative ADS delivery patterns and a baseline-relative EMG-based activation and switching control concept. Dependent claims refine how diaphragm EMG is sensed and how the baseline-relative criterion is evaluated.

Overall, the claims center on an apparatus that delivers ADS in dual-pulse, paired-pulse, or multiple-pulse forms and uses periodic diaphragm EMG sensing with baseline-relative criterion evaluation to switch between deactivated and activated therapy states. Dependent refinements specify composite ECG/EMG sensing with filtering and criterion evaluation based on EMG morphology, frequency, and amplitude compared to baseline.

Stated Advantages

Documented Applications