Implantable Neurostimulator Vagus Stimulation With Bradycardia-Safe Control
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Solution Overview
Problem
Current treatments for chronic cardiac dysfunction, including congestive heart failure and bradycardia, are palliative and do not effectively restore autonomic balance, leading to progressive cardiac deterioration and arrhythmogenesis, with existing vagus nerve stimulation (VNS) therapies being insufficient for comprehensive autonomic regulation.
Innovation Solution
An implantable neurostimulator delivers bi-directional afferent and efferent vagus nerve stimulation through intermittent, periodic electrical pulses, independent of the cardiac cycle, to restore autonomic balance, with a maintenance dose suspended upon sensing bradycardia and gradually resumed to avoid exacerbation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If vagus nerve stimulation is continuously delivered to restore autonomic balance, then cardiac function improves, but bradycardia risk increases
Solution Approach 1:
The patent implements periodic vagus nerve stimulation with alternating stimulation and inhibition cycles rather than continuous stimulation. The stimulation is delivered in bursts separated by inhibition periods, allowing the heart rate to recover and preventing excessive bradycardia while maintaining autonomic balance restoration benefits
Solution Approach 2:
The patent dynamically adjusts stimulation parameters including pulse width, amplitude, and duty cycle based on real-time heart rate feedback. The system transitions between different operational states (stimulation, inhibition, pacing) depending on detected cardiac conditions, optimizing therapeutic effect while preventing adverse bradycardic events
2Reliability
If vagus nerve stimulation intensity is increased to improve cardiac mechanical function, then arrhythmia suppression improves, but bradycardia severity increases
Solution Approach 1:
The patent employs closed-loop feedback control where heart rate is continuously monitored and stimulation parameters are adjusted in real-time. When heart rate drops below threshold, stimulation is reduced or paused; when arrhythmia is detected, stimulation intensity is increased, optimizing arrhythmia suppression while preventing excessive bradycardia
Solution Approach 2:
The patent dynamically changes multiple stimulation parameters including pulse width, amplitude, frequency, and duty cycle based on detected cardiac conditions. This multi-parameter adjustment allows fine-tuned control over vagal activation to suppress arrhythmias without causing severe bradycardia
3Ease of operation
If pharmacological agents are used to treat chronic cardiac dysfunction, then symptoms are relieved, but side effects and comorbidities increase
Solution Approach 1:
The patent replaces pharmacological chemical intervention with electrical neural stimulation. By directly stimulating the vagus nerve to modulate autonomic tone, the system achieves symptom relief and cardiac function improvement without the metabolic side effects and comorbidities associated with long-term pharmacological therapy
Data Source
AI summary
A method for managing bradycardia through vagus nerve stimulation is provided. An implantable neurostimulator configured to deliver electrical therapeutic stimulation in both afferent and efferent directions of a patient's cervical vagus nerve is provided. An operating mode is stored, which includes parametrically defining a maintenance dose of the electrical therapeutic stimulation tuned to restore cardiac autonomic balance through continuously-cycling, intermittent and periodic electrical pulses. The maintenance dose is delivered via a pulse generator through a pair of helical electrodes via an electrically coupled nerve stimulation therapy lead independent of cardiac cycle. The patient's physiology is monitored, and upon sensing a condition indicative of bradycardia, the delivery of the maintenance dose is suspended. A progressively increasing amount of time is spent waiting via a controller and, upon sensing a condition indicative of an absence or termination of the bradycardia, a progressively increasing partial maintenance dose is delivered via the pulse generator.