Low-Energy Atrial Cardioversion with Controllable Pulse-Shaped Waveforms
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Solution Overview
Problem
Current treatments for atrial fibrillation, including pharmacologic and non-pharmacologic interventions, often result in significant patient discomfort and recurrence of arrhythmia, with existing implantable cardioverter devices requiring high energy levels that exceed pain thresholds, leading to poor patient acceptance and limited effectiveness.
Innovation Solution
Development of an implantable device delivering low-energy, pain-free shocks using novel waveforms and algorithms that destabilize and terminate the reentry mechanisms maintaining atrial fibrillation, employing low-energy, biphasic electrical stimuli in a multi-pulse, controllable waveform to convert atrial fibrillation to normal sinus rhythm.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high energy levels are used to achieve cardioversion, then the effectiveness of converting atrial fibrillation to normal sinus rhythm is improved, but patient discomfort and pain increase significantly
Solution Approach 1:
The patent divides a single high-energy cardioversion shock into multiple lower-energy pulses delivered in sequence. This segmentation allows the total energy to be distributed over time, achieving effective cardioversion while keeping individual pulse intensities below the patient's pain threshold. The multiple pulses work cumulatively to destabilize and extinguish reentry mechanisms maintaining AF.
Solution Approach 2:
The patent employs periodic pulsed waveforms delivered at specific intervals rather than a continuous or single shock. The periodic action allows tissue recovery between pulses and enables cumulative effect buildup, achieving effective cardioversion with lower peak energy levels that avoid patient discomfort.
2Reliability
If conventional biphasic truncated exponential waveforms are used, then the cardioversion capability is achieved, but the energy requirement exceeds pain threshold
Solution Approach 1:
The patent changes the waveform parameters from conventional biphasic truncated exponential to controllable pulse-shaped waveforms with adjustable amplitude, duration, and inter-pulse intervals. These parameter modifications enable effective cardioversion at lower energy levels by optimizing the temporal and amplitude characteristics of each pulse in the sequence.
Solution Approach 2:
The patent introduces dynamically controllable pulse parameters including variable amplitude, duration, and spacing between pulses. This dynamic control allows optimization of energy delivery to achieve cardioversion at the lowest effective energy level, adapting to different patient thresholds and arrhythmia characteristics.
3Reliability
If implantable cardioverter devices are deployed, then the treatment effectiveness for recurrent AF is improved, but patient acceptance decreases due to discomfort
Solution Approach 1:
By segmenting the cardioversion therapy into multiple low-energy pulses, the patent eliminates the intense discomfort associated with single high-energy shocks. This makes implantable cardioverter devices acceptable to patients who would otherwise forego therapy due to pain, thereby improving patient acceptance and adherence to treatment.
Solution Approach 2:
The patent modifies the energy delivery parameters to operate below the patient's pain threshold while maintaining cardioversion effectiveness. This parameter optimization resolves the conflict between treatment effectiveness and patient comfort, enabling widespread acceptance of implantable devices.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively converts atrial fibrillation to normal sinus rhythm with energy levels below the pain threshold, reducing the risk of discomfort and recurrence, while being feasible for implantation and use in a broader patient population.
Implementation Method 1
low-energy, biphasic electrical stimuli in a multi-pulse, controllable waveform to convert atrial fibrillation to normal sinus rhythm
Data Source
AI summary
An implantable therapy generator that includes sensing circuitry that senses cardiac signals representative of atrial activity and ventricular activity; detection circuitry connected to the sensing circuitry; control circuitry that controls generation and selective delivery of a multi-stage atrial cardioversion therapy to implanted electrodes, each stage of the therapy including multiple pulses, each pulse including multiple high-frequency sub-pulses; and therapy circuitry. The therapy circuitry includes a high-voltage charging circuit charging a storage capacitor to a predetermined voltage; a delivery capacitor connectable to the storage capacitor; and a control circuit adapted to selectively cause the storage capacitor to be electrically connected to the delivery capacitor so as to charge the delivery capacitor to a predetermined delivery voltage, and to cause a delivery switching circuit to be repeatedly opened and closed at a predetermined rate, thereby causing the sub-pulses to be transmitted to the electrodes.