Leadless Pacemaker Amplitude and Pulse Width Control
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Solution Overview
Problem
Cardiac pacing devices face challenges in efficiently setting pacing pulse parameters, leading to potential waste of power supply energy and reduced longevity of implantable medical devices like leadless cardiac pacemakers.
Innovation Solution
Setting the pacing pulse amplitude to the power supply voltage, such as battery voltage, and adjusting the pulse width to ensure effective heart capture while minimizing energy conversion inefficiencies, thereby extending the device's useful life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If pacing pulse amplitude is set below power supply voltage, then energy is wasted in voltage conversion, but device complexity increases due to conversion circuitry
Solution Approach 1:
The patent removes the voltage conversion circuitry from the device entirely by setting the pacing pulse amplitude equal to the power supply voltage. This extraction of unnecessary conversion components eliminates both the energy loss associated with voltage transformation and the device complexity introduced by conversion circuitry, directly resolving the technical contradiction.
Solution Approach 2:
The patent applies equipotentiality by setting the pacing pulse amplitude at the same voltage level as the power supply (e.g., 3.0V). This eliminates potential difference and associated energy conversion losses, allowing direct coupling between the power supply and pulse generation without intermediate conversion stages, thereby reducing both energy waste and circuit complexity.
2Duration of action of stationary object
If pacing pulse parameters are optimized for energy efficiency, then device longevity increases, but therapy effectiveness may be compromised
Solution Approach 1:
The patent implements dynamic adjustment of pulse width parameters while maintaining fixed amplitude at power supply voltage. The system dynamically adapts pulse width based on captured threshold measurements and strength-duration curves, ensuring effective heart capture while optimizing energy consumption. This dynamic parameter adjustment resolves the contradiction between longevity and effectiveness.
Solution Approach 2:
The patent changes the operational parameters by setting amplitude to the maximum available voltage and compensating through pulse width adjustment. By utilizing the full power supply voltage range and dynamically adjusting pulse width based on tissue capture thresholds, the system achieves both energy efficiency and reliable therapy delivery, resolving the contradiction between extended device life and maintained effectiveness.
Data Source
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AI summary
Systems, devices, and methods for pacing a heart of a patient are disclosed. A device may include a leadless cardiac pacemaker (LCP) that includes a power supply, a pair of electrodes, and a controller operably connected to the electrodes and the power supply. The controller may identify a capture threshold by setting a pace amplitude at a power supply voltage of the power supply and deliver pacing stimulation pulses with different pulse widths to identify the capture threshold. The LCP may then deliver pacing stimulation pulses based, at least in part, on a pulse amplitude and pulse width associated with the capture threshold, and also adding a capture margin. In some cases, the pulse amplitude may change over time and the LCP may adjust a pulse width along a strength-duration curve to account for the pulse amplitude change and maintain a capture threshold and capture margin.