Cardiac Pacing Pulse Adjustment for Phrenic Nerve Stimulation Detection
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Solution Overview
Problem
Cardiac rhythm management devices often cause unwanted stimulation of skeletal muscle, such as the phrenic nerve, leading to annoying or painful side effects like hiccups, due to their proximity to the heart and the electrical stimulation used for pacing.
Innovation Solution
The system detects phrenic nerve stimulation by analyzing sensor data in the frequency domain using wavelet transformations and spectral analysis, allowing for the adjustment of pacing pulses to minimize such stimulation while ensuring heart capture, thereby reducing unwanted muscle contractions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pacing pulses are delivered to the heart to treat bradycardia, then cardiac rhythm is improved, but phrenic nerve stimulation occurs causing unwanted muscle contractions
Solution Approach 1:
The system continuously monitors for phrenic nerve stimulation during pacing and uses this feedback to adjust pacing parameters. When phrenic nerve stimulation is detected, the system modifies subsequent pacing pulses to reduce or eliminate the harmful effect while maintaining effective cardiac pacing.
Solution Approach 2:
The system changes pacing parameters such as pulse amplitude, duration, or timing based on the detection of phrenic nerve stimulation. By adjusting these parameters, the system can maintain effective heart capture while reducing stimulation of the phrenic nerve and associated muscle contractions.
2Reliability
If pacing pulses are increased in energy to ensure heart capture, then pacing reliability is improved, but unwanted stimulation of skeletal muscle and nerves increases
Solution Approach 1:
The system uses feedback from sensors detecting muscle or nerve stimulation to adjust pacing energy levels. When unwanted stimulation is detected, the system reduces energy while maintaining sufficient capture, or adjusts other parameters to achieve the same capture effect with lower energy.
Solution Approach 2:
The system delivers pacing pulses with just sufficient energy to achieve reliable capture, avoiding excessive energy that causes unwanted stimulation. The feedback mechanism ensures that the minimum effective dose is used rather than consistently using high energy levels.
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
This approach effectively minimizes phrenic nerve stimulation during cardiac pacing, enhancing patient comfort and the efficiency of cardiac rhythm management devices by optimizing pacing pulses to avoid unnecessary muscle contractions.
Implementation Method 1
A pacemaker, for example, is a cardiac rhythm management device that paces the heart with timed pacing pulses
Implementation Method 2
The processing circuit may be configured to: receive the sensor signal for a time after one or more pacing pulses; derive a time-frequency representation of the sensor signal based on the received sensor signal using wavelets
Implementation Method 3
the determination of whether the phrenic nerve of the patient has been stimulated is based at least in part upon data in the frequency domain
Data Source
AI summary
The disclosure relates to systems and methods for cardiac rhythm management. In some cases, a system may include a pulse generator for generating pacing pulses for stimulating a heart of a patient; a memory; and a sensor configured to sense a response to a unwanted stimulation and to produce a corresponding sensor signal. A processing circuit may receive the sensor signal for a time after one or more pacing pulses, and may derive a time-frequency representation of the sensor signal based on the received sensor signal. The processing circuit may use the time-frequency representation of the sensor signal to help identify unwanted stimulation. Once unwanted stimulation is detected, the processing circuit may change the pacing pulses to help reduce or eliminate the unwanted stimulation.