Multi-Phase Cardiac Stimulus Generator for Asynchronous Ventricular Contraction
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Solution Overview
Problem
Heart failure patients experience conduction delays in electrical impulses to the ventricles, leading to inefficient heart pumping due to asynchronous contraction of the left and right ventricles, which existing pacemakers cannot effectively address using cathodal pulses alone, as they result in higher stimulation thresholds and potential arrhythmogenesis.
Innovation Solution
A cardiac stimulation device that stores and selectively generates anodal, cathodal, and biphasic waveforms to differentially increase or decrease conduction and repolarization, using a multi-phase cardiac stimulus generator to apply appropriate waveforms based on sensor data and patient-specific rules, thereby improving cardiac contraction efficiency and reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cathodal pulses are used for cardiac stimulation, then the heart can be paced to maintain safe heart rate, but the stimulation threshold is higher and arrhythmogenesis may occur
Solution Approach 1:
The patent combines cathodal and anodal pulses into a biphasic waveform delivery system. The memory stores multiple waveforms including both cathodal and anodal configurations, and the stimulus generator can deliver sequences of both polarities to achieve reliable cardiac pacing while reducing arrhythmogenesis through the alternating polarity approach
Solution Approach 2:
The system changes the polarity parameter of stimulation pulses by storing and delivering both cathodal and anodal waveforms. This parameter variation allows the device to overcome the limitations of single-polarity stimulation by alternating between cathodal and anodal phases, thereby reducing stimulation thresholds and preventing arrhythmias
2Productivity
If multiple waveform types are stored and selectively generated, then cardiac contraction efficiency is improved and power consumption is reduced, but device complexity increases
Solution Approach 1:
The system dynamically selects and switches between different waveform types (cathodal, anodal, biphasic) based on real-time cardiac conditions and treatment requirements. The stimulus generator can adaptively change waveform parameters and polarity sequences to optimize cardiac contraction efficiency while managing power consumption through intelligent waveform selection
3Reliability
If anodal current is used for stimulation, then the stimulation threshold is lower, but power consumption increases and battery life decreases
Solution Approach 1:
The patent employs periodic alternation between cathodal and anodal pulses in biphasic waveform sequences. This periodic action allows the system to take advantage of the lower stimulation threshold of anodal current when needed, while using cathodal pulses for primary stimulation, thereby optimizing the balance between stimulation effectiveness and power consumption over time
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 enhances cardiac contraction speed and efficiency, reduces power consumption, and prolongs pacemaker battery life by using a combination of cathodal and anodal pulses, addressing the limitations of cathodal-only stimulation and improving heart function in heart failure patients.
Implementation Method 1
The job of the pacemaker is to maintain a safe heart rate by delivering to the pumping chambers appropriately timed electrical impulses that replace the heart's normal rhythmic pulses
Implementation Method 2
the bundle of His (i.e., the electrical conduction pathway located in the ventricular septum) and the bundle braides carry the excitation to many sites in the right and left ventricle at a relatively high velocity of 1-2 m/s
Data Source
AI summary
A rules engine acquires sensor data from sensors applied to the heart and determines whether an electrical waveform should be applied to the heart and, if so, the type of electrical waveform. A multi-phase cardiac stimulus generator generates waveforms in response to the rules engine from waveform data stored in a memory. The electrical waveform is applied to one or more electrodes implanted in or on the heart.