Implantable Cardiac Stimulation Timing for Safe CCM Therapy
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Solution Overview
Problem
Existing cardiac contractility modulation (CCM) devices for treating heart failure face issues such as interference with blood flow, risk of infection, misjudgment of electrical pulse delivery times, and reduced efficacy in patients with premature ventricular contractions, leading to potential arrhythmia and limited applicability to non-ventricular septum positions.
Innovation Solution
An implantable heart failure treatment device with anchoring members, stimulation electrodes, and a control module that uses far-field and local sense signals to determine the optimal timing for electrical stimulation during the absolute refractory period, enhancing cardiomyocyte contractility while minimizing interference and arrhythmia risk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two bipolar leads are implanted in the inter-ventricular septum for electrical stimulation, then cardiomyocyte contractility can be enhanced, but blood flow interference and infection risk increase
Solution Approach 1:
The patent extracts the stimulation function from traditional bipolar leads and relocates it to epicardial electrodes. The housing serves as one electrode while separate contact elements serve as counter-electrodes, eliminating the need for invasive intracardiac leads and their associated risks of blood flow interference and infection.
Solution Approach 2:
The patent introduces epicardial electrodes as an intermediary between the external stimulator and the myocardium. These electrodes provide electrical stimulation through the epicardium without requiring intracardiac lead placement, thus mediating the therapeutic effect while avoiding the harmful effects of lead implantation.
2Productivity
If electrical pulse stimulation is delivered based on local myocardial electrical signals, then stimulation timing can be determined, but misjudgment of deliverable time may occur leading to arrhythmia
Solution Approach 1:
The patent employs dual feedback mechanisms: local sense electrodes provide feedback on the local myocardial electrical status, while far-field sense electrodes provide feedback on the global cardiac electrical cycle. The control module integrates both feedback signals to accurately determine the deliverable time window, preventing misjudgment and arrhythmia.
Solution Approach 2:
The patent performs preliminary determination of the deliverable time window by analyzing far-field electrical signals before delivering stimulation. The control module identifies the appropriate timing based on the global cardiac cycle phase, ensuring stimulation is delivered at a safe time before local excitation events, thus preventing arrhythmia.
3Reliability
If stimulation electrodes are placed in the inter-ventricular septum to avoid arrhythmia risks, then safety is improved, but applicability to other myocardial positions is limited
Solution Approach 1:
The patent creates a universal stimulation system where the housing and contact elements can be positioned at various epicardial locations. The same basic electrode configuration can stimulate different myocardial regions by simply relocating the device, providing multi-functionality and broad applicability while maintaining safety through consistent electrical isolation.
4Reliability
If electrical stimulation is avoided during ventricular ectopic excitation to prevent arrhythmia, then safety is improved, but therapeutic effect on patients with premature ventricular contractions is reduced
Solution Approach 1:
The patent implements dynamic stimulation control that adapts to different cardiac conditions. The control module continuously monitors far-field electrical signals to identify ventricular ectopic excitations and adjusts the stimulation timing accordingly, delivering stimulation during safe windows even during premature ventricular contractions, thus maintaining both safety and therapeutic effect.
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 device effectively enhances cardiomyocyte contractility by accurately timing electrical pulses during the absolute refractory period, reducing arrhythmia risk and improving therapeutic efficacy for heart failure patients, including those with premature ventricular contractions.
Implementation Method 1
configured to sense a local sense signal generated by discharging of cardiac muscle cells at the predetermined stimulation position
Implementation Method 2
determine, at least based on the far-field sense signal and the local sense signal, whether a local excitation event of the cardiac muscle cells at the predetermined stimulation position corresponds to a specific global excitation event
Data Source
AI summary
Provided is an implantable heart failure treatment device, including a housing; an anchoring member, connected to the housing and fixing the housing to a heart; a pair of stimulation electrodes coupled to the housing, configured to be in contact with a predetermined stimulation position of the heart, and configured to apply an electrical stimulation pulse for enhancing cardiac contractility to the predetermined stimulation position; a pulse generation module accommodated within the housing, electrically coupled to the stimulation electrodes, and configured to generate the electrical stimulation pulse; and a control module accommodated within the housing, electrically coupled to the stimulation electrodes and the pulse generation module, and configured to: receive a far-field sense signal indicating a global excitation event of the heart of a patient and a local sense signal indicating a local excitation event of a local position of the heart of the patient; and determine, at least based on the far-field sense signal and the local sense signal, whether the local excitation event of the local position of the heart of the patient corresponds to a specific global excitation event, and transmit the electrical stimulation pulse to the stimulation electrodes in an absolute refractory period of the local excitation event.