Implantable Pacemaker Anodal Cathodal Capture Detection
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Solution Overview
Problem
Current pacemakers lack efficient techniques for determining and verifying capture thresholds for concurrent anodal and cathodal stimulation, particularly in multi-site left ventricular pacing, which limits energy efficiency and synchronization of heart contractions.
Innovation Solution
The method involves delivering bipolar stimuli and sensing bipolar intracardiac electrogram signals to detect evoked responses indicative of anodal and cathodal capture, determining the anodal/cathodal capture threshold, and adjusting pulse magnitude accordingly to enable or disable concurrent anodal/cathodal capture, using techniques that differentiate between cathodal-only and concurrent capture morphologies in IEGM signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If higher pulse magnitude is used to achieve concurrent anodal and cathodal capture, then myocardial synchronization is improved, but energy consumption increases
Solution Approach 1:
The system dynamically adjusts pulse magnitude based on detected capture status. When concurrent anodal and cathodal capture is detected through IEGM analysis, the system can reduce pulse magnitude to save energy while maintaining synchronization. The pulse delivery and magnitude are made adaptive rather than static, allowing energy optimization without sacrificing myocardial synchronization when capture is achieved.
Solution Approach 2:
The system employs feedback through IEGM sensing and analysis to detect evoked responses indicating anodal and cathodal capture. This feedback mechanism allows the system to verify whether concurrent capture is achieved and adjust pulse magnitude accordingly, preventing unnecessary high-energy pulses when capture is already obtained and reducing energy consumption while maintaining synchronization.
2Adaptability or versatility
If pulse magnitude is increased to achieve anodal capture in addition to cathodal capture, then dual-site myocardial activation is achieved, but device energy resources are burdened
Solution Approach 1:
The system applies partial action by delivering pulses at magnitudes sufficient for cathodal capture and uses IEGM analysis to detect whether anodal capture is also achieved. Rather than always using excessive magnitude to guarantee anodal capture, the system uses minimal necessary magnitude and verifies capture through sensing, reducing energy loss while maintaining dual-site activation capability when needed.
Solution Approach 2:
The system uses its own sensing capabilities (IEGM detection) to verify whether the delivered pulse achieved the desired dual-site activation. This self-service approach allows the device to confirm successful anodal and cathodal capture and adjust future pulse delivery accordingly, avoiding wasteful energy consumption from excessive pulse magnitudes while maintaining adaptability for dual-site activation.
3Use of energy by moving object
If conventional cathodal-only capture techniques are used, then energy consumption is reduced, but synchronization of myocardial contractions at multiple locations is not achieved
Solution Approach 1:
The system replaces conventional mechanical/electrical threshold-based capture verification with IEGM signal analysis. By analyzing the morphology and characteristics of evoked responses in the IEGM, the system can detect both anodal and cathodal capture without relying on higher pulse magnitudes. This substitution allows energy-efficient cathodal-only pulsing while achieving multi-location synchronization through intelligent detection rather than brute-force energy delivery.
Solution Approach 2:
The system changes the detection parameter from simple capture threshold monitoring to IEGM morphology analysis. By examining specific characteristics of the evoked response signals, the system can identify when both anodal and cathodal capture occur, enabling synchronization of myocardial contractions at multiple locations while maintaining energy-efficient pulse magnitudes rather than requiring continuous high-energy delivery.
Data Source
AI summary
Techniques are provided for use by an implantable medical device for assessing and controlling concurrent anodal/cathodal capture. In one example, the device delivers bipolar pacing stimulus while sensing a bipolar intracardiac electrogram (IEGM) and while adjusting a magnitude of the pacing stimulus. The device analyzes the bipolar IEGM signals to detect an indication of activation representative of concurrent anodal and cathodal capture. Preferably, the pulse magnitude is set relative to the anodal/cathodal capture threshold based upon clinician programming in response to the needs of the patient. In this manner, concurrent anodal and cathodal capture can be selectively activated or deactivated based on clinician instructions received from a device programmer or other external programming device. Techniques exploiting both bipolar and unipolar IEGM signals to assess and control concurrent anodal/cathodal capture are also described. Techniques for use with quad-pole leads to achieve dual-site or quad-site capture are also set forth.