Implantable Cardiac Device Intrinsic Conduction Control
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Solution Overview
Problem
Current pacemaker technologies face challenges in promoting intrinsic conduction of the heart without limiting maximum tracking rate, maintaining ventricular pacing support, or causing hemodynamic compromise, particularly in cases with intact AV nodal conduction.
Innovation Solution
An implantable cardiac stimulation device with a pulse generator that extends a delay interval from a base to an extended interval as long as the pulse generator is inhibited for at least one cardiac cycle, using an intrinsic conduction control circuit to manage the delay intervals and inhibit pacing upon R wave detection, thereby encouraging intrinsic ventricular activity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the AV interval is extended to encourage intrinsic ventricular activity, then intrinsic conduction is promoted, but the maximum tracking rate is limited and ventricular pacing support is reduced
Solution Approach 1:
The pacemaker dynamically adjusts the AV interval based on detected intrinsic ventricular activity. When intrinsic activity is detected, the AV interval is extended to encourage further intrinsic conduction. When intrinsic activity is insufficient, the AV interval returns to the base interval to maintain maximum tracking rate capability. This dynamic adjustment resolves the contradiction by making the system adaptive rather than static.
Solution Approach 2:
The system changes the AV interval parameter conditionally - extending it from the base interval when intrinsic conduction is detected, and maintaining it at the base interval otherwise. This parameter change allows the system to promote intrinsic conduction temporarily without permanently limiting the maximum tracking rate, thus resolving the contradiction between encouraging intrinsic activity and maintaining productivity.
2Reliability
If mode switching from DDD(R) to AAI(R) is used to aggressively promote intrinsic conduction, then intrinsic ventricular activity is encouraged, but ventricular pacing support is lost and hemodynamic compromise occurs
Solution Approach 1:
Instead of completely switching to AAI(R) mode which would fully lose ventricular pacing support, the system applies a partial action by selectively extending only the AV interval while maintaining DDD(R) mode. This allows intrinsic conduction to be encouraged through the extended AV interval without completely abandoning ventricular pacing support, thus avoiding hemodynamic compromise while still promoting intrinsic activity.
Solution Approach 2:
The system takes preliminary anti-action by maintaining the ability to provide ventricular pacing support even while attempting to encourage intrinsic conduction. By not fully committing to AAI(R) mode switching, the system prepares a countermeasure (ventricular pacing) to prevent the harmful effect (hemodynamic compromise) from occurring if intrinsic conduction fails to establish.
3Reliability
If prolonged AV interval is used to promote intrinsic conduction, then intrinsic ventricular activity is encouraged, but the programmable values for Maximum Tracking Rate are reduced
Solution Approach 1:
The system dynamically switches between base AV interval and extended AV interval based on the detection of intrinsic ventricular activity. This dynamic behavior allows the system to achieve prolonged AV interval benefits temporarily when needed, while maintaining the ability to return to shorter intervals, thus preserving adaptability and Maximum Tracking Rate programmable values without permanently reducing them.
Data Source
AI summary
An implantable cardiac stimulation device promotes intrinsic activity of a heart during demand pacing. The device increases the time and probability of an AV delay interval extension. The device may further increase the AV delay interval from a first extended AV delay interval to a longer second extended AV delay interval. The device may further encourage intrinsic AV conduction in patients with intact AV conduction by allowing multiple cycles during a search interval and multiple search times to further encourage intrinsic conduction from the atrium to the ventricle.