Heart Stimulator DDI(R)+ Mode Atrial Overdrive Pacing
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Solution Overview
Problem
Current heart stimulators face challenges in implementing atrial overdrive pacing in DDI(R) mode while maintaining atrioventricular (AV) synchrony, as DDD(R) mode risks pacemaker-mediated tachycardia and DDI(R) mode may lose hemodynamic benefits.
Innovation Solution
A heart stimulator that operates in DDI(R)+ mode, allowing asynchronous atrial and ventricular stimulation with an overdrive stimulation rate higher than the intrinsic heart rate, and includes a resynchronization cycle to regain AV synchrony when an intrinsic atrial event is sensed, enabling atrial overdrive pacing without pacemaker-mediated tachycardia.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If DDD(R) mode is used for atrial overdrive pacing, then AV synchrony is maintained, but pacemaker-mediated tachycardia risk increases
Solution Approach 1:
The patent introduces an intermediary sensing mechanism that detects intrinsic atrial events and uses them to trigger ventricular pacing only when appropriate, rather than continuously pacing both chambers. This intermediary step breaks the potential reentrant circuit while preserving AV synchrony benefits during normal sinus rhythm.
Solution Approach 2:
The pacemaker dynamically switches between different pacing modes based on detected intrinsic heart activity. When intrinsic atrial events are present, it operates in a more passive mode following natural conduction; when intrinsic activity is absent, it activates overdrive pacing. This dynamic adaptation prevents fixed-mode tachycardia risks.
2Object-affected harmful factors
If DDI(R) mode is used for atrial overdrive pacing, then pacemaker-mediated tachycardia risk is reduced, but hemodynamic benefits of AV synchrony are lost
Solution Approach 1:
The patent applies partial synchronization by sensing intrinsic atrial events and using them to trigger ventricular pacing only when they occur within an appropriate window, rather than synchronizing every ventricular pace to every atrial event. This partial action maintains sufficient AV coordination for hemodynamic benefit while avoiding excessive control that could cause tachycardia.
Solution Approach 2:
The system changes the control parameter from fixed asynchronous pacing in DDI mode to conditional triggered pacing based on intrinsic event timing. By adjusting the responsiveness to intrinsic events, it achieves an optimal balance between preventing tachycardia and maintaining hemodynamic efficiency.
3Reliability
If overdrive stimulation rate is increased to prevent intrinsic heart rhythm, then atrial fibrillation prevention improves, but energy consumption increases
Solution Approach 1:
Instead of continuous overdrive pacing at high rate, the system uses periodic sensing of intrinsic atrial events and delivers ventricular pacing only when needed. This periodic action maintains atrial fibrillation prevention while allowing the heart to utilize its own electrical activity when possible, reducing overall energy consumption.
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 DDI(R)+ mode allows for atrial overdrive pacing with AV synchrony, reducing the risk of pacemaker-mediated tachycardia and maintaining hemodynamic benefits, by adjusting the stimulation rate based on intrinsic atrial or activity sensor data to ensure effective heart rhythm control.
Implementation Method 1
An intrinsic excitation of a heart chamber results in characteristic electrical potentials that can be picked up via the sensing electrode and that can be evaluated by the sensing stage
Implementation Method 2
A stimulation pulse having strong enough strength causes an excitation of the myocardium that in turn is followed by a contraction of the respective heart chamber
Data Source
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AI summary
Heart stimulator that stimulates at least a heart's right atrium and ventricle in an atrium asynchronous stimulation mode with an overdrive stimulation rate. Interposes one resynchronization cycle after a sensed atrial event to regain AV synchrony during otherwise asynchronous stimulation mode. Allows for pacing mode that can pace the atrium with an overdrive stimulation rate in dual-chamber asynchronous mode while maintaining the AV synchrony and is called DDI(R)+. In DDI(R)+, pacemaker performs an atrial asynchronous (V synchronous) pacing mode such as DDI or DDI(R). The overdrive stimulation rate (OSR) is either a fixed rate (programmed by the external device) that is thought to be above the underlying intrinsic atrial rate, or is dynamically adjusted according to the measured atrial cycle length to be slightly above intrinsic atrial rate. The overdrive stimulation rate may be based on an intrinsic atrial rate or on hemodynamic need. DDI(R)+ timing may be ventricle-based.