Heart Stimulator Simulating Heart Rate Turbulence
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Solution Overview
Problem
Patients with weakened or absent Heart Rate Turbulence (HRT) responses are at a higher risk of sudden cardiac death, and existing technologies lack effective methods to simulate or enhance HRT in these individuals.
Innovation Solution
An implantable heart stimulator system that delivers pacing pulses to cardiac tissue and vagal stimulation pulses to the vagus nerve, simulating a healthy HRT response by accelerating and then decelerating heart rate in a controlled manner upon detection of a premature cardiac contraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the autonomic control system is impaired, then the heart rate turbulence response is weakened or absent, but the risk of sudden cardiac death increases
Solution Approach 1:
The system performs preliminary action by proactively inducing heart rate turbulence through controlled premature ventricular contractions and subsequent rate adjustments, rather than passively observing the natural response. The controller deliberately creates the turbulence pattern by pacing the ventricle at a rate that generates the characteristic acceleration-deceleration sequence, ensuring the protective hemodynamic effects are achieved even when autonomic reflexes are impaired.
Solution Approach 2:
The system employs self-service by using the heart's own electrical activity and the natural compensatory pause following a premature contraction as the foundation for generating heart rate turbulence. The controller detects the premature ventricular contraction and utilizes the ensuing compensatory pause to time the subsequent pacing stimulus, allowing the heart's intrinsic mechanisms to contribute to the turbulence generation rather than requiring external autonomic input.
2Productivity
If heart rate turbulence is simulated through controlled pacing, then cardiac output and coronary flow are enhanced, but the device complexity increases
Solution Approach 1:
The system achieves multi-functionality by integrating several capabilities into a single implantable stimulator platform: it can detect premature ventricular contractions, induce controlled heart rate turbulence through programmable pacing, and potentially treat arrhythmias. The same controller and sensing infrastructure used for standard pacing functions are leveraged to generate the turbulence pattern, avoiding the need for separate dedicated turbulence generation hardware.
Solution Approach 2:
The system utilizes parameter changes by dynamically adjusting pacing rates and pulse timings to create the characteristic heart rate turbulence pattern. The controller modifies the ventricular pacing rate relative to the sinus rate, creating the acceleration phase followed by the deceleration phase. These parameter adjustments are achieved through programmable control rather than complex hardware modifications.
3Measurement precision
If premature ventricular contractions are induced for diagnostic purposes, then cardiac ischemia can be detected, but the risk of triggering arrhythmias increases
Solution Approach 1:
The system applies partial action by inducing only the minimal necessary premature ventricular contractions required to generate detectable heart rate turbulence patterns. Rather than continuously stimulating the ventricle or using high-frequency pacing that could trigger arrhythmias, the controller uses isolated, carefully timed premature stimuli that are sufficient to elicit the diagnostic turbulence response without overwhelming the heart's protective mechanisms.
Solution Approach 2:
The system employs feedback by continuously monitoring the heart's response to each premature stimulation and adjusting subsequent pacing parameters accordingly. The controller detects the premature ventricular contraction, measures the resulting heart rate changes, and uses this information to determine whether to proceed with turbulence induction. This feedback loop allows the system to stop or modify stimulation based on real-time physiological responses, preventing excessive arrhythmogenic activity.
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 system effectively reduces the risk of sudden cardiac death by enhancing cardiac output and coronary flow, and reducing ischemia in cardiac tissue, even in patients with diminished intrinsic HRT responses.
Implementation Method 1
at least one lead comprising one or more electrodes for delivering vagal stimulation pulses to a vagus nerve site
Implementation Method 2
at least one lead comprising an electrode for picking up electrical cardiac signals
Implementation Method 3
a first pulse generator for producing said pacing pulses to cardiac tissue
Data Source
AI summary
In a system and method for controlling an implantable stimulator capable of producing pacing pulses to be delivered to cardiac tissue, as well as vagal stimulation pulses to be delivered to vagus nerve sites, upon detection of a premature cardiac event, such as a premature ventricular or atrial contraction, a simulated heart rate turbulence (HRT) procedure is applied if the intrinsic heart rate turbulence is weakened or absent. The simulated HRT includes a first phase in which the heart rate is increased, from the existing level, for a number of heart beats, a second phase in which the heart rate is decreased for a number of heart beats, and an optional third phase in which the heart rate is returned to said existing level.