Ascending Ramp Waveforms for ICD Energy Control

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Solution Overview

Problem

Current implantable cardioverter defibrillators (ICDs) face limitations in effectively managing cardiac arrhythmias like ventricular fibrillation (VF), ventricular tachycardia (VT), and atrial fibrillation (AF) due to their reliance on biphasic truncated exponential waveforms, which may not provide optimal energy delivery and can cause discomfort to patients, and are prone to lead wire failures.

Innovation Solution

The development of an amplifier-based subcutaneous and transvenous ICD system that uses a single-wire to deliver arbitrary biphasic ascending waveforms, allowing for constant current, voltage, or energy modes, with software-controlled waveform adjustments to optimize energy delivery and reduce cardiac damage, and the ability to switch between different waveform geometries for enhanced conversion efficacy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If biphasic truncated exponential waveforms are used in current ICDs, then defibrillation can be delivered, but energy delivery is not optimal and patient discomfort increases

Engineering Contradiction:

Improvedefibrillation effectivenessVSAvoidpatient discomfort

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the waveform parameters from traditional biphasic truncated exponential to ascending ramp waveforms with controlled rise times and durations. This parameter modification delivers defibrillation energy more effectively while reducing peak currents and patient discomfort, directly resolving the contradiction between reliability and harmful effects.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If traditional ICD waveforms are used, then defibrillation function is provided, but cardiac damage occurs as indicated by troponin I enzyme levels

Engineering Contradiction:

Improvedefibrillation functionVSAvoidcardiac damage

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent modifies waveform parameters including extending duration and controlling rise times to deliver energy more gradually. This reduces myocardial damage and troponin I release while maintaining defibrillation efficacy, resolving the contradiction between providing defibrillation function and preventing cardiac damage.

Inventive Principle:

Principle #35Parameter changes

3Device complexity

If fixed waveform geometry is used in ICDs, then device simplicity is maintained, but adaptability to different arrhythmias and patient conditions is limited

Engineering Contradiction:

Improvewaveform delivery systemVSAvoidwaveform adaptability

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent implements dynamic waveform generation where the ascending ramp parameters (duration, rise time, amplitude) can be adjusted based on detected arrhythmia type and patient impedance. This allows the same device to adapt to different clinical scenarios without increasing fundamental system complexity, resolving the contradiction between device simplicity and adaptability.

Inventive Principle:

Principle #15Dynamics

4Speed

If rapid energy delivery is used, then defibrillation shock is delivered quickly, but cardiac damage increases and patient discomfort rises

Engineering Contradiction:

Improveenergy delivery speedVSAvoidpatient discomfort and cardiac damage

Core Design Contradiction:

SpeedVSObject-affected harmful factors

Solution Approach 1:

The patent uses controlled periodic ascending ramp waveforms that deliver energy in a structured sequence with specific rise times and durations. This periodic delivery method spreads energy input over time, reducing peak power density and its harmful effects while maintaining overall defibrillation effectiveness, thus resolving the contradiction between delivery speed and harmful factors.

Inventive Principle:

Principle #19Periodic action

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

This approach significantly reduces troponin I enzyme levels, indicating less cardiac damage, and allows for more effective cardioversion and defibrillation with reduced peak voltages and slower energy delivery, improving the treatment of cardiac arrhythmias while minimizing patient discomfort and lead wire failures.

Implementation Method 1

deliver arbitrary biphasic ascending waveforms... constant current, voltage, or energy modes

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentUS9561383B2Implantable cardioverter defibrillator (ICD), subcutaneous implantable cardioverter defibrillator (SICD), and waveform energy control systems

Publication Date: 2017.02.07 RUSE TECH

AI summary

Cardiac defibrillation or cardioversion waveform energy control systems employ transvenous ICDs, subcutaneous SICDs, or pacemakers for treating cardiac conditions. The systems comprise differentially driven amplifier circuit operational modes to control the delivery of pacing, anti-tachycardia pacing, defibrillation, and/or cardioversion electrical shocks, wherein the pacing, anti-tachycardia pacing, and shock waveforms employ constant current, constant voltage, or constant energy. Biphasic arbitrary shock waveforms deliver increasing energy with increasing time as represented by phase 1 ascending ramp, ascending exponential, ascending chopped, ascending stepped, ascending curved, square, or rectilinear and/or any combination of geometric shaped ascending arbitrary waveforms or any BTE waveform.