Systolic Function Index for Non-Invasive Ejection Fraction
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Solution Overview
Problem
Current methods for measuring left ventricular ejection fraction (EF) are invasive, observer-dependent, or yield inconsistent results, making them impractical for widespread use, especially in patients with cardiac pacing modalities or those requiring fast and cost-effective assessments.
Innovation Solution
A non-invasive device and method using systolic function index (SFI) calculations based on heart rate, QRS duration, pre-ejection period, left ventricular ejection time, and inter-ventricular delay, allowing for prediction of EF in various cardiac conditions, including bundle branch blocks and pacing modalities, using a combination of hardware and dedicated software.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If contrast cine left ventriculography (CineLVG) is used to measure EF, then measurement precision is improved, but device complexity and invasiveness increase
Solution Approach 1:
The patent replaces the mechanical/invasive catheter-based CineLVG system with an electrical signal-based system using ECG and pulse waveform analysis. The systolic time intervals (PEP, LVET) are derived from electrical and peripheral pulse signals rather than direct mechanical visualization, eliminating the need for invasive catheters and contrast media while maintaining EF measurement capability
Solution Approach 2:
The patent introduces systolic time intervals (PEP and LVET) as intermediary parameters that mediate between the electrical cardiac cycle and hemodynamic performance. These time intervals serve as surrogate markers that correlate with EF without requiring direct visualization of ventricular volumes, thus avoiding the complexity of CineLVG
2Ease of operation
If echocardiography (Echo) is used to measure EF, then ease of operation and cost-effectiveness are improved, but measurement precision deteriorates due to observer-dependence
Solution Approach 1:
The patent employs automated detection and calculation systems that process ECG and pulse waveform signals through computer algorithms. The systolic time intervals are automatically measured and EF is calculated without requiring manual tracing or expert observer intervention, thereby eliminating observer-dependence while maintaining non-invasive operation
Solution Approach 2:
The patent replaces the mechanical manual tracing method used in Echo with automated digital signal processing. Electrical signals from ECG and peripheral pulses are processed through computer algorithms to extract timing parameters, eliminating the need for manual endocardial contour tracing and associated observer variability
3Measurement precision
If multi gated radionuclide ventriculography (RNV) is used to measure EF, then measurement precision is improved, but device complexity and radiation exposure increase
Solution Approach 1:
The patent replaces the radionuclide-based imaging system with an electrical signal-based system using ECG and peripheral pulse waveforms. The measurement of systolic time intervals and EF calculation is performed through digital signal processing rather than radioactive tracer imaging, eliminating radiation exposure while maintaining precision
Solution Approach 2:
The patent uses systolic time intervals (PEP, LVET) as intermediary parameters that can be derived from routine ECG and pulse measurements. These time intervals serve as substitutes for the complex radionuclide imaging process, providing accurate EF measurement without requiring radioactive contrast materials or specialized imaging equipment
4Measurement precision
If magnetic resonance imaging (MRI) is used to measure EF, then measurement precision is improved, but device complexity and procedure time increase
Solution Approach 1:
The patent replaces the complex MRI system with simple electrical signal recording devices (ECG and pulse waveform sensors). The measurement process uses automated detection of timing intervals from these signals, eliminating the need for complex MRI hardware, contrast agents, and specialized software interpolation while maintaining high measurement precision
5Ease of operation
If systolic time intervals are measured to estimate EF, then ease of operation and cost-effectiveness are improved, but measurement precision may be affected in patients with pacing modalities
Solution Approach 1:
The patent dynamically adjusts the measurement and calculation parameters based on the detected pacing modality. The system identifies whether the patient is in sinus rhythm or undergoing various pacing modes (RV pacing, LV pacing, biventricular pacing) and applies appropriate correction algorithms to the systolic time interval measurements, thereby maintaining precision across different cardiac rhythm conditions
Solution Approach 2:
The patent changes the calculation parameters and correction factors based on the detected cardiac rhythm and pacing modality. Different algorithms are applied for sinus rhythm versus paced rhythms, with specific corrections for inter-ventricular delay and pre-ejection period measurements in different pacing scenarios, ensuring accurate EF estimation across diverse patient populations
Data Source
AI summary
The invention consists of a device and method for the prediction of left ventricular ejection fraction (EF) and other cardiac hemodynamic parameters using systolic time intervals in patients with narrow QRS, right bundle branch block, left bundle branch block, right ventricular and/or left ventricular cardiac pacing and in the presence of arrhythmia, such as atrial fibrillation. The device has three inputs: the ECG, a peripheral pulse and a phonocardiogram. Timing parameters are obtained from these signals to calculate a systolic function index, used for the prediction of ejection fraction. Given the invention's features it would be now possible to assess cardiac performance and specifically left ventricular ejection fraction in ambulatory patients as well as during invasive procedures such as the implant of cardiac rhythm management devices. Also, an implantable embodiment of the invention would allow constant monitoring of cardiac performance, parameter adjustment of cardiac devices and automatic drug infusion.