System and method of identifying sources for biological rhythms
Inventors
Briggs, Carey Robert • Narayan, Sanjiv M.
Assignees
United States, As Represented By Department Of Veteans Affairs • US Department of Veterans Affairs • Topera Inc • University of California San Diego UCSD
Publication Number
US-10058262-B2
Publication Date
2018-08-28
Expiration Date
2032-05-14
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Abstract
In a system and method of determining regularity associated with a rhythm disorder of a heart, a derivative of a first cardiac signal at a plurality of first time points is processed against a derivative of a second cardiac signal at a plurality of second time points to define a plurality of coordinate pairs of the first cardiac signal against the second cardiac signal. Thereafter, an index of regularity that exceeds a threshold is determined. The index of regularity indicates an approximate congruence of the plurality of coordinate pairs among the first cardiac signal and the second cardiac signal.
Core Innovation
The invention provides a system and method for identifying sources of biological rhythm disorders, particularly heart rhythm disorders, without relying on identifying activation onset times in signals. It processes the derivatives of cardiac signals from different locations over time to define coordinate pairs, from which an index of regularity is calculated. This index indicates a degree of approximate congruence, or periodic repeating activity, between signals from different sensor locations, allowing determination of sources of rhythm disorders.
This method overcomes difficulties present in diagnosing complex rhythm disorders like atrial fibrillation and ventricular fibrillation, where activation signals have complex multi-deflection patterns that prevent reliable identification of activation onset times. By focusing on regularity and phase relationships between signals independently of beat-by-beat timings, the invention enables rapid and accurate localization of sources of complex rhythm disorders for effective treatment.
The system iteratively analyzes pairs of cardiac signals using derivatives, constructs a matrix of indexes of regularity, and identifies regions of the heart with higher regularity relative to adjacent regions as likely sources of rhythm disorders. This approach facilitates immediate treatment targeting these identified sources, improving upon prior systems lacking means to pinpoint such sources especially in complex rhythm disorders.
Claims Coverage
The claims include two independent claims directed to a method and a system for determining regularity associated with a cardiac rhythm disorder source, each encompassing multiple inventive features.
Processing derivatives of cardiac signals to define coordinate pairs
The invention processes zero order, first order, or higher order derivatives of a first cardiac signal at multiple time points against derivatives of a second cardiac signal at multiple time points to define coordinate pairs representing one signal against the other.
Determining an index of regularity indicating approximate congruence
An index of regularity is computed that exceeds a threshold and quantifies periodic repeating activity by indicating approximate congruence of the coordinate pairs between the first and second cardiac signals.
Iterative selection and processing of signal pairs and matrix construction
Pairs of cardiac signals are iteratively selected and processed to determine indexes of regularity, which are compiled into a matrix representing relationships among multiple cardiac signals.
Determining rhythm disorder sources from matrix of indexes
The system or method identifies one or more sources of the rhythm disorder by analyzing the matrix to find regions associated with higher indexes of regularity compared to adjacent regions.
Frequency domain analysis to support index determination
The index of regularity determination may involve frequency analysis, such as Fourier analysis, to generate frequency spectra, identify peaks including fundamental frequencies and harmonics, and calculate ratio metrics within defined frequency bands.
Use of cardiac signals from different heart regions and time points
The cardiac signals processed come from different spatial locations within the heart, and their time points may be contemporaneous to enable accurate comparison.
The independent claims cover methods and systems that use derivative-based comparisons of cardiac signals from multiple heart regions to compute indexes of regularity via coordinate pairs and frequency domain analysis. These indexes are aggregated in a matrix to identify sources of cardiac rhythm disorders based on relative high regularity regions, enabling targeted diagnosis and treatment.
Stated Advantages
Ability to identify sources of complex rhythm disorders without requiring beat-by-beat activation onset times.
Capability to detect rhythm disorder sources rapidly while a sensing device is in or near the patient.
Provision of a relatively simple number of steps to determine sources even in complex cardiac rhythm disorders like atrial and ventricular fibrillation.
Facilitation of immediate and effective treatment by providing locations of rhythm disorder sources.
Overcoming limitations of prior methods that lacked means to pinpoint sources of complex heart rhythm disorders.
Documented Applications
Identification and treatment of sources of complex heart rhythm disorders including atrial fibrillation (AF), ventricular tachycardia (VT), ventricular fibrillation (VF), atrial tachycardia (AT), supraventricular tachycardia (SVT), atrial flutter (AFL), premature atrial complexes/beats (SVE), premature ventricular complexes/beats (PVC), inappropriate sinus tachycardia, and sinus node reentry.
Detection and treatment of sources of other biological rhythm disorders such as neurological seizures, esophageal spasms, bladder instability, and irritable bowel syndrome.
Guidance of therapy including delivery of ablation, electrical energy, mechanical energy, drugs, cells, genes, and biological agents to identified sources in the heart.
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