System and method for reconstructing cardiac activation information
Inventors
Narayan, Sanjiv M. • Briggs, Carey Robert • Sehra, Ruchir
Assignees
US Department of Veterans Affairs • Topera Inc • University of California San Diego UCSD
Publication Number
US-9913615-B2
Publication Date
2018-03-13
Expiration Date
2031-08-24
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Abstract
In a system and method for reconstructing cardiac activation information, an analysis cardiac signal and a reference cardiac signal are accessed and processed to determine a first point of change in the analysis cardiac signal at which a derivative of the analysis cardiac signal diverges with respect to a derivative of the reference cardiac signal. The signals are processed to determine a second point of change in the analysis cardiac signal at which a different derivative of the analysis cardiac signal with respect to a different derivative of the reference cardiac signal. An activation onset time is assigned in the analysis cardiac signal at a point based on a mathematical association among the first point of change and the second point of change to define cardiac activation indicating a beat in the analysis cardiac signal.
Core Innovation
The invention relates to a system and method for reconstructing cardiac activation information, particularly the activation onset associated with heart rhythm disorders. It involves accessing and processing an analysis cardiac signal and a reference cardiac signal to determine points of change where derivatives of these signals diverge, assigning activation onset times based on a mathematical association of these points to define cardiac activation indicating a beat in the analysis signal.
The problem being solved arises from the difficulty in treating complex heart rhythm disorders such as atrial fibrillation, ventricular tachycardia, and ventricular fibrillation. Existing treatments like ablation are often ineffective because existing tools fail to reliably identify and locate the causes of these disorders due to complex, variable activation patterns and signals that include multiple deflections and far-field activations. Prior systems and methods also lack the capability to reconstruct activation information sufficient to identify the sources of such complex rhythm disorders.
The invention provides a novel approach whereby signals from sensors positioned in or near the heart are analyzed to detect points of change in derivatives of analysis and reference signals. This process is iteratively applied across multiple pairs of signals and time intervals, with mathematical associations used to assign activation onset times. The reconstructed activation information permits localization of the source of the heart rhythm disorder, thus enabling targeted and potentially curative treatment such as ablation.
Claims Coverage
The patent includes two independent claims encompassing a method and a system for reconstructing cardiac activation information with multiple inventive features.
Determining points of change based on derivatives of signals
Processing an analysis cardiac signal and a reference cardiac signal to determine a first point of change in the analysis signal where a derivative (zero, first, or second order) of the analysis signal diverges with respect to a corresponding derivative of the reference signal, and similarly determining a second point of change in the analysis signal based on a different derivative order diverging relative to the reference signal.
Assigning activation onset time based on mathematical association
Assigning an activation onset time in the analysis cardiac signal at a point determined by a mathematical association—such as an average or selection based on thresholds or difference values—of the first and second points of change to define cardiac activation indicating a beat.
Use of composite cardiac signals in determination
Forming a composite cardiac signal from the analysis and reference signals and determining ratio values at multiple points representing differences involving derivatives of the signals and the composite signal; selecting points with the largest ratio values as points of change.
Iterative selection and processing of signal pairs
Iteratively selecting pairs of cardiac signals from a plurality, performing processing and assigning activation onsets for each pair, with reconstruction of a cardiac activation pattern from the assigned onsets to indicate the source of a cardiac rhythm disorder.
Together, these inventive features enable accurate determination and assignment of activation onset times in complex cardiac signals through derivative-based signal comparisons and their mathematical association, facilitating reconstruction of activation patterns and identification of heart rhythm disorder sources for targeted treatment.
Stated Advantages
Ability to reconstruct cardiac activation information in complex heart rhythm disorders where previous systems could not.
Facilitation of rapid determination of the cause or source of heart rhythm disorders to enable immediate treatment during sensing.
Reduction in the number and complexity of steps required to identify activation onset times compared to prior known methods.
Documented Applications
Reconstructing activation information of heart rhythm disorders including complex rhythm disorders such as atrial fibrillation, ventricular tachycardia, and ventricular fibrillation.
Use with a catheter having a plurality of sensors inserted into the heart to detect electrical activity for mapping and treatment guidance.
Treatment of cardiac tissue at identified sources by ablation or other therapies to suppress or eliminate heart rhythm disorders.
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