System and method for reconstructing cardiac activation information
Inventors
Briggs, Carey Robert • Narayan, Sanjiv
Assignees
US Department of Veterans Affairs • Topera Inc • Office of General Counsel of VA • University of California San Diego UCSD
Publication Number
US-8165666-B1
Publication Date
2012-04-24
Expiration Date
2031-08-24
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Abstract
An example system and method of reconstructing cardiac activation information are disclosed. A first cardiac signal and a second cardiac signal are processed via a computing device to determine whether there is a point of change in a derivative of the first cardiac signal with respect to a derivative of the second cardiac signal above a threshold. An activation onset time is assigned in the first cardiac signal at the point of change to define cardiac activation indicating a beat in the first cardiac signal if it is determined that the point of change is above the threshold.
Core Innovation
The invention as disclosed relates to a system and method for reconstructing cardiac activation information associated with heart rhythm disorders, particularly complex rhythm disorders such as atrial fibrillation (AF), ventricular tachycardia (VT), and ventricular fibrillation (VF). It involves processing a first cardiac signal and a second cardiac signal through a computing device to identify points of change in the derivatives of these signals, which exceed a threshold. When such a significant point of change is found in the first cardiac signal relative to the second, an activation onset time is assigned to define cardiac activation indicating a beat in the first cardiac signal.
The background identifies that heart rhythm disorders are common and difficult to treat, especially complex ones like AF, VF, and polymorphic VT, due to malfunction of the heart’s electrical system. While simple rhythm disorders show consistent activation onset patterns that can be targeted, complex disorders lack identifiable earliest or latest activation points since their patterns change continuously. Existing systems are ineffective in reconstructing cardiac activation information in complex rhythm disorders, hindering identification and treatment of the disorder's cause.
The invention solves the problem of reconstructing cardiac activation onset information from complex cardiac signals, by comparing derivatives of paired signals and assigning activation onset times based on significant points of change, or alternatively by matching signal characteristics to a catalog of reference signals. This process is iteratively applied across multiple signals from sensor arrays located in the heart. This reconstruction enables the localization of sources of cardiac rhythm disorders, facilitating targeted treatment such as ablation.
Claims Coverage
The patent includes four independent claims covering methods and systems for reconstructing cardiac activation information and treatment of cardiac rhythm disorders with several inventive features.
Determination of activation onset times based on derivative comparison
Processing a first and second cardiac signal via a computing device to determine points of change in derivatives of the first signal relative to the second signal above a threshold, and assigning activation onset times in the first signal at these points to define cardiac activation indicating beats.
Use of composite cardiac signals in determining points of change
Forming a composite cardiac signal from the first and second cardiac signals, determining ratio values representing differences between derivatives of these signals, and selecting points with the largest ratio value as points of change.
Matching cardiac signals to reference signals when derivative threshold is not met
Matching characteristics of the first cardiac signal to reference cardiac signals in a catalog when no point of change is found above the threshold, then assigning activation onset time in the first signal as that of the matched reference signal.
Iterative processing of multiple cardiac signal pairs to reconstruct activation patterns
Iteratively selecting pairs of signals, processing each to define multiple cardiac activations, and reconstructing cardiac activation patterns from assigned activation onset times to indicate sources of cardiac rhythm disorders.
System configured to implement processing and assignment functionalities
A system including at least one computing device configured to perform the processing of signals, determining points of change and assigning activation onset times, including functionalities to form composite signals, match to reference catalogs, process multiple signal pairs, and reconstruct and display cardiac activation patterns to facilitate treatment.
Method of treating cardiac rhythm disorder based on reconstructed activation patterns
Iteratively accessing pairs of cardiac signals, processing them to assign activation onset times, reconstructing an activation pattern to identify disorder source, and treating cardiac tissue at the source to suppress or eliminate the rhythm disorder.
The independent claims collectively cover a method and system for reconstructing cardiac activation information by analyzing derivative changes between paired cardiac signals, optionally using composite signals and reference signal matching, iteratively applied across signal pairs to reconstruct activation patterns, and applying this reconstructed information in treating cardiac rhythm disorders.
Stated Advantages
Ability to reconstruct cardiac activation information from complex rhythm disorders where previous methods failed.
Providing rapid reconstruction during sensing that enables immediate treatment of cardiac tissue to suppress or eliminate rhythm disorders.
Reduction of complex prior methods to fewer steps to enable determination of activation onset times even in complex and continuously changing activation patterns.
Capability to identify the causes or sources of heart rhythm disorders facilitating targeted, curative treatments.
Documented Applications
Reconstruction of cardiac activation information to diagnose and localize sources of heart rhythm disorders, including complex disorders such as atrial fibrillation, ventricular fibrillation, and polymorphic ventricular tachycardia.
Use with catheter-based sensor arrays inserted into the heart to collect electrogram signals for analysis and reconstruction.
Facilitation of treatment through targeted cardiac tissue ablation guided by activation patterns reconstructed from collected cardiac signals.
Potential applicability to other biological rhythm disorders such as neurological seizures, esophageal spasms, bladder instability, and irritable bowel syndrome where biological activation information can be reconstructed for diagnosis or treatment.
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