System and method for reconstructing cardiac activation information
Inventors
Narayan, Sanjiv • Briggs, Carey Robert
Assignees
US Department of Veterans Affairs • Topera Inc • Office of General Counsel of VA • University of California San Diego UCSD
Publication Number
US-9055876-B2
Publication Date
2015-06-16
Expiration Date
2031-08-24
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Abstract
An example system and method of processing cardiac activation information are disclosed. The method includes accessing a first cardiac signal and a second cardiac signal obtained from a patient. The first cardiac signal and the second cardiac signal are processed to determine whether there is a point of change in the first cardiac signal at which a derivative of the first cardiac signal diverges 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 a cardiac activation if the point of change is in the first cardiac signal.
Core Innovation
The invention provides a system and method for reconstructing cardiac activation information, specifically activation onset times, from cardiac signals obtained from a patient. This is achieved by accessing a first cardiac signal and a second cardiac signal and processing them to identify a point of change in the first cardiac signal where its derivative diverges with respect to the derivative of the second cardiac signal above a threshold. An activation onset time is then assigned in the first cardiac signal at this point of change to define cardiac activation if such a point exists.
The method further includes forming a composite cardiac signal from the first and second signals to compute ratio values at various points in the first signal, representing differences between derivatives of the signals, and selecting the point of change as the one with the largest ratio value. If no point of change is identified above threshold, the first cardiac signal is matched to characteristics in a catalog of reference cardiac signals to assign an activation onset time accordingly. This process is iteratively applied across pairs of cardiac signals from multiple sensors to reconstruct a cardiac activation pattern indicating the source of a cardiac rhythm disorder.
The background identifies the problem of current treatments for heart rhythm disorders, particularly complex disorders like atrial fibrillation (AF), ventricular tachycardia (VT), and ventricular fibrillation (VF), being ineffective due to the inability to accurately identify and locate the cause of the disorder. Traditional systems lack the capability to reconstruct cardiac activation information in signals with complex and variable deflection patterns associated with these disorders, hindering effective treatment such as ablation. This invention addresses the challenge by providing a method to reconstruct activation onsets even in complex and variable cardiac signals to facilitate identification and treatment of the disorder's cause.
Claims Coverage
The claims include two independent claims directed to a method and a system for processing cardiac activation information with focus on detecting points of change in cardiac signals and assigning activation onset times accordingly.
Determining a point of change in cardiac signals
Processing a first and second cardiac signal to determine a point where the derivative of the first signal diverges from that of the second signal above a threshold, and assigning an activation onset time at that point in the first cardiac signal.
Forming and using a composite cardiac signal to identify points of change
Forming a composite cardiac signal from the first and second signals, determining ratio values that represent differences between derivatives of the signals, and selecting the point with the largest ratio value as the point of change.
Matching signals to a catalog of reference cardiac signals
When no point of change is detected, matching characteristics of the first cardiac signal to reference signals in a catalog and assigning activation onset times based on the matched reference signal.
Iterative processing of pairs of cardiac signals to reconstruct activation patterns
Iteratively accessing pairs of signals from a plurality, performing processing and assigning activation onsets to define multiple cardiac activations, and reconstructing a cardiac activation pattern indicating the source of a cardiac rhythm disorder.
System configured with computing device for processing and assigning activations
A system including at least one computing device configured to access cardiac signals, process them to detect points of change where derivatives diverge above a threshold, and assign activation onset times accordingly.
Use of derivatives of various orders in processing signals
Processing derivatives that can be zero order, first order, second order, higher order, or combinations thereof to detect points of change between cardiac signals.
Contemporaneous acquisition of cardiac signals by sensors
Obtaining the first and second cardiac signals contemporaneously from the patient using corresponding sensors.
Displaying reconstructed cardiac activation patterns
Displaying the reconstructed activation patterns to facilitate treatment targeting the source of the cardiac rhythm disorder.
The independent claims cover a method and system that process pairs of cardiac signals by analyzing derivatives to detect significant points of change to assign activation onset times, utilizing composite signals and reference catalogs when needed, and iteratively reconstructing cardiac activation patterns to identify and facilitate treatment of cardiac rhythm disorder sources.
Stated Advantages
Ability to reconstruct cardiac activation information in complex heart rhythm disorders where activation onset patterns vary beat to beat, enabling identification of the cause or source of the disorder.
Provides a system and method that can be executed rapidly during clinical procedures, allowing immediate treatment following reconstruction.
Overcomes limitations of prior systems that could not determine the source of complex heart rhythm disorders or reconstruct activation information effectively, thereby improving treatment efficacy.
Documented Applications
Reconstruction of cardiac activation information to diagnose and treat heart rhythm disorders, including complex arrhythmias like atrial fibrillation, ventricular tachycardia, and ventricular fibrillation.
Use in conjunction with catheters having sensor arrays placed within heart chambers to detect electrical activity for mapping and identifying origins of rhythm disorders.
Facilitating targeted treatment of cardiac tissue such as ablation or other therapies to suppress, lessen, or eliminate heart rhythm disorders based on reconstructed activation patterns.
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