scholarly journals Reconceptualising Atrial Fibrillation Using Renewal Theory: A Novel Approach to the Assessment of Atrial Fibrillation Dynamics

2021 ◽  
Vol 10 (2) ◽  
pp. 77-84
Author(s):  
Jing Xian Quah ◽  
Dhani Dharmaprani ◽  
Anandaroop Lahiri ◽  
Kathryn Tiver ◽  
Anand N Ganesan
Keyword(s):  
Atrial Fibrillation ◽  
Probability Distribution ◽  
Exponential Distribution ◽  
Rate Constants ◽  
Renewal Theory ◽  
Renewal Rate ◽  
Novel Approach ◽  
Precision And Accuracy

Despite a century of research, the mechanisms of AF remain unresolved. A universal motif within AF research has been unstable re-entry, but this remains poorly characterised, with competing key conceptual paradigms of multiple wavelets and more driving rotors. Understanding the mechanisms of AF is clinically relevant, especially with regard to treatment and ablation of the more persistent forms of AF. Here, the authors outline the surprising but reproducible finding that unstable re-entrant circuits are born and destroyed at quasi-stationary rates, a finding based on a branch of mathematics known as renewal theory. Renewal theory may be a way to potentially unify the multiple wavelet and rotor theories. The renewal rate constants are potentially attractive because they are temporally stable parameters of a defined probability distribution (the exponential distribution) and can be estimated with precision and accuracy due to the principles of renewal theory. In this perspective review, this new representational architecture for AF is explained and placed into context, and the clinical and mechanistic implications are discussed.

A Novel Approach to the Interpretation of PAL Spectra in Glycerol

2008 ◽  
Vol 607 ◽  
pp. 260-262
Author(s):  
Sergey V. Stepanov ◽  
Dmitry Zvezhinskiy ◽  
Gilles Duplâtre ◽  
Vsevolod Byakov ◽  
V.S. Subrahmanyam
Keyword(s):  
Positron Annihilation ◽  
Rate Constants ◽  
Reaction Rate ◽  
Volume Distribution ◽  
Viscous Liquids ◽  
Positron Annihilation Lifetime ◽  
Reaction Rate Constants ◽  
Novel Approach ◽  
New Strategy ◽  
Viscous Media

A new strategy for the treatment of positron annihilation lifetime (PAL) spectra in viscous liquids is proposed, enabling to extract values of the Ps reaction rate constants with intratrack radiolytic products as well as parameters of the free volume distribution in viscous media.

scholarly journals Effects of apixaban compared with warfarin as gain in event-free time – a novel assessment of the results of the ARISTOTLE trial

2019 ◽  
Vol 27 (12) ◽  
pp. 1311-1319 ◽  
Author(s):  
Erik Berglund ◽  
Lars Wallentin ◽  
Jonas Oldgren ◽  
Henrik Renlund ◽  
John H Alexander ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Intracranial Bleeding ◽  
Free Time ◽  
Systemic Embolism ◽  
Bleeding Events ◽  
Double Blind ◽  
Warfarin Group ◽  
Novel Approach ◽  
Atrial Fibrillation Trial

Background A novel approach to determine the effect of a treatment is to calculate the delay of event, which estimates the gain of event-free time. The aim of this study was to estimate gains in event-free time for stroke or systemic embolism, death, bleeding events, and the composite of these events, in patients with atrial fibrillation randomized to either warfarin or apixaban in the Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation trial (ARISTOTLE). Design The ARISTOTLE study was a randomized double-blind trial comparing apixaban with warfarin. Methods Laplace regression was used to estimate the delay in time to the outcomes between the apixaban and the warfarin group in 6, 12, 18 and 22 months of follow-up. Results The gain in event-free time for apixaban versus warfarin was 181 (95% confidence interval 76 to 287) days for stroke or systemic embolism and 55 (–4 to 114) days for death after 22 months of follow-up. The corresponding gains in event-free times for major and intracranial bleeding were 206 (130 to 281) and 392 (249 to 535) days, respectively. The overall gain for the composite of all these events was a gain of 116 (60 to 171) days. Conclusions In patients with atrial fibrillation, 22 months of treatment with apixaban, as compared with warfarin, provided gains of approximately 6 months in event-free time for stroke or systemic embolism, 7 months for major bleeding and 13 months for intracranial bleeding.

Enhancement of a Fault Measure for AMSs Using Probabilistic Timed Automata

2011 ◽  
Vol 317-319 ◽  
pp. 681-684
Author(s):  
Yi Sheng Huang ◽  
Ho Shan Chiang
Keyword(s):  
Probability Distribution ◽  
Working Conditions ◽  
Timed Automata ◽  
Probabilistic Automata ◽  
Discrete Probability ◽  
Novel Approach ◽  
Reasoning Strategy ◽  
Real Value ◽  
Target States ◽  
Probabilistic Timed Automata

A novel approach for probabilistic timed structure that is based on combining the formalisms of timed automata and probabilistic automata representation of the system is proposed. Due to their real-valued clocks can measure the passage of time and transitions can be probabilistic such that it can be expressed as a discrete probability distribution on the set of target states. The usage of clock variables and the specification of state space are illustrated with real value time applications. The transitions between states are probabilistic by events which describe either the occurrence of faults or normal working conditions. Additionally, the passage of discrete time and transitions can be probabilistic by mean of the theory of expectation sets to obtain a unified measure reasoning strategy.

scholarly journals Automatic Detection of Atrial Fibrillation and Other Arrhythmias in ECG Recordings Acquired by a Smartphone Device

Electronics ◽  
2018 ◽  
Vol 7 (9) ◽  
pp. 199 ◽  
Author(s):  
Lucia Billeci ◽  
Magda Costi ◽  
David Lombardi ◽  
Franco Chiarugi ◽  
Maurizio Varanini
Keyword(s):  
Atrial Fibrillation ◽  
Support Vector Machine Classifier ◽  
Least Square ◽  
Support Vector ◽  
Personal Health ◽  
Cardiac Complications ◽  
Linear Discriminant ◽  
Novel Approach ◽  
Health Monitoring Systems

Atrial fibrillation (AF) is the most common cardiac disease and is associated with other cardiac complications. Few attempts have been made for discriminating AF from other arrhythmias and noise. The aim of this study is to present a novel approach for such a classification in short ECG recordings acquired using a smartphone device. The implemented algorithm was tested on the Physionet Computing in Cardiology Challenge 2017 Database and, for the purpose of comparison, on the MIT-BH AF database. After feature extraction, the stepwise linear discriminant analysis for feature selection was used. The Least Square Support Vector Machine classifier was trained and cross-validated on the available dataset of the Challenge 2017. The best performance was obtained with a total of 30 features. The algorithm produced the following performance: F1 Normal rhythm = 0.92; F1 AF rhythm: 0.82; F1 Other rhythm = 0.75; Global F1 = 0.83, obtaining the third best result in the follow-up phase of the Physionet Challenge. On the MIT-BH ADF database the algorithm gave the following performance: F1 Normal rhythm = 0.98; F1 AF rhythm: 0.99; Global F1 = 0.98. Since the algorithm reliably detect AF and other rhythms in smartphone ECG recordings, it could be applied for personal health monitoring systems.

scholarly journals NOVEL APPROACH FOR RISK DIFFERENTIATION IN ATRIAL FIBRILLATION PATIENTS WITH POLYPHARMACY

2017 ◽  
Vol 69 (11) ◽  
pp. 486
Author(s):  
Stijn Van Vugt ◽  
Goaris Aarts ◽  
Jeroen Jaspers Focks ◽  
Lucie Bloem ◽  
Freek Verheugt ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Novel Approach

A novel approach to investigating propagation patterns in endocardial atrial fibrillation signals

2011 ◽  
Vol 44 (2) ◽  
pp. e27
Author(s):  
Ulrike Richter ◽  
Luca Faes ◽  
Alessandro Cristoforetti ◽  
Michela Masé ◽  
Flavia Ravelli ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Novel Approach
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