scholarly journals The Use of Electrocardiographic Imaging in Localising the Origin of Arrhythmias During Catheter Ablation of Ventricular Tachycardia

2021 ◽  
Vol 10 (3) ◽  
pp. 211-217
Author(s):  
Adam J Graham ◽  
Richard J Schilling
Keyword(s):  
Inverse Problem ◽  
Ventricular Arrhythmia ◽  
Clinical Tool ◽  
Electrocardiographic Imaging ◽  
Surface Electrodes ◽  
Non Invasive ◽  
Large Target ◽  
The Us ◽  
Activation Times ◽  
Unipolar Electrograms

Non-invasive electrocardiographic imaging (ECGI) is a novel clinical tool for mapping ventricular arrhythmia. Using multiple body surface electrodes to collect unipolar electrograms and conventional medical imaging of the heart, an epicardial shell can be created to display calculated electrograms. This calculation is achieved by solving the inverse problem and allows activation times to be calculated from a single beat. The technology was initially pioneered in the US using an experimental torso-shaped tank. Accuracy from studies in humans has varied. Early data was promising, with more recent work suggesting only moderate accuracy when reproducing cardiac activation. Despite these limitations, the system has been successfully used in pioneering work with non-invasive cardiac radioablation to treat ventricular arrhythmia. This suggests that the resolution may be sufficient for treatment of large target areas. Although untested in a well conducted clinical study it is likely that it would not be accurate enough to guide more discreet radiofrequency ablation.

Increased ventricular repolarization heterogeneity in patients with ventricular arrhythmia vulnerability and cardiomyopathy: a human in vivo study

2006 ◽  
Vol 290 (1) ◽  
pp. H79-H86 ◽  
Author(s):  
Vijay S. Chauhan ◽  
Eugene Downar ◽  
Kumaraswamy Nanthakumar ◽  
John D. Parker ◽  
Heather J. Ross ◽  
...  
Keyword(s):  
Ventricular Arrhythmia ◽  
Ventricular Arrhythmias ◽  
Conduction Block ◽  
Left Ventricular ◽  
Ventricular Repolarization ◽  
Similar Patient ◽  
T Wave Alternans ◽  
Activation Times ◽  
Unipolar Electrograms

Increased repolarization heterogeneity can provide the substrate for reentrant ventricular arrhythmias in animal models of cardiomyopathy. We hypothesized that ventricular repolarization heterogeneity is also greater in patients with cardiomyopathy and ventricular arrhythmia vulnerability (inducible ventricular tachycardia or positive microvolt T wave alternans, VT/TWA) compared with a similar patient population without ventricular arrhythmia vulnerability (no VT/TWA). Endocardial and epicardial repolarization heterogeneity was measured in patients with ( n = 12) and without ( n = 10) VT/TWA by using transvenous 26-electrode catheters placed along the anteroseptal right ventricular endocardium and left ventricular epicardium. Local activation times (AT), activation-recovery intervals (ARI), and repolarization times (RT) were measured from unipolar electrograms. Endocardial RT dispersion along the apicobasal ventricle was greater ( P < 0.005) in patients with VT/TWA than in those without VT/TWA because of greater ARI dispersion ( P < 0.005). AT dispersion was similar between the two groups. Epicardial RT dispersion along the apicobasal ventricle was greater ( P < 0.05) in patients with VT/TWA than in those without VT/TWA because of greater ARI dispersion ( P < 0.05). AT dispersion was similar between the two groups. A plot of AT as a function of ARI revealed an inverse linear relationship for no VT/TWA such that progressively later activation was associated with progressively shorter ARI. The AT-ARI relationship was nonlinear in VT/TWA. In conclusion, patients with cardiomyopathy and VT/TWA have greater endocardial and epicardial repolarization heterogeneity than those without VT/TWA without associated conduction slowing. The steep repolarization gradients in VT/TWA may provide the substrate for functional conduction block and reentrant ventricular arrhythmias.

scholarly journals Variability of serum IgG sialylation and galactosylation degree in women with advanced endometriosis

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Katarzyna Sołkiewicz ◽  
Hubert Krotkiewski ◽  
Marcin Jędryka ◽  
Ewa M. Kratz
Keyword(s):  
Cluster Analysis ◽  
Sialic Acid ◽  
Control Group ◽  
Clinical Tool ◽  
Non Invasive ◽  
Healthy Women ◽  
Serum Igg ◽  
And Cluster Analysis ◽  
Invasive Diagnostics ◽  
And Control

AbstractEndometriosis is an inflammatory disease which diagnostics is difficult and often invasive, therefore non-invasive diagnostics methods and parameters are needed for endometriosis detection. The aim of our study was to analyse the glycosylation of native serum IgG and IgG isolated from sera of women classified as: with endometriosis, without endometriosis but with some benign ginecological disease, and control group of healthy women, in context of its utility for differentiation of advanced endometriosis from the group of healthy women. IgG sialylation and galactosylation/agalactosylation degree was determined using specific lectins: MAA and SNA detecting sialic acid α2,3- and α2,6-linked, respectively, RCA-I and GSL-II specific to terminal Gal and terminal GlcNAc, respectively. The results of ROC and cluster analysis showed that the serum IgG MAA-reactivity, sialylation and agalactosylation factor may be used as supplementary parameters for endometriosis diagnostics and could be taken into account as a useful clinical tool to elucidate women with high risk of endometriosis development. Additionally, we have shown that the analysis of native serum IgG glycosylation, without the prior time-consuming and expensive isolation of the protein, is sufficient to differentiation endometriosis from a group of healthy women.

scholarly journals 3-Dimensional ventricular electrical activation pattern assessed from a novel high-frequency electrocardiographic imaging technique: principles and clinical importance

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Pavel Jurak ◽  
Laura R. Bear ◽  
Uyên Châu Nguyên ◽  
Ivo Viscor ◽  
Petr Andrla ◽  
...  
Keyword(s):  
High Frequency ◽  
Ex Vivo ◽  
Clinical Importance ◽  
Electrical Activation ◽  
Bundle Branch Block ◽  
Electrocardiographic Imaging ◽  
3 Dimensional ◽  
Intraventricular Conduction ◽  
Clinical Measurements ◽  
Activation Times

AbstractThe study introduces and validates a novel high-frequency (100–400 Hz bandwidth, 2 kHz sampling frequency) electrocardiographic imaging (HFECGI) technique that measures intramural ventricular electrical activation. Ex-vivo experiments and clinical measurements were employed. Ex-vivo, two pig hearts were suspended in a human-torso shaped tank using surface tank electrodes, epicardial electrode sock, and plunge electrodes. We compared conventional epicardial electrocardiographic imaging (ECGI) with intramural activation by HFECGI and verified with sock and plunge electrodes. Clinical importance of HFECGI measurements was performed on 14 patients with variable conduction abnormalities. From 3 × 4 needle and 108 sock electrodes, 256 torso or 184 body surface electrodes records, transmural activation times, sock epicardial activation times, ECGI-derived activation times, and high-frequency activation times were computed. The ex-vivo transmural measurements showed that HFECGI measures intramural electrical activation, and ECGI-HFECGI activation times differences indicate endo-to-epi or epi-to-endo conduction direction. HFECGI-derived volumetric dyssynchrony was significantly lower than epicardial ECGI dyssynchrony. HFECGI dyssynchrony was able to distinguish between intraventricular conduction disturbance and bundle branch block patients.

scholarly journals Effectiveness Testing of an Inverse Method for Balancing Nonlinear Rotordynamic Systems

2018 ◽  
Author(s):  
Sergio G. Torres Cedillo ◽  
Philip Bonello ◽  
Ghaith Ghanim Al-Ghazal ◽  
Jacinto Cortés Pérez ◽  
Alberto Reyes Solis
Keyword(s):  
Inverse Problem ◽  
Inverse Method ◽  
Linear Connection ◽  
The Other ◽  
Squeeze Film ◽  
Squeeze Film Damper ◽  
Operational Conditions ◽  
Non Invasive ◽  
Highly Nonlinear ◽  
Aero Engine

Modern aero-engine structures typically have at least two nested rotors mounted within a flexible casing via squeeze-film damper (SFD) bearings. The inaccessibility of the HP rotor under operational conditions motivates the use of a non-invasive inverse problem procedure for identifying the unbalance. Such an inverse problem requires prior knowledge of the structure and measurements of the vibrations at the casing. Recent work by the authors reported a non-invasive inverse method for the balancing of rotordynamic systems with nonlinear squeeze-film damper (SFD) bearings, which overcomes several limitations of earlier works. However, it was not applied to a common practical configuration wherein the HP rotor is mounted on the casing via just one weak linear connection (retainer spring), with the other connections being highly nonlinear SFDs. The analysis of the present paper considers such a system. It explores the influence of the condition number and how it is affected as the number of sensors and/or measurement speeds is increased. The results show that increasing the number of measurement speeds has a far more significant impact on the conditioning of the problem than increasing the number of sensors. The balancing effectiveness is reasonably good under practical noise level conditions, but significantly lower than obtained for the previously considered simpler configurations.

scholarly journals EEG Waveform Analysis of P300 ERP with Applications to Brain Computer Interfaces

2018 ◽  
Vol 8 (11) ◽  
pp. 199 ◽  
Author(s):  
Rodrigo Ramele ◽  
Ana Villar ◽  
Juan Santos
Keyword(s):  
Brain Computer Interface ◽  
Waveform Analysis ◽  
Computer Interface ◽  
Clinical Tool ◽  
Non Invasive ◽  
Computer Interfaces ◽  
Brain Signals ◽  
Public Dataset ◽  
Imaging Sensor ◽  
Clinical Eeg

The Electroencephalography (EEG) is not just a mere clinical tool anymore. It has become the de-facto mobile, portable, non-invasive brain imaging sensor to harness brain information in real time. It is now being used to translate or decode brain signals, to diagnose diseases or to implement Brain Computer Interface (BCI) devices. The automatic decoding is mainly implemented by using quantitative algorithms to detect the cloaked information buried in the signal. However, clinical EEG is based intensively on waveforms and the structure of signal plots. Hence, the purpose of this work is to establish a bridge to fill this gap by reviewing and describing the procedures that have been used to detect patterns in the electroencephalographic waveforms, benchmarking them on a controlled pseudo-real dataset of a P300-Based BCI Speller and verifying their performance on a public dataset of a BCI Competition.

scholarly journals Optimization of CRT programming using non‐invasive electrocardiographic imaging to assess the acute electrical effects of multipoint pacing

2019 ◽  
Vol 35 (2) ◽  
pp. 267-275 ◽  
Author(s):  
Benjamin J. Sieniewicz ◽  
Tom Jackson ◽  
Simon Claridge ◽  
Helder Pereira ◽  
Justin Gould ◽  
...  
Keyword(s):  
Electrocardiographic Imaging ◽  
Non Invasive ◽  
Multipoint Pacing

scholarly journals Spatial-Temporal Signals and Clinical Indices in Electrocardiographic Imaging (I): Preprocessing and Bipolar Potentials

Sensors ◽  
2020 ◽  
Vol 20 (11) ◽  
pp. 3131 ◽  
Author(s):  
Raúl Caulier-Cisterna ◽  
Margarita Sanromán-Junquera ◽  
Sergio Muñoz-Romero ◽  
Manuel Blanco-Velasco ◽  
Rebeca Goya-Esteban ◽  
...  
Keyword(s):  
Signal Processing ◽  
Clinical Practice ◽  
Cardiac Electrophysiology ◽  
Current Knowledge ◽  
Maximum Amplitude ◽  
Digital Signal ◽  
Clinical Tool ◽  
Electrocardiographic Imaging ◽  
Tissue Properties ◽  
Clinical Indices

During the last years, Electrocardiographic Imaging (ECGI) has emerged as a powerful and promising clinical tool to support cardiologists. Starting from a plurality of potential measurements on the torso, ECGI yields a noninvasive estimation of their causing potentials on the epicardium. This unprecedented amount of measured cardiac signals needs to be conditioned and adapted to current knowledge and methods in cardiac electrophysiology in order to maximize its support to the clinical practice. In this setting, many cardiac indices are defined in terms of the so-called bipolar electrograms, which correspond with differential potentials between two spatially close potential measurements. Our aim was to contribute to the usefulness of ECGI recordings in the current knowledge and methods of cardiac electrophysiology. For this purpose, we first analyzed the basic stages of conventional cardiac signal processing and scrutinized the implications of the spatial-temporal nature of signals in ECGI scenarios. Specifically, the stages of baseline wander removal, low-pass filtering, and beat segmentation and synchronization were considered. We also aimed to establish a mathematical operator to provide suitable bipolar electrograms from the ECGI-estimated epicardium potentials. Results were obtained on data from an infarction patient and from a healthy subject. First, the low-frequency and high-frequency noises are shown to be non-independently distributed in the ECGI-estimated recordings due to their spatial dimension. Second, bipolar electrograms are better estimated when using the criterion of the maximum-amplitude difference between spatial neighbors, but also a temporal delay in discrete time of about 40 samples has to be included to obtain the usual morphology in clinical bipolar electrograms from catheters. We conclude that spatial-temporal digital signal processing and bipolar electrograms can pave the way towards the usefulness of ECGI recordings in the cardiological clinical practice. The companion paper is devoted to analyzing clinical indices obtained from ECGI epicardial electrograms measuring waveform variability and repolarization tissue properties.

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