scholarly journals B-PO02-094 QUANTIFYING THE VARIABILITY OF BIPOLAR VOLTAGE AMPLITUDE WITH SENSING ANGLE IN RESIDUAL CONDUCTION ISTHMUSES IN ATRIAL SCAR

Heart Rhythm ◽  
2021 ◽  
Vol 18 (8) ◽  
pp. S134-S135
Author(s):  
Jose L. Merino ◽  
Steven Kim ◽  
Jatin Relan ◽  
Margarita Sanroman ◽  
Sergio Castrejon ◽  
...  
Keyword(s):  
Voltage Amplitude ◽  
Bipolar Voltage

scholarly journals Actuating Voltage Waveform Optimization of Piezoelectric Inkjet Printhead for Suppression of Residual Vibrations

Micromachines ◽  
2020 ◽  
Vol 11 (10) ◽  
pp. 900
Author(s):  
Muhammad Ali Shah ◽  
Duck-Gyu Lee ◽  
Bo Yeon Lee ◽  
Nam Woon Kim ◽  
Hyojin An ◽  
...  
Keyword(s):  
Dwell Time ◽  
Voltage Amplitude ◽  
Optimal Parameters ◽  
Voltage Waveform ◽  
Tuning Time ◽  
Waveform Optimization ◽  
Lumped Element ◽  
Bipolar Voltage ◽  
Inkjet Printhead ◽  
Rising Time

After a piezoelectric inkjet printhead jets the first droplet, the actuating membrane still vibrates, creating residual vibrations in the ink channel, which can degrade the inkjet printhead performance. For suppressing these vibrations, an optimized actuating voltage waveform with two pulses must be obtained, of which the first pulse is used for jetting and the second pulse is used to suppress the residual vibrations. In this study, the pressure history within the ink channel of a recirculating piezoelectric inkjet printhead was first acquired using lumped element modeling. Then, for suppressing residual vibrations, a bipolar voltage waveform was optimized via analysis of the tuning time (tt ), dwell time (td2), rising time (tr2), falling time (tf2), and voltage amplitude of the second pulse. Two voltage waveforms, Waveform 01 and Waveform 02, were optimized thereafter. In Waveform 01, tt=2 μs, td2=2 μs, and tr2 and tf2=1 μs were finalized as the optimal parameters; in the case of another waveform, the optimal parameters of td2, tr2, and tf2 were found to be 4, 1, and 1 μs, respectively. The optimal voltage amplitude of the second pulse was found to be 1/3 the amplitude of the first pulse. On the basis of our analysis, the tuning time in Waveform 01 is the most sensitive parameter, and the performance yielded is even poorer than that yielded by standard waveform, if not optimized. Therefore, the other waveform is recommended for the suppression of residual vibrations.

Standard peak-to-peak bipolar voltage amplitude criteria underestimate myocardial scar during substrate mapping with a novel microelectrode catheter

Heart Rhythm ◽  
2020 ◽  
Vol 17 (3) ◽  
pp. 476-484 ◽  
Author(s):  
Adam Lee ◽  
Tomos E. Walters ◽  
Christina Alhede ◽  
Eric Vittinghoff ◽  
Richard Sievers ◽  
...  
Keyword(s):  
Myocardial Scar ◽  
Voltage Amplitude ◽  
Bipolar Voltage

scholarly journals Monophasic action potential amplitude for substrate mapping

2019 ◽  
Vol 317 (4) ◽  
pp. H667-H673 ◽  
Author(s):  
Ikeotunye Royal Chinyere ◽  
Mathew Hutchinson ◽  
Talal Moukabary ◽  
Jordan Lancaster ◽  
Steven Goldman ◽  
...  
Keyword(s):  
Heart Failure ◽  
Atrial Fibrillation ◽  
Action Potential ◽  
Infarct Size ◽  
Scar Tissue ◽  
Monophasic Action Potential ◽  
Voltage Amplitude ◽  
Healthy Myocardium ◽  
Bipolar Voltage ◽  
Increased Sensitivity

Although radiofrequency ablation has revolutionized the management of tachyarrhythmias, the rate of arrhythmia recurrence is a large drawback. Successful substrate identification is paramount to abolishing arrhythmia, and bipolar voltage electrogram’s narrow field of view can be further reduced for increased sensitivity. In this report, we perform cardiac mapping with monophasic action potential (MAP) amplitude. We hypothesize that MAP amplitude (MAPA) will provide more accurate infarct sizes than other mapping modalities via increased sensitivity to distinguish healthy myocardium from scar tissue. Using the left coronary artery ligation Sprague-Dawley rat model of ischemic heart failure, we investigate the accuracy of in vivo ventricular epicardial maps derived from MAPA, MAP duration to 90% repolarization (MAPD90), unipolar voltage amplitude (UVA), and bipolar voltage amplitude (BVA) compared with gold standard histopathological measurement of infarct size. Numerical analysis reveals discrimination of healthy myocardium versus scar tissue using MAPD90 ( P = 0.0158) and UVA ( P < 0.001, n = 21). MAPA and BVA decreased between healthy and border tissue ( P = 0.0218 and 0.0015, respectively) and border and scar tissue ( P = 0.0037 and 0.0094, respectively). Contrary to our hypothesis, BVA mapping performed most accurately regarding quantifying infarct size. MAPA mapping may have high spatial resolution for myocardial tissue characterization but was quantitatively less accurate than other mapping methods at determining infarct size. BVA mapping’s superior utility has been reinforced, supporting its use in translational research and clinical electrophysiology laboratories. MAPA may hold potential value for precisely distinguishing healthy myocardium, border zone, and scar tissue in diseases of disseminated fibrosis such as atrial fibrillation. NEW & NOTEWORTHY Monophasic action potential mapping in a clinically relevant model of heart failure with potential implications for atrial fibrillation management.

scholarly journals Bipolar voltage amplitude: What does it really mean?

Heart Rhythm ◽  
2016 ◽  
Vol 13 (1) ◽  
pp. 326-327 ◽  
Author(s):  
Elad Anter ◽  
Mark E. Josephson
Keyword(s):  
Voltage Amplitude ◽  
Bipolar Voltage

scholarly journals B-PO03-125 ADJUSTING ENDOCARDIAL UNIPOLAR VOLTAGE CUTOFFS BASED ON ENDOCARDIAL BIPOLAR VOLTAGE AMPLITUDE TO BEST IDENTIFY EPICARDIAL VT SUBSTRATE IN NONISCHEMIC CARDIOMYOPATHY (NICM)

Heart Rhythm ◽  
2021 ◽  
Vol 18 (8) ◽  
pp. S239-S240
Author(s):  
Julia Aranyo ◽  
Victor Garcia ◽  
Victor Bazan ◽  
Martín Ricardo Arceluz ◽  
Pasquale Santangeli ◽  
...  
Keyword(s):  
Nonischemic Cardiomyopathy ◽  
Voltage Amplitude ◽  
Bipolar Voltage

scholarly journals Relationship between left atrial strain and left atrial bipolar voltage in patients undergoing catheter ablation for atrial fibrillation

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
Y Takahashi ◽  
T Kitai ◽  
T Watanabe ◽  
T Fujita
Keyword(s):  
Atrial Fibrillation ◽  
Left Atrial ◽  
Speckle Tracking ◽  
Longitudinal Strain ◽  
Low Voltage ◽  
Pulmonary Veins ◽  
Global Longitudinal Strain ◽  
Inferior Wall ◽  
Bipolar Voltage ◽  
Global Mean

Abstract Background Low-voltage zone (LVZ) in the left atrium (LA) seems to represent fibrosis. LA longitudinal strain assessed by speckle tracking method is known to correlate with the extent of fibrosis in patients with mitral valve disease. Purpose We sought to identify the relationship between LA longitudinal strain and LA bipolar voltage in patients with atrial fibrillation (AF). We tested the hypothesis that LA strain can predict LA bipolar voltage. Methods A total of 96 consecutive patients undergoing initial AF ablation were analyzed. All patients underwent transthoracic echocardiography including 2D speckle tracking measurement on the day before ablation during sinus rhythm (SR group, N=54) or during AF (AF group, N=42). LA longitudinal strain was measured at basal, mid, and roof level of septal, lateral, anterior, and inferior wall in apical 4- and 2-chamber view. Global longitudinal strain (GLS) was defined as an average value of the 12 segments. LA voltage map was created using EnSite system, and global mean voltage was defined as a mean of bipolar voltage of the whole LA excluding pulmonary veins and left atrial appendage. LVZ was defined as less than 1.0 mV. Results There was a significantly positive correlation between GLS and global mean voltage (r=0.708, p&lt;0.001). Multivariate regression analysis showed that GLS and age were independent predictors of global mean voltage. There was a significant negative correlation between global mean voltage and LVZ areas. Conclusions There was a strong correlation between LA longitudinal strain and LA mean voltage. GLS can independently predict LA mean voltage, subsequently LVZ areas in patients with AF. Funding Acknowledgement Type of funding source: None

scholarly journals Multi-Level Switching of Al-Doped HfO2 RRAM with a Single Voltage Amplitude Set Pulse

Electronics ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 731
Author(s):  
Jinfu Lin ◽  
Shulong Wang ◽  
Hongxia Liu
Keyword(s):  
Random Access ◽  
Resistive Random Access Memory ◽  
Programming Algorithm ◽  
Voltage Amplitude ◽  
Strength Change ◽  
Value Range ◽  
Multi Level ◽  
Conductance States ◽  
Switching Characteristics ◽  
Sandwiched Structure

In this paper, the resistive switching characteristics in a Ti/HfO2: Al/Pt sandwiched structure are investigated for gradual conductance tuning inherent functions. The variation in conductance of the device under different amplitudes and voltage pulse widths is studied. At the same time, it was found that the variation in switching parameters in resistive random-access memory (RRAM) under impulse response is impacted by the initial conductance states. The device was brought to a preset resistance value range by energizing a single voltage amplitude pulse with a different number of periodicities. This is an efficient and simple programming algorithm to simulate the strength change observed in biological synapses. It exhibited an on/off of about 100, an endurance of over 500 cycles, and a lifetime (at 85 °C) of around 105 s. This multi-level switching two-terminal device can be used for neuromorphic applications to simulate the gradual potentiation (increasing conductance) and inhibition (decreasing conductance) in an artificial synapse.

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