Deflection Amplitude Research Articles

Alfvénic velocity spikes and rotational flows in the near-Sun solar wind.

The prediction of a supersonic solar wind1 was first confirmed by spacecraft near Earth2,3 and later by spacecraft at heliocentric distances as small as 62 solar radii4. These missions showed that plasma accelerates as it emerges from the corona, aided by unidentified processes that transport energy outwards from the Sun before depositing it in the wind. Alfvénic fluctuations are a promising candidate for such a process because they are seen in the corona and solar wind and contain considerable energy5-7. Magnetic tension forces the corona to co-rotate with the Sun, but any residual rotation far from the Sun reported until now has been much smaller than the amplitude of waves and deflections from interacting wind streams8. Here we report observations of solar-wind plasma at heliocentric distances of about 35 solar radii9-11, well within the distance at which stream interactions become important. We find that Alfvén waves organize into structured velocity spikes with duration of up to minutes, which are associated with propagating S-like bends in the magnetic-field lines. We detect an increasing rotational component to theflow velocity of the solar wind around the Sun, peaking at 35 to 50 kilometres per second-considerably above the amplitude of the waves. These flows exceed classical velocity predictions of a few kilometres per second, challenging models of circulation in the corona and calling into question our understanding of how stars lose angular momentum and spin down as they age12-14.

Nonlinear stability and optimization of thin nanocomposite multilayer organic solar cell using Bees Algorithm

Abstract This paper carries out the nonlinear stability of nanocomposite multilayer organic solar cell (NMOSC) subjected to axial compressive loads. The model of organic solar cell is assumed to consist five layers: Al, P3HT:PCBM, PEDOT:PSS, IOT and Glass. Based on the classical plate theory, the basic equations are established taking into account the effect of elastic foundations and initial imperfection. The approximation solutions are selected based on the boundary conditions of the four edges of NMOSC. The equation which indicates the relationship between axial compressive loads and deflection amplitude of NMOSC is obtained by using the Galerkin method. Bees Algorithm is applied to maximize the value of critical buckling load with nine variables including the thickness of five layers, the length and the width of NMOSC and two stiffness coefficients of elastic foundations. The numerical results show the effect of geometrical and material parameters, initial imperfection and elastic foundations on the nonlinear static stability and the critical buckling load of NMOSC. Optimal values of nine geometrical parameters of NMOSC are also determined.

The Effect of the Electrode Position on the Dynamic Behavior of an Electrostatically Actuated Microcantilever

Abstract Electrostatic actuators have major role in many MEMS devices, e.g. sensors, actuators. The amount of applied voltage to an electrostatic micro-actuator has a direct impact on the amplitude of deflection throughout the cantilever. This research aims to study the effect of the electrode length and the applied voltage on the amplitude of deflection of the micro-cantilever. Also, the resonant frequency for the cantilever was computed for full length and compared with simulation results. Finite element method, ANSYS was used as a simulation tool.

Clinical stability in the fellow non‐operated eye from asymmetric keratoconus patients

AbstractPurposeTo assess the clinical status of corneal ectasia, including clinical outcomes and tomographic/biomechanical assessments of asymmetric keratoconus patients who had surgical treatment only in the most advanced eye.MethodsThis retrospective study included 100 eyes of 50 asymmetric keratoconus patients who had surgery in one eye. The eyes were divided in two groups, the operated group (OG) which underwent surgery and the fellow non‐operated eyes (NOG). Both groups received medical treatment for ocular allergic disease and ocular surface optimization, along with the general advice to avoid eye rubbing.ResultsMean follow‐up time was 41 ± 33.26 months (range 6.4–182.4) and mean age at the first visit was 25 ± 9.8 years (range 6–60), including 43 patients with less than 34 years. Regarding to the NOG, the baseline average UDVA was 0.40 (20/50) ± 0.46 logMAR and CDVA was 0.10 (20/25) ± 0.17 logMAR. In the last visit, despite of no surgical treatment, average UDVA and CDVA showed improvement to 0.34 (20/44) ± 0.43 (p > 0.05) and 0.06 (20/23) ± 0.15 logMAR (p = 0.02), respectively. Analysis of biomechanical parameters of the NOG showed a statistically significant difference (p < 0.05) of deflection amplitude ratio. The comparison of ABC parameters of Belin’s tomographic grading system between first and last visit showed non statistically significant difference (p > 0.05) in the NOG.ConclusionClinical anti‐allergic and ocular surface optimization treatment, along with patient education for avoiding eye rubbing (as in the Violet June Keratoconus Awarenes Campaign) is indicated to all keratoconus/ectasia patients best first line of treatment. The stability of the ABCD parameters of Belin grading system in the NOG and even the improvement of CDVA supports that, regardless age, in many cases with mild ectasia, medical management is sufficient without the need for surgical procedure, even in young patients.

PULSE BENDED BEAM WITH BINARY BOUNDARY CONDITIONS

A theoretical study of the movement of a beam with binary boundary conditions at a short-term pulsed load is carried out in the article. The non-stationary oscillations of the beam, caused by short-term force loading, are evenly distributed along its length. Beam movement is considered in two stages. It is assumed that the conditions for fixing the ends of the beam are associated with the direction (sign) of their rotation when the beam is bending. It is assumed that under the action of the load, the edges of the beam are rigidly clamped, that is, the angles of their rotation are equal to zero, and after unloading and changing the sign of the curvature of the beam they become pivotally supported in cylindrical hinges. According to the second boundary conditions, the free oscillation of the beam passes. Due to the use of the method of compensating loads, the analytical part of the isolation is expressed in rows of sines. Since the system has an asymmetric elastic characteristic with respect to the position of static equilibrium, the method of adding solutions is used to achieve this goal. As a result, the calculation is reduced to the numerical solution of the Volterra type integral equation on a computer. In addition, an approximation is proposed, which gives simpler calculation formulas than a piecewise linear approximation. The proposed approximation allows us to calculate the value of the boundary moments and obtain the formula for the beam deflections. Numerical analysis showed that for certain durations of force loading, the beam deflection amplitude with pinched edges in the direction of the external impulse is less than the deflection amplitude in the opposite direction during the movement of the unloaded beam with hinged edges. This dynamic effect is characteristic of systems with an asymmetric characteristic of elasticity, which occurs when a binary fixing of the edges of the beam or when it is supported by unilateral elastic supports. Formulas are derived by which it is possible to calculate the time when the effect of asymmetry will be most clearly expressed, and also in which case it will be absent. Numerical results confirming the adequacy of the proposed dependencies are presented.

Nonlinear post-buckling and vibration of 2D penta-graphene composite plates

The newly developed penta-graphene is a two-dimensional (2D) carbon allotrope with promising mechanical properties. This paper investigates the nonlinear post-buckling and vibration of imperfect three-dimensional penta-graphene composite plates resting on elastic foundations and subjected to uniform external pressure and axial compressive load. The elastic constants of the single-layer penta-graphene are fully determined by the density functional theory by fitting the equation of strain energy to the density functional theory energy. Specifically, the elastic constant $$C_{66}$$ which has not been considered by other authors is also determined. The motion and compatibility equations are derived based on the classical plate theory taking into account von Karman geometrical nonlinearity, initial geometrical imperfection and Pasternak type elastic foundations. For nonlinear post-buckling, the Bubnov–Galerkin method is applied to obtain the load–deflection amplitude curves while the Runge–Kutta method and harmonic balance method are used to obtain the deflection amplitude–time curves and the amplitude–frequency curves for nonlinear vibration. Numerical results show the effects of geometrical parameters, initial imperfection and elastic foundations on the nonlinear post-buckling and vibration of the imperfect 2D penta-graphene plates. The present results are also compared to others to validate the accuracy of the applied method and approach.

Glassy carbon microelectrodes minimize induced voltages, mechanical vibrations, and artifacts in magnetic resonance imaging

The recent introduction of glassy carbon (GC) microstructures supported on flexible polymeric substrates has motivated the adoption of GC in a variety of implantable and wearable devices. Neural probes such as electrocorticography and penetrating shanks with GC microelectrode arrays used for neural signal recording and electrical stimulation are among the first beneficiaries of this technology. With the expected proliferation of these neural probes and potential clinical adoption, the magnetic resonance imaging (MRI) compatibility of GC microstructures needs to be established to help validate this potential in clinical settings. Here, we present GC microelectrodes and microstructures—fabricated through the carbon micro-electro-mechanical systems process and supported on flexible polymeric substrates—and carry out experimental measurements of induced vibrations, eddy currents, and artifacts. Through induced vibration, induced voltage, and MRI experiments and finite element modeling, we compared the performances of these GC microelectrodes against those of conventional thin-film platinum (Pt) microelectrodes and established that GC microelectrodes demonstrate superior magnetic resonance compatibility over standard metal thin-film microelectrodes. Specifically, we demonstrated that GC microelectrodes experienced no considerable vibration deflection amplitudes and minimal induced currents, while Pt microelectrodes had significantly larger currents. We also showed that because of their low magnetic susceptibility and lower conductivity, the GC microelectrodes caused almost no susceptibility shift artifacts and no eddy-current-induced artifacts compared to Pt microelectrodes. Taken together, the experimental, theoretical, and finite element modeling establish that GC microelectrodes exhibit significant MRI compatibility, hence demonstrating clear clinical advantages over current conventional thin-film materials, further opening avenues for wider adoption of GC microelectrodes in chronic clinical applications.

Local buckling of subsea pipelines as a walking mitigation technique

Various factors influence the design of subsea pipeline subjected to high temperature and pressure operating loads. Cycles of operating shut-down and start-up have been shown to cause pipeline axial movement, which is called ‘walking’. Walking can influence pipeline performance and cause lateral deflection amplitudes at buckled zones as a result of walking and lateral buckling interaction. A novel cost-effective method for walking mitigation is investigated in this paper using of FE modeling to simulate the novel way of eliminating the occurrence of walking. The proposed technique for mitigating pipeline walking involves creating initial local lateral deformations along the pipeline via imposed local curvature during pipeline reel laying. The interaction between walking and lateral buckling is also explored for an example pipeline with initial local deformations imposed at regular small intervals along the pipeline. The effects of the residual curvatures on pipeline response to temperature and pressure loading are considered in this paper. The reduction in walking rate of subsea pipelines with different numbers of initial deformations is considered. Furthermore, a continuous snake-lay form of deformations is proposed as a very effective method for controlling walking and attaining virtually a zero value of incremental walking per cycle.

Corneal Viscous Properties Cannot Be Determined From Air-Puff Applanation.

To assess whether corneal viscous properties are measureable with air-puff applanation in patients. The study had 312 normal eyes, 107 fellow eyes of patients with keratoconus, and 289 keratoconic eyes. The Corvis ST (Oculus Optikgeräte GmbH, Wetzlar, Germany) deformation data for all eyes were analyzed using two models. First, a standard linear solid model (SLM) assumed the cornea was an elastic material only. Second, a two-compartment Kelvin-Voigt model (KVM) assumed the cornea was a visco-elastic material. Corneal stiffness and viscosity were calculated. Further, the deflection amplitude was phase shifted virtually relative to the air-puff applanation force to assess whether the KVM was capable of detecting corneal viscous properties from air-puff applanation. This was similar in concept to measured viscoelastic deformations in other soft tissues. The hysteresis area was also calculated with deformation (cornea and whole globe) and deflection (cornea only) amplitude. The greater the magnitude of the hysteresis area, the greater was the magnitude of corneal viscosity (µc). Both the SLM and KVM reported similar magnitudes of corneal stiffnesses (correlation coefficient > 0.99). However, for a given model, corneal stiffness was significantly different between normal, fellow, and keratoconic eyes (P = .001). From the KVM, the corneal viscosity was different between groups (P = .001) but was small in magnitude (order of 10-9). The deflection hysteresis area was also small in magnitude (order of 10-6). In contrast, the KVM detected significant corneal viscosity only when the deflection amplitude was virtually phase shifted with respect to the air-puff applanation force. No significant corneal viscous response was detected in patients who had air-puff applanation. [J Refract Surg. 2019;35(11):730-736.].

Composite spherical shells at large deflections. Asymptotic analysis and applications

The asymptotic method for spherical shells at large deflections was developed in the case of composite shell subject to external pressure. Reissner’s equations describing axially symmetric deformation of deep shells with arbitrary deflections and rotation angles were considered as initial ones. They were significantly simplified and asymptotic formulae for deformation energy, external pressure and stresses depending on deflection amplitude were obtained. The energy barrier criterion was applied for the composite shell for estimation of the shell metastability. Formula for design buckling pressure was derived for composite shells. It improves the significantly more conservative NASA SP-8032 recommendations. The full inversion of the shell was studied as well. Asymptotic formulae were obtained for evaluation of stresses and load deflection dependencies. They can be useful for design of diaphragms for positive expulsion propellant spherical tanks of launch vehicles and for other applications.

Effect of morphed trailing-edge flap on aerodynamic load control for a wind turbine blade section

Application of Morphed Trailing-Edge Flap (MTEF) can significantly reduce the excessive loads that cause damage of blades and surrounding components in wind turbine. The present paper investigates the effect of MTEF on the aerodynamic load control of a large-scale wind turbine blade. Three design parameters that control MTEF kinematics, such as deflection length, amplitude and phase shift, are analyzed in detail by a validated Computational Fluid Dynamic (CFD) model, in which a specially-designed mesh update method is adopted. Results show that, compared with fully rigid airfoil, the morphed airfoil exhibits an excellent load control capability owing to the appropriate change of aft effective camber as deflection motion of MTEF, which significantly alters the pressure distribution and air flow. Furthermore, the performances are linearly improved with increasing MTEF deflection length, wherein every 0.1c increase in length results in the percentage variation of CL, min (+45%), CL, max (−3%), CD, max (−5%) and CL/CD (+30%). Whereas the improved performance due to the increase of deflection amplitude shows a reducing trend, and an oversize deflection amplitude (greater than βamp = 10°) leads to the depravation of aerodynamic efficiency. Moreover, the analysis of deflection phase shift suggests that a slight phase–lag is beneficial to stabilize the aerodynamic load exerted on wind turbine blade. Especially, the lift coefficient fluctuation (CL, max−CL, min) for the phase-lag case of φ = 1/8π has reduced by about 50% while the cycle-averaged lift coefficient has increased by 16.67% as compared to the fully rigid airfoil. The results of this paper will help guide future development and application of MTEF in practice.

Delaying stall of morphing wing by periodic trailing-edge deflection

Morphing wings can improve aircraft performance during different flight phases. Recently research has focused on steady aerodynamic characteristics of the morphing wing with a flexible trailing-edge, and the unsteady aerodynamic and stall characteristics in the deflection process of the morphing wing are worthy further investigation. The effects of the angle of attack and deflection rate on aerodynamic characteristics were examined, and based on the aerodynamic characteristics of the morphing wing, a method was developed to delay stall by using the flexible periodic trailing-edge deflection. The numerical results show that the lift coefficients in the deflection process are smaller than those in the static situation at small angles of attack, and that the higher the deflection rate is, the smaller the lift coefficients will be. On the contrary, at large angles of attack, the lift coefficients are higher than those in the static case, and they become larger with the increase of the deflection rate. Further, the periodic deflection of the flexible trailing-edge with a small deflection amplitude and high deflection rate can increase lift coefficients at the critical stall angle.

Evaluation of Steel Stairwell Dynamic Characteristics, Under Few Mass Configurations Using Ambient Vibration Method

Application of external mass on existing emergency steel stairwell in this study has altered the natural frequency when the resonance threshold has been reached and allows disruption to the human comfort feeling. Ambient vibration testing and modal analysis were carried out on 6 meter height of emergency steel stairway portal frame by using 1 Hz of tri-axial seismometer sensor and open source software of GEOPSY as the processing tool. The stairwell platforms were subjected by cumulative ascending static mass configurations of 300 kg, 600 kg and 900 kg. Identification of the predominant first mode frequency, f1, and mode shapes were made with specified empirical filtering protocols were applied. Fourier Amplitude Spectra (FAS) was used to transform the ambient vibration time series, when the first predominant frequency under bare frame (BF) condition shows at 8.32 Hz. f1 decreased linearly to 7.35 Hz (BF+300kg), 6.77 Hz (BF+600kg) and 6.23 Hz (BF+900 kg), when the masses were increased. In addition, at these frequencies’ ranges, bad human subjective experiences could be triggered as recommended by previous researchers between 8 to 5 Hz. Besides, the deflection shapes from the first mode frequency was also illustrated at higher deflection amplitude to one of the portal frame’s column which resisting two stairwell platforms. These amplitudes are higher when f1 is decreasing. It can be concluded that, ambient vibration approach has efficiently evaluated the dynamic characteristics and its influence against the structure-person interaction on existing steel stairwell portal frame in this study. Further strengthening work on the steel frame could decrease the reductions percentages of the predominant frequencies, deflection amplitudes and even increase the human comfort level when using the stairwell, especially during building evacuation procedure.

Effects of Phase Lags on Thermoelastic Damping in Micro-Beam Resonators

The aim of the present paper is to study the thermoelastic damping of a micro-beam resonator in the context of the generalized thermoelasticity theory with three-phase-lag (TPL). The thermoelastic damping of the micro-beam resonator is obtained by the Laplace transform procedure as well as by the finite-sine Fourier transformation. The vibration responses of deflection and thermal moment are obtained for the micro-beams with simply supported and isothermal ends. Initially, the analytic solution is obtained for the amplitudes of deflection and thermal moment. It was observed that both amplitudes are attenuated and the vibration frequency is increased with the three-phase-lag. The effects of phase-lags on the deflection and thermal moment are obtained and evaluated by comparing the present numerical results with the corresponding results based on the theory of thermoelasticity of type GN-III. It was observed that higher values of deflection and thermal moment of the resonator are obtained for the TPL when compared with those of the GN-III model. It was also found that these properties are size-dependent.

Correlation Between the Myopic Retinal Deformation and Corneal Biomechanical Characteristics Measured With the Corvis ST Tonometry.

PurposeWe previously reported that the retinal deformation due to myopia was represented by the peripapillary retinal arteries angle (PRAA). In this study, we investigated the relationship between the PRAA and biomechanical properties measured with Corvis ST (CST) tonometry.MethodsThirty-four normative eyes of 34 subjects who underwent CST measurement were enrolled. The PRAA was calculated from a fundus photograph. Variables related to the PRAA were identified from age, axial length, spherical equivalent refractive error, and 10 CST parameters using model selection with the second-order bias-corrected Akaike information criterion index.ResultsThe PRAA was best described with axial length (coefficient = −5.66, P < 0.0001), maximum deflection amplitude (mm; coefficient = 130.5, P = 0.0004), and deflection amplitude ratio (DA ratio) 2 mm (coefficient = −25.8, P = 0.0032), where mm was the amount of the maximum corneal apex movement and DA ratio 2 mm was the ratio between the deformation amplitudes at the apex and 2 mm away from the apex. The optimal model was significantly better than the model only with axial length (P = 0.0014, analysis of variance).ConclusionsThe PRAA was significantly better described with the CST parameters compared to the axial length model only; eyes with small PRAA (larger myopic retinal deformation) showed narrow and shallow maximum corneal deflection.Translational RelevanceThe Corvis ST parameters, which represents corneal biomechanical characteristics, were associated with myopic retinal deformation.

Corneal deflection amplitude and visual field progression in primary open-angle glaucoma.

PurposeTo investigate the relationship between corneal deflection amplitude and visual field progression rate in patients with primary open-angle glaucoma (POAG).MethodsThis study included 113 eyes of 65 patients with POAG followed for an average of 4.81 ± 1.24 years. Evaluation of visual field progression rate was performed using mean deviation of standard automated perimetry. Corneal deflection amplitude was measured using Corvis ST (Oculus Optikgeräte GmbH, Wetzlar, Germany). Linear mixed models were performed to determine the relationship between corneal deflection amplitude, intraocular pressure (IOP), and visual field progression rate.ResultsMean age was 56.36 ± 14.58 years. Baseline average mean deviation was -8.20 ± 9.12 dB and mean treated IOP was 14.38 ± 3.08 mmHg. Average deflection amplitude was 0.90 ± 0.13 mm. In both univariate and multivariate analysis, IOP (P = 0.028 and P < 0.001, respectively) and deflection amplitude (P = 0.034 and P < 0.001, respectively) significantly affected visual field progression rate. Eyes with high IOP and greater deflection amplitude showed faster progression rate.ConclusionsCorneal deflection amplitude was significantly related with glaucoma progression. Eyes with greater corneal deflection amplitude showed faster visual field progression rate in patients with POAG.

An Experimental Investigation on Uncertainty in Measuring Vibration Deflection Shapes With Digital Image Correlation

3-D digital image correlation (DIC) is a widespread full-field displacement measurement technique based on stereo vision. It was formulated to deal with static problems in experimental mechanics in the early seventies, and since then, the applicability of the technique increased due to increasing frame rates and dropping prices of machine vision cameras. As a consequence, DIC became a feasible solution for general-purpose vibration testing. This paper, however, does not offer a comprehensive analysis of DIC accuracy when applied to vibration testing, and therefore, this paper offers a “Type A” evaluation of uncertainty when measuring vibration deflection shapes with DIC. Uncertainty is evaluated for different experimental conditions on a stepped sine test. Data show that the average value of uncertainty normally lies below 0.02 mm, but in resonant conditions, it can increase up to 0.05 mm (considering a field of view of about half a meter). This demonstrates a strong correlation between the deflection amplitude and the random uncertainty due to motion blur.

Three-dimensional dynamics of functionally graded piezoelectric cylindrical panels by a semi-analytical approach

Nowadays, intelligent piezoelectric materials are widely used in transducer devices and aerospace structures. To investigate the dynamic behaviour of a functionally graded piezoelectric material (FGPM) cylindrical panel, a semi-analytical approach by introducing the Laplace transform, differential quadrature method, state space approach and Durbin’s numerical inversion of Laplace transform is presented. The accuracy of this method is validated by comparing the results with the published literature and by ANSYS under various boundary conditions. Convergence studies showed the proposed approach has a quick convergence rate with growing sample point numbers and increasing layer numbers. The analysis of initial electric potential on the outer surface and bottom surface indicated that when the plus and minus signs of two sides are opposite, the value of central electric potential will decrease. Under simply supported condition, if FG index γ increases, the deflection amplitude of the panel will increase, while the electric potential amplitude decreases. Moreover, the amplitude of displacements along the radial direction becomes larger when the central angle increases, but the period time decreases at the same time. The proposed method fills a gap of 3-D semi-analytical investigations for the dynamic behaviour of FGPM cylindrical panels in different boundary conditions.

Nonlinear dynamic response and vibration of shear deformable piezoelectric functionally graded truncated conical panel in thermal environments

The novelty of this study is using the analytical approach to investigate the nonlinear dynamic response and vibration of shear deformable functionally graded truncated conical panel with piezoelectric actuators, resting on Pasternak type elastic foundations in thermal environments. Material properties are graded in the thickness direction according to a simple power law distribution in terms of the fractions of constituents. The governing equations are derived based on the first order shear deformation shell theory with a von Karman – Donnell type of kinematic nonlinearity in which the Hamilton's principle is used to derive the equations of motion of piezoelectric functionally graded truncated conical panel. The those equations are solved by the Galerkin method and Runge – Kutta method to determine the nonlinear deflection amplitude – time curves and natural frequency of the functionally graded panel. In numerical results, the effects of applied actuator voltage, temperature increment, dimensional parameters, semi – vertex angle, material properties and elastic foundations on the nonlinear dynamic response and vibration of the piezoelectric functionally graded truncated conical panel are discussed in details. The approach are verified with the known results in the literature.

Deep Negative Deflection in Unipolar His-Bundle Electrogram as a Predictor of Excellent His-Bundle Pacing Threshold Postimplant.

Background His-bundle pacing (HBP) is a physiological form of pacing. Although high capture thresholds are common, few predictors of low HBP threshold have been determined. We aimed to identify electrophysiological predictors. Methods Fifty-one patients (53% with atrioventricular block) underwent HBP for bradycardia with an intrinsic QRS duration of <120 ms. Attempts to anchor the HBP lead were guided by unipolar His-bundle electrograms (HB EGMs) recorded with an electrophysiology recording system. Patients were followed-up for >6 months. Results In total, 153 attempts at anchoring the HBP lead were made, of which, 45 achieved acceptable HBP thresholds (≤2.5 V at 1 ms). The amplitude of negative deflection in HB EGM and the selective HBP form at fixation were independently associated with achieving an acceptable threshold. A negative amplitude of ≥0.060 mV in HB EGM was determined as the optimal value for identifying the acceptable threshold. This deep negative HB EGM was recorded with an HBP threshold of 1.4±1.3 V (in 34 attempts), significantly lower than that of positive HB EGM without deep negative deflection (2.8±1.3 V, in 31 trials; or >5 V, in 38 trials). The permanent HBP lead remained with deep negative (≥0.060 mV) or positive HB EGMs in 28 and 14 patients, respectively, and with positive or negative HB injury current in 19 and 23 patients, respectively. During follow-up, increased HBP threshold of >1 V was significantly more prevalent in the positive HB EGM group. The HBP thresholds of deep negative HB EGM and HB injury current, but not of the selective HBP group, were significantly lower than the other subgroups during follow-up. Conclusions Deep negative HB EGM at fixation was associated with an excellent short-term HBP threshold, similar to HB injury current. Analysis of unipolar HB EGM postfixation may enable prediction of permanent HBP threshold.