Deflection Index Research Articles

Predictor of A4-amplitude using preprocedural electrocardiography in patients with leadless pacemakers

Abstract Background Based on the historical studies of leadless pacemakers (LP), high atrio-ventricular synchrony (AVS) with mechanical sensing-based VDD pacing is largely influenced by A4-amplitude. A limited study investigated the predictors of A4-amplitude using clinical and echocardiographic parameters. Objective This study aimed to investigate the predictors of A4-amplitude preoperatively to select patients who could benefit the most from AVS among patients with VDD LPs. Methods Data from patients who received VDD LP implantations from November 2021 to August 2023 at our institution were analyzed. Twelve-lead electrocardiography and transthoracic echocardiography were performed before VDD LP implantations. To assess the electrical indices associated with the A4-signal, the electrocardiographic morphological P-wave parameters were analyzed including the P-wave duration, P-wave amplitude, maximum deflection index (MDI), and P-wave dispersion. Results A total of 50 patients who underwent VDD LP implantations (median age, 84 years; 64% male) were included and divided into two groups based on the median value of A4-amplitude, the high-A4 group (A4-amplitude >2.5m/s2, n=26) and low-A4 group (A4-amplitude ≤2.5m/s2, n=24). There was a significant difference between the high-A4 and low-A4 groups in the LVEF (P=0.01), P-wave dispersion (P=0.01), and MDI (P<0.001). A multivariate logistic analysis revealed that a lower MDI was an independent predictor of a high A4-amplitude (odds ratio: 0.78, 95% confidence interval: 0.67 to 0.92; P=0.003). Conclusion Preoperative electrocardiographic evaluations of the P-wave morphology may be useful for predicting A4-amplitude. The MDI was the only independent A4-amplitude predictor that seemed promising for selecting VDD LP patients.abstract figure

Complete mitochondrial genomes of two Phoretic mites (Parasitidae: Poecilochirus) on burying beetle: Genome characterization and phylogenetic analysis

A pair of intriguing phoretic instances are the burying beetle and Poecilochirus mites. Their interaction is environment-dependent and can be either mutualistic or antagonistic hostile depending on various biological and physical circumstances. In this study, we sequenced the complete mitogenomes of two Poecilochirus mite species, P. davydovae and P. mrciaki, which are associated with burying beetles, using Illumina HiSeq sequencing technology. Each mitochondrial genome comprised 37 typical genes, including 13 protein-coding genes (PCGs), 22 tRNA genes, two rRNA genes, and one control region (CR). The size of these mitogenomes were determined to be 14,489 bp and 14,517 bp, respectively. These two mitochondrial genomes contain a notable AT bias in their nucleotide composition, with positive AT and negative GC skews in the deflection index of mitochondrial genomes, and a unique incomplete stop codon T- in both protein-coding genes. The DHU arm of tRNA-S1 (AGN) only forms a simple loop structure, while the secondary structures of 21 tRNA genes in both species showed the conventional cloverleaf structures, like those of most metazoans. The phylogenetic tree of Gamasina was constructed using Maximum likelihood and Bayesian inference based on two rRNA genes and 13 PCGs. Based on the existing data, the Parasitidae forms a monophyletic, and Poecilochirus and Parasitus are closely related, possibly belonging to the same genus.

Electrocardiogram predictors of leadless pacemaker implantation in the right ventricular free wall

Abstract Background Leadless pacemakers (LLP) carry the potential risk of cardiac injury, especially when implanted in the free wall of the right ventricle. Purpose To investigate the ECG criteria for distinguishing free wall implantation of LLP, further clarification is needed. Methods We conducted a retrospective study involving 17 patients who underwent LLP implantation, followed by chest computed tomography to confirm the implantation site. Patients were categorized into three groups based on the location of implantation (septum [Sep], apex [Apex], and free wall [FW]), and we compared the morphology of the 12-lead ECG during LLP pacing. Results Among the implantation sites, nine were in the Sep (52.9%), five in the Apex (29.4%), and three in the FW (15.8%). In terms of pacing QRS morphology, the FW group exhibited significantly longer QRS duration (Sep: 145.6±15.2 vs. Apex: 161.6±3.6 vs. FW: 175.3±16.6, P<0.01), a notched QRS complex in lead III (Sep: 0.0% vs. Apex: 0.0% vs. FW: 100.0%, P<0.01), and a shorter peak deflection index (PDI) in lead V1 (Sep: 0.59±0.07 vs. Apex: 0.55±0.06 vs. FW: 0.40±0.02, P<0.01) than the other two groups. Receiver operating curve analysis to predict FW implantation revealed that a PDI of 0.42 in lead V1 (Area under the curve [AUC]=1.00, specificity=100.0%, sensitivity=100.0%, P<0.01) and a QRS duration of 173 msec (AUC=0.89, specificity=100%, sensitivity=66.7%, P<0.01) were the optimal cutoff values. Conclusion The LLP FW implantation group had a longer QRS duration, a notched QRS complex in lead III, and a shorter PDI in lead V1 compared to the other pacing sites.

Discrimination between ventricular tachycardia and wide-QRS preexcited tachycardia.

To develop a new algorithm to differentiate ventricular tachycardia (VT) from preexcited tachycardia (pre-ET) according to left bundle branch block (LBBB) and right bundle branch block (RBBB) patterns. This study included 67 electrocardiograms (ECGs) with VT and 63 ECGs with pre-ET, collected from our hospital and through PubMed. Of those, 64 were allocated to the derivation cohort and the rest to the validation cohort. The diagnoses of the ECGs were confirmed using an electrophysiological study. Parameters and classifiers from prior algorithms along with the propagation speeds in the early portion of the QRS complex (initial deflection index) in leads V1, V6, aVR, II, and III were manually measured. The performance of the new algorithm was compared with that of prior algorithms. The initial deflection index in lead III was the strongest predictor of pre-ET in LBBB-pattern wide-QRS tachycardia (p = 0.003, AUC 0.805). The initial deflection index in lead V1 was the most powerful predictor of pre-ET in RBBB-pattern wide-QRS tachycardia (p = 0.001, AUC 0.848). Compared to earlier algorithms, those using the initial deflection indexes: lead III in LBBB patterns (cutoff value >0.3) and lead V1 in RBBB patterns (cutoff value ≤0.48), demonstrated superior performance in screening VT, with AUC values of 0.828. The initial deflection indexes proved effective as discriminators between VT and pre-ET in the validation cohort. In LBBB-pattern wide-QRS tachycardia, the early propagation speed of pre-ET was faster than that in VT. Conversely, in RBBB-pattern wide-QRS tachycardia, it was slower.

Predictor of A4 amplitude using preprocedural electrocardiography in patients with leadless pacemakers

BackgroundBased on historical studies of leadless pacemakers (LPs), high atrioventricular synchrony (AVS) with mechanical sensing-based VDD pacing is largely influenced by A4 amplitude. A limited study investigated the predictors of A4 amplitude using clinical and echocardiographic parameters. ObjectiveThe purpose of this study was to investigate the predictors of A4 amplitude preoperatively to select patients who could benefit the most from AVS among patients with VDD LPs (Micra-AV, Medtronic). MethodsData from patients who received Micra-AV implantations from November 2021 to August 2023 at Tottori University Hospital were analyzed. Twelve-lead electrocardiography and transthoracic echocardiography were performed before the Micra-AV implantations. To assess the electrical indices associated with the A4 signal, electrocardiographic morphologic P-wave parameters were analyzed, including P-wave duration, P-wave amplitude, maximum deflection index (MDI), and P-wave dispersion. ResultsA total of 50 patients who underwent Micra-AV implantations (median age 84 years; 64% male) were included and divided into 2 groups based on the median value of A4 amplitude, the high-A4 group (A4 amplitude >2.5 m/s2; n = 26), and low-A4 group (A4 amplitude ≤2.5 m/s2; n = 24). There was a significant difference between the high-A4 and low-A4 groups with regard to left ventricular ejection fraction (P = .01), P-wave dispersion (P = .01), and MDI (P <.001). Multivariate logistic analysis revealed that lower MDI was an independent predictor of high A4-amplitude (odds ratio 0.78; 95% confidence interval 0.67–0.92; P = 0.003). ConclusionPreoperative electrocardiographic evaluations of P-wave morphology may be useful for predicting A4 amplitude. MDI was the only independent A4 amplitude predictor that seemed promising for selecting Micra-AV patients.

Application of the Air-Jet Laser Detection Technology for Asphalt Binders

AbstractA fast and convenient technique for Asphalt Binders was proposed in this paper, which was based on air-jet pressurized and laser to detect the transient deformation and creep recovery of asphalt. Taking five kinds of asphalt and modified asphalt commonly used in China as the research objects, the performance of asphalt were tested and analyzed by adopting the Penetration Test, Dynamic Shear Rheological (DSR) Test, Multiple Stress Creep and Recovery (MSCR) Test and the proposed test technology. The results verified the feasibility of the proposed test technology and the correlation between the traditional tests and the proposed test technology. The results demonstrated that the proposed test technology had good discrimination ability for different kinds of asphalt and could effectively reflect the performance differences. The new test protocol was similar to the Penetration Test. There was a significant correlation between the maximum deformation index and penetration index. The correlation coefficient was above 0.8, and the p value was much less than 0.01. It could be used as a possible alternative to the Penetration Test. The proposed new test was relatively convenient and fast compared with the dynamic shear test. There was a linear correlation between the maximum deflection index and the complex shear modulus G*, and the correlation coefficient between the recovery index and the phase angle is above 0.8, which indicated that the proposed new test and the DSR test had a significant correlation. There was also a good correlation between the creep recovery index of MSCR test and the recovery data of the proposed new test method. The research results provided a new solution for the performance test and evaluation of asphalt in China.

Electrocardiographic Characteristics of Ventricular Arrhythmias Originating from Different Areas Adjacent to the Mitral Annulus.

This study aimed to explore the electrocardiographic (ECG) characteristics of ventricular arrhythmias (VAs) arising from epicardial and endocardial areas adjacent to the mitral annulus (MA). This study involved 283 patients with MA-VAs who received radiofrequency catheter ablation at the center. The ECG characteristics of these patients were analyzed retrospectively. The origin of MA-VAs was judged based on the ECG variables. Among all MA-VAs, intrinsicoid deflection time (IDT) > 77 ms or maximum deflection index (MDI) > 0.505 predicted the VAs arising from the epicardium (sensitivity of 70.20% and 73.51%, specificity of 94.70% and 82.58%, positive predictive value (PPV) of 93.81% and 82.84%, and negative predictive value (NPV) of 73.53% and 73.15%). Among all epicardial MA-VAs, the RV1/RV2 ratio > 0.87 predicted the VAs originating from the epicardial anteroseptal wall adjacent to the MA. It had a sensitivity, specificity, PPV, and NPV of 62.86%, 98.06%, 91.67%, and 88.60%, respectively. Among all endocardial MA-VAs, Q(q)R(r) morphology in lead V1 predicted the VAs arising from the endocardial septal wall adjacent to the MA. It had a sensitivity, specificity, PPV, and NPV of 92.98%, 100%, 100%, and 94.94%, respectively. Among all endocardial septal MA-VAs, a predominant positive wave in lead II and a predominant negative wave in lead III predicted the VAs arising from the endocardial midseptal portion adjacent to the MA. It had a sensitivity, specificity, PPV, and NPV of 86.04%, 100%, 100%, and 70.00%, respectively. the ECG characteristics of VAs from the different sites adjacent to the MA can enable judging the arrhythmia's origin and designing the ablation plan accordingly.

Endocardial, epicardial, and right atrial approach for catheter ablation of premature ventricular contractions from the inferoseptal process of the left ventricle.

Inferoseptal process of the left ventricle (ISP-LV) might be a source of idiopathic ventricular arrhythmias. In these cases, ectopic foci are accessible from the LV endocardium, epicardially from the middle cardiac vein as well as from the right atrium (RA). This study reports a series of patients with premature ventricular contractions (PVCs) arising from the ISP-LV that were successfully ablated following access from different structures. Five patients (4 males, age 61 ± 12.8 years) with PVCs arising from the ISP-LV were successfully ablated using three different approaches for ablation-endocardial, epicardial (through coronary sinus or its branches), and RA approaches. Endocardial LV mapping, RA, and coronary sinus (CS) mapping were performed in all five cases. PVCs demonstrated RBBB or LBBB-like morphology and left superior axis. The three patients ablated endocardially had a maximum deflection index (MDI) of 0.36, 0.43, and 0.54, whereas in the remaining 2 patients, MDI was 0.57 and both demonstrated QS morphology in the inferior leads. Local activation time at the successful ablation site was 35 ± 8.9 (26-55) msec pre-QRS. Pacemapping at the successful ablation site resulted in a good (11/12) or perfect (12/12) QRS match in all cases. Three of the patients demonstrated frequent monomorphic PVCs of another morphology suggesting a remote exit site. All patients remained arrhythmia-free after a mean follow-up of 21 ± 15 (6-36) months. Successful ablation of PVCs from ISP-LV may require access from the CS or even RA apart from LV endocardial approach. Not infrequently patients demonstrate additional PVC foci.

Effectiveness of hybrid discarded tire/Industrial steel fibers for improving the sustainability of concrete structures

Using waste and raw materials in construction materials is vital for sustainable construction. In this respect, the use of discarded tire steel fibers (DSFs) is encouraged in the construction industry to decrease pollution. On the other hand, the production of commonly used industrial steel fibers (ISFs) involves emissions of CO2. Many studies have been conducted to evaluate the influence of discarded tire steel fibers (DSFs) on concrete. It is found that using DSFs in raw form could not improve the desired properties as ISFs do. Therefore, it is expected that using both ISFs and DSFs together can help achieve the desired improvements in concrete properties for various civil engineering applications. The main objective of the current investigation is the effective use of DSFs for developing eco-friendly, sustainable concrete. This study aims to evaluate the experimental properties of fiber-reinforced concrete, incorporating hybrid fibers (DSFs and ISFs together). Concrete specimens containing 0%, 0.50%, 0.60%, and 0.70% hybrid fibers by volume fraction are prepared. The hybrid fibers (HFs) comprise 30% of industrial steel fibers (ISFs) and 70% of discarded tire steel fibers (DSF) for each proportion. The 28th-day properties are examined. The slump and densities are determined. The experimental testing includes elastic modulus, compression (CS), split-tensile (SS), and bending testing (FS). The strength properties, deflection index, residual flexure strength, energy absorption, toughness index, and cracking behavior are reported. Moreover, the water absorption and linear shrinkage are also calculated. Except for the elastic modulus test, ASTM standards are used for casting and testing. A reduction of 45% in the LS and enhancements of 9.1%, 38%, 37%, and 23% are noticed in the EM, CS, SS, and FS of HFRC in contrast to zero-fiber concrete. Significant improvements are noticed in the properties of hybrid fiber-reinforced concrete compared to zero-fiber concrete.

Experimental study on the shear behavior of RC beams strengthened with cementitious grout

Strengthening the existing damaged RC beams with a layer of cementitious grout can effectively overcome the limitations of the conventional concrete–replacement method, which has been considered as an effective way to improve the performance of damaged RC beams. This study presented an experimental study on the shear behavior of 24 RC beams strengthened with cementitious grout. The effects of replacement positions, replacement thicknesses, and shear span to effective depth ratios on the shear behavior of the strengthened beams were discussed. Results indicate that (1) No obvious bonding cracks and peeling failures were observed at the interface between the cementitious grout and concrete. (2) Compared with the beams strengthened on the compressive side, the beams strengthened on the tensile side had a smaller load and deflection index value, which indicated that the beams strengthened on the compressive side had a better reinforcement effect than those on the tensile side. (3) With the increase of the replacement thickness, the load and deflection index value of the specimens with different shear span to effective depth ratios increased gradually, and the increment decreased with the increase of the shear span to effective depth ratio. (4) Calculation methods were proposed to evaluate the shear capacity of RC beams strengthened with cementitious grout based on Code GB 50010-2010 and the truss-arch model, respectively, and verified well with experimental data.

Deflection of an Isotropic All-Round Simply Supported Rectangular Plates Incorporating Shear Effect Using Characteristic Orthogonal Polynomial Function

The breadth and dexterity with which plates are used in the vast majority of engineering structures necessitates an ever-increasing and deeper study focus on plate strength and stiffness at the ultimate and serviceability limit states of response. From Kirchhoff’s hypothesis, thin plates when subjected to transverse loading, bend and experience transverse deflections that are typically minor in comparison to the plate thickness. However, for thicker plates there is an observed limitation in the application of Kirchhoff’s hypothesis, as this theory ignore the effect of transverse shear on the deformation of plates. This study therefore analytically examines the effect of induced shear on the deflection indices of plates with varying aspect ratios, using the characteristic orthogonal polynomial function. Result obtained shows a close agreement between present study and Kirchhoff’s hypothesis for membrane and thin plates. However, a significant difference was observed for moderately thick plates and thick plates, which clearly shows the effect of transverse shear as the plate thickness increases, which further validates the limitations of Kirchhoff’s hypothesis for moderately thick as well as thick plates. For an aspect ratio of 1.0 – 2.0 at 0.1 interval, results obtained indicated a percentage difference in deflection between the Present study and Kirchhoff’s hypothesis to range between -0.040 – 3.508%, 0.527 – 3.552%, 4.266 – 5.858%, and 13.980 – 17.011% for membrane, stiffened, moderately thick, and thick plates respectively. The validation of the Kirchhoff’s hypothesis for membrane as well as stiffened plates by the present study, indicates the suitability of the application of the characteristic orthogonal polynomial function in the evaluation of the deflection of plates regardless of thickness.

Ten Years of Traffic Speed Deflectometer Research in the United States: A Review

This paper summarizes the research efforts into and applications of the traffic speed deflectometer (TSD) that have occurred over the last 10 years in the United States (U.S.). These are divided into three main topics which are: (1) data analysis methods including data processing, calculation of indices and structural parameters, and temperature correction; (2) evaluation efforts of TSD including repeatability and comparison with the falling weight deflectometer (FWD); and (3) applications of TSD with a focus on flexible pavement management applications, although some efforts on rigid and composite pavements are mentioned. The data analysis methods reviewed are data averaging length and reporting interval, and how deflections are calculated from the measured deflection slopes. For the calculation of indices and structural parameters the following are reviewed: deflection indices that have been proposed, the effective structural number ( SNeff), and backcalculation of layer moduli. Efforts to evaluate TSD precision (or measurement standard error) are discussed. Then, some comparisons of short-term (time frame of 1 day) and long-term (time frame of 1 year) repeatability of TSD are presented. Compared with FWD, TSD and FWD generally have good correlation, although the measurement principles of the two devices are slightly different. The focus is on network-level applications of TSD, and, more specifically, efforts to include TSD measurements in the pavement management system, especially for flexible pavements applications.

Development and validation of a new ECG algorithm based on the analysis of lead V3 to determine the origin of outflow tract ventricular arrhythmias

Abstract Funding Acknowledgements Type of funding sources: None. Introduction (Aim) To preoperatively differentiate the site of origin outflow tract ventricular arrhythmias (OT-VA) it is of utmost importance for procedure planning yet challenging for those with a precordial transition (PT) at lead V3: close-proximity anatomical structures produce similar VA morphologies, thus leading to possible misdiagnosis. We sought to create an ECG algorithm that could be accurate and useful in overcoming this problem. Methods and Results 74 consecutive patients (Pts) with OT-VA who underwent successful radio-frequency catheter ablation (V3 PT 60.8%) were enrolled. The ECG characteristics of the first 30 Pts were analyzed (retrospective cohort); those with a PT at lead V3 underwent activation-mapping of both OT to ensure a correct diagnosis. LV-OT and RV-OT groups shared similar characteristics, including BMI and BSA. Above all ECG measurements, the V3 duration index (DI) and amplitude percentage, both calculated with the formula [R\(R+S)]*100 (computing duration and amplitude measurements respectively), showed the greatest AUC. A V3 DI &amp;lt; 50% established a certain diagnosis of origin at RV-OT (sensitivity 86.7%, specificity 100%, PPV 100%, NPV 88.2%; AUC 0.931). If the V3 DI was ≥ 50%, a V3 R wave percentage ≥ 50% established a certain diagnosis of origin at LV-OT (sensitivity 86.7%, specificity 100%, PPV 100%, NPV 88.2%, AUC 0.951). While a direct study of the RV-OT or LV-OT is suggested in these first two cases, few classification errors occurred only in the rare event of a V3 DI ≥ 50% with a V3 R wave percentage &amp;lt; 50% (Figure 1). In the prospective cohort, the two indices were confirmed to have the two best AUCs (0.992 and 0.986, respectively), and the algorithm showed an accuracy of 95.45%. Since the aortic cusps are structures posterior to RV-OT, therefore further away from V2, these foci more frequently show a QRS onset at ≥ V3; a characteristic which in our series was associated with an odds ratio for LV-OT origin of 4.1 [95% CI 1.47 – 11.39], p = 0.007. Using the transition ratio, we found a statistical significance only in lead V3, with a cut-off of ≥ 1 for predicting an LV-OT origin (LV-OT vs. RV-OT: 7.70 ± 12.75 vs. 0.70 ± 0.55, p &amp;lt; 0.001; AUC 0.898). Analyzing the overall case series, we can generalize the following: duration and amplitude indices showed an increasing AUC passing from lead V1 to V3 (Figure 2). The indices based on the complete measurement of the wave R compared to the QRS showed better AUCs than those on partial measures in V2 and V3: the duration index was better than the deflection index, as well as the amplitude percentage was better than the amplitude ratio. Conclusions The usefulness of the algorithm lies in providing preoperatively two assured outcomes in most cases (86.36%), allowing to limit the procedure to one OT directly - even in the event of a V3 PT - while it can select a small subgroup of complex Pts in which a study of both OT is recommended.

Influence of incinerated biomedical waste ash and waste glass powder on the mechanical and flexural properties of reinforced geopolymer concrete

ABSTRACT An extensive experimental study was implemented to investigate the structural and material properties of Waste Glass Powder (WGP) as fine aggregate in Incinerated Bio-Medical Waste Ash (IBWA) – Ground Granulated Blast Furnace Slag (GGBFS) based Geopolymer Concrete (GPC). The research was based on the compressive, splitting tensile and flexural efficiency of GGBS-based geopolymer concrete mixed with IBWA as binder and WGP as fine aggregate. To determine the concrete strength, four different types of proportions were designed as beams and columns. The mechanical properties such as compressive strength and splitting tensile strength and flexural properties for beams such as deflection, ductility factor, flexural strength, and toughness index, and flexural properties for columns such as load-carrying capacity, stress-strain behaviour, and load-deflection behaviours were calculated. Comparative analyzes were performed to assess the efficiency of Waste Glass Powder and Incinerated Biomedical Waste Ash in GGBS-based geopolymer concrete against Reinforced Cement Concrete (RCC). The findings showed that the Waste Glass Powder and Incinerated Bio-Medical Waste Ash embedded in GGBS-based Geopolymer concrete exhibited the highest fracture energy, as predicted from the mechanical bond between the waste materials and the GGBS-based Geopolymer concrete.

Reliability Analysis of Flexural Deflection of Reinforced Concrete Members under Ultra-Low Temperature

Based on the Monte Carlo method, the functional function under the normal use limit state given by the specification introduces the concrete tensile strength of each temperature gradient under ultra-low temperature, and the coefficient of change of concrete elastic modulus. By changing the temperature of the member, the thickness of the protective layer, the bending moment effect ratio, the reinforcement size,the concrete grade and the length of the bending beam. Analyze the reliable index of the deflection control of the flexural member under ultra-low temperature to obtain: When the reinforced concrete flexural member is reduced from normal temperature 20°C to-160°C, the reliable deflection index of the component increases non-linearly, reaches the maximum value at-130°C, and then decreases slightly, the concrete strength grade and the thickness of the protective layer under each temperature gradients have the greatest influence on the deflection control of the bending beam under ultra-low temperature, followed by beam length, steel bar size, load effect ratio,which is different from normal temperature.

Evaluation of the effects of transverse cracking on the falling weight deflectometer data of asphalt pavements

ABSTRACT This study aims to investigate the effects of transverse cracking on the deflections of asphalt pavements. 3D finite element models were developed to simulate various intact and cracked asphalt pavements. The deflections of intact and cracked pavements under falling weight deflectometer (FWD) loading were computed and compared. In most cases analyzed, the deflections of cracked pavements are greater than those of intact pavements. For pavements with thermal cracking, the deflections can be 12% and 25% greater than those of intact pavements for cement treated base (CTB) and granular base (GB), respectively. For pavements with reflective cracking, the deflections of cracked pavements can be 98% greater than those of intact pavements, and the deflection decreases sharply across the reflective crack and in some cases it can even increase with increasing distance from the loading center. Crack location and width mainly affect the deflections on the loaded side of crack. Both thermal and reflective cracking have greater influences on the deflections of pavement with a thicker AC layer and a weaker subgrade. The effects of reflective cracking on the deflections are significantly greater than thermal cracking. LTE30–60cm is recommended as a deflection index to distinguish reflective cracking from thermal cracking.

Evaluation of influence of pavement data on measurement of deflection on asphalt surfaced pavements utilizing traffic speed deflection device

Structural condition data is one of the critical data elements in pavement design and management for determining the needs of pavements rehabilitation. However, it is time-consuming and may raise safety concerns to use Falling Weight Deflectometer (FWD) for collecting pavement structure data at network-level. The traffic-speed deflection device seems to be a promising way to collect network-level structural capacity information in a safe and timely manner. To better understand the deflection collected from traffic-speed deflection devices, this paper focused on the influence of pavement data on deflection measurements. The pavement data in this study included pavement structure and surface condition data. The associations between deflection and pavement data was assessed by non-parametric rank correlation analysis. The pavement data elements that may influence deflection measurement were identified by random forest regression models. The relationship between deflection indices and surface condition indices were quantified by Tukey’s HSD test.Results indicated that D0 and SCI appeared to be more influenced by pavement type, surface roughness and distress than SCI of subgrade. IRI on the right wheel path tended to be more closely associated with SCI than other surface condition data. The change of surface condition indices appeared to be more sensitive to deflection indices on flexible pavements than on composite pavements.

Deriving Pavement Deflection Indices from Layered Elastic Theory

Pavement deflection indices such as the surface curvature index or base damage index are widely used to characterize the condition of pavements. Often, the indices are constructed to provide an estimate of a particular strain component somewhere in the pavement structure. Since the pavement damage is a function of the strain, structural indices provide a simple way of estimating the damage rate in a pavement. Despite their widespread use, it has so far proven difficult to derive deflection indices from first principles; instead, new indices are found by evaluating a range of candidates using a trial-and-error approach. In this paper, a systematic method of deriving deflection indices is presented. The method is based on applying the convolution theorem for Hankel transforms to the solution of a layered elastic problem. Besides allowing for easy derivation of new deflection indices, the method can be used to account for the impact of varying layer thicknesses in the pavement.

Radiofrequency catheter ablation of premature ventricular contractions from the mitral annulus in patients without structural heart disease.

IntroductionWe previously reported the clinical benefits of radiofrequency catheter ablation (RFCA) of premature ventricular contractions (PVCs) from the right ventricular outflow tract or near the His‐bundle, which can often deteriorate the clinical status. PVCs from the mitral valve (MA‐PVCs) also often deteriorate the patients’ clinical status. This study aimed to evaluate the effect of ablating MA‐PVCs with RFCA from a trans‐interatrial septal approach on the clinical status in symptomatic patients with frequent MA‐PVCs without structural heart disease.MethodsThe frequency of PVCs per the total heart beats by 24‐hours Holter monitoring and New York Heart Association (NYHA) functional class in 22 patients with MA‐PVCs were evaluated before and 6 months after RFCA.ResultsProcedural success was achieved in 20 (91%) of 22 patients. Of the 22 patients, in 15 (68%) and 1 (5%) patient, a successful RFCA on the left ventricular side of the MA using the trans‐interatrial septal approach and trans‐coronary sinus approach was achieved. Interestingly, in four (18%) patients, a successful RFCA on the left atrial (LA) side of the MA using a trans‐interatrial septal approach was achieved. Ablating MA‐PVCs readily improved the NYHA functional class compared to that before. A ≥0.62 peak deflection index and ≤30 years old may be one of the important predictors of successfully ablated MA‐PVCs from the LA side of the MA.ConclusionsRFCA produces clinical benefits in patients with MA‐PVCs. Further, it may be necessary to initially consider a trans‐interatrial septal approach to ablate these PVCs.

Electrocardiographic localization of ventricular arrhythmias successfully ablated from the distal great cardiac vein.

Idiopathic ventricular arrhythmias (IVAs) from the left ventricular (LV) summit may be successfully ablated from the distal great cardiac vein (dGCV). Using a 12-lead electrocardiogram (ECG) to localize IVAs that can be ablated from the dGCV is valuable for ablation planning. To determine if a "w" wave, a notch in the Q wave in lead I, and other ECG features can identify IVAs that can be successfully ablated from the dGCV. We reviewed outflow tract premature ventricular contraction (PVC) ablations performed at two centers between September 2010 and June 2018. Successful PVC ablations, in which the PVCs were mapped from the right ventricular outflow tract, coronary cusps, commissures, endocardial LV, and the coronary venous system including the dGCV were included. ECG characteristics were compared between patients with successful ablations in the dGCV and non-dGCV sites. Of the 120 patients (age 56.8 ± 13.8 years, 45% female) that met the inclusion criteria, the dGCV was the successful ablation site in 18 patients (15%). Multivariate analysis with binary logistic regression showed that a "w" in lead I in combination with an early precordial pattern break and a maximum deflection index (MDI) ≥ 0.5 had sensitivity and specificity for a successful ablation in the dGCV of 94.4% and 96.1%, respectively. Combining a "w" wave in lead I with an early precordial pattern break and an MDI ≥ 0.5 is highly sensitive and specific for identifying the dGCV as a successful ablation site for PVCs.