A study of physicians' experiences with recommending HPV vaccines to adolescent boys.

Assessing physicians' experiences in HPV vaccine recommendation and delivery to adolescent boys is essential to providing an understanding of the issues of vaccine acceptance and an insight for policymakers to enhance HPV vaccinations among adolescent boys. Between January and April 2014 a mail survey was conducted using physicians in Malaysia known to provide either one or both HPV vaccine (Gardasil and Cervarix) immunisation services. A total of 357 completed questionnaires were received (response rate 22.5%). Of these, 335 physicians see adolescent boys aged 11 to 18 years old in their practice. Only 26.3% (n = 88) recommended the HPV vaccine to these boys. A total of 46.6% (n = 41) have successfully given the HPV vaccine to adolescent boys. A lack of proper guidelines from the health authorities regarding the recommendation of HPV vaccine to the boys (37.2%) and a lack of awareness of the availability of the vaccine for boys (32.8%) were the most commonly cited reasons for non-recommendation. Impact statement Recommending the HPV vaccine for adolescent boys remains a challenge for physicians. Our study provides evidence of challenges and barriers faced by Malaysian physicians who recommend the HPV vaccines (Gardasil and Cervarix) in their practices. In this study, physicians reported HPV vaccine uptake by adolescent boys was very poor. A lack of proper guidelines from the health authorities regarding the recommendation of HPV vaccine to boys and a lack of awareness of the availability of the vaccine for boys were the most commonly cited reasons for non-recommendation. Physicians viewed that support and encouragement from the health authorities are needed to promote the recommendation of the HPV vaccine to adolescent boys. Physicians were also of the opinion that the lay public should be educated about the availability of the HPV vaccine for boys, and its benefits, safety and efficacy, and the high susceptibility of boys to getting HPV infections. The findings provide insights that could be helpful to policymakers or high-level decision-makers of the potential strategies to enhance HPV uptake among adolescent boys.

Knowledge and utilization of Integrated Child Development Services among antenatal women during COVID-19 pandemic.

Introduction: The coronavirus disease 2019 (COVID-19) pandemic has affected the healthcare delivery system in both developed and developing countries. Many antenatal women skipped their regular antenatal check-ups due to fear of viral contamination and lack of transport facilities. Integrated Child Development Services (ICDS), which plays a major role in antenatal care, also suffered a great deal during the pandemic. Objectives: 1. To assess knowledge and utilization of ICDS services by antenatal women during the COVID-19 pandemic. 2. To determine factors influencing the knowledge and utilization of ICDS services by antenatal women. 3. To determine the barriers to utilization of ICDS services during the pandemic. Methodology: This study was conducted as a descriptive study in a tertiary care center. Antenatal women whose pregnancy period coincided with the second wave of the COVID-19 pandemic were interviewed using a structured questionnaire. The sample size was calculated as 198. Data were entered in Microsoft Excel and analyzed using Statistical Package for Social Sciences (SPSS). Results: Around 61% of the study population had adequate knowledge about ICDS services. The proportion of antenatal women utilizing ICDS services reduced from 87.8% to 69.6% during the pandemic. Only a few of the mothers were followed up by the Anganwadi workers during the pandemic. The main barriers to not utilizing ICDS services were fear of the spread of the pathogen and lack of awareness about the availability of services during the pandemic. Conclusion: There has been a reduction in the utilization of ICDS services by antenatal women during the COVID-19 pandemic. Measures should be taken by the government to ensure undisrupted care for antenatal women during such hard times.

Elevated T-wave alternans predicts nonsustained ventricular tachycardia in association with percutaneous coronary intervention in ST-segment elevation myocardial infarction (STEMI) patients.

INTRODUCTION: Successful reperfusion with primary percutaneous coronary intervention (PCI) can paradoxically elicit temporary vulnerability to ventricular arrhythmia. We examined whether T-wave alternans (TWA) level is correlated with nonsustained ventricular tachycardia (NSVT) incidence in association with PCI in patients with acute ST-segment elevation myocardial infarction (STEMI). METHODS AND RESULTS: We analyzed continuous 24-hour ambulatory electrocardiograms in 48 STEMI patients during and after successful primary PCI, achieving Thrombolysis in Myocardial Infarction (TIMI) grade 3 flow. TWA was measured using modified moving average method. Maximum TWA was elevated in patients with (N = 22) compared to without (N = 26) NSVT (75.1 ± 6.3 vs 49.9 ± 3.6 µV, P < 0.005) during the 22-hour monitoring period. TWA ≥ 60µV predicted NSVT with sensitivity of 77%; specificity, 73%; positive predictive value, 71%; and negative predictive value, 79%. Area under receiver operator characteristic curve (AUC) was 0.87 for maximum TWA in predicting NSVT. By comparison, ST-segment levels did not differ in patients with versus without NSVT and were not predictive (AUC = 0.52). TWA was elevated prior to PCI and remained elevated at 30 minutes after balloon inflation despite restoration of TIMI grade 3 flow in all patients, declining by 22 hours (P < 0.05). Maximum ST-segment levels decreased from before PCI to 30 minutes after balloon inflation. TWA is regionally specific, with higher values prior to PCI in precordial lead V5 than in V1 for left coronary lesions. CONCLUSIONS: TWA may be useful in identifying individuals at heightened risk for arrhythmia in association with primary PCI and can potentially signal time-dependent changes in arrhythmia vulnerability.

Patterns of ectopy leading to increased risk of fatal or near-fatal cardiac arrhythmia in patients with depressed left ventricular function after an acute myocardial infarction.

AIMS: To identify potential new markers for assessing the risk of sudden arrhythmic events based on a method that captures features of premature ventricular complexes (PVCs) in relation to sinus RR intervals in Holter recordings (heartprint). METHODS AND RESULTS: Holter recordings obtained 6 weeks after acute myocardial infarction from 227 patients with reduced ventricular function (left ventricular ejection fraction ≤ 40%) were used to produce heartprints. Measured indices were: PVCs per hour, standard deviation of coupling interval (SDCI), and the number of occurrences of the most prevalent form of PVCs (SNIB). Predictive values, survival analysis, and Cox regression with adjustment for clinical variables were performed based on primary endpoint, defined as an electrocardiogram-documented fatal or near-fatal arrhythmic event, death from any cause, and cardiac death. High ectopy (PVCs per hour ≥10) was a predictor of all endpoints. Repeating forms of PVCs (SNIB ≥ 83) was a predictor of primary endpoint, hazard ratio = 3.5 (1.3-9.5), and all-cause death, hazard ratio = 2.8 (1.1-7.3), but not cardiac death. SDCI ≤ 80 ms was a predictor of all-cause death and cardiac death, but not of primary endpoint. CONCLUSION: High ectopy, prevalence of repeating forms of PVCs, and low coupling interval variability are potentially useful risk markers of fatal or near-fatal arrhythmias after myocardial infarction.

Intracardiac electrogram T-wave alternans/variability increases before spontaneous ventricular tachyarrhythmias in implantable cardioverter-defibrillator patients: a prospective, multi-center study.

BACKGROUND: T-wave alternans (TWA) increases before ventricular tachycardia (VT) or fibrillation (VF), suggesting that it may warn of VT/VF in implantable cardioverter-defibrillator patients. Recently, we described a method for measuring alternans and nonalternans variability (TWA/V) from electrograms (EGMs) stored in implantable cardioverter-defibrillators before VT/VF. The goal of this prospective, multicenter study was to determine whether EGM TWA/V was greater before VT/VF than at baseline. METHODS AND RESULTS: We enrolled 63 implantable cardioverter-defibrillator patients. TWA/V was computed from stored EGMs before spontaneous VT/VF and from sequential windows of 8 pairs of beats using 4 different control recordings: baseline rhythm, rapid pacing at 105 bpm, segments of ambulatory Holter EGMs matched to the time of VT/VF episodes, and EGMs before spontaneous supraventricular tachycardia. During follow-up, 28 patients had 166 episodes of VT/VF. TWA/V was greater before VT/VF (62.9 ± 3.1 µV; n = 28) than during baseline rhythm (12.8 ± 1.8 µV; P < 0.0001; n = 62), during rapid pacing (14.5 ± 2.0 µV; P < 0.0001; n = 52), before supraventricular tachycardia (27.5 ± 6.1 µV; P < 0.0001; n = 9), or during time-matched ambulatory controls (12.3 ± 3.5 µV; P < 0.0001; n = 16). By logistic regression, the odds of VT/VF increased by a factor of 2.2 for each 10-µV increment in TWA/V (P < 0.0001). CONCLUSIONS: In implantable cardioverter-defibrillator patients, EGM TWA/V is greater before spontaneous VT/VF than in control recordings. Future implantable cardioverter-defibrillators that measure EGM TWA/V continuously may warn patients and initiate pacing therapies to prevent VT/VF.

Psidium guajava Linn confers gastro protective effects on rats.

BACKGROUND AND OBJECTIVES: The best alternatives to synthetic medicines, available, for the treatment of gastric ulcer disorders, are the natural products found in plants. They are known to exhibit a variety of activities. The present study is aimed at the screening of Psidium (P.) guajava Linn for its gastro protective effect. MATERIAL AND METHODS: The methanol extracts of the leaves of P. guajava were tested in three different ulcer models viz. aspirin (ASP), pyloric ligation (PL) and ethanol (EtoH) induced ulcer models in rats. RESULTS AND DISCUSSION: The treatment of P. guajava at varying doses (100 mg/kg and 200 mg/kg) significantly (p < 0.001) inhibited the gastric lesions induced by ASP (70.5%), PL (65.07%) and EtoH (70.4%) respectively and the potency was found to be equivalent as compared to the standard drug, omeprazole. Reduction in the gastric secretory volume, acid secretion and increased gastric pH were the factors observed in treated rats. The presence of volatile oil, flavonoids and saponins present in the extracts of P. guajava may be responsible for the anti-ulcer property exhibited. CONCLUSIONS: The results further suggest that P. guajava possess gastro protective as well as ulcer healing properties which might also be due to its anti-secretory properties.

The relationship between the high-risk disordered eating and social network navigation among Saudi college females during the COVID pandemic.

Background: Disordered eating behaviors (DEBs) are complex health issues that may lead to negative physical and mental health outcomes among college students. More studies should be directed toward the screening of DEBs. This study aimed to determine the prevalence of DEBs among Saudi female university students and their association with social networking site (SNSs) usage and composite lifestyle behaviors during the unprecedented period of COVID-19. Methods: This cross-sectional study included 445 females recruited using stratified random sampling. The participants self-reported demographic, social, medical, and lifestyle data and completed the validated Arabic version of the Eating Attitudes Test-26, Social Networking Sites (SNSs) Usage Questionnaire, Bergen Social Media Addiction Scale, and Body Shape Questionnaire. Results: The prevalence of DEBs was 27.2% among the female students at Taif University. From the pre-pandemic period until the current time, the DEBs-risk group had a significantly higher SNS navigation rate (36.4%) than the normal group (20.4%) (X 2 = 30.015, p = 0.001). The regression analysis revealed that females with a significant body image concern, higher number of SNSs friends, and frequent visits to SNSs, and those seeking social-dependent information in relation to weight loss/dieting were more likely to develop DEBs (Overall Model: Chi-Square X 2 = 158.071, p < 0.000**). Conclusions: SNSs usage and DEBs were associated during the COVID-pandemic. However, the composite lifestyle score did not demonstrate a significant association with DEBs among the female students at Taif University. Investigating the magnitude of DEBs and understanding the role of SNS are essential for preventing disordered eating among young females.

Noninvasive electrocardiographic imaging for cardiac electrophysiology and arrhythmia.

Over 7 million people worldwide die annually from erratic heart rhythms (cardiac arrhythmias), and many more are disabled. Yet there is no imaging modality to identify patients at risk, provide accurate diagnosis and guide therapy. Standard diagnostic techniques such as the electrocardiogram (ECG) provide only low-resolution projections of cardiac electrical activity on the body surface. Here we demonstrate the successful application in humans of a new imaging modality called electrocardiographic imaging (ECGI), which noninvasively images cardiac electrical activity in the heart. In ECGI, a multielectrode vest records 224 body-surface electrocardiograms; electrical potentials, electrograms and isochrones are then reconstructed on the heart's surface using geometrical information from computed tomography (CT) and a mathematical algorithm. We provide examples of ECGI application during atrial and ventricular activation and ventricular repolarization in (i) normal heart (ii) heart with a conduction disorder (right bundle branch block) (iii) focal activation initiated by right or left ventricular pacing, and (iv) atrial flutter.

Testicular abscess caused by Salmonella para-typhi.

This case is the first report of a bacteriologically proven testicular abscess in a child caused by Salmonella paratyphi 'A' in Pakistan that clinically simulates a testicular tumour. The case also emphasises that a course of 2 weeks antibiotic is sufficient for testicular abscess if complete surgical debridement is done.

Exosomes isolated from two different cell lines using three different isolation techniques show variation in physical and molecular characteristics.

Exosomes are the nanoscopic lipid bi-layered extracellular vesicles with the potential to be utilized as targeted therapeutics. In our investigation, we compared three major exosome isolation techniques that were Total Exosome Isolation reagent (TEI), Protein organic solvent precipitation (PROSPR) and differential ultracentrifugation (UC) based on the biophysical and physicochemical characteristics of exosomes isolated from COLO 205 and MCF-7 cancer cell's conditioned media with an aim to select a suitable method for translational studies. 3D image analysis and particle size distribution of exosomes from their HRTEM images depicted the morphological differences. Molecular and analytical characterization of exosomes using western blotting, Raman and ATR-FTIR spectroscopy and the multivariate analysis on the spectral data obtained, assessed for better molecular specifications and purity of particle. TEI method isolated exosomes with higher exosomal yield, purity, and recovery directly translatable into drug delivery and targeted therapeutics whereas ultracentrifuge had good recovery of particle morphology but showed particle aggregation and yielded exosomes with smaller mean size. PROSPR technique isolated a mixture of EVs, showed lower protein recovery in PAGE and western blotting but higher spectroscopic protein to lipid ratio and distinguishable EV population in multivariate analysis compared to exosomes isolated by TEI and UC. This comparative study should help in choosing a specific exosome isolation technique required for the objective of downstream applications.

Extraction and Evaluation of Corpus Callosum from 2D Brain MRI Slice: A Study with Cuckoo Search Algorithm.

The work proposes a computer-based diagnosis method (CBDM) to delineate and assess the corpus callosum (CC) segment from the 2-dimensional (2D) brain magnetic resonance images (MRI). The proposed CBDM consists of two parts: (1) preprocessing and (2) postprocessing sections. The preprocessing tools have a multithreshold technique with the chaotic cuckoo search (CCS) algorithm and a preferred threshold procedure. The postprocessing employs a delineation process for extracting the CC section. The proposed CBDM finally extracts the vital CC parameters, such as total brain area (TBA) and CC area (CCA) to classify the considered 2D MRI slices into the control and autism spectrum disorder (ASD) groups. This attempt considers the benchmark brain MRI database which includes ABIDE and MIDAS for the experimental investigation. The results obtained with ABIDE dataset are further confirmed against the fuzzy C-means driven level set (FCM + LS) and multiphase level set (MLS) technique and the proposed CBDM with Shannon entropy along with active contour (SE + AC) presented improved result in comparison to the existing methodologies. Further, the performance of CBDM is confirmed on MIDAS and clinical dataset. The experimental outcomes approve that the proposed CBDM extracts the CC section from the 2D MR brain images that have higher accuracy compared to alternative techniques.

Age, Disease Severity and Ethnicity Influence Humoral Responses in a Multi-Ethnic COVID-19 Cohort.

The COVID-19 pandemic has affected all individuals across the globe in some way. Despite large numbers of reported seroprevalence studies, there remains a limited understanding of how the magnitude and epitope utilization of the humoral immune response to SARS-CoV-2 viral anti-gens varies within populations following natural infection. Here, we designed a quantitative, multi-epitope protein microarray comprising various nucleocapsid protein structural motifs, including two structural domains and three intrinsically disordered regions. Quantitative data from the microarray provided complete differentiation between cases and pre-pandemic controls (100% sensitivity and specificity) in a case-control cohort (n = 100). We then assessed the influence of disease severity, age, and ethnicity on the strength and breadth of the humoral response in a multi-ethnic cohort (n = 138). As expected, patients with severe disease showed significantly higher antibody titers and interestingly also had significantly broader epitope coverage. A significant increase in antibody titer and epitope coverage was observed with increasing age, in both mild and severe disease, which is promising for vaccine efficacy in older individuals. Additionally, we observed significant differences in the breadth and strength of the humoral immune response in relation to ethnicity, which may reflect differences in genetic and lifestyle factors. Furthermore, our data enabled localization of the immuno-dominant epitope to the C-terminal structural domain of the viral nucleocapsid protein in two independent cohorts. Overall, we have designed, validated, and tested an advanced serological assay that enables accurate quantitation of the humoral response post natural infection and that has revealed unexpected differences in the magnitude and epitope utilization within a population.

Is surface ECG a useful surrogate for subcutaneous ECG?

BACKGROUND: Surface electrocardiograms (ECGs) have been used as surrogates for subcutaneous ECGs to optimize and evaluate subcutaneous devices, but differences between surface and subcutaneous ECGs remain poorly understood. This study evaluated the correspondence between surface and subcutaneous ECGs in Reveal Plus (Medtronic Inc., Minneapolis, MN, USA) patients during various maneuvers. METHODS: Surface electrodes were placed over the Reveal electrodes of 48 subjects (23 men, age 60 +/- 14.3 years, body mass index 27 +/- 4.9 kg/m(2), implant time 45 +/- 29 weeks). Surface and subcutaneous ECGs were recorded simultaneously for 30 seconds during rest, isometric myopotential noise (pushing palms together), and artifact-inducing maneuvers (repetitive displacement of device, chest thumping on device, arm flaps, handshake, hallwalk). RESULTS: During rest, subcutaneous and surface ECGs were highly correlated (R = 0.96), had similar R-wave amplitude (487 +/- 40 vs 507 +/- 49 microV, NS), and signal-to-noise ratio (SNR) (13.4 +/- 0.8 vs 13.5 +/- 0.7, NS). During myopotential noise, subcutaneous and surface ECGs were highly correlated (R = 0.91) and had similar SNR (10.0 +/- 0.6 vs 9.7 +/- 0.6, NS). During artifact-inducing maneuvers, subcutaneous and surface ECGs were less correlated (R = 0.82 displacement, 0.84 chest thumping, 0.93 arm flaps, 0.90 handshake, 0.92 hallwalk) with subcutaneous SNR significantly higher than surface (11.4 +/- 0.7 vs 9.9 +/- 0.7 displacement, 11.1 +/- 0.6 vs 8.4 +/- 0.6 chest thumping, 11.5 +/- 0.4 vs 10.3 +/- 0.5 arm flaps, 9.5 +/- 0.4 vs 8.4 +/- 0.4 handshake, 12.0 +/- 0.4 vs 10.0 +/- 0.4 hallwalk, P < 0.05). CONCLUSION: Surface ECGs are adequate surrogates for subcutaneous ECGs in situations free from motion artifacts but not in situations involving movement of the device, surface electrodes, or recording equipment. During artifact-inducing maneuvers, subcutaneous ECGs are of higher quality and less susceptible to artifacts than surface ECGs.

First principles calculations of the thermodynamic stability of Ba, Zr, and O vacancies in BaZrO3.

The temperature dependence of the stability of bulk BaZrO3 (BZO) and of the vacancies in this material are investigated by considering phonon contributions to the free energy. The stability diagram of BZO is determined for different chemical environments. With increasing temperature the stability region becomes smaller which is particularly caused by the strong temperature dependence of the chemical potential of gaseous oxygen. The free formation energy of Ba, Zr, and O vacancies in BZO is calculated for all possible charge states and for different atomic reservoirs. While the free formation energy of Zr vacancies is strongly influenced by temperature a weaker dependence is found for Ba and O vacancies. This also has an effect on the charge transition levels at different temperatures. The present results demonstrate that O poor reservoir conditions and a Fermi level close to the valence band maximum favour a high concentration of doubly positively charged O vacancies which is a prerequisite to get a large number of protonic defects and good proton conductivity. In such a chemical environment the number of Ba and Zr vacancies is low so that Ba and Zr deficiencies are not an important issue and BZO remains sufficiently stable.

Extracorporeal shock wave lithotripsy versus ureteroscopy for management of pediatric nephrolithiasis in upper urinary tract stones: multi-institutional outcomes of efficacy and morbidity.

INTRODUCTION: As the incidence of pediatric nephrolithiasis rises, understanding the efficacy and morbidity of surgical treatment options is critical. Currently, there are limited comparative data assessing shock wave lithotripsy (SWL) and ureteroscopy (URS) outcomes in children. OBJECTIVE: The objective of this study was to compare stone clearance, 30-day emergency department visits, and the number of general anesthetics required per stone treatment for both modalities. STUDY DESIGN: A multi-institutional retrospective review of children presenting for either URS or SWL between 2000 and 2017 was performed. Stone clearance, need for retreatment, the number of anesthetics, as well as the number and reason for emergency room visit were captured and compared between groups. Multivariate statistical analysis accounting for age, stone location, stone diameter, pre-intervention stent, and provider volume was performed for adjusted analysis. RESULTS: A total of 84 SWL and 175 URS procedures were included. Complete stone clearance and rates of residual stone fragments <4 mm after final procedure for SWL were 77.0% and 90.8% and for URS were 78.5% and 91.7%, respectively. Retreatment rates for both procedures were not significantly different (17.9% SWL vs. 18.9% URS, P = 0.85). Children who underwent SWL had lower rates of emergency room visits for infections (0% vs. 5.1%, P = 0.03) and flank pain (3.6% vs. 10.9%, P = 0.05) and required fewer general anesthetics per treatment (1.2 vs. 2.0, P < 0.01) than those who underwent URS (Figure). DISCUSSION: Stone clearance after both the initial and final treatments and need for repeat interventions were similar between surgical modalities. However, SWL carries less morbidity than URS. Specifically, patients who underwent SWL experienced lower rates of ED visits for urinary tract infection and for flank pain, parallel to conclusions in current comparative literature. In addition, SWL requires less general anesthetics (2.0 vs. 1.2), secondary to lower rates of ureteral stent placement and removal. Data on the potential risk of general anesthetics to neurodevelopment support thoughtful utilization of these medications. Limitations of this study include its retrospective nature and the prolonged 20-year time period over which data were collected. CONCLUSIONS: When adjusting for confounders, SWL and URS achieve similar stone clearance. In the setting of equivalent efficacy, considerations regarding necessity of repeat interventions, morbidity of anesthesia, and complications should be integrated into clinical practice.

Binuclear ruthenium(III) Schiff base complexes bearing N(4)O(4) donors and their catalytic oxidation of alcohols.

An interesting series of binuclear ruthenium(III) Schiff base complexes bearing bis-salophen/bis-naphophen units of the general composition [(EPh(3))(X)Ru-L-Ru(X)(EPh(3))] (where E=P or As; X=Cl or Br; L=binucleating dianionic tetradentate ligands) have been synthesized and characterized by analytical (elemental analysis, magnetic susceptibility measurements), spectral (FT-IR, UV-vis and EPR) and electrochemical methods. These ruthenium(III) complexes have two N(2)O(2) metal binding sites, which are linked to each other with a biphenyl bridge and acts as potential catalyst for oxidation of wide range of primary and secondary alcohols to corresponding aldehydes or ketones with moderate to high conversion in the presence of N-methylmorpholine-N-oxide (NMO). The formation of high-valent Ru(V)=O species as a catalytic active intermediate is proposed for the catalytic processes.

Noninvasive electrocardiographic imaging of arrhythmogenesis: insights from modeling and human studies.

BACKGROUND: Sudden cardiac death remains the leading cause of death, claiming more than 1000 lives per day in the United States alone. Noninvasive means to diagnose rhythm disorders of the heart have relied heavily on the 12-lead electrocardiogram and, to a lesser extent, on higher-resolution body-surface mapping. These lack sensitivity and specificity due to the smoothing effect of the torso volume conductor. In contrast, noninvasive electrocardiographic imaging (ECGI) reconstructs potentials, electrograms, and activation sequences directly on the heart surface from body-surface electrocardiograms and has been applied in animal as well as clinical studies. This presentation summarizes the application of ECGI for imaging epicardial arrhythmogenic substrates and associated properties, in particular, dispersion of myocardial repolarization, fractionated electrograms, and heterogeneous multipolar potential distributions. METHODS: Electrocardiographic imaging was evaluated in a canine model of temperature-induced dispersion of myocardial repolarization through localized warming and cooling and in 3 patients with preserved left ventricular ejection fraction (>or=50%) undergoing open heart surgery. Noninvasively reconstructed epicardial potentials, electrograms (and derived measures), as well as activation sequences were compared with their measured counterparts. RESULTS: Epicardial measures of dispersion of repolarization (activation recovery intervals [ARIs] and QRST integrals) accurately reflected the underlying repolarization properties: prolonged ARIs and increased QRST (warming), shortened ARIs and decreased QRST (cooling), and gradients of adjacent prolonged and shortened ARIs (increased and decreased QRST) during simultaneous warming and cooling. In open-heart surgery patients, ECGI reflected the underlying arrhythmogenic substrate by noninvasively reconstructing fractionated electrograms (cross-correlation with measured electrograms = 0.72 +/- 0.25), regions of heterogeneous multipolar potential distributions, and areas of slow conduction. CONCLUSION: These studies demonstrate that ECGI can capture and localize noninvasively important electrophysiologic properties of the heart. Its clinical significance lies in mapping arrhythmogenic substrates, evaluation and guidance of therapy, and risk stratification.

Evaluation of a new electrochemical sensor for selective detection of non-enzymatic hydrogen peroxide based on hierarchical nanostructures of zirconium molybdate.

The construction and characterization of selective and sensitive non-enzymatic hydrogen peroxide (H2O2) electrochemical sensor based on sphere-like zirconium molybdate (ZrMo2O8) nanostructure are reported for the first time. The sphere-like ZrMo2O8 were prepared via a simple hydrothermal route followed by annealing process. The structural and morphological properties were investigated by various analytical and spectroscopic techniques such as XRD, Raman, SEM, EDX, TEM, and XPS analysis. Furthermore, the electrochemical properties were investigated by cyclic voltammetry and amperometric techniques. The obtained results displayed that the prepared ZrMo2O8 materials hold excellent-crystallinity, well-defined sphere-like formation and demonstrated superior electrochemical properties. Interestingly, the electrochemical H2O2 sensor was constructed based on ZrMo2O8 nanostructure on the glassy carbon electrode exhibited wide linear response ranges, good sensitivity and lower detection limit (LOD). The estimated sensitivity, wide linear ranges and LOD of the fabricated electrochemical sensor was 2.584µAµM-1cm-2, 0.05-523, 543-3053µM and 0.01µM respectively. The proposed sensor had excellent selectivity even in the presence of biologically co-interfering substances such as uric acid, dopamine, ascorbic acid and glucose. This effortless, fast, inexpensive technique for constructing a modified electrode is a gorgeous approach to the growth of new sensors.

Electrocardiographic imaging of cardiac resynchronization therapy in heart failure: observation of variable electrophysiologic responses.

BACKGROUND: Cardiac resynchronization therapy (CRT) for congestive heart failure patients with delayed left ventricular (LV) conduction is clinically beneficial in approximately 70% of patients. Unresolved issues include patient selection, lead placement, and efficacy of LV pacing alone. Being an electrical approach, detailed electrical information during CRT is critical to resolving these issues. However, electrical data from patients have been limited because of the requirement for invasive mapping. OBJECTIVES: The purpose of this study was to provide observations and insights on the variable electrophysiologic responses of the heart to CRT using electrocardiographic imaging (ECGI). METHODS: ECGI is a novel modality for noninvasive epicardial mapping. ECGI was conducted in eight patients undergoing CRT during native rhythm and various pacing modes. RESULTS: In native rhythm (six patients), ventricular activation was heterogeneous, with latest activation in the lateral LV base in three patients and in the anterolateral, midlateral, or inferior LV in the remainder of patients. Anterior LV was susceptible to block and slow conduction. Right ventricular pacing improved electrical synchrony in two of six patients. LV pacing in three of four patients involved fusion with intrinsic excitation resulting in electrical resynchronization similar to biventricular pacing. Although generally electrical synchrony improved significantly with biventricular pacing, it was not always accompanied by clinical benefit. CONCLUSION: Results suggest that (1) when accompanied by fusion, LV pacing alone can be as effective as biventricular pacing for electrical resynchronization; (2) right ventricular pacing is not effective for resynchronization; and (3) efficacy of CRT depends strongly on the patient-specific electrophysiologic substrate.

Noninvasive electrocardiographic imaging (ECGI): comparison to intraoperative mapping in patients.

OBJECTIVES/BACKGROUND: Cardiac arrhythmias are a leading cause of death and disability. Electrocardiographic imaging (ECGI) is a noninvasive imaging modality that reconstructs potentials, electrograms, and isochrones on the epicardial surface from body surface measurements. We previously demonstrated in animal experiments through comparison with simultaneously measured epicardial data the high accuracy of ECGI in imaging cardiac electrical events. Here, images obtained by noninvasive ECGI are compared to invasive direct epicardial mapping in open heart surgery patients. METHODS: Three patients were studied during sinus rhythm and right ventricular endocardial and epicardial pacing (total of five datasets). Body surface potentials were acquired preoperatively or postoperatively using a 224-electrode vest. Heart-torso geometry was determined preoperatively using computed tomography. Intraoperative mapping was performed with two 100-electrode epicardial patches. RESULTS: Noninvasive potential maps captured epicardial breakthrough sites and reflected general activation and repolarization patterns, localized pacing sites to approximately 1 cm and distinguished between epicardial and endocardial origin of activation. Noninvasively reconstructed electrogram morphologies correlated moderately with their invasive counterparts (cross correlation = 0.72 +/- 0.25 [sinus rhythm], 0.67 +/- 0.23 [endocardial pacing], 0.71 +/- 0.21 [epicardial pacing]). Noninvasive isochrones captured the sites of earliest activation, areas of slow conduction, and the general excitation pattern. CONCLUSIONS: Despite limitations due to nonsimultaneous acquisition of the surgical and noninvasive data under different conditions, the study demonstrates that ECGI can capture important features of cardiac electrical excitation in humans noninvasively during a single beat. It also shows that general excitation patterns and electrogram morphologies are largely preserved in open chest conditions.