P936Atrial remodeling in rat hearts after exposure to high-intensity infrasound

EP Europace ◽  
2020 ◽  
Vol 22 (Supplement_1) ◽  
Author(s):  
A Lousinha ◽  
G Pereira ◽  
G Borrecho ◽  
J Brito ◽  
A Oliveira De Carvalho ◽  
...  
Keyword(s):  
High Intensity ◽  
Connexin 43 ◽  
Noise Exposure ◽  
Experimental Studies ◽  
Blue Staining ◽  
P Value ◽  
Atrial Remodeling ◽  
Atrial Fibrosis ◽  
Rat Hearts ◽  
Arrhythmogenic Substrate

Abstract Background Noise is an important environmental risk factor. Industrial environments are rich in high-intensity infrasound (hi-IFS), which we have found to induce myocardial and coronary perivascular fibrosis in rats. Recently, a significant association between noise exposure and the incidence of atrial fibrillation (AF) was found in large cohort studies but the pathophysiology is unclear. Atrial fibrosis remains the cornerstone of atrial pathology in AF. Purpose: We hypothesized that rats exposed to hi-IFS develop atrial remodeling involving fibrosis and connexin 43, which we sought to evaluate. Material and Methods: Seventy-two Wistar rats, half exposed to hi-IFS (120dB, <20Hz) during a maximum period of 12 weeks and half age-matched controls, were studied. Atrial fibrosis was analyzed by Chromotrope-aniline blue staining. The immunohistochemical evaluation of Cx43 was performed using the polyclonal antibody connexin-43m diluted 1:1000 at 4ºC overnight. Digitized images were obtained with an optical microscope using 400× magnifications. The measurements were performed using image J software. A two-way ANOVA model was used to compare the groups. Results: The mean values of the ratio "atrial fibrosis / cardiomyocytes" increased to a maximum of 0,1095 ± 0,04 and 0,5408 ± 0,01, and of the ratio "CX43 / cardiomyocytes" decreased to 0,0834 ± 0,03 and 0,0966 ± 0,03, respectively in IFS-exposed rats and controls. IFS-exposed rats exhibited a significantly higher ratio of fibrosis (p < 0,001) and lower ratio of Cx43 (p = 0,009). Conclusion: High-intensity infrasound exposure triggers atrial remodeling in rat hearts. Whether this finding correlates to arrhythmogenic substrate in noise induced-AF is not known and reinforces the need for further experimental studies. Table 1 Time of exposure (weeks) Group IFS (n = 36) Group CTL (n = 36) P value Ratio of atrial fibrosis / cardiomyocytesMean ± SD 1 0,0896 ± 0,04 0,0460 ± 0,03 0,007 6 0,0936 ± 0,03 0,0491 ± 0,01 0,001 12 0,1095 ± 0,04 0,0541 ± 0,01 0,001 Ratio of atrial CX43 / cardiomyocytesMean ± SD 1 0,1100 ± 0,03 0,1371 ± 0,03 0,047 6 0,0829 ± 0,04 0,1036 ± 0,03 0,170 12 0,0834 ± 0,03 0,0966 ± 0,03 0,259 Mean ± SD of the two measured outcomes in the two groups. IFS – Infrasound; CTL – Control; SD – standard deviation; Cx43 – Connexin 43 Abstract Figure. Atrial fibrosis and Cx43 /cardiomyocytes

scholarly journals Atrial fibrosis and decreased connexin 43 in rat hearts after exposure to high-intensity infrasound

2020 ◽  
Vol 114 ◽  
pp. 104409
Author(s):  
Ana Lousinha ◽  
Gonçalo Pereira ◽  
Gonçalo Borrecho ◽  
José Brito ◽  
António Oliveira de Carvalho ◽  
...  
Keyword(s):  
High Intensity ◽  
Connexin 43 ◽  
Atrial Fibrosis ◽  
Rat Hearts

scholarly journals Overexpression of MiR-29b-3p Inhibits Atrial Remodeling in Rats by Targeting PDGF-B Signaling Pathway

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Xiangwei Lv ◽  
Pan Lu ◽  
Yisen Hu ◽  
Tongtong Xu
Keyword(s):  
Western Blot ◽  
Signaling Pathway ◽  
Connexin 43 ◽  
Collagen I ◽  
Luciferase Reporter ◽  
Atrial Remodeling ◽  
Ang Ii ◽  
Atrial Fibrosis ◽  
Intravenous Injections ◽  
Masson Staining

Purpose. Studies have found that microRNAs (miRNAs) are closely associated with atrial fibrillation, but their specific mechanism remains unclear. The purpose of this experiment is to explore the function of miR-29b-3p in regulating atrial remodeling by targeting PDGF-B signaling pathway and thereby also explore the potential mechanisms. Methods. We randomly divided twenty-four rats into four groups. Caudal intravenous injections of angiotensin-II (Ang-II) were administered to establish atrial fibrosis models. Expressions of miR-29b-3p and PDGF-B were then tested via RT-PCR, western blot, and immunohistochemistry. Binding sites were then analyzed via the bioinformatics online software TargetScan and verified by Luciferase Reporter. We used Masson staining to detect the degree of atrial fibrosis, while immunofluorescence and western blot were used to detect the expressions of Collagen-I and a-SMA. We used immunohistochemistry and western blot to detect the expression of connexin 43 (Cx43). Results. In comparison with the Ang-II group, miR-29b-3p was seen to lower the degree of atrial fibrosis, decrease the expression of fibrosis markers such as Collagen-I and a-SMA, and increase the protein expression of Cx43. MiR-29b-3p can lower the expression of PDGF-B, while the Luciferase Reporter showed that PDGF-B is the verified target gene of miR-29b-3p. Conclusions. MiR-29b-3p was able to reduce atrial structural and electrical remodeling in the study’s rat fibrosis model. This biological function may be expressed through the targeted regulation of the PDGF-B signaling pathway.

scholarly journals Interleukin-6-Mediated-Ca2+ Handling Abnormalities Contributes to Atrial Fibrillation in Sterile Pericarditis Rats

2021 ◽  
Vol 12 ◽  
Author(s):  
Jie Liao ◽  
Shaoshao Zhang ◽  
Shuaitao Yang ◽  
Yang Lu ◽  
Kai Lu ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Ex Vivo ◽  
Atrial Fibrosis ◽  
Regional Heterogeneity ◽  
Western Blots ◽  
Talcum Powder ◽  
Rat Hearts ◽  
Arrhythmogenic Substrate ◽  
Atrial Ectopy

Pre-existing Ca2+ handling abnormalities constitute the arrhythmogenic substrate in patients developing postoperative atrial fibrillation (POAF), a common complication after cardiac surgery. Postoperative interleukin (IL)-6 levels are associated with atrial fibrosis in several animal models of POAF, contributing to atrial arrhythmias. Here, we hypothesize that IL-6-mediated-Ca2+ handling abnormalities contribute to atrial fibrillation (AF) in sterile pericarditis (SP) rats, an animal model of POAF. SP was induced in rats by dusting atria with sterile talcum powder. Anti-rat-IL-6 antibody (16.7 μg/kg) was administered intraperitoneally at 30 min after the recovery of anesthesia. In vivo electrophysiology, ex vivo optical mapping, western blots, and immunohistochemistry were performed to elucidate mechanisms of AF susceptibility. IL-6 neutralization ameliorated atrial inflammation and fibrosis, as well as AF susceptibility in vivo and the frequency of atrial ectopy and AF with a reentrant pattern in SP rats ex vivo. IL-6 neutralization reversed the prolongation and regional heterogeneity of Ca2+ transient duration, relieved alternans, reduced the incidence of discordant alternans, and prevented the reduction and regional heterogeneity of the recovery ratio of Ca2+ transient. In agreement, western blots showed that IL-6 neutralization reversed the reduction in the expression of ryanodine receptor 2 (RyR2) and phosphorylated phospholamban. Acute IL-6 administration to isolated rat hearts recapitulated partial Ca2+ handling phenotype in SP rats. In addition, intraperitoneal IL-6 administration to rats increased AF susceptibility, independent of fibrosis. Our results reveal that IL-6-mediated-Ca2+ handling abnormalities in SP rats, especially RyR2-dysfunction, independent of IL-6-induced-fibrosis, early contribute to the development of POAF by increasing propensity for arrhythmogenic alternans.

scholarly journals Interatrial block is related to atrial dysfunction in hypertensive subjects

2021 ◽  
Vol 22 (Supplement_1) ◽  
Author(s):  
L Tirapu Sola ◽  
F Loncaric ◽  
M Mimbrero ◽  
LG Mendieta ◽  
L Nunno ◽  
...  
Keyword(s):  
Global Longitudinal Strain ◽  
Female Gender ◽  
Left Ventricular ◽  
P Wave ◽  
P Value ◽  
Atrial Remodeling ◽  
Maximal Volume ◽  
Surface Ecg ◽  
Interatrial Block ◽  
And Function

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): La Marató TV3 Background Interatrial block (IAB), a delay of conduction of the sinus stimulus from right to left atria (LA), is defined as surface ECG P-wave duration ≥120 ms. Arterial hypertension (AH) and IAB have been related to development of atrial fibrillation. Aim To investigate the IAB prevalence in a cohort of AH patients and relate it to LA function. Methods 162 patients with well-regulated AT were included. 12-lead ECG were performed and analysed with a digital caliper. 2D and 3D echocardiography were performed, and LA function assessed with speckle-tracking deformation imaging.  Results The median age was 56 ± 6 years, 54% were males. Average duration of AH was 10 ± 6 years. IAB was seen in 25% of AH patients.  The comparison between groups is shown in Table 1. There were no differences in demographic characteristics,  QRS complex duration (p = 0.179) or left ventricular (LV) size and function between subgroups. LA was enlarged in IAB patients, which was coupled with impairment of the LA reservoir strain.  Conclusion Our results show considerable prevalence of IAB in AH patients. The demonstrated LA enlargement and function impairment is not associated with LV dysfunction, therefore suggesting an independent role of IAB in atrial remodeling. Table 1 Interatrial block P value Yes (n= 40) No (n= 142) Age 59 (54-62) 57 (53-61) 0.157 Female gender 16 (40%) 58 (48%) 0.467 Duration of Hypertension (years) 10 (6-12) 8 (5-15) 0.421 Systolic blood pressure (mmHg) 136 (125-150) 136 (127-147) 0.799 Diabetes 3 (8%) 16 (13%) 0.410 LVEDV (mL) 73 (63-91) 71 (57-87) 0.424 E/A 0.98 (0.84-1.25) 0.94 (0.79-1.11) 0.230 E/e’ 7.0 (4.9-8.9) 6.6 (5.2-8.4) 0.779 LVEF (%) 63 ± 7 64 ± 6 0.864 LV global longitudinal strain (%) 21.22 ± 2.63 21.19 ± 2.30 0.932 3D LA maximal volume (mL/m2) 36 (30-39) 30 (26-37) 0.028 3D LA minimal volume (mL/m2) 16 (12-18) 14 (11-17) 0.050 LA reservoir strain (%) 27.64 (24.90-31.23) 29.55 (26.17-32.81) 0.032 LA conduit strain (%) 13.91 (10.71-15.47) 14.37 (11.75-16.72) 0.192 LA contractile strain (%) 14.46 (11.86-16.59) 15.52 (13.66-16.96) 0.079 LVEDV Left Ventricular End Dyastolic Volume

Experimental Studies on a Mineral Containing Titanium in Baoding Area

2013 ◽  
Vol 826 ◽  
pp. 34-37 ◽  
Author(s):  
Guo Zhen Liu ◽  
Shu Juan Dai ◽  
Li Mei Bai ◽  
Yu Xin Ma ◽  
Yong Zhang
Keyword(s):  
Magnetic Separation ◽  
High Intensity ◽  
Ph Value ◽  
Experimental Studies ◽  
Mineral Processing ◽  
Shaking Table ◽  
Gravity Concentration

The main elements can be recovered for mineral processing in a mineral containing titanium of Baoding area were Ti, Fe and V, and the elements in the main gangue minerals were Si and Al. Gravity concentration, gravity concentration-high intensity magnetic separation and gravity concentration-flotation tests were performed on the ore sample respectively. The results showed that, in the test of shaking table, when the grinding fineness was -0.074mm 93%, the productivity of concentrate can reach 32.24%; when grinding fineness was -0.074mm 93%, after gravity concentration-magnetic separation, 30.25% of concentrate productivity can be attained; when the grinding fineness was -0.074mm 85%, after gravity concentration-flotation, the productivity of concentrate was 3.31%. Maybe it's the condition of the tests wasn't controlled well, especially adjusting pH value in the flotation stage, it's hard to control, so the results were not very good.

scholarly journals Glycolytic inhibition causes spontaneous ventricular fibrillation in aged hearts

2011 ◽  
Vol 301 (1) ◽  
pp. H180-H191 ◽  
Author(s):  
Norishige Morita ◽  
Jong-Hwan Lee ◽  
Aneesh Bapat ◽  
Michael C. Fishbein ◽  
William J. Mandel ◽  
...  
Keyword(s):  
Ventricular Fibrillation ◽  
Connexin 43 ◽  
Left Ventricular ◽  
Triggered Activity ◽  
Adult Rat ◽  
Rat Hearts ◽  
Intracellular Calcium Ion ◽  
Dependent Protein ◽  
Isolated Cardiac Myocytes ◽  
Delayed Afterdepolarizations

Selective glycolytic inhibition (GI) promotes electromechanical alternans and triggered beats in isolated cardiac myocytes. We sought to determine whether GI promotes triggered activity by early afterdepolarization (EAD) or delayed afterdepolarizations in intact hearts isolated from adult and aged rats. Dual voltage and intracellular calcium ion (Cai2+) fluorescent optical maps and single cell glass microelectrode recordings were made from the left ventricular (LV) epicardium of isolated Langendorff-perfused adult (∼4 mo) and aged (∼24 mo) rat hearts. GI was induced by replacing glucose with 10 mM pyruvate in oxygenated Tyrode's. Within 20 min, GI slowed Cai2+ transient decline rate and shortened action potential duration in both groups. These changes were associated with ventricular fibrillation (VF) in the aged hearts (64 out of 66) but not in adult hearts (0 out of 18; P < 0.001). VF was preceded by a transient period of focal ventricular tachycardia caused by EAD-mediated triggered activity leading to VF within seconds. The VF was suppressed by the ATP-sensitive K (KATP) channel blocker glibenclamide (1 μM) but not (0 out of 7) by mitochondrial KATP block. The Ca-calmodulin-dependent protein kinase II (CaMKII) blocker KN-93 (1 μM) prevented GI-mediated VF ( P < 0.05). Block of Na-Ca exchanger (NCX) by SEA0400 (2 μM) prevented GI-mediated VF (3 out of 6), provided significant bradycardia did not occur. Aged hearts had significantly greater LV fibrosis and reduced connexin 43 than adult hearts ( P < 0.05). We conclude that in aged fibrotic unlike in adult rat hearts, GI promotes EADs, triggered activity, and VF by activation of KATP channels CaMKII and NCX.

Modeling the operation of structures made of dispersed-reinforced concrete with an alternating dynamic load of high intensity

2021 ◽  
Vol 14 (3) ◽  
pp. 36-44
Author(s):  
S. Nikolenko ◽  
Svetlana Sazonova ◽  
Viktor Asminin
Keyword(s):  
Reinforced Concrete ◽  
Dynamic Load ◽  
High Intensity ◽  
Concrete Beam ◽  
Static Load ◽  
Dynamic Compression ◽  
Experimental Studies ◽  
Reinforced Concrete Beam ◽  
Beam Elements ◽  
Laminated Structures

A study of the properties of dispersed-reinforced concrete and a study of the effect of dispersed reinforcement on the operation of structures was carried out, mainly with a static load of the same sign. Based on the results of experimental studies, a comparison was made of the work of dispersed-laminated structures under alternating dynamic action of high intensity with the work of reinforced concrete beam elements under similar influences. The results of experimental studies of cubes and prisms for static and dynamic compression are also presented. The results of experimental studies allow us to conclude that there is a significant effect of dispersed reinforcement on the operation of structures under the investigated influences and the feasibility of combined reinforcement of structures. The use of dispersed reinforcement in structures will increase the resistance of structures to such influences.

Effect of high dose statin preloading on TIMI flow in patients presenting with ST-Elevation Myocardial Infarction undergoing Primary Percutaneous Coronary Intervention

QJM ◽  
2021 ◽  
Vol 114 (Supplement_1) ◽  
Author(s):  
K Eletriby ◽  
A Desoky ◽  
N Shawky ◽  
A Farag
Keyword(s):  
Myocardial Infarction ◽  
High Intensity ◽  
Coronary Intervention ◽  
Control Group ◽  
P Value ◽  
Primary Pci ◽  
Timi Flow ◽  
St Segment ◽  
Percutaneous Coronary ◽  
St Elevation

Abstract Aim and objectives The aim of this study was to assess the impact of high intensity statins used prior to primary PCI in patients presenting with acute STEMI (ST-elevation Myocardial Infarction) on myocardial perfusion and in-hospital MACE (major adverse cardiac events). Patients and Methods The study included 170 patients who presented with acute STEMI to the cardiology department of Ain Shams university hospitals and underwent primary PCI (percutaneous coronary intervention). They were divided into two groups where the first group received high intensity statins (40-80mg of atorvastatin or 20-40mg of rosuvastatin) besides guideline recommended therapy before primary PCI and the 2nd group served as a control group and received guideline recommended therapy, and high intensity statins after going back to the coronary care unit after primary PCI. Post interventional thrombolysis in myocardial infarction (TIMI) flow grade and myocardial blush grade (MBG) were recorded and ST-segment resolution was measured. Results The majority of patients in both groups had the LAD as the culprit vessel for their presentation. In the control group there were 4 patients with TIMI I flow and MBG I, 13 with TIMI II flow and MBG II and 68 with TIMI III flow and MBG III. Meanwhile in the cases group there was 1 patient with TIMI I flow and MBG I, 3 with TIMI II flow and MBG II and 81 with TIMI III flow and MBG III. This difference was statistically significant with a P value of 0.010. There were 34 patients in the cases group who showed complete ST-segment resolution (40%) vs 19 patients (22.4%) in the control group which was statistically significant with a P value of 0.013. In addition, ejection fraction measured by M-mode had values of Mean+-SD of 45.91 ± 5.49 in cases group vs 43.01 ± 8.80 in control group which was statistically significant with a P value of 0.011. There was not a statistically significant difference between the two groups regarding in-hospital death of all causes and stroke after primary PCI. Conclusion High intensity statin loading before primary PCI resulted in improved post-procedural TIMI flow, MBG, complete ST-segment resolution and ejection fraction as measured by M-mode but did not decrease incidence of in-hospital MACE.

Problems of Communication and Ear Protection in the Royal Marines

1970 ◽  
Vol 56 (1) ◽  
pp. 162-169
Author(s):  
M. R. Forrest ◽  
R. R. A. Coles
Keyword(s):  
High Intensity ◽  
Pure Tone ◽  
Noise Exposure ◽  
Simple Modification

AbstractA simple modification to the V.51R-type plug has enabled ease of communication to be combined with adequate protection against high-intensity noises, notably of gunfire origin. These Gundefenders were developed and tested in the laboratory by means of hard-walled artificial ears, cadaver ears, pure-tone and speech audiometric threshold shifts. Their performance was proved by means of series of TTS studies and communication trials. It is believed that these earplugs should now replace conventional earplugs for usage in all gunfire noise exposure situations in which the latter are normally used.

Abstract 16572: Association of Atrial Fibrosis With Major Adverse Cardiac Events in Patients With Non-valvular Atrial Fibrillation

Circulation ◽  
2015 ◽  
Vol 132 (suppl_3) ◽  
Author(s):  
Jordan B King ◽  
Mukul Singhal ◽  
Gagan Kaur ◽  
Kara Johnson ◽  
Christina Pacchia ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Major Adverse Cardiac Events ◽  
P Value ◽  
Advanced Degree ◽  
Atrial Fibrosis ◽  
Cardiac Events ◽  
Historical Cohort ◽  
Logistic Regression Models ◽  
Increased Risk ◽  
Adverse Cardiac Events

Background: Extensive of atrial fibrosis has been demonstrated to significantly predict success of catheter ablation. However, impact of extensive fibrosis on other aspects of patient care and long-term prognosis is unknown. Methods: We conducted a historical cohort study to assess the hypothesis that increased degree of atrial fibrosis is independently associated with major adverse cardiac events (MACE). We reviewed 853 patients with non-valvular atrial fibrillation (NVAF) and quantified fibrosis. Logistic regression models were used to evaluate the association of percent fibrosis on experiencing a MACE. Linear splines were utilized to allow the functional form of the exposure to vary at high (>15%) and low (<15%) fibrosis scores. The outcome of interest was a composite of MACE: myocardial infarction (MI), ischemic stroke (IS), or venous thromboembolism (VTE). Results: The mean age of the cohort was 66.2±12.4 with 66% male and 79% white. During a median follow-up of 2.9 years, 69 (8.1%), 46 (5.4%), 52 (6.1%), and 156 (18.3%) of patients experienced an MI, IS, VTE, or MACE, respectively. High fibrosis patients were more likely to be older, male, and have a higher CHA2DS2-VASc score. In the unadjusted analysis, increased fibrosis was associated with increased odds of a MI (OR [95% CI] P-Value: 1.30 [1.00, 1.68] 0.05) or any MACE (1.28 [1.06, 1.56] 0.01), but not with IS or VTE. After adjusting for potential confounders, increasing fibrosis levels had significantly increased odds of MI (1.53 [1.02, 2.28] 0.04) and VTE (1.52 [1.17, 2.86] <0.01) when fibrosis levels were above 15%. There was no significant association below 15%. The odds of a MACE was significant above 15% (1.64 [1.18, 2.27] <0.01) and across all fibrosis scores (1.23 [1.01, 1.49] 0.04), but was insignificant when only fibrosis levels below 15% were examined. Conclusions: Advanced degree of atrial fibrosis in patients with NVAF is independently associated with increased risk of MI, VTE and a composite of MACE.

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