Search results for "Repolarization"
showing 10 items of 21 documents
Dual-sided Mapping During Global Stretch Using a Custom Miniaturized Endocardial Balloon with a Multipurpose Multichannel Acquisition System for Prec…
2017
Acute regional myocardial stretch (STR) is known to induce myocardial electrophysiological modifications via mechano-electric feedback (MEF), including abnormal repolarization, premature excitation and increased complexity of activation leading to the initiation, maintenance and acceleration of arrhythmic events. Due to technical limitations little is known about intramural and endo-epicardial (ENDO-EPI) phenomena during these events. Understanding ENDO-EPI modifications produced by STR through MEF may require a dual-sided approach to simultaneously correlate macroscopic surface modifications and their independent or interconnected components. For that purpose, we optically mapped (OM) the …
The Disease-Specific Phenotype in Cardiomyocytes Derived from Induced Pluripotent Stem Cells of Two Long QT Syndrome Type 3 Patients
2013
Long QT syndromes (LQTS) are heritable diseases characterized by prolongation of the QT interval on an electrocardiogram, which often leads to syncope and sudden cardiac death. Here we report the generation of induced pluripotent stems (iPS) cells from two patients with LQTS type 3 carrying a different point mutation in a sodium channel Nav1.5 (p.V240M and p.R535Q) and functional characterization of cardiomyocytes (CM) derived from them. The iPS cells exhibited all characteristic properties of pluripotent stem cells, maintained the disease-specific mutation and readily differentiated to CM. The duration of action potentials at 50% and 90% repolarization was longer in LQTS-3 CM as compared t…
Ventricular remodelling in rabbits with sustained high-fat diet.
2013
Aim Excess weight gain and obesity are one of the most serious health problems in the western societies. These conditions enhance risk of cardiac disease and have been linked with increased prevalence for cardiac arrhythmias and sudden death. Our goal was to study the ventricular remodelling occurring in rabbits fed with high-fat diet (HFD) and its potential arrhythmogenic mechanisms. Methods We used 15 NZW rabbits that were randomly assigned to a control (n = 7) or HFD group (n = 8) for 18 weeks. In vivo studies included blood glucose, electrocardiographic, and echocardiographic measurements. Optical mapping was performed in Langendorff-perfused isolated hearts. Results Body weight (3.69 ±…
T-wave alternans analysis improvement by means of curve alignment prior to distance calculation.
2007
Tracking of repolarization instabilities in the ECG, such as T-wave alternans (TWA), has become a popular non-invasive method to assess the vulnerability to malignant arrhythmic events. These instabilities are usually characterized by small amplitude changes and their measurement is difficult due to the presence of noise and artifacts. Several methods have been recently proposed to address this problem. Most of them are based on amplitude analysis of beat-to-beat alternation of the T wave. This paper describes a preprocessing stage intended to be used prior to amplitude analysis and aimed at improving the alignment between consecutive T waves. This increases the accuracy of the difference c…
�ber den Einflu� von Thyroxin auf die Repolarisationsphase des Aktionspotentials vom Meerschweinchenvorhof
1961
Mit intracellularen Mikroelektroden werden Aktionspotentiale von Meerschweinchenvorhofen in vitro abgeleitet. Nach Vorbehandlung der Tiere mit Thyroxin (5 Tage lang 1 mg dl-Thyroxin je Kilogramm) ist die Repolarisationsphase und damit die Refraktarperiode im Vergleich zu Kontrolltieren bei gleicher Schlagfrequenz verkurzt.
ST segment elevations: Always a marker of acute myocardial infarction?
2013
AbstractChest pain is one of the chief presenting complaints among patients attending Emergency department. The diagnosis of acute myocardial infarction may be a challenge. Various tools such as anamnesis, blood sample (with evaluation of markers of myocardial necrosis), ultrasound techniques and coronary computed tomography could be useful. However, the interpretation of electrocardiograms of these patients may be a real concern. The earliest manifestations of myocardial ischemia typically interest T waves and ST segment. Despite the high sensitivity, ST segment deviation has however poor specificity since it may be observed in many other cardiac and non-cardiac conditions. Therefore, when…
Targeted Repolarization of Tumor‐Associated Macrophages via Imidazoquinoline‐Linked Nanobodies
2021
Abstract Tumor‐associated macrophages (TAMs) promote the immune suppressive microenvironment inside tumors and are, therefore, considered as a promising target for the next generation of cancer immunotherapies. To repolarize their phenotype into a tumoricidal state, the Toll‐like receptor 7/8 agonist imidazoquinoline IMDQ is site‐specifically and quantitatively coupled to single chain antibody fragments, so‐called nanobodies, targeting the macrophage mannose receptor (MMR) on TAMs. Intravenous injection of these conjugates result in a tumor‐ and cell‐specific delivery of IMDQ into MMRhigh TAMs, causing a significant decline in tumor growth. This is accompanied by a repolarization of TAMs to…
HIF-Overexpression and Pro-Inflammatory Priming in Human Mesenchymal Stromal Cells Improves the Healing Properties of Extracellular Vesicles in Exper…
2021
Extracellular vesicles (EVs) derived from mesenchymal stromal cells (MSCs) have therapeutic potential in the treatment of several immune disorders, including ulcerative colitis, owing to their regenerative and immunosuppressive properties. We recently showed that MSCs engineered to overexpress hypoxia-inducible factor 1-alpha and telomerase (MSC-T-HIF) and conditioned with pro-inflammatory stimuli release EVs (EVMSC-T-HIFC) with potent immunomodulatory activity. We tested the efficacy of EVMSC-T-HIFC to repolarize M1 macrophages (Mφ1) to M2-like macrophages (Mφ2-like) by analyzing surface markers and cytokines and performing functional assays in co-culture, including efferocytosis and T-cel…
Use of QT intervals for a more accurate diagnose of syncope and evaluation of syncope severity.
2014
Abstract BACKGROUND: This study aimed to evaluate the use of QT intervals, their diagnostic predictive value in patients with syncope and their relationship with syncope severity. METHODS: One hundred and forty nine patients with a diagnosis of syncope were admitted to Internal Medicine departments at the University of Palermo, Italy, between 2006 and 2012, and 140 control subjects hospitalised for other causes were enrolled. QT maximum, QT minimum, QTpeak, QT corrected, QT dispersion and Tpeak-to-Tend interval were compared between two groups. The paper medical records were used for scoring with San Francisco Syncope Rule (SFSR), Evaluation of Guidelines in SYncope Study (EGSYS) score and …
Global electrical heterogeneity as a predictor of cardiovascular mortality in men and women
2018
Aims The aim of this study was to investigate the contribution of depolarization and repolarization abnormalities, specially abnormalities in global electrical heterogeneity of heart in cardiovascular disease (CVD) and all-cause mortality. Methods and results Eight hundred and forty men and 911 women, average age of 63 years participated in this study with average follow-up was 14 years. Six electrocardiogram/vector electrocardiogram (ECG/VECG) markers QRS-duration, QTc-interval, QRST-angle, sum of absolute QRST integral (SAI QRST), T-wave roundness, and TV1-amplitude were estimated from VECG measurements. Hazard ratios (HRs) for CVD events (164 deaths) and all-cause mortality (383 deaths) …