Aim: Prolongation of ventricular repolarization is characteristic of myocardial cooling. In the present study, we investigated whether this prolongation is uniform or not throughout ventricular epicardium and how these hypothermia-induced changes express in the body surface potential distribution.
Methods: Epicardial and body surface potential mapping from 64 unipolar leads was carried out in 18 anaesthetized adult rabbits. Mild hypothermia documented by lowering the mediastinal and rectal temperature from 38 to 32 degrees C was elicited by perfusion of the mediastinum with cooled saline. Activation times, repolarization times and activation-recovery intervals were determined in each epicardial lead.
Results: Baseline activation-recovery intervals distributed non-uniformly on the ventricular epicardium, increasing progressively from the apex to the base and from the left ventricular (LV) sites to the right ventricular (RV) sites (P < 0.05), governing the repolarization sequence of ventricular epicardium. Heart cooling from 38 to 32 degrees C produced the heterogeneous prolongation of activation-recovery intervals which was more pronounced at the apex than at the base, and in the LV areas compared to the RV areas (P < 0.05). These nonuniform changes in local repolarization durations resulted in the development of base-to-apex repolarization sequence and inversion of the body surface potential distribution during the T wave.
Conclusion: Thus, under cooling the rabbit heart from 38 to 32 degrees C, the nonuniform prolongation of local repolarization durations resulted in the reversal of ventricular epicardial repolarization sequence which, in turn, was responsible for the inversion in the body surface potential distribution during the T wave.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1111/j.1748-1716.2008.01835.x | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Higher abdominal fat area associates with lower donor kidney function before and after living kidney donation.
Sci Rep
December 2024
Department of Surgery, Division of Transplant Surgery, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
Central body fat distribution affects kidney function. Abdominal fat measurements using computed tomography (CT) may prove superior in assessing body composition-related kidney risk in living kidney donors. This retrospective cohort study including 550 kidney donors aimed to determine the association between CT-measured abdominal fat areas and kidney function before and after donor nephrectomy.
View Article and Find Full Text PDFThe Mediating Roles of Objectified Body Consciousness About Acceptance of Cosmetic Surgery Among International Students in China.
Aesthetic Plast Surg
December 2024
School of Public Health, Shandong Second Medical University, 7166 Baotong West Street, Weifang, Shandong, China.
Background: Studies on acceptance of cosmetic surgery may not be cross-culturally invariant, but little is known about it in non-Western populations. Therefore, it is necessary to develop cross-cultural research on it.
Methods: 230 international students in China aged 18-27 years (M = 21.
PTEN loss in glioma cell lines leads to increased extracellular vesicle biogenesis and PD-L1 cargo in a PI3K-dependent manner.
J Biol Chem
December 2024
Department of Molecular Medicine, College of Veterinary Medicine, Cornell University, Ithaca, NY, 14853, USA; Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, 14853, USA. Electronic address:
Phosphatase and Tensin Homologue (PTEN) is one of the most frequently lost tumor suppressors in cancer and the predominant negative regulator of the PI3K/AKT signaling axis. A growing body of evidence has highlighted the loss of PTEN with immuno-modulatory functions including the upregulation of the programmed death ligand-1 (PD-L1), an altered tumor derived secretome that drives an immunosuppressive tumor immune microenvironment (TIME), and resistance to certain immunotherapies. Given their roles in immunosuppression and tumor growth, we examined whether the loss of PTEN would impact the biogenesis, cargo, and function of extracellular vesicles (EVs) in the context of the anti-tumor associated cytokine interferon-γ (IFN-γ).
View Article and Find Full Text PDFEsculin-loaded nanoparticles ameliorate adjuvant-induced polyarthritis via subduing inflammatory and oxidative stress biomarkers in Wistar rats.
Inflammopharmacology
December 2024
Riphah Institute of Pharmaceutical Sciences, Riphah International University, Lahore Campus, Lahore, 5400, Pakistan.
Rheumatoid arthritis is an autoimmune disorder affecting multiple joints and requires lifelong treatment. Present study was designed to formulate Esculin-loaded chitosan nanoparticles (ENPs) and evaluation of its anti-inflammatory and anti-arthritic action. The acute toxicity study of ENPs was also performed.
View Article and Find Full Text PDFBiomimetic intelligent nanoplatform with cascade amplification effect for tumor synergy therapy.
Sci Rep
December 2024
Department of Clinical Laboratory, The Affiliated People's Hospital of Jiangsu University, Zhenjiang, 212002, Jiangsu, China.
Tumor heterogeneity, immune-suppressive microenvironment and the precise killing of tumor cells by drugs are important factors affecting tumor treatment. In this study, we developed environment-responsive drug delivery system (FM@IQ/PST&ZIF-8/DOX) based on ZIF-8 for tumor photothermal/immunotherapy/chemotherapy synergistic therapy. The prepared FM@IQ/PST&ZIF-8/DOX nanoplatfrom not only has highly drug loading capacity for chemotherapeutic drug-doxorubicin, but also erythrocyte membrance modified on their surface can endow their immunity-escaping property and prolong their blood circulation time.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!