Background: Aim of the study was to find out which myocardial repolarization parameters predict reperfusion ventricular tachycardia and fibrillation (VT/VF) and determine how these parameters express in ECG.
Methods: Coronary occlusion and reperfusion (30/30min) was induced in 24 cats. Local activation and end of repolarization times (RT) were measured in 88 intramyocardial leads. Computer simulations of precordial electrograms were performed.
Results: Reperfusion VT/VF developed in 10 animals. Arrhythmia-susceptible animals had longer RTs in perfused areas [183(177;202) vs 154(140;170) ms in susceptible and resistant animals, respectively, P<0.05]. In logistic regression analysis, VT/VFs were associated with prolonged RTs in the perfused area (OR 1.068; 95% CI 1.012-1.128; P=0.017). Simulations demonstrated that prolonged repolarization in the perfused/border zone caused precordial terminal T-wave inversion.
Conclusions: The reperfusion VT/VFs were independently predicted by the longer RT in the perfused zone, which was reflected in the terminal negative phase of the electrocardiographic T-wave.
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http://dx.doi.org/10.1016/j.jelectrocard.2017.12.003 | DOI Listing |
World J Cardiol
January 2025
Cardiac Care Unit, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou 325000, Zhejiang Province, China.
Background: Myocardial ischemia/reperfusion (I/R) injury, which is associated with high morbidity and mortality, is a main cause of unexpected myocardial injury after acute myocardial infarction. However, the underlying mechanism remains unclear. Circular RNAs (circRNAs), which are formed from protein-coding genes, can sequester microRNAs or proteins, modulate transcription and interfere with splicing.
View Article and Find Full Text PDFFront Biosci (Landmark Ed)
January 2025
Department of Cardiology, Affiliated Hospital of Jiangnan University, 214122 Wuxi, Jiangsu, China.
Background: Myocardial ischemia-reperfusion (I/R) injury refers to cell damage that occurs as a consequence of the restoration of blood circulation following reperfusion therapy for cardiovascular diseases, and it is a primary cause of myocardial infarction. The search for nove therapeutic targets in the context of I/R injury is currently a highly active area of research. p70 ribosomal S6 kinase (S6K1) plays an important role in I/R induced necrosis, although the specific mechanisms remain unclear.
View Article and Find Full Text PDFInt J Mol Sci
January 2025
Division of Cardiology, Department of Internal Medicine, Chang Gung Memorial Hospital, Taoyuan Branch, Taoyuan 33304, Taiwan.
The electrophysiological mechanisms underlying melatonin's actions and the electrophysiological consequences of superimposed therapeutic hypothermia (TH) in preventing cardiac ischemia-reperfusion (IR) injury-induced arrhythmias remain largely unknown. This study aimed to unveil these issues using acute IR-injured hearts. Rabbits were divided into heart failure (HF), HF+melatonin, control, and control+melatonin groups.
View Article and Find Full Text PDFBiomedicines
December 2024
Ludwig Boltzmann Institute for Cardiovascular Research, Center for Biomedical Research and Translational Surgery, Medical University of Vienna, 1090 Vienna, Austria.
Previously, we showed that blood-based polarizing cardioplegia exerted beneficial cardioprotection during hypothermic ischemia; however, these positive effects of blood-based polarizing cardioplegia were reduced during normothermic ischemia compared to blood-based hyperkalemic (depolarizing) cardioplegia. This study compares crystalloid polarizing cardioplegia to crystalloid depolarizing cardioplegia in a normothermic porcine model of cardiopulmonary bypass; Methods: Twelve pigs were randomized to receive either normothermic polarizing ( = 7) or depolarizing ( = 5) crystalloid cardioplegia. After the initiation of cardiopulmonary bypass, normothermic arrest (34 °C, 60 min) was followed by 60 min of on-pump and 90 min of off-pump reperfusion.
View Article and Find Full Text PDFActa Pharmacol Sin
January 2025
Department of Pharmacology, National Key Laboratory of Frigid Zone Cardiovascular Diseases, State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Medicine Research, Ministry of Education, College of Pharmacy, Harbin Medical University, Harbin, 150086, China.
Eukaryotic translation initiation factor 4A1 (eIF4A1) is an ATP-dependent RNA helicase that participates in a variety of biological and pathological processes such as cell proliferation and apoptosis, and cancer. In this study we investigated the role of eIF4A1 in ischemic heart disease. The myocardial ischemia/reperfusion (I/R) model was established in mice by ligation of the left anterior descending artery for 45 min with the subsequent reperfusion for 24 h; cultured neonatal mouse ventricular cardiomyocytes (NMVCs) treated with HO (200 μM) or H/R (12 h hypoxia and 12 h reoxygenation) were used for in vitro study.
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