Humans ; Myocardial Infarction ; complications ; therapy ; Myocardial Reperfusion Injury ; etiology ; therapy

Animals ; Humans ; Ischemic Preconditioning, Myocardial ; methods ; Myocardial Ischemia ; complications ; therapy ; Myocardial Reperfusion ; methods ; Myocardial Reperfusion Injury ; etiology ; prevention & control

OBJECTIVETo investigate the clinical implications of reperfusion arrhythmias during primary percutaneous coronary intervention (PCI) for patients with acute myocardial infarction (AMI).

METHODSData from 228 AMI patients in whom the infarct-related artery (IRA) were successfully recanalized by primary PCI were retrospectively analyzed. The 228 patients were divided into 2 groups: myocardial ischemia-reperfusion injury (MIRI) group (n=119) in whom MIRI events occurred within minutes after successful recanalization of IRA, and non-MIRI group (n=109). The 119 patients in MIRI group were further divided into 3 subgroups: severe bradycardia with hypotension (brady-arrhythmia subgroup), lethal ventricular arrhythmias requiring electrical cardioversion (tachy-arrhythmia subgroup), and IRA antegrade flow less than or equal to TIMI 2 grade without angiographic evidence of abrupt closure (no-reflow subgroup).

RESULTS(1) Clinical and angiographic data: Compared with non-MIRI group, MIRI group was characterized by more inferior infarct location, shorter ischemic duration, more frequently right coronary artery as IRA, more diseased vessels, more often TIMI 0 grade of initial antegrade flow in IRA, less pre-infarction angina, more renal insufficiency, and higher in-hospital mortality (13.4% vs. 4.6%, P=0.021). (2) The peak CK level was remarkably lower in brady-arrhythmia subgroup than that in non-MIRI group (2010 IU/L vs. 2521 IU/L, P=0.039). The peak CK or CK-MB level was notably higher in no-reflow subgroup than in non-MIRI group (4573 IU/L, 338 IU/L, respectively, P=0.000). (3) Left ventricular ejection fraction in no-reflow subgroup was significantly lower than in non-MIRI group (38.7% +/- 8.3% vs. 51.2% +/- 8.1%, P=0.000), left ventricular end-diastolic volume in no-reflow subgroup was greater than that in tachy-arrhythmia subgroup [(135 +/- 32) ml vs. (105 +/- 19) ml, P=0.029].

CONCLUSIONReperfusion arrhythmias may imply the existence of much survived myocardium and do not enhance myocardial damage, while no-reflow increases myocardial injury and induces permanent impairment of cardiac function.

Arrhythmias, Cardiac ; complications ; Cell Survival ; Humans ; Myocardial Infarction ; therapy ; Myocardial Reperfusion ; Myocardial Reperfusion Injury ; etiology ; Myocardium ; enzymology ; Retrospective Studies

OBJECTIVETo study the effects of "half-conditioning", a modified postconditioning process, on myocardial injury induced by severe myocardial ischemia/reperfusion (I/R) in anesthetized dogs.

METHODSMongrel dogs of both sexes were subjected to 40 min ischemia (coronary blood flow reduced by 80% via controlled coronary stenosis). At the end of ischemia, dogs were randomly received one of the following treatments: (1) control, reperfusion for 3 h (n = 7); (2) post-conditioning, three cycles of ischemia 30 s followed by reperfusion for 30 s and then reperfusion for 3 h (n = 7); (3) half-conditioning, coronary blood flow recovered to 50% for 2 min, then 80% for 2 min, thereafter 100% for 3 h (n = 7). Electrocardiogram (ECG), arterial blood pressure and left ventricular pressure were monitored throughout the experiment. Plasma creatine kinase (CK) and lactate dehydrogenase (LDH) activity were measured spectrophotometrically. Myocardial necrosis was defined by TTC-staining.

RESULTSCompared with control animals, arrhythmia incidence, LVEDP at 2 and 3 h reperfusion, CK and LDH were significantly reduced in animals received post-conditioning and half-conditioning treatments, infarct size as a percentage (%) of the area at risk was also significantly reduced by post-conditioning and half-conditioning treatments. No differences were observed in the post-conditioning and half-conditioning groups.

CONCLUSIONHalf-conditioning exerts the same cardioprotective effects on post-ischemic hearts as postconditioning.

Animals ; Disease Models, Animal ; Dogs ; Female ; Ischemic Preconditioning, Myocardial ; Male ; Myocardial Reperfusion Injury ; therapy

Humans ; Ischemia ; metabolism ; pathology ; therapy ; Ischemic Postconditioning ; methods ; Myocardial Reperfusion Injury ; metabolism ; pathology ; therapy

OBJECTIVEThe main objective of this study is to assess the the effect of simvastatin (sim) on myocardial no-reflow (NR) and explore the possible potential mechanisms.

METHODSAdult male Wistar rats were randomized into sham group (n = 12), I/R (90 min ischemia via coronary ligation/120 min reperfusion, n = 18) and I/R plus sim group (20 mgxkg(-1)xd(-1) sim pretreated via gavage beginning 3 days before I/R, n = 18). After reperfusion, area at risk/area of left ventricular (RA/LVA), area of NR, determined by the area not perfused by thioflavin-S/area at risk (NA/RA) and area of myocardial infarction/area at risk (MIA/RA) were measured. Myocardium homogenate was used to determine the activity of eNOS, iNOS and MPO, and the content of NO and MDA. Myocardial immunohistochemistry was performed to determine the positive index of NF-kappaB p65 in cardiomyocytes and arteriole.

RESULTSThe NR and myocardial infarction areas in I/R plus sim group were significantly smaller than those in I/R group (34.10 +/- 7.05 vs. 52.09 +/- 6.89, 78.80 +/- 7.60 vs. 90.13 +/- 5.72, each P < 0.05) while the ischemia area was similar between the 2 groups (P > 0.05). The myocardial activities of iNOS and MPO, the contents of NO and MDA were significantly lower while eNOS activity was significantly higher in I/R plus sim group than those in I/R group (5.02 +/- 1.64 vs. 9.19 +/- 2.89, 586.21 +/- 126.97 vs. 744.49 +/- 137.53, 257.72 +/- 93.43 vs. 384.10 +/- 40.68, 72.10 +/- 18.56 vs. 111.84 +/- 38.58, 7.08 +/- 1.74 vs. 3.72 +/- 0.98, all P < 0.05). The positive index of NF-kappaB p65 in cardiocytes and arteriole at left ventricular wall near the area of myocardial infarction was significantly lower in I/R plus sim group than that in I/R group (21.59 +/- 10.5 vs. 34.32 +/- 9.55, 27.27 +/- 13.19 vs. 44.91 +/- 15.06, each P < 0.05).

CONCLUSIONSimvastatin could improve myocardial NR after ischemia-reperfusion by attenuating endothelial dysfunction and inhibiting inflammation and neutrophil activation.

Animals ; Disease Models, Animal ; Endothelium, Vascular ; drug effects ; Male ; Myocardial Infarction ; drug therapy ; physiopathology ; Myocardial Reperfusion ; Myocardial Reperfusion Injury ; drug therapy ; Myocardium ; metabolism ; Rats ; Rats, Wistar ; Simvastatin ; pharmacology

OBJECTIVETo explore the effects of astragalus (AST) , total flavone of astragalus (TFA), total saponins of astragalus (TSA) and astragalus polysaccharides (APS) on ischemia/reperfusion (40 min/60 min) injury in isolated guinea-pig heart.

METHODSIsolated guinea-pig hearts underwent ischemia, then followed by K-H perfusion (I/R group), AST (60 mg/L),AST (60 mg/L), TFA (60 mg/L), TSA (60 mg/L) and APS (60 mg/L) perfusion (n = 6 each).Isolated hearts without ischemia serve as control group (n = 6). Activity of lactate dehydrogenas (LDH) and creatine kinase (CK) in effluent were measured.Infarct size, myocardial superoxide dismutase (SOD) activity and malondiadehyde (MDA) contents were also determined.

RESULTSCompared to control hearts, heart rate, coronary flow and myocardial superoxide dismutase (SOD) activity were significantly reduced, while LDH and CK in effluent as well as myocardial MDA were significantly increased in the I/R hearts during reperfusion (all P < 0.05), these changes could be partly reversed by AST and TFA perfusion.Infarct size was also significantly reduced in AST (11.9 ± 2.03) % and TFA (13.31 ± 1.17) % treated hearts compared to that in I/R group (18.9 ± 2.27) % (all P < 0.01).

CONCLUSIONSThe findings indicate that AST and TFA could attenuate I/R injury in isolated guinea-pig heart possibly through enhancing the activity of SOD and reducing lipid peroxidation.

Animals ; Astragalus Plant ; Guinea Pigs ; Heart ; Heart Rate ; Myocardial Ischemia ; Myocardial Reperfusion Injury ; drug therapy ; Myocardium ; Plant Extracts ; pharmacology ; Reperfusion Injury ; Superoxide Dismutase

Reperfusion is the most effective treatment for acute myocardial infarction, markedly reducing mortality and morbidity. Reperfusion however induces necrotic and apoptotic damages to cardiomyocytes, that were viable prior to reperfusion, a process called myocardial ischemia/reperfusion injury(MI/RI). Over the past 30 years, hundreds of experimental interventions (both pharmacologic and nonpharmacologic) have been reported to protect the ischemic myocardium in experimental animals; however, with the exception of early reperfusion, none has been translated into clinical practice. The population-based survey assessed men have about twice the total incidence of morbidity and mortality of women, and the sex gap in morbidity tends to diminish after age 45 years. So hormone replacement therapy (HRT) is given to treat the MI/RI, and lots of studies shows that the side effect is greater for estrogen, compared with phyestrogen. In this article, we review the important pathogenesis of myocardial ischemia reperfusion injury, the prevention and limitations of HRT. And we highlight the mechanism of phyestrogens treatment the MI/RI in experiment. The aim is to provide the theoretically new way of develop the safe and effective products for the researchers.
Animals ; Humans ; Myocardial Ischemia ; drug therapy ; Myocardial Reperfusion Injury ; drug therapy ; Phytoestrogens ; administration & dosage ; Plant Extracts ; administration & dosage

Animals ; Codonopsis ; chemistry ; Drugs, Chinese Herbal ; pharmacology ; Myocardial Reperfusion Injury ; drug therapy ; Rats ; Selenium ; pharmacology

"Stunning" represents prolonged contractile depression of any muscular component after alleviation of severe ischemia, as shown in reperfusion following acute myocardial ischemia or ischemic stroke. Clinically, it presents with no or delayed recovery past to thrombolytic therapy but its pathogenic mechanism is not fully uncovered yet. We describe a unique case of a 63-year-old woman, who was undertaken endovascular coiling for the aneurysms, deteriorated several hours later without known cause, and showed delayed clinical improvement over the next 3 days following thrombolysis. Immediate post-thrombolysis magnetic resonance imaging scan showed no apparent abnormality except for high signal intensity within the corresponding hemisphere. Reversible, but delayed nature of "brain stunning" can be explained by these images and it seems to be caused by a certain type of reperfusion injury.
Aneurysm* ; Depression ; Female ; Humans ; Ischemia ; Magnetic Resonance Imaging ; Middle Aged ; Myocardial Ischemia ; Reperfusion ; Reperfusion Injury ; Stroke ; Thrombolytic Therapy