| Acute myocardial infarction(AMI) is a kind of myocardial necrosis which is caused by acute, persistent coronary occlusion, and this phenomenon mostly occurs on the basis of coronary atherosclerosis. AMI is a severe heart disease to us, which threatens the life safety of human. Because of the development of economic strength, health conditions and the progress of the whole society, the mobility of AMI is increasing year by year. In 2008, the third cause of death nationwide survey which is released by the Ministry of Health shows that heart disease is ranked third in ordinal cause of death in urban while ranked fourth in country. Epidemiological data shows that, about 50% of the dead patients with acute ST-segment elevation infarction prehospitally die of life-threatening arrhythmias in 1 hour after the AMI occurs. In recent years, percutaneous coronary intervention(PCI) is widely applied in clinical. This therapy can rapidly reperfusion the occluded coronary artery, provide an effective way to save the dying cadiocyte, and greatly improve the prognosis of patients with AMI. However, the myocardial reperfusion injury which is induced by ischemia-reperfusion can lead to multiple kinds of arrhythmias, even including fatal malignant arrhythmia. Reperfusion injury also offsets the benefit in some patients that accept the primary PCI. Ischemic preconditioning as an endogenous protective mechanism is becoming a research hotspot at home and abroad. Metallothionein(MT) is a class of inducible and endogenous protective protein, it can remove free radical, lighten oxidative strss. Animal experiments had proved that preconditioning could improve the MT concentration in myocardial tissue, resulted in protection against reperfusion arrhythmias. QT dispersion(QTd) means the difference between QT interval of each lead of 12-lead ECG. It reflects for the heterogenetics of repolarization and instabilityof electric activity of cadiocyte. In AMI patients who accepted the primary PCI, preconditioning whether affected the expression of MT, changed QTd values and the relationship with reperfusion arrhythmias required further study.Objective: In this study, AMI patients who accepted primary PCI wassimulated as ischemia / reperfusion model. Preconditioning or control groupwas divided based on whether the patients appear angina before myocardialinfarction. ABC-ELISA method was used to test plasma MT concentration.In different time before and after the surgery ECG was needed to measureQTd values. Arrhythmia could be observed by patient monitor and centralmonitoring system. They used Curtis-Walker score system to quantitativelyanalyzed ventricular arrhythmias. The author expected to explore therelationship between MT, QTd and reperfusion arrhythmias in Ischemicpreconditioning, providing the theoretical basis for clinical prevention and treatment.Methods: 42 Patients were studied in the study, who were treated in Hebei General Hospital Heart Center from october 2013 to october 2014, and were in line with the diagnostic criteria of AMI in "2010 China’s diagnosis and treatment of acute ST segment elevation myocardial infarction guide", also were with emergency PCI incidation. At the same time, they must be consistent with our grouping criteria, and not consistent with the exclusion standard.1 Grouping: The 42 patients were divided into preconditioning group and control group according to their clinical histories. Patients in preconditioning group meaned they sustained typical angina 3 days before the AMI occurred, everytime last less than 30 minutes, the pain could relieve when they had a rest or sublingual nitroglycerin or other drugs.when they had a rest or and other drugs can be alleviated. Patients in control group meaned they did not have angina or ECG evidence of myocardial ischemia before the occurrence of AMI, also had no coronary heart disease history.2 Surgical procedure: All enrolled patients were routinely given aspirinenteric-coated tablets 300 mg, clopidogrel bisulfate tablets 300 mg to chew before surgery. After entering the cath lab patients were routinely given disinfection, shop towels, local anesthesia with 1% lidocaine. Using modified Seldinger technique to punt right radial artery puncture(or femoral artery), placed 6F sheath and conventionally gave heparin 2000 units through sheath. Through the left and right coronary angiography, infarction related artery was defined. Explaining the results to relatives of patients, the coronary intervention only underwent with their permission. Before the cardiac stent was planted, thrombus aspiration catheter was routinely used and balloon pre-dilatation is necessary, too. After the cardiac stent was planted balloon dilation was also needed to make sure that the sent was in good adherence. After surgery, all patients entered the CCU to accept care treatment routinely. Successful surgery standard: the culprit artery residual stenosis <20%, postoperative achieve TIMI 3 blood flow and no deaths during hospitalization, acute myocardial infarction again, urgent coronary artery bypass and other complications.3 After the infarction related artery was perfused, they should observe the monitor of ECG whether reperfusion arrhythmias occurred. When patients entered CCU, they were immediately connected with ECG and were monitored for 72 hours continuous. The staff could discover arrhythmia cases by the bedside monitor and central monitoring system, retrospective analysis of the ECG dynamic changes through a central monitoring system. The score of arrhythmias was calculated with Curtis-Walker system.4 QT dispersion measurement: All patients with the primary PCI were examined by electrocardiogram pre-operation, post-operation and 12 h, 24 h, 48 h, 72 h after surgery to measure the QT interval of all leads manually. QTd = QTmax-QTmin.5 Baseline data collection: collecting the date of gender, age, the onset to surgery time, hypertension, diabetes, plasma potassium concentration, heart rate, blood pressure, infarction related artery, number of lesion vessel, peak c Tn T of all patients in the two group.6 All patients who accepted primary PCI were exsanguinated 5m L blood through vein before and 12 h, 24 h, 48 h and 72 h after surgery. Then, using ABC-ELISA method to measure the MT concentrationResults:1 42 patients were enrolled in the study, preconditioning group included 22 cases while 20 cases was included in control group, and all operations of the patients were successful.2 Preconditioning group and control group, clinical baseline data of the two groups at gender, age, the onset to surgery time, hypertension, diabetes, plasma potassium concentration, heart rate, blood pressure, infarction related artery, number of lesion vessel, peak c Tn T was not in significant difference.3 The incidence of reperfusion arrhythmias of preconditioning group was lower than the control group, but the difference was not statistically significant(P> 0.05); the arrhythmia score of preconditioning was also lower than the control group, and the difference was statistically significant(P <0.05).4 Before surgery, after surgery immediately, 12 h after surgery and 24 h after surgery, the QTd values of preconditioning group was lower than the control group, the difference was statistically significant(P <0.05). However, 48 h and 72 h after surgery, the data of two groups was not statistically significant(P> 0.05).5 The MT concentration of preconditioning group were higher than control group before surgery and within 72 hours after sugery, the difference was statistically significant(P <0.05).Conclusion:1 Preconditioning can reduce the arrhythmia scores of the patients accepted primary PCI in patients with, so that is can also reduce the risk of malignant reperfusion arrhythmias.2 Preconditioning decreases QTd values of the patients accepted primary PCI, lightens heterogenetics of repolarization, and this may help reduce reperfusion arrhythmias.3 Preconditioning can induce metallothionein, which may be involved in cardiac protection against reperfusion arrhythmias. |
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