Myocardial infarction (MI) has the characteristics of high mortality rate, strong suddenness and invisibility. There are problems such as the delayed diagnosis, misdiagnosis and missed diagnosis in clinical practice. Electrocardiogram (ECG) examination is the simplest and fastest way to diagnose MI. The research on MI intelligent auxiliary diagnosis based on ECG is of great significance. On the basis of the pathophysiological mechanism of MI and characteristic changes in ECG, feature point extraction and morphology recognition of ECG, along with intelligent auxiliary diagnosis method of MI based on machine learning and deep learning are all summarized. The models, datasets, the number of ECG, the number of leads, input modes, evaluation methods and effects of different methods are compared. Finally, future research directions and development trends are pointed out, including data enhancement of MI, feature points and dynamic features extraction of ECG, the generalization and clinical interpretability of models, which are expected to provide references for researchers in related fields of MI intelligent auxiliary diagnosis.
Abstract: Objective To investigate the relationship between graft flow and incidence of perioperative myocardial infarction (MI) in coronary artery bypass grafting (CABG). Methods Between January 2010 and June 2010, 58 consecutive patients with coronary artery disease who underwent offpump CABG in the First Hospital of Peking University were enrolled in this study. An anastomosis between left internal mammary arteries (LIMA) and left ant erior descending coronary artery (LAD) were performed. And saphenous vein (SV) graft s were used as bypass grafts. Graft flow was measured intraoperatively using a transi t time flowmeter, and the total graft flow of each patient was calculated as a parameter of myocardial revascularization. The 58 patients were divided into a MI group and a nonMI group retrospectively. There were 11 patients in the MI group, including 7 males and 4 females, with an average age of 67.4±10.3 years.There were 47 patients in the nonMI group, 38 males and 9 females, with a mean age of 633±99 years. The graft flow of the two groups was tested and compared, and the preoperative variables were compared. Results There was no statistically significant difference in operation time (205.4±59.6min versus 1834±32.4 min, t=1.691, P=0.096) between the two groups. Therewere also no statistical differences in the average number of grafts (3.00±1.00 branches versus 2.96±0.78 branches, t=0.154, P=0878) or LIMALAD flow (1540±11.37 ml/min versus 16.50±10.83 ml/min, t=0.301, P=0.764) between the two groups. However, a significant difference was found in the total graft flow between the two groups (41.03±19.50 ml/min versus 64.09±32.44 ml/min, t=2.254, P=0.028), with lower total graft flow in the MI group. Further analysis showed [CM(159mm]that a total graft flow lt;48.5ml/min was a risk factor for MI (odds ratio 4.706, 95% confidence interval 1.099 to 20.147). Conclusion Total graft flow could be used to predict the occurrence of perioperative myocardial ischemia, as there is a high probability of MI for patients with a total graft flow of less than 48.5 ml/min.
Objective To report a reliable left heart failure model in sheep using selected ligation of the diagonal branch. Methods Four male sheep were used. After a left anterior thoracotomy in sheep, the diagonal branch of coronary artery was ligated at a point approximately 40% of the distance from the apex to the base of the heart. Hemodynamic and echocardiography measurements were done preligation, 30 minutes and 7 days after the coronary artery of diagonal branch ligation. The electrocardiograms were obtained as needed, and cardiac function was also evaluated. The sheep were killed for postmortem examination of their hearts. Results Four sheep survived the experimental procedures. Comparing with before surgery, systemic arterial blood pressure and cardiac output were decreased, pulmonaryartery systolic pressure, pulmonary capillary wedge pressure and central venous pressure were increased at 30 min and 7 days after selected ligation of the coronary artery of diagonal branch; left ventricular end-diastolic dimension and left ventricular end-systolic dimension were increased; left ventricular ejection fraction and left ventricular fractional shortening were also decreased (Plt;0.05). Conclusion A reliable ovine model of left ventricular failure using selected ligation of the diagonal branch of the coronary artery can be achieved. This animal model is comparable to the clinical correlation.
The capacity for self-regeneration of the adult heart is very limited, conventional therapies cannot solve the loss of cardiomyocytes in the infarcted heart leads to continuous ventricular remodeling. Cell transplantation therapy is emerging as a novel approach for myocardial repair over conventional therapies. Various types of cell transplantation have improved cardiac function and angiogenesis in animal models and clinical settings. The safety and feasibility of some clinical trials have been initiated. In this review, we summarize the advantages and limitations of different cell types proposed for cell transplantation in myocardial infarction and give an overview of the clinical trials using this novel therapeutic approach in patients with myocardial infarction.
Objective To investigate the effects of granulocyto-colony stimulating factor (G-CSF) on the mobil ization of endothel ial progenitor cells (EPCs) in the rats with myocardial infarction (MI), to observe the density of neovascularization and the mRNA expressions of vascular endothel ial growth factor (VEGF) and its receptor (Flk-1) in the border area of MI. Methods Thirty-six adult male rats (weighing 250-280 g) were divided randomly into control group, MI group, and G-CSF group. In MI group and G-CSF group, the models of MI were establ ished by left anterior descenting coronary artery l igation and were treated with intraperitoneal injection of sal ine (0.3 mL/d) or G-CSF [30 μg/(kg•d)] for 5 days. In control group, after open chest operation, chest was closed without treatment. The level of EPCs was surveyed and the plasma concentrations of VEGF and C-reaction protein (CRP) were measured at 7 days. The mRNA expressions of VEGFand its receptor Flk-1 in the border area of infarct myocardium were determined through RT-PCR. Results Compared withcontrol group, the number of circulating white blood cell (WBC) and EPCs levels, and the serum concentrations of VEGF and CRP were all significantly increased in MI group and G-CSF group (P lt; 0.05); when compared with MI group, the number of circulating WBC and EPCs levels, and the serum concentrations of VEGF were increased and the concentration of CRP was decreased in G-CSF group (P lt; 0.05). Compared with control group, the mRNA expressions of VEGF and Flk-1, and the density of neovascularization in the border area of infarct myocardium were increased in MI group and G-CSF group, whereas those in G-CSF group were significantly augmented compared with MI group (P lt; 0.05). Conclusion In the rats with MI, G-CSF could promote EPCs mobil ization, increase the mRNA expressions of VEGF and Flk-1, and augment the density of neovascularization in the border area of infarct myocardium.
Electrocardiogram (ECG) signal is an important basis for the diagnosis of arrhythmia and myocardial infarction. In order to further improve the classification effect of arrhythmia and myocardial infarction, an ECG classification algorithm based on Convolutional vision Transformer (CvT) and multimodal image fusion was proposed. Through Gramian summation angular field (GASF), Gramian difference angular field (GADF) and recurrence plot (RP), the one-dimensional ECG signal was converted into three different modes of two-dimensional images, and fused into a multimodal fusion image containing more features. The CvT-13 model could take into account local and global information when processing the fused image, thus effectively improving the classification performance. On the MIT-BIH arrhythmia dataset and the PTB myocardial infarction dataset, the algorithm achieved a combined accuracy of 99.9% for the classification of five arrhythmias and 99.8% for the classification of myocardial infarction. The experiments show that the high-precision computer-assisted intelligent classification method is superior and can effectively improve the diagnostic efficiency of arrhythmia as well as myocardial infarction and other cardiac diseases.
ObjectiveTo improve and assess the method of establishing myocardial infarction model in New Zealand rabbits. MethodsA total of 60 New Zealand rabbits were randomly divided into two groups:the left anterior descending coronary artery was ligated in a LAD group (n=30); the left circumflex coronary artery was ligated in a LC group (n=30). Electrocardiogram (ECG), ultrasound cardiogram (UCG), hemodynamics and histology procedures were performed to detect the changes of cardiac structure and function after myocardial infarction induced by LAD and LC ligation. ResultsSuccess rate of the LC group was significantly higher than that in the LAD group (P < 0.01), but the survival rate in the LC group was slightly lower than the LAD group (P < 0.05); ECG within 24 h and 1 week after surgery showed that the average values of ST segment elevation in the LC group were significantly higher than that in the LAD group (P < 0.05); UCG and hemodynamics results showed cardiac function in the LAD group did not decrease significantly (P > 0.05). In contrast, cardiac function in the LC group were significantly decreased (P < 0.05). Histopathologic analysis showed that the area of myocardial infarction in the LC group was significantly larger than that in the LAD group (P < 0.01). ConclusionThe myocardial infarction induced by the left circumflex coronary artery ligation is more consistent than that induced by the left anterior descending coronary artery ligation, suggesting that the former is a more appropriate experimental model for evaluations.
Objective To investigate the effect of bone marrow mesenchymal stem cell (MSCs) transp1antation combined with transmyocardial drilling revascularization (TMDR) and degradable stent on myocardium revascu1arization after acute myocardial infarction(AMI), and to provide the experimental evidence for surgical treatment of myocardial infarction. Methods After established models of AMI, the 24 pigs were divided into four groups with random number table, 6 pigs each group. Control group: only established models of AMI; MSCs group: AMI immediately followed by MSCs implantation; TMDR combined with stent group: AMI followed by TMDR and absorbable basic fibroblast growth factor (bFGF) stent implantation; MSCs combined with TMDR and stent group: AMI followed by TMDR and absorbable bFGF stent implantation, and then MSCs implantation. Three months after operation, the infarcted areas and vessel density in infarcted zone were detected by histopathology method. Results Three months after operation, the histopathological examination showed that infarcted areas in MSCs group, TMDR combined with stent group, and MSCs combined with TMDR and stent group were decreased as compared with control group （27.9%±3.1% vs. 48.9%±2.7%，P=0.000；20.3%±1.7% vs. 48.9%±2.7%，P=0.000；12.5%±1.9% vs. 48.9%±2.7%，P=0.000）; and vessel density was further increased （8.4±1.2/HP vs.4.5±14/HP，P=CM(1583mm] 0.001；11.5±2.6/HP vs.4.5±1.4/HP，P=0.001;15.6±1.4/HP vs.4.5±1.4/HP，P=0.000）. Conclusion [CM)]MSCs transplantation combined with TMDR and absorbable bFGF stents implantation could significantly reduce the infarction areas, increase the vessel density. This method may enhance the efficacy of MSCs transplantation in acute cardiac infarction model, which provide a new ideas for the surgical treatment of myocardial infarction.
Abstract: Objective To transplant the microencapsulated recombinanted Chinese hamster ovary (CHO ) cells into the infracted myocardium of rodent animals and investigate whether vascular endothelial growth factor (VEGF) secreted by the implanted CHO cells could augment angiogenesis and improve cardiac function. Methods The cDNA of VEGF was transferred into CHO cells with plasmid stable transfection. After microencapsulation, the cell growth in microcapsules and the VEGF level in the culture supernatant were evaluated. Two weeks after myocardial infarction, the microencapsulated CHO cells (MC-CHO group ) were implanted into the border of infracted myocardium, as well as similar amount of CHO cells (CHO group ) , blank microcapsule (MC group ) and non-serum culture medium (control group ) as controls, 12 rats per group. The cardiac function improvement was evaluated 3 weeks after transplantation, while the survival status of implanted CHO cells, in situ secretion of VEGF and capillary density were assayed by histology. Results CHO cells could grow and proliferate after microencapsulation. The secretion of VEGF was detectable in culture media supernatant, with the highest concentration of 3 852 pg/m l at day 8. As compared to the other three groups, the left ventricular dimension and cardiac function were significantly improved in MC-CHO group 3 weeks after transplantation. The capillary density of MC-CHO group were increased significantly than those of CHO group, MC group and control group (22. 3±3. 1 vs. 15. 6±2. 8, 11. 4±2. 5, 13. 2±2. 7 vessels per 0.13 mm2, P lt; 0.05). The implanted microcapsule maintained its original shape and protected theCHO cells in it. Conclusion M icroencapsulaed recombinanted CHO cells transplantation might be a promising app roach to augment angiogenesis and improve the cardiac function in infarction myocardium.
Ischemic mitral regurgitation is the common complication after myocardial infarction. Ischemic mitral regurgitation which can be described as the modification of the ventricle caused by myocardial infarction remarkably increases the risk of developing congestive heart failure and mortality after myocardial infarction. The imbalanced dynamic of tethering and occluding of the leaflets or the annular dilatation can result in ischemic mitral regurgitation. We have to diagnose, evaluate ischemic mitral regurgitation timely and perform surgical treatment effectively. It has significant meaning to improve the prognosis of patients.