Electrocardiogram (ECG) is a low-cost, simple, fast, and non-invasive test. It can reflect the heart's electrical activity and provide valuable diagnostic clues about the health of the entire body. Therefore, ECG has been widely used in various biomedical applications such as arrhythmia detection, disease-specific detection, mortality prediction, and biometric recognition. In recent years, ECG-related studies have been carried out using a variety of publicly available datasets, with many differences in the datasets used, data preprocessing methods, targeted challenges, and modeling and analysis techniques. Here we systematically summarize and analyze the ECG-based automatic analysis methods and applications. Specifically, we first reviewed 22 commonly used ECG public datasets and provided an overview of data preprocessing processes. Then we described some of the most widely used applications of ECG signals and analyzed the advanced methods involved in these applications. Finally, we elucidated some of the challenges in ECG analysis and provided suggestions for further research.

Objective To investigate the impact of microvascular obstruction (MVO) on the global and regional myocardial function by cardiac magnetic resonance feature-tracking (CMR-FT) in ST-segment-elevation myocardial infarction (STEMI) patients after percutaneous coronary intervention.

Methods Consecutive acute STEMI patients who underwent cardiac magnetic resonance imaging 1 - 7 days after successful reperfusion by percutaneous coronary intervention treatment were included in this retrospective study. Based on the presence or absence of MVO on late gadolinium enhancement images, patients were divided into groups with MVO and without MVO. The infarct zone, adjacent zone, and remote zone were determined based on a myocardial 16-segment model. The radial strain (RS), circumferential strain (CS), and longitudinal strain (LS) of the global left ventricle (LV) and the infarct, adjacent, and remote zones were measured by CMR-FT from cine images and compared between patients with and without MVO using independent-samples t-test. Logistic regression analysis was used to assess the association of MVO with the impaired LV function.

Results A total of 157 STEMI patients (mean age 56.66 ± 11.38 years) were enrolled. MVO was detected in 37.58% (59/157) of STEMI patients, and the mean size of MVO was 3.00 ±3.76 mL. Compared with patients without MVO (n =98 ), the MVO group had significantly reduced LV global RS (t= -4.30, P < 0.001), global CS (t= 4.99, P < 0.001), and global LS ( t= 3.51, P = 0.001). The RS and CS of the infarct zone in patients with MVO were significantly reduced (t= -3.38, P = 0.001; t= 2.64, P = 0.01; respectively) and the infarct size was significantly larger (t= 8.37, P < 0.001) than that of patients without MVO. The presence of LV MVO [OR= 4.10, 95%CI: 2.05 - 8.19, P<0.001) and its size [OR=1.38, 95%CI: 1.10-1.72, P=0.01], along with the heart rate and LV infarct size were significantly associated with impaired LV global CS in univariable Logistic regression analysis, while only heart rate (OR=1.08, 95%CI: 1.03 - 1.13, P=0.001) and LV infarct size (OR=1.10, 95%CI: 1.03 - 1.16, P=0.003) were independent influencing factors for the impaired LV global CS in multivariable Logistic regression analysis.

Conclusion The infarct size was larger in STEMI patients with MVO, and MVO deteriorates the global and regional LV myocardial function.

Myocardial perfusion imaging (MPI) is valuable for the diagnosis, prognosis, and management of coronary artery disease (CAD). The most commonly used pharmacologic stress agents at present are vasodilators and adrenergic agents. However, these agents have contraindications and may cause adverse effects in some patients. Thus, other stress agents feasible for more patients are required. Higenamine (HG) is a β-adrenergic receptor agonist currently approved for clinical trials as a stress agent for myocardial infarction. It also has a promising value in MPI for the detection of CAD in preclinical and clinical studies. This review summarizes the application of HG on MPI, including its mechanism of action, stress protocol, efficacy, and safety.

Objective To forecast the future burden and its attributable risk factors of infective endocarditis (IE).
Method We analyzed the disease burden of IE and its risk factors from 1990 to 2019 using the Global Burden of Disease 2019 database and projected the disease burden from 2020 to 2030 using a Bayesian age-period-cohort model.
Results By 2030, the incidence of IE will increase uncontrollably on a global scale, with developed countries having the largest number of cases and developing countries experiencing the fastest growth. The affected population will be predominantly males, but the gender gap will narrow. The elderly in high-income countries will bear the greatest burden, with a gradual shift to middle-income countries. The incidence of IE in countries with middle/high-middle social-demographic indicators (SDI) will surpass that of high SDI countries. In China, the incidence rate and the number of IE will reach 18.07 per 100,000 and 451,596 in 2030, respectively. IE-associated deaths and heart failure will continue to impose a significant burden on society, the burden on women will increase and surpass that on men, and the elderly in high-SDI countries will bear the heaviest burden. High systolic blood pressure has become the primary risk factor for IE-related death.
Conclusions This study provides comprehensive analyses of the disease burden and risk factors of IE worldwide over the next decade. The IE-associated incidence will increase in the future and the death and heart failure burden will not be appropriately controlled. Gender, age, regional, and country heterogeneity should be taken seriously to facilitate in making effective strategies for lowering the IE disease burden.

Complex coronary heart disease (CHD) has become a hot spot in medicine due to its complex coronary anatomy, variable clinical factors, difficult hemodynamic reconstruction, and limited effect of conservative drug treatment. Identifying complex CHD and selecting optimal treatment methods have become more scientific as revascularization technology has improved, and coronary risk stratification scores have been introduced. SYNTAX and its derivative scores are decision-making tools that quantitatively describe the characteristics of coronary lesions in patients based on their complexity and severity. The SYNTAX and its derivative scores could assist clinicians in rationalizing the selection of hemodynamic reconstruction treatment strategies, and have demon-strated outstanding value in evaluating the prognosis of patients with complex CHD undergoing revascularization treatment. The authors in this article summary the practical application of SYNTAX and its derivative scores in complex CHD in order to deepen the understanding of the relationship between the choice of different revascularization strategies and SYNTAX and its derived scores in complex CHD and provide a further reference for clinical treatment of complex CHD.

Rapid development of anticancer treatments in recent years has greatly improved prognosis of cancer patients. However, with extension of survival time of cancer patients, various short-term and long-term side effects brought about by anticancer treatments, especially cardiotoxicity, have become increasingly prominent. Nonetheless, at present, there is few diagnostic methods with extremely high sensitivity and specificity to detect and accurately predict whether patients with anticancer treatment will experience cardiovascular complications. Inflammation, fibrosis and oxidative stress are considered to be important mechanisms involved in cardiotoxicity anticancer treatments. The cardiovascular biomarkers having the ability to predict and detect cardiovascular dysfunction earlier than clinical symptoms as well as left ventricular ejection fraction monitored by echocardiography, are of great value to timely treatment adjustment and prognosis evaluation. Cardiac troponin T/I and brain natriuretic peptide/N-terminal prohormone of brain natriuretic peptide have been routinely used in clinical practice to monitor cardiotoxicity, and some new biomarkers such as soluble suppression of tumorigenecity-2, myeloperoxidase, growth differentiation factor-15, galectin-3, endothelin-1, have potential in this area. In the future, larger-scale experimental studies are needed to provide sufficient evidences, and how to detect them quickly and at low cost is also a problem to be dealed with.

Objective To explore the characteristics and clinical outcomes of patients with Heyde syndrome (HS) who undergo aortic valve replacement (AVR).
Methods Electronic databases including PubMed, Embase, Ovid, WANFANG, VIP and CNKI were searched to identify all case reports of HS patients undergoing AVR surgery, using different combinations of search terms “Heyde syndrome”, “gastrointestinal bleeding”, “aortic stenosis”, and “surgery”. Three authors independently extracted the clinical data including the patients’ characteristics, aortic stenosis severity, gastrointestinal bleeding sites, surgical treatments and prognosis.
Results Finally, 46 case reports with 55 patients aging from 46 to 87 years, were determined eligible and included. Of them, 1 patient had mild aortic stenosis, 1 had moderate aortic stenosis, 42 had severe aortic stenosis, and 11 were not mentioned. Gastrointestinal bleeding was detected in colon (n=8), jejunum (n=6), ileum (n=4), cecum (n=3), duodenal (n=3) and multiple sites (n=8). No specific bleeding site was identified in 23 patients. Preoperative hemoglobin level ranged from 43 to 117 g/L. All but one of 16 patients showed decreased level of high molecule weight von Willebrand factor. Of the 55 patients, 43 underwent AVR, and 12 received transcatheter AVR. Aortic valves of 14 cases were replaced by mechanical valves, and 33 cases by biological valves. All patients recovered well during the follow-up, except 5 patients. One patient who had perivalvular leakage and gastrointestinal bleeding after AVR underwent the second AVR. Two patients had recurrent gastrointestinal bleeding. Two patients died of life-threatening acute subdural hematoma and multiple organ failure, respectively.
Conclusions HS is a rare syndrome characterized by aortic stenosis and gastrointestinal bleeding. AVR is an effective treatment for HS.

Pheochromocytomas or paragangliomas are rare and the diagnosis remains a challenge for clinicians. We present a woman suffering from recurrent myocardial infarction and cardiomyopathy, who was finally diagnosed with paraganglioma. Pheochromocytomas or paraganglioma should be considered in the differential diagnosis of a patient with symptoms possibly referring to acute coronary syndrome and cardiomyopathy.

Objective Chronic cardiovascular diseases induced by long-term poor blood glucose control are the main cause of death in patients with type 2 diabetes mellitus (T2DM). Previous researches report that methylenetetrahydrofolate reductase gene (MTHFR) polymorphisms might influence the occurrence of coronary heart disease (CHD) in T2DM patients. The purpose of this study was to evaluate whether MTHFR C677T and A1298C mutations are associated with the risk of CHD in T2DM patients.
Methods A total of 197 subjects with T2DM were studied, of which 95 patients with CHD. The genotypes of MTHFR C677T and A1298C were analyzed by using dideoxy chain-termination method, and compared between patients with CHD and those without CHD.
Results We found that the frequency of the 677T allele was significantly higher in T2DM patients with CHD than those without CHD (P=0.011). However, there was no significant difference in any of the examined haplotypes between T2DM patients with and without CHD. Furthermore, the 677T allele was associated with a higher risk of CHD development in diabetic patients with lower homocysteine (Hcy) levels (≤15 μmol/L) (P=0.006), while no effect of MTHFR gene polymorphism on the incidence of CHD was found in patients with higher Hcy levels (>15 μmol/L) (P=0.491).
Conclusion The MTHFR C677T gene polymorphism is associated with the risk of CHD of diabetic patients and could be used as an effective marker for CHD in Chinese diabetic populations with normal Hcy levels.

Objective To explore the therapeutic effects of trimetazidine (TMZ) on diabetic patients with coronary heart diseases.
Methods We conducted a comprehensive electronic search of PubMed, EMBASE, and Cochrane databases between the inception dates of databases and May 2019 (last search conducted on 30 May 2019) to identify randomized controlled trials. The evaluation method recommended by Cochrane Collaboration for bias risk assessment was employed for quality assessment. Random or fixed models were used to investigate pooled mean differences in left ventricular function, serum glucose metabolism, serum lipid profile, myocardial ischemia episodes and exercise tolerance with effect size indicated by the 95% confidence interval (CI).
Results Additional TMZ treatment contributed to considerable improvement of left ventricular ejection fraction (WMD=4.39, 95%CI: 3.83, 4.95, P<0.00001), left ventricular end diastolic diameter (WMD=-3.17, 95%CI: -4.90, -1.44, P=0.0003) and left ventricular end systolic diameter (WMD=-4.69, 95%CI: -8.66, -0.72, P=0.02). TMZ administration also significantly decreased fasting blood glucose (SMD=-0.43, 95%CI: -0.70, -0.17, P=0.001), glycosylated hemoglobin level (WMD=-0.59, 95%CI: -0.95, -0.24, P=0.001), serum level of total cholesterol (WMD=-20.36, 95%CI: -39.80, -0.92, P=0.04), low-density lipoprotein cholesterol (WMD=-20.12, 95%CI: -32.95, -7.30, P=0.002) and incidence of myocardial ischemia episodes (SMD=-0.84, 95%CI: -1.50, -0.18, P=0.01). However, there were no significant differences in serum triglyceride level, high-density lipoprotein cholesterol, exercise tolerance between the TMZ group and the control group.
Conclusion TMZ treatment in diabetic patients with coronary heart disease is effective to improve cardiac function, serum glucose and lipid metabolism and clinical symptoms.

Objective To examine if the variations at sea level would be able to predict subsequent susceptibility to acute altitude sickness in subjects upon a rapid ascent to high altitude.
Methods One hundred and six Han nationality male individuals were recruited to this research. Dynamic electrocardiogram, treadmill exercise test, echocardiography, routine blood examination and biochemical analysis were performed when subjects at sea level and entering the plateau respectively. Then multiple regression analysis was performed to construct a multiple linear regression equation using the Lake Louise Score as dependent variable to predict the risk factors at sea level related to acute mountain sickness (AMS).
Results Approximately 49.05% of the individuals developed AMS. The tricuspid annular plane systolic excursion (22.0±2.66 vs. 23.2±3.19 mm, t=1.998, P=0.048) was significantly lower in the AMS group at sea level, while count of eosinophil [(0.264±0.393)×10⁹/L vs. (0.126±0.084)×10⁹/L, t=-2.040, P=0.045], percentage of differences exceeding 50 ms between adjacent normal number of intervals (PNN50, 9.66%±5.40% vs. 6.98%±5.66%, t=-2.229, P=0.028) and heart rate variability triangle index (57.1±16.1 vs. 50.6±12.7, t=-2.271, P=0.025) were significantly higher. After acute exposure to high altitude, C-reactive protein (0.098±0.103 vs. 0.062±0.045 g/L, t=-2.132, P=0.037), aspartate aminotransferase (19.7±6.72 vs. 17.3±3.95 U/L, t=-2.231, P=0.028) and creatinine (85.1±12.9 vs. 77.7±11.2 mmol/L, t=-3.162, P=0.002) were significantly higher in the AMS group, while alkaline phosphatase (71.7±18.2 vs. 80.6±20.2 U/L, t=2.389, P=0.019), standard deviation of normal-to-normal RR intervals (126.5±35.9 vs. 143.3±36.4 ms, t=2.320, P=0.022), ejection time (276.9±50.8 vs. 313.8±48.9 ms, t=3.641, P=0.001) and heart rate variability triangle index (37.1±12.9 vs. 41.9±11.1, t=2.020, P=0.047) were significantly lower. Using the Lake Louise Score as the dependent variable, prediction equation were established to estimate AMS: Lake Louise Score=3.783+0.281×eosinophil-0.219×alkaline phosphatase+0.032×PNN50.
Conclusions We elucidated the differences of physiological variables as well as noninvasive cardiovascular indicators for subjects after high altitude exposure compared with those at sea level. We also created an acute high altitude reaction early warning equation based on the physiological variables and noninvasive cardiovascular indicators at sea level.

Objective To summarize cases of acute myocardial infarction (AMI) after tranexamic acid (TXA) administration.
Methods Electronic databases were searched to identify all case reports presenting AMI after use of TXA. Two authors independently extracted data of patients’ manifestation, examinations, medical history, treatment and outcome.
Results Our search yielded seven case reports including seven patients. Among the seven reports, two were from USA, and the other five were from India, Turkey, UK, Italy and France, respectively. Of the seven patients aged between 28- and 77-year-old who developed AMI after TXA, five patients were female and two were male. TXA was prescribed for four patients to reduce surgical bleeding, for two patients to treat menorrhagia and for one patient to manage hemoptysis. The diagnosis of AMI was made based upon patients’ symptoms, ECG, myocardium-specific enzymes, and confirmed by coronary angiography. Coronary stents were placed in four patients, for whom anti-platelet and anti-coagulation drugs were prescribed. No death or major cardiovascular events were reported during hospitalization and follow-up.
Conclusion These case reports suggested a possible association of TXA administration and an increased risk of AMI, even in patients with relatively low thrombotic risk.

Regional healthcare platforms collect clinical data from hospitals in specific areas for the purpose of healthcare management. It is a common requirement to reuse the data for clinical research. However, we have to face challenges like the inconsistence of terminology in electronic health records (EHR) and the complexities in data quality and data formats in regional healthcare platform. In this paper, we propose methodology and process on constructing large scale cohorts which forms the basis of causality and comparative effectiveness relationship in epidemiology. We firstly constructed a Chinese terminology knowledge graph to deal with the diversity of vocabularies on regional platform. Secondly, we built special disease case repositories (i.e., heart failure repository) that utilize the graph to search the related patients and to normalize the data. Based on the requirements of the clinical research which aimed to explore the effectiveness of taking statin on 180-days readmission in patients with heart failure, we built a large-scale retrospective cohort with 29647 cases of heart failure patients from the heart failure repository. After the propensity score matching, the study group (n=6346) and the control group (n=6346) with parallel clinical characteristics were acquired. Logistic regression analysis showed that taking statins had a negative correlation with 180-days readmission in heart failure patients. This paper presents the workflow and application example of big data mining based on regional EHR data.

Objects The aim of this trial was to evaluate the effect of short-term high-dose atorvastatin therapy on levels of high-sensitivity C-reactive protein (hs-CRP), malonaldehyde (MDA), endothelin-1(ET-1), matrix metalloproteinases (MMPs), and left ventricular (LV) remodeling in patients with first time attack of acute anterior myocardial infarction (AAMI) .Methods A hundred and three patients with first time attack of AAMI who underwent successful primary percutaneous coronary intervention were randomized to receive atorvastatin 40 mg once daily for 1 week followed by 20 mg once daily (intensive treatment group, IT group, n=49), or atorvastatin 20 mg once daily (standard treatment group, ST group, n=54). Plasma levels of hs-CRP, MDA, ET-1, MMP-2 and MMP-9 were measured on admission, at 1 week, 2 weeks and 6 months follow up and compared between the IT group and ST group. Echocardiography was performed on admission, at 2 week, and 1 year follow up. The left ventricular end-diastolic volume (LVEDV), left ventricular end-systolic volume (LVESV) and left ventricular ejection fraction (LVEF) were measured at each echocardiographic examination and compared between the IT group and ST group.Results Plasma levels of hs-CRP (F=7.718, P=0.009), ET-1 (F=7.882, P=0.006), MMP-9 (F=4.834, P=0.028) and pro-BNP (F=4.603, P=0.032) were significantly lower at 1 week after initial onset of AAMI in the IT group compared with the ST group. The changes of LVEDV, LVESV, and LVEF at the 1 year follow-up from the admission did not differ between the IT group and the ST group (t=0.722, P=0.444; t=1.228, P=0.221; t=1.354, P=0.187, repectively).Conclusions Short-term high-dose atorvastatin treatment for AAMI was associated with lower hs-CRP, ET-1 and MMP-9 levels compared to the standard dose treatment. However, this beneficial effect is not likely to related to the left ventricular remodeling.

Objective To identify the risk factors that are associated with the midterm coronary artery bypass grafting (CABG) functionality by assessing patency of left internal mammary artery (LIMA) graft and saphenous vein (SV) graft with 64-slice multi-detector computed tomography (64-MDCT).Methods Patients who underwent CABG operation and postoperative 64-MDCT follow-up examinations from August 2012 to December 2015 were included. The graft patent status was classified into patent and poor patent according to MDCT findings predominantly on 3D reconstructed images by two radiologists. The clinical data and imaging findings of the patients were collected and compared between the patent group and poor patent group. Univariate analysis and the multivariate logistic regression analysis were performed to identify the risk factors that affect graft patency.Results Among 341 patients in the study, there were 330 LIMA grafts [326 anastomosed to the left anterior descending artery (LAD), 4 to right coronary artery (RCA)] and 564 SV grafts (SVG) [100 anastomosed to the diagonal branch (D), 226 to the obtuse marginal branch (OM), and 238 to the RCA territory]. The approximal vessel stenosis exceeding 90% occurred in 268 of 292 patent LIMA grafts, and in 1 of 34 poor patent grafts (χ ²=167, P<0.001). The patency rate was higher when SVG was anastomosed to OM (85.4%) or RCA territory (81.9%) than to D (69.0%) (χ ²=15.471, P=0.004). The proximal target vessel stenosis < 90% (OR= 0.015, 95% CI: 0.01-0.14, P=0.000) was independently associated with the closure risk of LIMA grafts, the dyslipidemia (OR= 1.52, 95% CI: 1.0-2.5, P=0.048), history of diabetes (OR = 1.28, 95% CI : 0.90-2.26, P=0.045) and typical angina symptoms (OR=1.81, 95% CI :1.33-4.15, P=0.003) were independently associated with the closure risk of SVG. Conclusions The proximal LAD stenosis less than 90% was adversely associated with graft patency in LIMA recipients; dyslipidemia, diabetes and angina symptoms were associated with the midterm failure in SVG recipients. The choice of the target anastomosis sites may affect the patency of SVG.