Diagnosis Of Acute Myocardial Ischemia Research Articles

Myocardial motion in acute ischemia: revealing invisible deformation by echocardiography.

Echocardiography has been used clinically to assess regional myocardial wall motion for the diagnosis of acute myocardial ischemia or stress-induced ischemia, but it is often difficult to distinguish hypokinetic motion from normal motion. Myocardial wall motion is affected by loading conditions as well as intrinsic contractility, making it challenging to define a normal range of wall motion. Therefore, hypokinesis is usually diagnosed by comparing target areas with other areas of myocardium considered normal (relative hypokinesis). Myocardial strain analysis by tissue Doppler echocardiography and speckle-tracking echocardiography has enabled objective and quantitative evaluation of regional myocardial wall motion. Peak systolic strain decreases during acute ischemia, but subtle and invisible myocardial motion, such as early systolic lengthening (ESL) and postsystolic shortening (PSS), also occurs, and the analysis of these subtle motions can improve the diagnostic accuracy of ischemia. However, the diagnosis of ischemic myocardium by strain analysis is not widely performed in clinical practice at this time due to several limitations. This article reviews the features of myocardial motion during acute ischemia, the mechanisms of ESL and PSS, the diagnosis of ischemic myocardium using strain analysis, and current approaches and future challenges to overcome the limitations in the detection of relative hypokinesis. This article also explains the use of ESL and PSS to detect myocardial ischemic memory that remains after brief ischemia.

Electrocardiographic Diagnosis of Acute Myocardial Ischemia During His Bundle Pacing

Electrocardiographic Diagnosis of Acute Myocardial Ischemia During His Bundle Pacing

Combined metabolomics and machine learning algorithms to explore metabolic biomarkers for diagnosis of acute myocardial ischemia.

Acute myocardial ischemia (AMI) remains the leading cause of death worldwide, and the post-mortem diagnosis of AMI represents a current challenge for both clinical and forensic pathologists. In the present study, the untargeted metabolomics based on ultra-performance liquid chromatography combined with high-resolution mass spectrometry was applied to analyze serum metabolic signatures from AMI in a rat model (n = 10 per group). A total of 28 endogenous metabolites in serum were significantly altered in AMI group relative to control and sham groups. A set of machine learning algorithms, namely gradient tree boosting (GTB), support vector machine (SVM), random forest (RF), logistic regression (LR), and multilayer perceptron (MLP) models, was used to screen the more valuable metabolites from 28 metabolites to optimize the biomarker panel. The results showed that classification accuracy and performance of MLP model were better than other algorithms when the metabolites consisting of L-threonic acid, N-acetyl-L-cysteine, CMPF, glycocholic acid, L-tyrosine, cholic acid, and glycoursodeoxycholic acid. Finally, 17 blood samples from autopsy cases were applied to validate the classification model's value in human samples. The MLP model constructed based on rat dataset achieved accuracy of 88.23%, and ROC of 0.89 for predicting AMI type II in autopsy cases of sudden cardiac death. The results demonstrated that MLP model based on 7 molecular biomarkers had a good diagnostic performance for both AMI rats and autopsy-based blood samples. Thus, the combination of metabolomics and machine learning algorithms provides a novel strategy for AMI diagnosis.

Diagnostic and prognostic significance of premature ventricular complexes in community and hospital-based participants: A scoping review.

While there are published studies that have examined premature ventricular complexes (PVCs) among patients with and without cardiac disease, there has not been a comprehensive review of the literature examining the diagnostic and prognostic significance of PVCs. This could help guide both community and hospital-based research and clinical practice. Scoping review frameworks by Arksey and O'Malley and the Joanna Briggs Institute (JBI) were used. A systematic search of the literature using four databases (CINAHL, Embase, PubMed, and Web of Science) was conducted. The review was prepared adhering to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis Extension for Scoping Review (PRISMA-ScR). A total of 71 relevant articles were identified, 66 (93%) were observational, and five (7%) were secondary analyses from randomized clinical trials. Three studies (4%) examined the diagnostic importance of PVC origin (left/right ventricle) and QRS morphology in the diagnosis of acute myocardial ischemia (MI). The majority of the studies examined prognostic outcomes including left ventricular dysfunction, heart failure, arrhythmias, ischemic heart diseases, and mortality by PVCs frequency, burden, and QRS morphology. Very few studies have evaluated the diagnostic significance of PVCs and all are decades old. No hospital setting only studies were identified. Community-based longitudinal studies, which make up most of the literature, show that PVCs are associated with structural and coronary heart disease, lethal arrhythmias, atrial fibrillation, stroke, all-cause and cardiac mortality. However, a causal association between PVCs and these outcomes cannot be established due to the purely observational study designs employed.

Cecal Gut Microbiota and Metabolites Might Contribute to the Severity of Acute Myocardial Ischemia by Impacting the Intestinal Permeability, Oxidative Stress, and Energy Metabolism.

Emerging evidence highlights the role of gut microbiota in regulating the pathogenesis of coronary heart disease. Here, we performed 16S rRNA gene sequencing and UPLC-Q-TOF/MS-based metabolomics to investigate the gut microbiome and metabolomes of cecal contents in the isoproterenol (ISO)-induced acute myocardial ischemia (AMI) rats. As expected, considerable gut microbiota alterations were observed in the AMI rats compared with the control rats, paralleling with intestinal inflammation and apoptosis. At phylum level, the abundance of Firmicutes was significantly decreased, whereas the abundance of Bacteroidetes and Spirochaetae was strikingly enriched in the AMI group. At genus level, the significant alteration of genera Treponema 2, Rikenellaceae RC9 gut group, Prevotellaceae UCG-003, and Bacteroides may contribute to the pathogenesis of AMI. These altered microbiota might influence the intestinal permeability and subsequently impair intestinal barrier and stimulate gut inflammation. Consistently, significantly metabolic differences of cecal contents between the AMI and control groups were revealed, and threonic acid, L-urobilin and L-urobilinogen were considered the most associated cecal metabolites with AMI. These strikingly altered metabolites were mainly related to energy metabolism and oxidative stress which could lead to apoptosis and further affect gut barrier. Ultimately, we revealed the potential link of these altered gut microbiota/metabolomes and intestinal inflammatory factors and apoptotic proteins and further confirmed their intimate connections with intestinal inflammation and gut barrier. Our findings depict uncovered potential relationship among the gut microbiome, cecal metabolomes and AMI.

Influence of Left Bundle Branch Block on the Electrocardiographic Changes Induced by Acute Coronary Artery Occlusion of Distinct Location and Duration.

Background: Electrocardiographic (ECG) diagnosis of acute myocardial ischemia is hampered in the presence of left bundle branch block (LBBB).Objectives: We analyzed the influence of location and duration of myocardial ischemia on the ECG changes in pigs with LBBB.Methods: LBBB was acutely induced in 14 closed chest anesthetized pigs by local electrical ablation. Thereafter, episodes of 5 min catheter balloon occlusion followed by 10 min reperfusion of the left anterior descending (LAD), left circumflex (LCX), and right (RCA) coronary arteries were done sequentially in 5 pigs. Additionally, a 3-h occlusion of these arteries was performed separately in the other 9 pigs. A 15-lead ECG including leads V7 to V9 was continuously recorded.Results: Ablation induced LBBB showed QRS widening, loss of r wave in V1, and predominant R waves in V2 to V9. After 5 min of ischemia the occluded artery could be identified in all cases: the LAD by R waves and ST elevation in V1–V3; the LCX by both ST segment elevation in II, III, aVF, V7 to V9 and ST segment depression in V1 to V4; and the RCA by ST depression and new S-waves in all precordial leads. Three hours after coronary occlusion, ST segment changes declined progressively and only the LAD occlusion could be reliably recognized.Conclusion: LBBB did not mask the ECG recognition of the occluded coronary artery during the first 60 min of ischemia, but 3 h later only the LAD occlusion could be reliably identified. ST elevation in leads V7 to V9 is specific of LCX occlusion and it could be useful in the diagnosis of acute myocardial ischemia in the presence of LBBB.

Application of Ischemia Modified Albumin for Acute Ischemic Heart Disease in Forensic Science

To explore the application value and forensic significance of ischemia modified albumin （IMA） in pericardial fluid to diagnose sudden cardiac death. IMA level in pericardial fluid was detected in acute ischemic heart disease group （n=36）, acute myocardial infarction group （n=6）, cardiomyopathy group （n=4） and control group （n=15） by albumin cobalt binding method. The levels of IMA were compared among these groups. The best cut-off IMA value was estimated and the sensitivity and specificity of acute myocardial ischemia group was distinguished from control group by receiver operating characteristics （ROC） curve. The IMA level in acute ischemic heart disease group was significantly higher than that of control group （P<0.05）. Compared with acute myocardial infarction group and cardiomyopathy group, the IMA level in acute ischemic heart disease group had no significant difference （P>0.05）. The cut-off value for the identification of acute myocardial ischemia which obtained by ROC analysis was 40.65 U/mL. And the sensitivity and specificity for distinguishing acute ischemia cardiac disease was 60.0% and 80.5%, respectively. The IMA value in pericardial fluid can be a reference marker for the diagnosis of acute myocardial ischemia, which also can provide objective basis for the forensic identification of sudden cardiac death.

The Changes of HIF-1α and VEGF-A in Myocardial Tissue of Rats with Arrhythmias

To observe the expression changes of hypoxia inducible factor-1α（HIF-1α） and vascular endothelial growth factor-A （VEGF-A） in rats with arrhythmias, and to explore the differences of the expression pattern in the two indicators of acute myocardial ischemia caused by arrhythmias and coronary insufficiency. The arrhythmia was induced by CaCl₂, and the expression changes of HIF-1α and VEGF-A were detected by immunohistochemistry, Western blotting and real-time PCR within 6 h after the arrhythmia in rats. The expression of HIF-1α and VEGF-A showed diffuse in the myocardial tissue of rats died from arrhythmias. Both of them increased in the early arrhythmia, then decreased. Extensive myocardial ischemia happened at the beginning of arrhythmia occurrence and its range didn't expand with time. The expressions of HIF-1α and VEGF-A in myocardium of the rats with arrhythmia can provide evidence for the differential diagnosis of acute myocardial ischemia caused by fatal arrhythmia and coronary insufficiency.

PERSPECTIVES OF LASER-POLARIMETRIC METHODS OF BIOLOGICAL TISSUE INVESTIGATION IN FORENSIC MEDICINE

Abstract: The aim of our work was to analyze existing research methods of investigating damage to human tissues and to search for and develop modern methods of diagnosis of lifetime and postmortem changes of biological tissues and bodily fluids for solving forensic science and practice problems. In particular, we investigated the establishment of the time of death for various causes, the time of formation of hematomas, lifetime of injury formation and diagnosis of acute myocardial ischemia.

Early markers for myocardial ischemia and sudden cardiac death.

The post-mortem diagnosis of acute myocardial ischemia remains a challenge for both clinical and forensic pathologists. We performed an experimental study (ligation of left anterior descending coronary artery in rats) in order to identify early markers of myocardial ischemia, to further apply to forensic and clinical pathology in cases of sudden cardiac death. Using immunohistochemistry, Western blots, and gene expression analyses, we investigated a number of markers, selected among those which are currently used in emergency departments to diagnose myocardial infarction and those which are under investigation in basic research and autopsy pathology studies on cardiovascular diseases. The study was performed on 44 adult male Lewis rats, assigned to three experimental groups: control, sham-operated, and operated. The durations of ischemia ranged between 5min and 24h. The investigated markers were troponins I and T, myoglobin, fibronectin, C5b-9, connexin 43 (dephosphorylated), JunB, cytochrome c, and TUNEL staining. The earliest expressions (≤30min) were observed for connexin 43, JunB, and cytochrome c, followed by fibronectin (≤1h), myoglobin (≤1h), troponins I and T (≤1h), TUNEL (≤1h), and C5b-9 (≤2h). By this investigation, we identified a panel of true early markers of myocardial ischemia and delineated their temporal evolution in expression by employing new technologies for gene expression analysis, in addition to traditional and routine methods (such as histology and immunohistochemistry). Moreover, for the first time in the autopsy pathology field, we identified, by immunohistochemistry, two very early markers of myocardial ischemia: dephosphorylated connexin 43 and JunB.

Metabolomics in the Diagnosis of Acute Myocardial Ischemia

Despite recent advances in the diagnosis of myocardial ischemia, its biochemical identification in patients with acute chest pain is still a challenge, and alternative approaches for further improvement are needed. Metabolic alterations are the first consequences of acute myocardial ischemia. Metabolomics coupled with potent multivariate analyses allows for a simultaneous and relative quantification of thousands of different metabolites within a given sample. Thus, this discipline might exert a great impact on medical practice in cardiovascular medicine by providing a wealth of relevant biochemical data. Metabolomics is a promising tool to improve current, single biomarker-based approaches by identifying metabolic biosignatures that embody global biochemical changes in disease. This is especially relevant for conditions requiring early treatment like myocardial ischemia. This review discusses the potential application of metabolomics in the diagnosis of myocardial ischemia.

Assessment of ischaemia modified albumin levels for early diagnosis of acute myocardial ischaemia in emergency room

BackgroundThe aim of this study was to retrospectively evaluate assessment of ischaemia-modified albumin (IMA) levels for early diagnosis of acute myocardial ischaemia particularly for patients admitted in emergency room.MethodsThe following...

Heart Failure with Transient Left Bundle Branch Block in the Setting of Left Coronary Fistula

Coronary arterial fistulas are rare communications between vessels or chambers of the heart. Although cardiac symptoms associated with fistulas are well described, fistulas are seldom considered in the differential diagnosis of acute myocardial ischemia. We describe the case of a 64-year-old man who presented with left shoulder pain, signs of heart failure, and a new left bundle branch block (LBBB). Cardiac catheterization revealed a small left anterior descending (LAD)-to-pulmonary artery (PA) fistula. Diuresis led to subjective improvement of the patient's symptoms and within several days the LBBB resolved. We hypothesize that the coronary fistula in this patient contributed to transient ischemia of the LAD territory through a coronary steal mechanism. We elected to observe rather than repair the fistula, as his symptoms and ECG changes resolved with treatment of his heart failure.

TNNI3K Could be a Novel Molecular Target for the Treatment of Cardiac Diseases

Recently, regenerative medicine using the transplantation of embryonic stem cells and bone marrow stem cells has been a great success but still has many unconfirmed problems including its clinical evaluation. The aim of this article is to review current literature and some patents regarding molecular therapeutic agents including using MAP kinase TNNI3K for the treatment and diagnosis of acute myocardial ischemia or infarction. TNNI3K is a novel cardiac troponin I-interacting kinase gene and its overexpression may promote cardiac myogenesis, improve cardiac performance, and attenuate ischemia-induced ventricular remodeling. The modulation of embryonal stem cells with high TNNI3K activity using a TNNI3K active peptide could be a useful therapeutic approach for ischemic cardiac diseases. For overexpressing TNNI3K or enhancing TNNI3K activity in cardiac precursor cells, the engraftment of bone marrow cells or embryonic stem cells can effectively promote cardiac myogenesis, beating frequency, and contractile functions, and decrease "silent" (no contraction) cardiac cells after cell transplantion, indicating that the overexpression of TNNI3K can increase the success rate of transplanting embryonic stem cells or bone marrow cells into ischemic hearts for the treatment of ischemic cardiac diseases. Although previous investigations showing that TNNI3K may be involved in the development of cardiac hypertrophy, it is still unclear whether TNNI3K has a role in cardiac hypertrophy or what mechanism is involved in the effects of TNNI3K. To confirm this, further investigations need to be undertaken.

Abstract 711: Diagnosis of Acute Myocardial Ischemia by Speckle Tacking Echocardiography -A Comparative Animal Study-

Since the subendocardium is known to be more vulnerable to ischemia than the subepicardium, indexes of subendocardial function are expected to be more sensitive than indexes of whole LV wall. The aim of our study is to compare the diagnostic values of systolic and diastolic indexes measured by 2D speckle tracking echocardiography in an animal experiment. The proximal left circumflex coronary artery was balloon-occluded for 3 minutes in 14 pigs. LV short-axis view was recorded at rest and 30 minutes after release of the occlusion by transthoracic 2D echocardiography except for one pig with ventricular fibrillation. Peak circumferential and radial strain (CR, RS), peak systolic and diastolic strain rate (CSR-S′ and CSR-E′), time from QRS to peak CS and RS, time from QRS to E′, and the incidence of post-systolic shortening (PSS) were measured in the subendocardium of the LV posterior wall. ROC curve analysis of these indexes was done for the diagnosis of acute myocardial ischemia followed by reperfusion. Only 5 indexes showed significant change before and after the occlusion. ROC curve revealed that CSR-E′ had the highest predictive value for detecting the ischemic memory, followed by peak CS, and CSR-S′. Peak early diastolic circumferential strain rate of the subendocardium was the most powerful index for diagnosing ischemic memory after acute coronary occlusion. Table. Results of meaurement (mean±SD)

Universal Definition of Myocardial Infarction

Myocardial infarction is a major cause of death and disability worldwide. Coronary atherosclerosis is a chronic disease with stable and unstable periods. During unstable periods with activated inflammation in the vascular wall, patients may develop a myocardial infarction. Myocardial infarction may be a minor event in a lifelong chronic disease, it may even go undetected, but it may also be a major catastrophic event leading to sudden death or severe hemodynamic deterioration. A myocardial infarction may be the first manifestation of coronary artery disease, or it may occur, repeatedly, in patients with established disease. Information on myocardial infarction attack rates can provide useful data regarding the burden of coronary artery disease within and across populations, especially if standardized data are collected in a manner that demonstrates the distinction between incident and recurrent events. From the epidemiological point of view, the incidence of myocardial infarction in a population can be used as a proxy for the prevalence of coronary artery disease in that population. Furthermore, the term myocardial infarction has major psychological and legal implications for the individual and society. It is an indicator of one of the leading health problems in the world, and it is an outcome measure in clinical trials and observational studies. With these perspectives, myocardial infarction may be defined from a number of different clinical, electrocardiographic, biochemical, imaging, and pathological characteristics. In the past, a general consensus existed for the clinical syndrome designated as myocardial infarction. In studies of disease prevalence, the World Health Organization (WHO) defined myocardial infarction from symptoms, ECG abnormalities, and enzymes. However, the development of more sensitive and specific serological biomarkers and precise imaging techniques allows detection of ever smaller amounts of myocardial necrosis. Accordingly, current clinical practice, health care delivery systems, as well as epidemiology and clinical trials all require a …

Accuracy of N-Terminal Probrain Natriuretic Peptide to Predict Mortality or Detect Acute Ischemia in Patients with Coronary Artery Disease

Objective: The aim of the study was to assess the accuracy of N-terminal probrain natriuretic peptide (NT-proBNP) to predict mortality or detect acute ischemia in patients with coronary artery disease (CAD). Methods: This study included 1,552 patients with stable (n = 1,059) or unstable (n = 493) CAD undergoing percutaneous coronary intervention. NT-proBNP was measured before percutaneous coronary intervention. The primary endpoint of the study was mortality. Patients were followed for 3.6 years. Results: There were 171 deaths (11%) during follow-up. In the entire group of patients, NT-proBNP had the best accuracy to predict mortality (area under receiver operating characteristic curve 0.76, 95% CI 0.72–0.80). In patients without congestive heart failure (n = 760) there were 46 deaths (6%). The area under receiver operating characteristic curve of NT-proBNP was reduced to 0.70 (95% CI 0.63–0.79) which was not better than the area under curve of age (p = 0.981) or C-reactive protein (p = 0.082) regarding mortality. NT-proBNP showed limited power to detect patients with acute ischemia (area under curve 0.63, 95% CI 0.60–0.66) among consecutive patients with stable and unstable CAD. Conclusions: NT-proBNP has a moderate accuracy to predict mortality and does not assist in the diagnosis of acute myocardial ischemia in patients with CAD.

Injury to the circumflex coronary artery following mitral valve repair

In a recent issue of the journal, Zegdi et al. [1] courageously reported a complication that occurred after a mitral valve repair case in which the circumflex coronary artery was acutely occluded due to the prosthetic ring implantation. We too encountered the same complication in three cases: two patients following an extensive annulus decalcification and another following a simple posterior leaflet quadrangular resection. In all patients, the diagnosis of acute myocardial ischemia was suspected in the operating room when facing a variable degree of hemodynamic instability with localized EKG abnormalities; intraoperative echography revealed a segmental lateralwall dysfunction. Revascularization with a saphenous vein graft anastomosed to the obtuse margin immediately improved the situation and all three patients had a normal postoperative outcome. As in Zegdi et al.’s case, all patients had a large and dominant left coronary artery. The circumflex coronary artery is in intimate relation with the mitral annulus, particularly in its anterolateral commissure, P1 and to a lesser degree P2 portions; it is noteworthy that injury to this vessel can occur even in teams with a significant experience in mitral valve repair surgery.

Re: Injury to the circumflex coronary artery following mitral valve repair

In a recent issue of the journal, Zegdi et al. [1] courageously reported a complication that occurred after a mitral valve repair case in which the circumflex coronary artery was acutely occluded due to the prosthetic ring implantation. We too encountered the same complication in three cases: two patients following an extensive annulus decalcification and another following a simple posterior leaflet quadrangular resection. In all patients, the diagnosis of acute myocardial ischemia was suspected in the operating room when facing a variable degree of hemodynamic instability with localized EKG abnormalities; intraoperative echography revealed a segmental lateralwall dysfunction. Revascularization with a saphenous vein graft anastomosed to the obtuse margin immediately improved the situation and all three patients had a normal postoperative outcome. As in Zegdi et al.’s case, all patients had a large and dominant left coronary artery. The circumflex coronary artery is in intimate relation with the mitral annulus, particularly in its anterolateral commissure, P1 and to a lesser degree P2 portions; it is noteworthy that injury to this vessel can occur even in teams with a significant experience in mitral valve repair surgery.

Rate-dependent Left Bundle Branch Block during General Anesthesia - A case report -

Department of Anesthesiology and Pain Medicine, College of Medicine, The Catholic University of Korea, Seoul, Korea Rate-dependent left bundle branch block during general anesthesia is rare, but its occurrence makes the electrocardiographic diagnosis of acute myocardial ischemia or infarction difficult. It can also be confused with slow rate ventricular tachycardia. Herein, a case of rate-dependent left bundle branch block, in a patient with no previous history of ischemic heart disease, is reported. The administration of esmolol resulted in a decrease in the heart rate, with reversion to normal sinus rhythm.