Detection Of Transient Myocardial Ischemia Research Articles

Analysis of the application of echocardiography technology in diagnosis of acute myocardial infection

The purpose of this study is to enhance the diagnosis and treatment of acute myocardial infarction, prolong the life of patients with coronary heart disease, and improve the survival rate. In this study, 30 healthy adults are classified as the control group, and real-time three-dimensional echocardiography technology is used to observe the myocardial changes and characteristics of right ventricular morphology after acute myocardial infarction, which provides a theoretical basis for early clinical diagnosis and early intervention. The results show that the real-time three-dimensional echocardiography can provide more diagnostic information through the three-dimensional imaging of the cardiac structure and the real-time observation of the cardiac structures and their adjacent relations from any angle by combining the cutting and rotation of the image. Conventional examination methods such as two-dimensional echocardiography have a narrow time window for the detection of transient myocardial ischemia, which can clearly diagnose the ischemia in early stage, but its diagnostic ability in the late stage of ischemia is limited. When obtaining the cardiac full volume image within one cardiac cycle, echocardiography can quickly acquire dynamic images of ventricular volume without splicing and combine with the function of automatic delineation of endocardium of the 3d workstation to construct a real ventricular stereo image independent of the assumptions of the geometric model, so as to solve the inconvenience of the complex right ventricular space configuration and the obvious difference of its shape with the different load state. Therefore, as a new non-invasive imaging technique, it has unique advantages in accurate measurement of heart volume and evaluation of heart function.

Nardilysin is a promising biomarker for the early diagnosis of acute coronary syndrome

BackgroundBiomarkers for detection of transient myocardial ischemia in patients with unstable angina (UA) or for very early diagnosis of acute myocardial infarction (AMI) are not currently available. Methods and resultsWe performed two sequential screenings of autoantibodies elevated shortly after the onset of acute coronary syndrome (ACS), and focused on metalloendopeptidase nardilysin (NRDC) among 19 identified candidate antigens. In a retrospective analysis among 93 ACS and 117 non-ACS patients, the serum level of NRDC was significantly increased in patients with ACS compared with that in patients with non-ACS (2073.5±189.8pg/ml versus 775.7±63.4pg/ml, P<0.0001). The area under the curve of NRDC for the diagnosis of ACS was 0.822 by the receiver operating characteristic curves analysis. In the time course analysis in 43 consecutive ACS patients (AMI: N=35 and UA: N=8), serum concentration of NRDC was significantly increased even in UA patients with a peak serum NRDC levels reached at admission both in AMI and UA patients. In a mouse model of AMI, we found an acute increase in serum NRDC and reduced NRDC expression in ischemic regions shortly after coronary artery ligation. NRDC expression was also reduced in infarcted regions in human autopsy samples from AMI patients. Moreover, the short treatment of primary culture of rat cardiomyocytes with H2O2 or A23187 induced NRDC secretion without cell toxicity. ConclusionNRDC is a promising biomarker for the early detection of ACS, even in UA patients without elevation of necrosis markers.

Electrocardiographic Body Surface Mapping: Potential Tool for the Detection of Transient Myocardial Ischemia in the 21st Century?

Coronary artery disease (CAD) is one of the leading causes of cardiovascular mortality and morbidity worldwide. CAD presents as a wide spectrum of clinical disease from stable angina to ST segment elevation myocardial infarction. The 12-lead electrocardiogram (ECG) has been the main tool for the diagnosis of these events for almost a century but is limited in its diagnostic ability. For patients with suspected angina, the exercise tolerance test is often used to provoke and detect stress-induced ischemia but does not provide a definitive answer in a substantial proportion of patients. Body surface mapping (BSM) is a technique that samples multiple points around the thorax to provide a more comprehensive electrocardiographic data set than the conventional 12-lead ECG. Moreover, recent preliminary data demonstrate that BSM can detect and display transient regional myocardial ischemia in an intuitive fashion, employing subtraction color mapping, making it potentially valuable for diagnosing CAD causing transient regional ischemia. Research is ongoing to determine the full extent of its utility.

Serial Holter ST-Segment Monitoring after First Acute Myocardial Infarction

Based on serial Holter monitoring performed 7 times within 3 years after a first acute myocardial infarction, we assessed the prevalence, variability and long-term clinical importance of transient myocardial ischemia (TMI) defined as episodes of ambulatory ST-segment depression. In all, 121 consecutive male patients <70 years old were studied. The prevalence of TMI on different Holter recordings varied around 20% ranging between 18 and 27%. Fifty-five of the patients (46%) had TMI on at least 1 of the 7 Holter recordings. Considerable variability was found within and between patients for the presence of TMI. No high-risk group for cardiac death, nonfatal reinfarction or coronary revascularization during up to 10 years of follow-up could be identified by the detection of TMI. From these results we conclude that a routine search for TMI on serial Holter monitoring cannot be recommended in male survivors of an uncomplicated first acute myocardial infarction.

ST segment monitoring with a derived 12-lead electrocardiogram is superior to routine cardiac care unit monitoring

Prior studies have shown that a derived 12-lead electrocardiogram with a simple electrode configuration is comparable with the standard electrocardiogram for arrhythmia analysis. A prospective, comparative, within subjects design was used to compare the value of the derived 12-lead electrocardiogram with that of routine monitoring of leads V1 and II for detection of transient myocardial ischemia in 250 patients treated for unstable angina or myocardial infarction. During 11,532 hours of derived 12-lead ST segment monitoring, 55 (22%) of 250 patients had 176 episodes of ischemia. Of the 55 patients with ischemia, 75% reported no chest pain and 64% had no ischemic ST changes with routine monitoring leads. All five patients who developed angiographically confirmed abrupt reocclusion after percutaneous transluminal coronary angioplasty had ischemic ST changes with the derived electrocardiogram (sensitivity, 100%), compared with only two patients with routine monitoring (sensitivity, 40%). Serious complications occurred in 17% of angina patients with ischemic events compared to 3% of those without ischemia. Length of stay in the cardiac care unit was twice as long in angina patients who had ischemic events. In patients with acute myocardial infarction, ischemic events were not associated with a more complicated hospital course; however, length of stay in the cardiac care unit was longer in patients with recurrent ischemia. The findings show that derived 12-lead ST monitoring is superior to routine monitoring of leads V1 and II for detecting transient myocardial ischemia. ST monitoring of the derived 12-lead electrocardiogram may identify high-risk patients with unstable angina and provide prognostic information that would not be otherwise available from the usual clinical measures.

Relative importance of electrode placement over number of channels in transient myocardial ischemia detection by Holter monitoring

To compare the efficacy of 3-channel ambulatory electrocardiographic monitoring (Holter monitoring) with 2-channel Holter monitoring in the detection of transient myocardial ischemia (TMI), channels CM2, CM5, and modified II were studied. Sixty patients with documented coronary artery disease underwent 48-hour Holter monitoring during their normal daily life, followed by exercise stress testing in the laboratory monitored by means of radionuclide ventriculography and standard 12-lead electrocardiography. Analysis revealed that 3-channel Holter monitoring identified 24 patients with a total of 205 TMI episodes and a total ischemic burden of 371.00 mV·min. By itself, CM2 would have detected only 3 patients (13% of the TMI population), 6 TMI episodes (3% of the total TMI episodes), and a 2.4 mV·min ischemic burden (0.7% of the total ischemic burden). Modified II alone would have identified 17 patients (71% of the TMI population), 160 TMI episodes (78% of the total TMI episodes), and 307.24 mV·min of the ischemic burden (82% of the total ischemic burden). The combination of CMS/modified II identified 23 patients (96% of the TMI population), 201 TMI episodes (98% of the total TMI episodes), and 370.44 mV·min of the ischemic burden (98% of the total ischemic burden). These findings suggest that the electrode placement is more important than the absolute number of channels in the detection of TMI by Holter monitoring.

Value of a derived 12-lead ECG for detecting transient myocardial ischemia

Detection of transient myocardial ischemia (TMI) is an important objective for the t reatment of ischemic heart disease in patients admitted to the cardiac care unit. The purpose of this study was to evaluate ST-segment monitoring of a derived 12-lead electrocardiogram (ECG) and compare it with routinely monitored V 1 and II leads for detecting TMI. Three hypotheses were tested, and it was found that the derived 12-lead ECG is superior to routine monitoring for (1) detecting TMI during coronary angioplasty balloon occlusion, (2) detecting abrupt coronary artery reocclusion following angioplasty, and (3) predicting inhospital complications. Patients were monitored simultaneously with both routine and experimental methods. The sample population consisted of I50 patients, of whom 77 underwent coronary angioplasty. Seventy-five of the 77 angioplasty

Improved detection of transient myocardial ischemia by a new lead combination: Value of bipolar lead Nehb D for Holter monitoring

The investigations of ST-segment changes by Holter monitoring demonstrate asymptomatic and symptomatic episodes of myocardial ischemia, which may occur during daily activities. One factor, which is of great importance for the detection of silent myocardial ischemia during ambulatory monitoring, is the combination of the leads. Former studies showed that the analysis of two channels alone may not adequately detect silent myocardial ischemia. We therefore used a three-channel ambulatory ECG monitoring system with a new lead combination. The Holter monitoring results were correlated with the distribution of coronary stenosis detected by coronary angiography. In 54 patients with single coronary vessel disease and ischemic ST-segment depressions during exercise testing, standard Holter lead combination CM2/CM5 was extended by a bipolar Nehb D-like lead. Lead combination CM2/CM5 identified 23 patients (43%) with ST-segment depressions (total number of ischemic episodes = 372). Additional Nehb D-like lead identified 30 patients (55%) with ST-segment depressions (total number of ischemic episodes = 1048). The combination of leads CM2/CM5 and Nehb D raised the number of patients with documented ST-segment depressions to 33 of 54 (61%). Lead Nehb D showed the highest sensitivity for the detection of inferior wall ischemia (stenosis of the right coronary artery); nevertheless, this lead may not be regarded as specific for ST-segment alterations only caused by inferior wall ischemia. The correlation of ischemic ST-segment depressions during exercise testing (classified as anterior, inferior, or anterior and inferior type of ischemia) and documented ST-segment changes in the different Holter leads underline these results. A control group of 40 healthy volunteers demonstrated the high specifity of this new lead combination. In comparison with the standard lead combination CM2/CM5 for the detection of ST-segment changes, lead combination CM2/CM5 extended by a bipolar Nehb D lead is more sensitive for the detection of ST-segment alterations by Holter monitoring.

Ambulatory Electrocardiography Evaluation of Asymptomatic, Unstable, and Stable Coronary Artery Disease Patients for Myocardial Ischemia

Transient episodes of myocardial ischemia can be reliably detected by AEM in patients with known CAD. AEM appears to be particularly useful for patients in whom symptom control has been achieved with conventional antianginal drugs because many of these patients (up to 50%) continue to have residual silent ischemia that would otherwise remain undetected. Despite the lack of symptoms, numerous studies in patients with stable and unstable coronary syndromes have shown that the presence of silent ischemia during AEM is associated with an increased risk of subsequent coronary events and cardiac death. Although Holter monitoring is a practical and reliable tool for prolonged evaluation of myocardial ischemia, its routine use can not be advocated until its clinical role has been clearly defined in the ongoing large prospective studies.

Automated production of carbon-11 labelled acetate to allow detection of transient myocardial ischemia in man, using positron emission tomography

The synthesis of11C-acetate has been achieved via carbonation of methyl magnesium bromide with11C-labelled carbon dioxide. Using this procedure, 7.4 GBq /200 mCi/ of11CO2 produced by the14 N/P,α/11C nuclear reaction, was converted, within 20 min into11C-acetate with an activity higher than 2.22 GBq /60 mCi/. Chemical and biologic quality control shows that the product is pure, sterile, and pyrogen-free and therefore suitable for human use. Handling considerable amounts of activity has led us to automate the11C-acetate synthesis. The different parts of the system-programmable controller, sensors, automatic neutralization system-are described in detail.