The diagnostic value of different enzymes and standard ECG in acute myocardial infarction

High-Sensitivity Troponin: A Review on Characteristics, Assessment, and Clinical Implications

The use of high-sensitivity cardiac troponin (hs-cTn) assays has become part of the daily practice in most of the laboratories worldwide in the initial evaluation of the typical chest pain. Due to their early surge, the use of hs-cTn may reduce the time needed to recognise myocardial infarctions (MI), which is vital for the patients presenting in the emergency departments for chest pain. The latest European Society of Cardiology Guidelines did not only recognise their central role in the diagnosis algorithm but also recommended their use for rapid rule-in/rule-out of MI. High-sensitivity cardiac troponins are also powerful prognostic markers for long-term events and mortality, not only in a wide spectrum of other cardiovascular diseases (CVD) but also in several non-CVD pathologies. Moreover, these biomarkers became a powerful tool in special populations, such as paediatric patients and, most recently, COVID-19 patients. Although highly investigated, the assessment and interpretation of the hs-cTn changes are still challenging in the patients with basal elevation such as CKD or critically ill patients. Moreover, there are still various analytical characteristics not completely understood, such as circadian or sex variability, with major clinical implications. In this context, the present review focuses on summarizing the most recent research in the current use of hs-cTn, with a main consideration for its role in the diagnosis of MI but also its prognostic value. We have also carefully selected the most important studies regarding the challenges faced by clinicians from different specialties in the correct interpretation of this biomarker. Moreover, future perspectives have been proposed and analysed, as more research and cross-disciplinary collaboration are necessary to improve their performance.

Use of biochemical tests for myocardial infarction in the county of Västernorrland, a clinical chemistry routine for the diagnosis of myocardial infarction

A study of 116 patients admitted on the suspicion of myocardial infarction is presented. Twenty three of the patients were found to have infarction. For the diagnosis of infarct the most reliable biochemical analyses at present appear to be serum creatine kinase (S-CK, E.C.2.7.3.2.) with its isoenzyme S-CKMB and serum lactate dehydrogenase (S-LD, E.C.1.1.1.27.) with its isoenzyme S-LD-1. If an organization with blood samples at fixed intervals after the appearance of symptoms could be arranged, this would be most recommendable. In many hospitals this is, however, difficult and the blood samples have to be drawn at specified hours. In the four hospitals in the county of Västernorrland, Sweden, this latter procedure has been introduced. Blood is drawn at the arrival of the patient, at 8 am and 8 pm the first day, and at 8 am the next two days of the stay in hospital. In the first two samples S-CK and S-LD are determined, in the third S-CK, in the fourth S-CK and S-LD and in the fifth S-CK. If the values are elevated, S-CKMB and S-LD-1 are determined. S-Myoglobin has been found valuable in the early exclusion of the diagnosis of infarction.

Two-dimensional electrophoresis of human serum proteins following acute myocardial infarction

Serum proteins associated with acute myocardial infarction (AMI) have been monitored by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and high resolution two-dimensional electrophoresis (2-DE) under nonreducing conditions. Proteins a, b, c (Mr 13,000; pI6.2, 6.7 and 7.5, respectively) and e(Mr27,000; pI5.2) appear simultaneously approximately 30 h after infarction, reach maximum intensity after 48 h and progressively decline thereafter. Protein d (Mr15,000; pI7-8.5; identified as hemoglobin) sometimes appears within 18 h of infarction. Proteins a-c are not detected in the 2-DE patterns of healthy myocardium, infarcted myocardium, pectoral muscle or tongue, but e is present in all and tentatively identified as myosin light chain. Other myocardial proteins which are either reduced in amount following infarction or more specifically associated with myocardium than pectoral muscle are not detected in the serum of AMI patients. Analysis of unconcentrated urine by SDS-PAGE and silver staining does not reveal proteins specific to AMI.