Ans. A: First week The most often used markers are the creatine kinase-MB (CK-MB) fraction and the troponin I (TnI) or troponin T (TnT) levels. On the basis of the ECG, a distinction is made between ST elevation MI (STEMI) or non-ST elevation MI (NSTEMI). Risk Factors Older age Male sex Tobacco smoking Hypercholesterolemia (more accurately hyperlipoproteinemia, especially high low density lipoprotein and low high density lipoprotein) Hyperhomocysteinemia Diabetes (with or without insulin resistance) High blood pressure Obesity (defined by a body mass index of more than 30 kg/ m2) Stress Occupations. Women who use combined oral contraceptive pills. The most serious of these arrhythmias is ventricular fibrillation (V-Fib/VF), an extremely fast and chaotic hea rhythm that is the leading cause of sudden cardiac death. Another life threatening arrhythmia is ventricular tachycardia (V-Tach/VT). Different zones of the hea can become injured: - An occlusion of the left anterior descending coronary aery(LAD) will result in an anterior wall myocardial infarct. - Infarcts of the lateral wall are caused by occlusion of the left circumflex coronary aery(LCx) or its oblique marginal branches (or even large diagonal branches from the LAD.) Both inferior wall and posterior wall infarctions may be caused by occlusion of either the right coronary aery or the left circumflex aery, depending on which feeds the posterior descending aery. Right ventricular wall infarcts are also caused by right coronary aery occlusion. Electrocardiogram The 12 lead ECG is used to classify patients into one of three groups: Those with ST segment elevation or new bundle branch block Those with ST segment depression or T wave inversion Those with a so-called non-diagnostic or normal ECG. Complications - Congestive hea failure Myocardial rupture is most common three to five days after myocardial infarction, commonly of small degree. - Life-threatening arrhythmia-The re-entry phenomenon may cause rapid hea rates (ventricular tachycardia and even ventricular fibrillation), and ischemia in the electrical conduction system of the hea may cause a complete hea block - Pericarditis-In Dressler's syndrome, this occurs several weeks after the initial event. - Cardiogenic shock