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# Cardiology Part I ## Myocardial Infarction * Coronary artery disease contributes to the maximum amount of mortality in India. * India is the diabetic capital of the world and the number one reason why diabetics would be dying is from cardiovascular causes ranging from ST elevation to non-ST elev...

# Cardiology Part I ## Myocardial Infarction * Coronary artery disease contributes to the maximum amount of mortality in India. * India is the diabetic capital of the world and the number one reason why diabetics would be dying is from cardiovascular causes ranging from ST elevation to non-ST elevation, unstable angina. * Let's look at the cut section of a coronary artery: Left Anterior Descending (LAD)/ Right Coronary Artery (RCA). ### Fibrous Cap * Yellow is a fat deposition i.e., lipid core. * Green is the fibrous capsule: Atherosclerosis (contains the lipid core in the middle i.e., in tunica intima and the covering is the fibrous cap) * The event showed is plaque fissure. * Because of this plaque fissure, the platelets would be attracted to collagen and collagen act like the magnet here and very soon there would be a platelet plug formation and then there is going to be a clot formation or thrombus formation. * This thrombus will occlude the entire lumen of the coronary artery, resulting in muscle death / myocardial necrosis in a couple of minutes. * In STEMI, the clot is rich in fibrin and RBCs. Therefore, fibrinolytic drugs like Streptokinase, Alteplase, Reteplase, Tenecteplase will work. * In NSTEMI, clot is rich in platelets. Therefore, we use antiplatelet/ antithrombotic drugs and don't use thrombolytics as they're not effective. Thrombolysis is contraindicated in NSTEMI. ## ECG Interpretation * Most of the time in exam they give a question starting with a patient presenting with chest pain and the ECG image with ST elevation in Lead II, III, and AVF. In this question you need to calculate HR, and look at the infarct localization i.e., find which surface of the heart is involved. ### Important Information * **Which leads to look for changes in MI?** * Inferior wall MI: Lead II, III, aVF * Anterior wall MI: Lead 1, aVL, V1 to V4 * Lateral wall MI: V5, V6 * Septal MI: V1, V2 * In Inferior wall MI, the thrombus mainly presents in RCA. * **ECG interpretation:** * In Lead II: P wave present, no Q wave, characteristic ST elevation present k/a TOMBSTONE PATTERN (ST elevation, convex in upward direction) * Whereas, if ST elevation is present but it is concave upwards, it is due to inflammation of the outer layer of the heart called Acute Pericarditis. * **STE Concave Upwards** * To differentiate MI from Acute Pericarditis. Cardiac biomarkers like troponin I, troponin T, CPKMB are grossly elevated in MI and usually normal in Acute Pericarditis. * In this ECG: ST elevation in lead II, III, aVF & reciprocal changes of ST depression in V1,2,3,4 S/O Inferior wall MI.