Theheart is a hollow muscular, cone shaped and pumping organ having weight of296grams sheltered by a protective covering pericardium present in themediastinum on the back side of sternum and on the dome of diaphragm in thethorax, the muscular and pumping organ which carry out the oxygenated blood toeach and every parts of the body and collect deoxygenated blood from allappendages of the body.
Heartcan be examined as a two pump that drive in series, the RA and RV, whichdelivered blood from systemic veins into pulmonary circulation, the LA and LVdelivered blood from pulmonary circulation to systemic veins. Ventricles havesolid muscular walls due to which it build up much higher pressure than atria,the walls of LV two times thicker than RV due to which it generate a very highpressure and known as pressure pump, AV valves that avoid blood reverse flowfrom the ventricles into the atria such as TV on the right region and MV on theleft region of the heart. Semilunar valve detach each ventricle from itsarteries such as pulmonic valve among RV and pulmonry artery and aortic valveamong the LV and aorta.Thesevalves lounge in a plane with in connective tissue skeletal that detach theatria and ventricles in which the MV,TV and AV enclose a fibrous triangle knownas central fibrous body. such connective tissue skeletal effort is an insulatorthat avoid electrical impulses from transmission among the atria andventricles.
1.1 CoronarycirculationThemuscular organ is composed of special type of muscles(myocardium), supplied bymain coronary arteries such as LCA, RCA, LAD, CIRC and PDA that are present inthe furrow among the cardiac chambers, RCA and CIRC are among the atria andventricles while LAD and PDA are among the left and right ventricles.Twomain coronary arteries that arise from the ostia in the ascending aorta whichare RCA and LCA, LAD and CIRC as a continuation of LCA while PDA arise either from RCA or CIRC , so thecardiac muscles are supplied by four main coronaries(RCA,LAD,CIRC and PDA). Left coronary arteryLeftposterior sinus of valsava gives up the left coronary artery as a distinctvessle with changeable length and givesup two main branches the LAD and CIRC.TheLAD runs down in the anterior furrow between the ventricles, gives up theseptal perforating, diagonal ateries and right ventricular branches whichsupply the two third of the septum between the ventricles, anterior wall ofleft ventricle and anterior wall of right ventricle respectively.
TheCIRC runs to the left in the anterior AV furrow, gives up branches such asobtuse marginal that supply the lateral wall of LV.ThePDA as a contineuation of either CIRC or RCA that moves inferiorly in theposterior furrow between the ventricles which are joined by septal perforatersand supply posterior third of septum between the ventricles. Right coronary arteryRightanterior sinus of valsava gives up the right coronary artery runs towards rightin the anterior atrioventricular furrow and gives up acute marginal branchessupply the right ventricle, as the RCA cross the acute margin and reach to thecrux of heart, start moving in the posterior furrow between the ventricles asthe PDA. 1.3 CORONARY HEART DISEASE Coronaryheart disease(CHD) also known is ischemic heart disease(IHD), it is caused bythe accumulation of waxy substance(plaque) in the coronaries, become narrow andleads to restriction of blood flow to the myocardium.
Depending on the extentof narrowing and fats accumulation, the patients may experience chest pain thatrelieve on bed rest or remain without chest pain until the accumulated fatsruptures and leads to the formation of clots causing acute coronary syndrome.Themost contributing agents that lead to CHD are high level of low densitylipo-protein(LDL), diabetes mellitus(DM), smoking, hypertension(HTN), poordiet, lack of exercise and advance ages.1.2.1 Atherosclerosis Atherosclerosisis an illness in which plaque assemble insides your arteries and leads to thehardening and stenosis of an arteries that limit the oxygen rich blood flow toyour body. Plaque is a waxy substancemade of fat, cholesterol, calcium and other substances found in the blood. Thevessels of vital organs such as brain, heart and kidneys are suppose to be theleading targets of atherosclerosis due to their particular accessibility.
1.2.2 Patho physiology of AtherosclerosisInthe pathogenesis of atherosclerosis, there is some complex series of events,the endothelial cells of an artery become injured and not able to perform theirfunction, leukocytes and vascular smooth muscle cells are attracted by theinjured endothelial cells and become accumulated and proliferated in thearterial walls, these cells produced an excessive amount of connective tissuematrix that leads to formation of mature fibrous plaque.