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IN THE NAME OF GOD

IN THE NAME OF GOD. PATHOLOGY OF THE HEART. M.A.BOROUMAND M.D. TEHRAN UNIVERSITY OF MEDICAL SCIENCE.

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IN THE NAME OF GOD

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  1. IN THE NAME OF GOD

  2. PATHOLOGY OF THE HEART M.A.BOROUMAND M.D. TEHRAN UNIVERSITY OFMEDICAL SCIENCE

  3. The human heart is a remarkably efficient, durable, and reliable pump that propels over 6000 liters of blood through the body daily and beats more than 40 million times a year during an individual's lifetime

  4. The Heart Wall Figure 20–4

  5. The normal heart weight varies with body height and weight; • 250 to 300 g in females • 300 to 350 g in males • The usual thickness of the free wall of the right ventricle is 0.3 to 0.5 cm and that of the left ventricle 1.3 to 1.5 cm. • So What is cardiomegaly?

  6. Myocardium • Cardiac myocytes have five major components: (1) cell membrane (sarcolemma) and T-tubules, for impulse conduction; (2) sarcoplasmic reticulum, a calcium reservoir needed for contraction; (3) contractile elements; (4) mitochondria; and (5) nucleus.

  7. The myocytescomprise only approximately 25% of the total number of cells in the heart. However, because cardiac myocytes are so much larger than the intervening cells, they account for more than 90% of the volume of the myocardium. • Atrial myocytes are generally smaller in diameter and less structured than their ventricular counterparts. Some atrial cells also differ from ventricular cells in having distinctive electron-dense granules in the cytoplasm called specific atrial granules. • natriuretic peptidesconsist of A type , B type and C type

  8. Conduction system specialized excitatory and conducting myocytes are involved in regulating the rate and rhythm of the heart. Components include: • (1) the SA node, located near the junction of the right atrial appendage with the superior vena cava; • (2) the atrioventricular (AV) node, located in the right atrium along the atrial septum; • (3) the bundle of His, which courses from the right atrium to the summit of the ventricular septum; and its division into • (4)right and left bundle branches that further arborize in the respective ventricles.

  9. Heart valves • The four cardiac valves (tricuspid, pulmonary, mitral, and aortic) maintain unidirectional blood flow. • The ability of the valves to permit unobstructed forward flow depends on the mobility and pliability of their leaflets

  10. Competency of valves • The competency of the semilunar valves (aortic and pulmonary) depends on the stretching and molding of their three leaflets . The function of the semilunar valves also depends on the integrity and coordinated movements of the cuspal attachments. • Normal mitral valve competency depends on the coordinated actions of annulus (the outer edge of the value orifice, where the leaflets attach), leaflets, cords, papillary muscles, and associated left ventricular wall (collectively themitral apparatus)

  11. Increased left atrial cavity size Decreased left ventricular cavity size Sigmoid-shaped ventricular septum Aortic valve calcific deposits Mitral valve annular calcific deposits Fibrous thickening of leaflets Buckling of mitral leaflets toward the left atrium Brown atrophy Lipofuscin deposition Amyloid deposits Changes In The Aging Heart

  12. Heart Disease • Non neoplastic -Congenital heart disease -Ischemic heart disease -Hypertensive heart disease (systemic and pulmonary) -Valvular heart disease -Nonischemic (primary) myocardial disease • Neoplastic • Pericardial disease

  13. Congenital Heart Disease • Abnormalities of the heart or great vessels that are present from birth. • Most such disorders arise from faulty embryogenesis • Some forms of congenital heart disease produce manifestations soon after birth however, Others do not necessarily become evident until adulthood

  14. Incidence • The most common type of heart disease among children • Generally accepted incidence is approximately 6 to 8 of every 1000 of live births • The incidence is higher in premature infants and in stillborns • Twelve disorders account for about 85% of cases

  15. Etiology and Pathogenesis • Well-defined genetic or environmental influences are identifiable in only about 10% of cases of congenital heart disease • The obvious role of genetic factors in some cases is demonstrated by the occurrence of familial forms of congenital heart disease • Environmental factors • Multifactorial genetic, environmental, and maternal factors probably account for the remaining majority of cases

  16. Transcription factors and several signaling pathways and molecules which involve in cardiac morphogenesis include • Vascular endothelial growth factor (VEGF) • Bone morphogenetic protein (BMP) • Transforming growth factor- ß (TGF-ß) • Fibroblast growth factor

  17. Clinical Features Congenital heart disease fall primarily into three major categories: • Malformations causing a left-to-right shunt • Malformations causing a right-to-left shunt • Malformations causing an obstruction.

  18. left-to-right shunts • Increase pulmonary blood flow and are not initially associated with cyanosis • Can result in right ventricular hypertrophy and, potentially, failure • Increased pulmonary blood flow and pressure result in pulmonary artery medial hypertrophy and eventually obstructive intimal lesion • Eisenmenger syndrome

  19. right-to-left shunt • Dusky blueness of the skin and mucous membranes (cyanosis) • Paradoxical embolism • Clubbing of the tips of the fingers and toes (hypertrophic osteoarthropathy) • polycythemia

  20. obstructive congenital heart disease • Produce obstructions to flow because of abnormal narrowing of chambers, valves, or blood vessels • Atresia • In some disorders (e.g., tetralogy of Fallot), an obstruction is associated with a shunt (right-to-left through a VSD).

  21. Ventricular Septal Defect • Incomplete closure of the ventricular septum,the most common congenital cardiac anomaly • About 30% occur as isolated anomalies • Most are about the size of the aortic valve orifice • About 90% involve the region of the membranous septum (membranous VSD) • The remainder lie below the pulmonary valve (infundibular VSD) or within the muscular septum • About 50% of small muscular VSDs close spontaneously • Large defects are usually membranous or infundibular

  22. Patent Foramen Ovale • During normal cardiac development patency is maintained between right and left atria by a series of ostia (primum and secundum) that eventually become the foramen ovaI • 80% of cases, the higher left-sided pressures in the heart that occur at birth permanently fuse the septa against the foramen ovale.

  23. Atrial Septal Defect • The three major types of ASDs, classified according to their location in the septum, are secundum, primum, and sinus venosus. • secundum ASD, accounting for approximately 90% of all ASDs, is a defect located near foramen ovale • Primum anomalies (5% of ASDs) occur adjacent to the AV valves and are usually associated with a cleft anterior mitral leaflet. This combination is known as a partial AV septal defect • Sinus venosus defects (5%) are located near the entrance of the superior vena cava. They are commonly accompanied by anomalous connections of right pulmonary veins to the superior vena • ASDs are usually isolated

  24. Patent Ductus Arteriosus • About 90% of PDAs occur as an isolated anomaly • Associated with VSD, coarctation of the aorta, or pulmonary or aortic stenosis • Most often PDA does not produce functional difficulties at birth • There is general agreement that an isolated PDA should be closed early in life

  25. Tetralogy of Fallot • Tetralogy of Fallot constitutes the most common form of cyanotic congenital heart disease • The four features of the tetralogy of Fallot are: (1) VSD (2) obstruction to the right ventricular outflow tract (subpulmonary stenosis), (3) an aorta that overrides the VSD (4) right ventricularhypertrophy

  26. Tetralogy of Fallot • The heart is often enlarged and may be "boot-shaped" owing to marked right ventricular hypertrophy • The VSD is usually large and approximates the diameter of the aortic orifice. • The aortic valve forms the superior border of the VSD, thereby overriding the defect and both ventricular chambers. • The obstruction to right ventricular outflow is most often due to narrowing of the infundibulum (subpulmonic stenosis) but is often accompanied by pulmonary valvular stenosis • The severity of obstruction to right ventricular outflow determines the direction of blood flow

  27. Transposition of the Great Arteries • Implies ventriculoarterial discordance • Condition incompatible with postnatal life unless a shunt exists for adequate mixing of blood. • Patients with TGA and a VSD (about 35%) have a stable shunt. Those with only a patent foramen ovale or PDA (about 65%), however, have unstable shunts that tend to close and therefore require immediate intervention to create a shunt (such as balloon atrial septostomy) within the first few days of life • The outlook for infants with TGA depends on the degree of "mixing" of the blood, the magnitude of the tissue hypoxia, and the ability of the right ventricle to maintain the systemic circulation.

  28. Coarctation of the Aorta • Males are affected twice as often as females • Two classic forms have been described: (1) an "infantile" form with tubular hypoplasia of the aortic arch proximal to a PDA that is often symptomatic in early childhood (2) an "adult" form in which there is a discrete ridge-like infolding of the aorta, just opposite the closed ductus arteriosus • Clinical manifestations depend almost entirely on the severity of the narrowing and the patency of the ductus arteriosus.

  29. Coarctation of the Aorta • Coarctation of the aorta with a PDA, it may cause signs and symptoms • Immediately after birth.. In such cases, the delivery of unsaturated blood through the ductus arteriosus produces cyanosis localized to the lower half of the body. • Coarctation of the aorta without a PDA, unless it is very severe. Most of the children are asymptomatic, and the disease may go unrecognized until well into adult life. • Typically there is hypertension in the upper extremities, but there are weak pulses and a lower blood pressure in the lower extremities, • Characteristic in adults is the development of collateral circulation between the precoarctation arterial branches and the postcoarctation arteries

  30. Ischemic Heart Disease

  31. Ischemic Heart Disease • Generic designation for a group of closely related syndromes resulting from myocardialischemia • Ischemia-an imbalance between the supply (perfusion) and demand of the heart • In more than 90% of cases, the cause of myocardial ischemia is reduction in coronary blood flow due to atherosclerotic coronary arterial obstruction.

  32. Ischemic Heart Disease • IHD can be divided into four syndromes: - Myocardial infarction (MI), the most important form of IHD, in which the duration and severity of ischemia is sufficient to cause death of heart muscle. - Angina pectoris, in which the ischemia is less severe and does not cause death of cardiac muscle. Of the three variants—stable angina, Prinzmetal angina, and unstable angina—the latter is the most threatening as a frequent harbinger of MI. - Chronic IHD with heart failure. - Sudden cardiac death. • Acute coronary syndrome ?

  33. epidemiology • leading cause of death in the U.S. for men and women • 42% of all deaths (1 out every 2.4 deaths) • an average of one death every 33 seconds

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