Heart - chapter 10

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• IHD IS A CONSEQUENCE OF INADEQUATE CORONARY PERFUSION RELATIVE TO MYOCARDIAL DEMAND
• >70% of vessel wall is occluded  stable angina pectoris occurs Critical stenosis
• When occlusion of >90% of coronary artery occurs unstable angina pectoris develops
• aerobic glycolysis stops, leading to accumulation of noxious metabolites like lactic acid ischemic heart (biochemically)
• Rapid loss of contractility that can be reversible or irreversible (depending on severity and duration of ischemia) Ischemic heart (functionally)
• Arrythmias Ischemic heart electrical instability (irritability)
• predictable chest pain associated with increased demand ( physical activity, tachycardia) typical/ stable angina
• increasingly frequent pain that is precipitaed by progressively less exertion. Associated with acute plaque changes that may lead to MI/SCD unstable angina
• chest pain that occurs at rest, caused by coronary artery vasospasm Pritzmetal angina
• Thin fibrous cap, thick lipid pool, many inflammatory cells, few smooth cells composition of stable plaque
• Tick fibrous cap, smaller lipid poo. few inflammatory cells, dense ECM stable "plaque"
• MI is a coagulative necrosis of heart muscle resulting from ischemia.
• Most Mi occur because of acute coronary artery thrombosis (in 90%) of cases. Other cases could be b.c.o LAD artery
• involve inner third of the myocardium no elevation of ST segmentss subendocardial infections
• An anginas lasts shorter than 20 min.
• An Mi lasts longer than 20 min.
• 10 -15 % patients are asymptomatic during an MI which include woman, diabetes, elderly
• The gross and microscopic appearance of MI depends on the age of the injury
• occur 12-24 hours after MI, caused by stagnated, trapped blood red-purple discoloration
• ( host reaction to necrosis) begins 12-24 hours after MI and becoms most prominent 1-3 days after MI. Hemorrgages, edema, congestion, neutrophil infiltrate. Acute inflammation
• Fully developed granulation tissue occurs 1-2 weeks after MI.
• Sscarring as an outcome of chronic inflammation, is well-developed by the end of 6th week.
• a collection of three medical signs associated with acute cardiac tamponade, an emergency condition wherein fluid accumulates around the heart and impairs its ability to pump blood. The signs are (1) low Art. BP (2) distended neck veins, (3) distant, muffled heart sounds. This is known as Beck's triad
• Dressler syndrome is a secondary form of pericarditis that occurs in the setting of injury to the heart or the pericardium (the outer lining of the heart). It consists of fever, pleuritic pain, pericarditis and/or a pericardial effusion.
• sudden cardiac death is due to sustained ventricular arrythmias in individuals who have underlying structural heart disease.e.g. coronary artery disease
• A diverse group of heart muscle diseases which are not connected with coronary arteries diseases, valvular diseases or hypertension. cardiomyopathies
• 90% of cardiomyopathies occur because of dilated cardiomyopathy
• Gene mutated in dilated cardiomyopathy is the dystrophin gene
• Genes mutated in Atrial Septal Defects and Patent Foramen Ovale NKX2.5 or GATA4
• affects small circulation: lung congestion and edema, heart failure cells, increased pleural effusion Left-sided HF
• affects big circulation: nutmeg liver, cardiac cirrhosis, portal hypertension, congestive splenomegaly, transudates in plaural and pericardial cavities, peripheral edema, ascites Right-sided HF
• In HF Myocardial structural changes, including augmented muscle mass. In pressure overload states (e.g., hypertension or valvular stenosis), new sarcomeres tend to be added parallel to the long axis of the myocytes, adjacent to existing sarcomeres. The growing muscle fiber diameter thus results in concentric hypertrophy—the ventricular wall thickness increases without an increase in the size of the chamber.
• In HF Myocardial structural changes, including augmented muscle mass. In volume overload states (e.g., valvular regurgitation or shunts), the new sarcomeres are added in series with existing sarcomeres, so that the muscle fiber length increases. Consequently, the ventricle tends to dilate, and the resulting wall thickness can be increased, normal, or decreased; thus, heart weight— rather than wall thickness—is the best measure of hypertrophy in volume-overloaded hearts.
• Another name for RHF cor pulmonale and occurs when chronic lung disease leads to R sided hypertrophy.
• Occurs when the ejection fraction (less than 40%) decreases because the heart can't pump hard enough systolic HF
• Occur when the heart is not filling enough. The ejection fraction is normal. Diastolic HF the heart would try to compensate for this with volume overload.
• Left sided HF is usually caused by systolic HF (less commonly by diastolic HF)
• Right sided HF is usually caused by diastolic HF
• Restrictive occurs because the heart becomes stiffer & less compliant (can't stretch) which leads to diastolic HF.
• When fluid from the Right side of the heart backs up because of RSHF its's called dependent/pitting edema
• Second most common congenital heart defect where the septum (secudnum or primum) of the artiums doesn't close and leds to a R-to-L shunts even after birth. This called ASD & Patent Foramen Ovale e.g. secundum is often the one defective, but in down's syndrome & Fetal alcohol syndrome the primum would be defective. Blood would either either enter the L. ventricles (cyantoic) or the R. atrium (asyanotic).
• Mutations found in VSD GATA4
• The most common congenital heart defect (in children) where the wall in the ventricle is not properly fused and leads to blood pumping from the LV to the RV (or to aorta as notmal) since the pressure is higher in ventricle. VSD e.g. the membranous part is often the defective part and can occur in fetal alcohol syndrome & down syndrome. A holosystolic murmur would be heard and patient would develop a pulmonary hypertension after long while (cause the pressure has incr. in the R side)
• A congenital heart disease where the duct between the fetal aortic trunk and pulmonary trunk fails to close (because of e.g. Rubella or as more often as a isolated defect) is called patent ductus arteriosus (PDA) – this would result in L-to-R shunt from the aorta (high pressure) to the pulmonary trunk (low pressure). The baby would be acyoanotic and continuous murmur would be heard (Gibson murmur). Later in life the person could develop pulmonary hypertension (shift of shunt)
• “machinery-like” murmurs PDA
• The most common cause of cyanotic congenital heart disease composed of: (1) subpulmonic stenosis (narrowing of right ventricular outflow tract (pulmonary trunk)) (2) Right ventricular hypertrophy (because of incr. workload) (3) VSD (with R-to-L shunt because of the high BP in the RV) (4) Aorta overrides the septal defect. The defect is called tetralogy of Fallot (TOF) – and could vary in severity and symptoms. On imaging you would see a "boot shaped" heart.
• A congenital disease where the pulmonary artery and the aorta switches place is called transposition of the Great Arteries (d-TGA) – and it would result in the blood on the right never getting oxygenated and the blood on the left side never getting DEoxygenated. In the fetal life the baby would be asymptomatic (because of mothers circulation & the fetal circulation) – later life it would be fatal (unless they have a VSD or ASD in adult life).
• A subtype of a R-to-L shunting congenital disease where the L. and R. ventricles switch place Levo-TGA (congenitally corrected TGA) – babies would not be cyanotic and but develop a hypertrophic right ventricle would be hypertrophied & left ventricle would be atrophied.
• Genes mutated in dilated cardiomyopathy dystrophin, desmin & lamin a/c
• Dilated Cardiomyopathy (DCM) is characterized by progressive cardiac dilation & systolic dysfunction. because of genetic factors, Coxsackie virus B, enteroviruses, alcohol, metabolites, chemo, iron overload.
• Dilated cardiomyopathy manifests with 2ndary mitral regurgitation, abnormal cardiac rhythms and anifests with signs of slowly progressive chronic heart failure ( dyspnea, easy fatigability, poor exertional capacity).
• What happens to the cardiac ejection fraction in dilated cardiomyopathy it's decreased to <40 %.
• Autosomal dominant subtype of DCM with variable penetrance that Manifestswithright-sidedheartfailureandrhythm disturbances is know as Arrhythmogenic right ventricular cardiomyopathy – here the Myocytes are replaced with massive fatty infiltration and fibrosis.
• A cardiac myopathy characterized by myocardial hypertrophy, defective diastolic filling & ventricular outflow obstruction is called hypertrophic cardiomyopathy (HCM) and os heard as a “harsh systolic ejection murmur”.
• Genes mutated in hypertrophic cardiomyopathy (HCM) Sarcomeric protein e.g. Beta-myosin heavy chain (mostly), Protein C, troponin T.
• The ejection fraction in hypertrophic cardiomyopathy (HCMA) normal of 50-80 %.
• The ejection fraction in restrictive cardiomyopathy (RCM) Normal (isch) – slightly elevated of 45-90 %.
• (1) Myocyte hypertrophy (2) Haphazard myocyte and myofiber disarray (3) Intersitial fibrosis Characteristic histologic features in HCM
• Stroke volume in HCM markedly reduced
• Impaired filling during diastole because of a stiff heart wall cause by Idiopathic/ radiation fibrosis/ amyloidosis/ sarcoidosis/ errors of metabolism/ hypereosynophilic myeloproliferative disorder Restrictive cardiomyopathy
• The outcome of the valvular disease depends on valve involved, degree of impairment, progression, compensatory mechanisms
• The most common congenital valvular lesion is bicuspid aortic valve where the cusps are of unequal size-larger one exhibits the midline raphe – this might lead to degenerative calcification.
• The third most common heart disease after hypertensive heart disease and ischemic heart disease is aortic stenosis
• Common primary form of myxomatous mitral degeneration seen in Marfan syndrome mitral valve prolapse – where leaflets are floppy and baloon back into LA during systole.
• thinning of the fibrosa ( dimnished fibrillar collagen) and thickening of the middle spongiosa layer ( accumulation of proteoglycan) Myxomatous degeneration
• Fibrotic mitral stenosis caused by rheumatic fever
• Diagnosis of acute rheumatic fever= serologic evidence of streptoccocal infction + ones criteria – and it could cause pancreatitis !!!
• fibrinous pericarditis is seen in acute rheumatic fever
• Aschoff bodies, myocardial inflammatory lesions, are pathognomonic for rheumatic fever – these are the collections of lymphocytes, plasma cells and plump activated macrophages called Anitschkow cells.
• Anitschkow cells are plump activated macrophages found with lymphocytes, plasma cells in rheumatic fever.
• Anitschkow cells - activated macrophages with abundant cytoplasm and nuclei with chromatin condensed to form of a slender, wavy ribbon know as caterpillar cells
• 1-2 mm vegetations along the lines of mitral valve closure that consist of fibrin. Verrucae
• fish mouth stenosis is seen in chronic rheumatic heart disease and is caused by Fibrous bridging across the valvular comissures.
• No valve destruction & masses om thrombin + platelets are seen in thrombotic endocarditis
• valve destruction & vegetations are seen in infective endocarditis
• Genes mutated in Restrictive Cardiomyopathy transthyretin
• Most common form of RCM. Affecting mostly children & young adults in africa. Related to nutritional deficiency or helminthic infections. Characterized by dense diffuse fibrosis. Endomyocardial fibrosis
• Seen in restrictive cardiomyopathy. Fibrosis associated with large mural thrombi. Hypereosinophilia, release of major basic protein followed by scarring and thrombus organization. Loeffler endomyocarditis
• The most frequent primary tumors of the heart in infants and children is Rhabdomyoma
• Mutations seen in Rhabdomyoma TSC1, TSC2
• The most common primary tumors of the adult heart myxoma
• “wrecking ball” effect seen in Myxoma & Lipomas of the heart
• A cardiac tumor with myxoid CT with abundant mucopolysaccharide matrix & laminated elastic fibers, all surrounded by endothelium Papillary fibroelastomas

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