Cardiac Pathology

Subject: Pathology  Topic: Cardiac Pathology Lecturer: Dr. Cruz Date of Lecture: September 26, 2011  Transcriptionist: & The Soloist Pages: 11 ᄏᄋᄐ

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ISCH ISCHEM EMIC IC HEA HEART RT DIS DISEA EASE SE Ischemic heart disease (IHD) is the generic designation for a group of closely related syndromes resulting from myocardial myocardial ischemia—an imbalance between the supply (perfusion) and demand of the heart for oxygenated blood. Ischemia comprises not only insufficiency of oxygen, but also reduced availability of nutrient substrates and inadequate removal of metabolites Reduction or absence of blood supply to the heart 80-90% of all heart dse mortality CAUSES o Atherosclerosis (90-95%) Vasospasm- d/t vascular phenomena o  Thrombosis- Virchow’s Triad (hypercoagulability, (hypercoagulability, endothelial damage, hemodynamic o changes: stasis and turbulence) Stenosis- d/t thrombosis or thickening of vessels o o Inflammatory arteritis SYNDROMES CHRONIC ANGINA PECTORIS SUDDEN MYOCARDIAL ISCHEMIC (reversible) CARDIAC INFARCTION HEART - Sudden ch chest pa pain DEATH DISEASE - post postin infa farc rcti tio o - unexpecte Stable/typical Prinzmetal/var Unstable/cresce - permanent n angina iant angina ndo angina myocardial d death decompensa - ches chestt pai pain n d/t d/t - chest pain damage d/t from - chest pain tion (CHF) vasospasm even at total cardiac during (dec in vessel rest occlusion of  * CHF- end pt causes exertion  do of all cardiac caliber) B V a r e after or bld supply more work  partially without the heart dies-> dse increase occluded onset of  coagulative   an demand MORPHOLOG (preinfarct symptoms necrosis uncommon the most  Y: ) - congenital  pattern of  due to common form or acquired episodic   Refers to a irreversible   appears Heart usually - fatal pattern of  angina that  myocardial to be enlarged and arrhythmia pain that occurs at  ischemia caused  heavy, (most occurs with rest and is by the secondary to common due to  progressively  reduction left cause) coronary  increasing of  ventricular , is artery  frequency  ( e.g., e.g., coronary  hypertrophy precipitated spasm. asystole,  perfusion . and dilation with ventricular    Usually there to a  Invariably progressively fibrillation) is an critical there is less effort, elevated ST  level by  moderate to often occurs segment on chronic severe at rest, and the stenosing stenosing tends to be of  electrocardi coronary  atheroscleros more ogram atheroscl is of the prolonged (ECG), erosis; coronary duration. indicative of    is usually arteries and transmural relieved sometimes ischemia. by rest total   the anginal (thereby occlusion. attacks are decreasin unrelated to g Discrete, physical demand) gray-white activity, or scars of healed heart rate, nitroglyce infarcts are or blood rin, a usually pressure. strong present.  The vasodilat mural or. endocardium is generally normal except • • •

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for some superficial, patchy, fibrous thickenings, although mural thrombi may be present.  The major microscopic findings include myocardial hypertrophy, diffuse subendocardi al vacuolization , and scars of  previously healed infarcts. NOTE: In more than 90% of cases, the cause of myocardial ischemia is reduction in coronary blood flow due to atherosclerotic coronary arterial obstruction. Thus, IHD is often termed coronary artery disease most cases, cases, there is a long long period period (decades (decades)) of silent silent,, slowly slowly (CAD) (CAD) or coronary coronary heart heart dis disease ease. In most progressive, coronary atherosclerosis before these disorders become manifest. Thus, the syndromes of  IHD are only the late manifestations of coronary atherosclerosis that probably began during childhood or  adolescence •

 Acute myocardial infarction, unstable angina, and sudden cardiac death are sometimes referred to as acute coronary coronary syndromes. syndromes.   Acute Acute corona coronary ry syndro syndromes mes are are freque frequentl ntly y initia initiated ted by an unpred unpredict ictabl able e and and abrup abruptt conver conversio sion n of a stable stable athero atheroscl sclero erotic tic plaque plaque to an unstab unstable le and    poten potentia tially lly life-t life-thre hreat ateni ening ng athero atherothr thromb omboti otic c lesio lesion n throug through h superf superfici icial al erosio erosion, n, ulcera ulceratio tion, n, fissuring, rupture, or deep hemorrhage, hemorrhage, usually with superimposed thrombosis PATHOGENESIS: The dominant influence in the causation of the IHD syndromes is diminished coronary perfusion relative to myocardial demand, owing largely to a complex and dynamic interaction among fixed  atherosclerotic narrowing of the epicardial coronary arteries, intraluminal thrombosis overlying a disrupted atherosclerotic plaque, platelet aggregation, and vasospasm In summary, Acute coronary syndromes—angina, acute MI, and sudden death—share a common   pathophysiologic basis in coronary atherosclerotic plaque disruption and associated intraluminal  platelet-fibrin thrombus formation. The critical consequence is downstream myocardial ischemia. Stable angina results from increases in myocardial oxygen demand that outstrip the ability of  markedly stenosed coronary arteries to increase oxygen delivery but is not usually associated with  plaque disruption. Unstable angina derives from a sudden change in plaque morphology, which induces partially occlusive platelet aggregation aggregation or mural thrombus, and vasoconstriction leading to severe but transient reductions in coronary blood flow. In some cases, distal microinfarcts occur  secondar secondary y to thromboem thromboemboli. boli. In MI, acute plaque plaque change change induces induces total total thromboti thrombotic c occlusion. occlusion. Finally, sudden cardiac death frequently involves a coronary lesion in which disrupted plaque and  often partial thrombus and possibly embolus have led to regional myocardial myocardial ischemia that induces a fatal ventricular ventricular arrhythmia

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* Fibrin strand- stabilizes platelet aggregates thus contributing to atheroma formation

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Happ Happen ens s dur durin ing g the the first irst decade of life Plaques inc size rupture causes severe

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II. MYOCAR MYOCARDIAL DIAL INFARCT INFARCTION ION produced most often by atherosclerosis leading leading to thrombosis ischemic coagulative necrosis of myocardial fibers with loss of normal contractile (vascular • portion) and conductive (subendocardium) (subendocardium) responses responses of affected myocardium microscopic examination of an infarct can be seen 3hours post infarction and some of the infarcted parts are mostly evident 6hours post infarction Epidemiology o age peak : 55-64yrs (males); 80’s (females)- may be d/t estrogen sex : 3:1, M:F o o risk factors: HPN, hypercholesterolemia, cigarette smoking , diabetes melittus, sedentary lifestyle and oral contraceptive use PATHOGENESIS: In the typical case of MI, the following sequence of events can be proposed: • The initial event is a sudden change in the morphology of an atheromatous plaque plaque , that is, disruption —manifest as intraplaque hemorrhage, hemorrhage, erosion or ulceration, or rupture or fissuring. • Exposed Exposed to suben subendothe dothelial lial collagen collagen and and necrotic necrotic plaqu plaque e contents, contents,   platelet platelets s undergo undergo adhesion adhesion,, aggregation, aggregation, activation, and release of potent aggregators aggregators including thromboxane A2, serotonin, and platelet factors 3 and 4. • Vasospasm is stimulated by platelet aggregation and the release of mediators. • Other mediators mediators activate the extrinsic pathway of coagulation, coagulation, adding to the bulk of the the thrombus. thrombus. • Frequently within minutes, the thrombus evolves to completely occlude the lumen of the coronary  vessel. •

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Pathology common location: left ventricle (because this is the active portion of the heart) o 2 forms: o  Transmural infarct -

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Most myocardial infarcts are transmural , in which the ischemic necrosis involves the full or nearly full distributio tion n of a single single corona coronary ry artery artery.. This This patter pattern n of  thickn thickness ess of the ventric ventricula ular r wall wall in the distribu infarction is usually associated with coronary atherosclerosis, acute plaque change, and superimposed thrombosis 

Subendocardial- inner 1/3 of the heart, mistaken for epigastric pain or heartburn

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constitutes an area of ischemic necrosis limited to the inner one third or at most one half of the ventricular wall ; under some circumstances, it may extend laterally beyond the perfusion territory of  a single coronary artery. The subend subendoca ocardi rdial al zone zone is normal normally ly the least     The least well-p well-perfu erfused sed region region of myocar myocardiu dium m and and therefore is most vulnerable to any reduction in coronary flow . •

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Distribution of arterial involvement and resultant infarction LAD/Left anterior descending coronary artery (40% to 50%): infarct involves o anterior wall of left ventricle near apex; anterior portion of ventricular septum; apex circumferentially o RAD: Right Anterior Descending (30-40%) - post. wall of LV, post 1/3 of IVS o LCA: Left Circumflex Artery (15-20%) - lateral wall of LV except at apex Location, size, morphology depends on location, severity and rate of occlusion o size of vascular bed perfused by occluded vessel o o duration of occlusion metabolic/oxygen demands of myocardium at r isk o extent of collateral blood vessels o o presence, site, site, and severity of coronary spasm alterations in BP, heart rate, cardiac rhythm o

Collateralization May be d/t diligent/ aerobic excercise o o Is the growth of a blood vessel or several blood vessels that serve the same end organ or vascular bed as another blood vessel that cannot adequately supply that end organ or vascular bed sufficiently. (Wikipedia) Complications cardiac arrhythmias - 75-95% of complicated cases (most common) o LV congestive heart failure - 60% o o cardiogenic shock - 10-15% o rupture of free wall (cardiac (cardiac tamponade), septum septum or papillary muscle (murmurs)(murmurs)- 15% thromboembolism- 15-40% o o OTHERS: pericarditis, pericarditis, ventricular aneurysms aneurysms (portion of the heart wall is not not ruptured but weakened)

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Infarcted part of the heart is the pale area on the circle (d/t loss of bld supply): DxOld MI

Enlarged coronary artery - Almo lmost 70% 70% occlusi lusio on Cholesterol clefts -Thickening of smooth muscle -No intima

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Coronary Artery Atheromatous plaque

 Tigering Ischemia

 Thrombus aneurysm

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Cardiac enzymes r/t MI CPK (Creatine Phosphokinase) - More common is CPKMB1 and 2 •

III. HYPERTENSIVE HYPERTENSIVE HEART HEART DISEASE DISEASE Response of the heart to increased demands induced induced by systemic or pulmonary • hypertension Causes 95%- d/t essential HPN, idiopathic, or benign o o 5%- d/t secondary HPN Endocrine o Structural defect o Systemic HHD • o Minimal Criteria for Dx of HHD:  LVH in the absence of other cardiovascular cardiovascular pathology history of hypertension  •

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Pathologic features: concentric hypertrophy without dilatation(compensated) dilatation(compensated)   dilatation and thinning of wall (marks decompensation)

Concentric Hypertrophy - Glo Global bal thic hicknes kness s of LV - Previous in infarct

Pulmonary HHD (Cor Pulmonale) o right ventricular enlargement secondary to pulmonary HPN not a primary heart condition but d/t a pulmonary dse o Acute vs Chronic o  Acute cor pulmonale can follow massive pulmonary embolism. o Chronic cor pulmonale usually implies right ventricular hypertrophy (and dilation) o secondary to prolonged pressure overload caused by obstruction of the pulmonary arteries or arterioles or compression or obliteration of septal capillaries (e.g., owing to primary pulmonary hypertension or emphysema). Morphology. •

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In acute cor pulmonale, there is marked dilation of the right ventricle without hypertrophy hypertrophy . On crosssection, the normal crescent shape of the right ventricle is transformed to a dilated ovoid. In chronic cor  pulmonale, the right ventricular wall thickens, sometimes up to 1.0 cm or more, and may even come to approximate that of the left ventricle. More subtle stages of right ventricular hypertrophy may be observed as thickening of the muscle bundles in the outflow tract, immediately below the pulmonary valve, or of the moderator band, the muscle bundle that connects the ventricular septum to the anterior right ventricular  papillary muscle. Sometimes there is secondary compression of the left ventricular chamber or tricuspid regurgitation with fibrous thickening of this valve.

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Causes  Obstructive  Carcinoma emphysema Bronchiectasis   Chronic bronchitis  Cystic lung Pneumoconiosis   Chronic pneumonia Fibrosis  Pleural effusion  Pathogenesis  RV enlargement enlargement due due to pulmonary pulmonary hypertension hypertension caused by by lung disorders COPD, DIP, atelectasis, cystic fibrosis Pulmonary embolism (acute CP), Primary Pulmonary HPN Kyphoscoliosis (structural defect) Pickwickian Pickwickian habitus (aka: Obesity O besity Hypoventilation Hypoventilation Syndrome; is a • condition in which severely overweight people fail to breathe rapidly enough or deeply enough, enough , resulting in low blood oxygen levels and high blood carbon dioxide (CO2) levels. ~~ Wikipedia) metabolic acidosis, hypoxia • • •

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Saddle Pulmonary Embolism - Embo Embolu lus s sits sits on on the the bifu bifurc rcat atio ion n of the the rig right ht and left pulmonary arteries  occludes the RPA so bld cannot flow to the RV

IV. CONGENITAL CONGENITAL HEART HEART DISEASES Structural abnormality of heart present at birth May be COMPATIBLE vs. INCOMPATIBLE with life (depends on the presence of life-saving life-saving • shunts) Incidence/ etiology: Affects 0.3to 1% of all livebirths/1000; 9births/1000 • Frequencies o VSD- 33% (most common)  TOF- 9% o o  T ARTERIOSUS- 1% o ASD- 5% AS- 8% o PDA- 10% o o  TA- 1%  TGA- 5% o CoA- 5% o o PS- 10%  TAPVC- 1 o A-V SD- 4% o Clinical effects of congenital heart disease o Cyanosis Clubbing o PolycythemiaPolycythemia- compensatory mech d/t o poor oxygenation pulmonary vascular disease- d/t too much o bld in the pulmonary vascular bed hypertrophic changes o stunted growth o o paradoxical embolization- venous embolus becomes a systemic embolism, shunt vessel should be present infectious endocarditis o •

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Classification of Congenital Heart Diseases by RUBIN INITIAL LEFT TO RIGHT SHUNTS

RIGHT TO LEFT SHUNTS

VSD

ASD

PDA

TOF

TGA

- most common congenital heart defect, defect, 30% isolated - frequently associated with other anomalies - defect is significant if  greater than 1.0cm in diameter - Life- saving defect: TOF

- most common in ADULTS communicati on between atria because of abnormal opening - most common CHD in adults to be clinically apparent

aortopulmona ry channel remains open: 85-90% isolated normally • open for 1-2month after birth (closes at the end of  2mos) prematuri ty delayed closure especially if large distressed with low O2 tensiondelayed closure - Life-saving defect: TOGV and Pulmonary atresia - cyanosis of  the lower extremities since after subclavian artery - Mngt: surgical

- results embryologicall y from anterosuperior displacement of the infundibular septum - most common form of cyanotic congenital heart disease

- AKA: Ventriculoarte rial discordance - aorta arises from the right ventricle and the pulmonary artery emanates from the left ventricle - embryologic defect is abnormal formation of  the truncal and aortopulmona ry septa incompatible with life in the absence of  shunts: a. VSD (35%) stable shunt b. PDA AND PATENT FORAMEN OVALE (65%)unstable - RHV and thin-walled left ventricle

closure, INDOMETHACI N (PG inhibitor)

Right Ventricular Hypertrophy Overriding of  the aorta VSD

Types: a. Membranou s- close to AV bundle of HIS 90% b. Musc ular below pulmonary valve; muscular septum c. Infrac Infracris ristal tal d. Supracrist Supracristal al ROGER'S DISEASE - musc muscul ular ar,, less than 0.5cm in diameter)

Major Types: a. Ostium Ostium Secundum - 90% of  all ASD deficiency or fenestratio n of  septum primum, deficiency of septum secundum, or both - involves the valve or limbus of the fossa ovalis b. Ostium

Primum Defect - 5% of all ASD - occurs low and adjacent to valves, anteroinfe rior to the fossa ovalis c. Sinus Venosus Defect - 5% of all ASD - located high in the septum, posterior to fossa ovalis near the entrance of  the SVC

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4 Features: 1. VSD (membrano us, size of  the aortic lumen) life saving 2. OBSTRUCTI ON TO THE RIGHT VENTRICUL AR OUTFLOW  TRACT (Subpulmon ary stenosis) 3. AORTA AORTA OVERRIDES  THE VSD 4 . R VH VH * remember: PROV PDA

Truncus Arteriosus development al failure of  separation of  the embryologic arteriosus into the aorta and pulmonary artery resulting in a single artery receiving blood from both ventricles - usually accompanied by VSD

TA - complete occlusion of  the tricuspid valve orifice - results from unequal distribution of the normal AV canal - associated with right ventricular hypoplasia - right to left shunt maintained thru ASD/ patent foramen ovale with VSD so communicat ion between Left and great artery from the hypoplastic right ventricle

NO SHUNTS Total Anomalous Pulmonary Venous Connection - results embryologically when the common pulmonary vein fails to develop or becomes atretic causing primitive systemic venous channels from the lungs to remain patent - 50% cases drains into the innominate/ brachiocephalic vein (L) or the coronary sinus - associated with PDA or patent foramen ovale

- Mngt: surgery STAT

Coarctation of  aorta

Pulmonary stenosis

- constriction, narrowing of  aorta - more common in MALES

- a dynamic or fixed obstruction to flow from the right ventricle of  the heart to 2 Types: a. PrePre-du duct ctal al the pulmon (Infantile ary artery. artery . type) - usually d/t - tubular isolated hypoplasia of  valvular the aortic obstruction, arch but may be - patency of  d/t PDA subvalvular necessary for or life supravalvul - RVH in ar utero obstruction. - early CHF - It may - cyanosis of  occur in the lower association half of the with more body complicate b. Post Post-d -duc ucta tall d (adult type) congenital heart asymptomati disorders. c in early (Wikipedia) stage hypertension in the upper extremities but with weak pulses and lower BP in extremities

development of collateral vessels--"rib notching" 2/t enlarged internal mammary and intercostal arteries

- severity of  obstruction to RV outflow determines direction of  blood flow "pink tetralogy"- mild pulmonary stenosis (baby is not cyanotic but dusky looking)

LUTEMBACHE R'S SYNDROME - small ASD associated with mitral stenosis * Eisenmenge r syndrome (or Eisenm enger's reac tion) - is defined as the proces s in which a left-to-right shunt caused by a congenital heart defect causes increased flow through the pulmonary vasculature, vasculature, causing pulmonary hypertension, hypertension , which in turn, causes increased pressures in the right side of the heart and reversal of the shunt into a right-to-left shunt. shunt. (Wikipedia) * Atrioventricular Septal Defect - abnormal development of embryologic AV canal - failure failure of fusion of superi superior or and and inferio inferiorr endocard endocardial ial

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cushions with incomplete closure of AV septum and inadequate inadequate formation of septal septal tricuspid and anterior

ASD- Secundum t e

VSD- Muscular t e

mitral leaflet

NOTICE TO THE PUBLIC:

Guys kindly read your books, I’ve tried to put some infos coming from the book but its not enough ..I think..  Transposition of the Great Arteries

Primum Defect - 5% of all ASD - occurs low and adjacent to valves, anteroinfe rior to the fossa ovalis c. Sinus Venosus Defect - 5% of all ASD - located high in the septum, posterior to fossa ovalis near the entrance of  the SVC

closure, INDOMETHACI N (PG inhibitor)

Right Ventricular Hypertrophy Overriding of  the aorta VSD

- Mngt: surgery STAT

development of collateral vessels--"rib notching" 2/t enlarged internal mammary and intercostal arteries

- severity of  obstruction to RV outflow determines direction of  blood flow "pink tetralogy"- mild pulmonary stenosis (baby is not cyanotic but dusky looking)

LUTEMBACHE R'S SYNDROME - small ASD associated with mitral stenosis * Eisenmenge r syndrome (or Eisenm enger's reac tion) - is defined as the proces s in which a left-to-right shunt caused by a congenital heart defect causes increased flow through the pulmonary vasculature, vasculature, causing pulmonary hypertension, hypertension , which in turn, causes increased pressures in the right side of the heart and reversal of the shunt into a right-to-left shunt. shunt. (Wikipedia) * Atrioventricular Septal Defect - abnormal development of embryologic AV canal - failure failure of fusion of superi superior or and and inferio inferiorr endocard endocardial ial

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cushions with incomplete closure of AV septum and inadequate inadequate formation of septal septal tricuspid and anterior

ASD- Secundum t e

VSD- Muscular t e

mitral leaflet

NOTICE TO THE PUBLIC:

Guys kindly read your books, I’ve tried to put some infos coming from the book but its not enough ..I think..  Transposition of the Great Arteries

Please read and review Netter’s atlas plus Robbin’s and Cotran Patho book…..



~~Happy Studying! ^_^

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cushions with incomplete closure of AV septum and inadequate inadequate formation of septal septal tricuspid and anterior

ASD- Secundum t e

VSD- Muscular t e

mitral leaflet

NOTICE TO THE PUBLIC:

Guys kindly read your books, I’ve tried to put some infos coming from the book but its not enough ..I think..  Transposition of the Great Arteries

Please read and review Netter’s atlas plus Robbin’s and Cotran Patho book…..



~~Happy Studying! ^_^