Robbins Essential Pathology Heart PDF

CHAPTER 8 Heart 133...

CHAPTER 8 Heart 133 A B Fig. 8.18 Hypertrophic cardiomyopathy with asymmetric septal hypertrophy. (A) The septal muscle bulges into the left ventricular outflow tract, giving rise to a banana-shaped ventricular lumen, and the left atrium is enlarged. The anterior mitral leaflet has been moved away from the septum to reveal a fibrous endocardial plaque (arrow) (see text). (B) Histologic appearance demonstrating disarray, extreme hypertrophy, and charac- teristic branching of myocytes, as well as interstitial fibrosis. exer  ona  dyspne a. T e ou  ow obs r u c  on may pro duc e a ars eosnopa can be prmar y (somemes as par o a myeod neo- sysoc ej e c  on mu r mur Massve yp er  ropy and  g  e   - ve n- pasm) or secondar y (e.g., o emnc necon). Major basc  r c u  ar pressures  a comprom s e  e dever y o bo o d by  n ra- proen reease rom eosnop granues s oug o cause endo- mura  ar er es  re qu en y e ad o myo c ard a  s ce m  a and ang na, carda and myocarda necross, eadng o scarrng and mura e ven n  e abs ence o coronar y ar er y d s e as e. Maj or comp  c a ons romboss. ncude a r  a   br    a  on w   mur a    rombus or ma  on ,  n e c  ve endo c ard s o  e m ra  va ve, conge s ve e ar   a ure, and ven-  r c u  ar  br    a on e ad  ng o su dd en c ard  ac d e a . Sudd en d e a  , Morphology. In resrcve cardomyopay e venrces are o p ar  c u  ary common n young a   ees, s s ome  me s  e   rs man - norma sze or ony sgy enarged, e caves are no daed, es a on o  e ds e as e. D r ugs  a promoe ven r c u  ar re a x a  on and e myocardum s rm. Bo ara are ypcay daed as a prov de sy mpoma  c re e, and ou   ow  rac  obs r uc   on c an be consequence o reduced venrcuar ng and pressure overoad. ree ve d by surg c a  excs  on or  e c on ro e d n arc   on o s ep a  Mcroscopc ndngs var y accordng o e cause, and may ncude mus ce nduce d by cem c a   nj e c   ons. nersa amyod deposs; ssue eosnopa; nersa and endomyocarda bross; and mura romboss. Restrictive Cardiomyopathy Restrictive cardiomyopathy is caused by disorders that increase the stiffness of the ventricular wall, resulting in impaired ventric- Myocarditis ular lling during diastole. Myocarditis encompasses a diverse group of clinical entities in hs ype o cardomyopay s mos commony assocaed w which infectious agents and/or inammatory processes primarily sysemc dsorders a afec e myocardum. hree orms o resrc- target the myocardium. ve cardomyopay mer bre menon:    Amyodoss. Cardac amyodoss (see Caper 4) can occur n e Pathogeness. In e Uned Saes, vra necons are e mos com- seng o sysemc amyodoss or can be resrced o e ear mon cause o myocards, w coxsackevruses A and B and oer (Suppemena eFg. 8.4). Amyod n e aer s derved rom enerovruses accounng or a majory o e cases. Myocye dea norma or muan orms o ransyren (a ver-syneszed cr- may sem rom drec cyopac efecs o e vrus or may be caused cuang proen a ranspors yroxne and reno) and usuay by e mmune response o vray neced ces. In some nsances,  s occurs n oder adus. suspeced a vruses rgger a cross-reacve mmune reacon agans    Endomyocarda ibross s an dopac dsease a afecs cdren os proens suc as e myosn eavy can. and young adus n Arca and oer ropca areas. here s dense Nonvra causes o myocards ncude Cagas dsease, Lyme ds- dfuse bross o e venrcuar endocardum and subendocar- ease, and ypersensvy reacons nduced by drugs and auommune dum, oten nvovng e rcuspd and mra vaves. Wordwde, dsorders. Chagas dsease s caused by e proozoan Trypanosoma  s e mos common orm o resrcve cardomyopay. cruz and afecs up o one a o e popuaon n endemc areas    L oeler endomyocardts aso exbs endocarda bross, yp- o Sou Amerca, w myocarda nvovemen n e vas major- cay assocaed w ormaon o arge mura romb. I s car- y. Abou 10% o e paens de durng an acue aack; n oers, acerzed by eosnopa and eosnopc ssue nraes. e mmunoogcay medaed njur y eads o congesve ear aure and  CHAPTER 8 Heart 133.e1 A B Supplemental eFig. 8.4 Cardiac amyloidosis. (A) Hematoxylin-and-eosin stain, showing amyloid appearing as amorphous pink material around myocytes. (B) Congo red stain viewed under polarized light, in which amy- loid shows characteristic apple-green birefringence (compared with collagen, which appears white). 134 CHAPTER 8 Heart arrymas 10 o 20 years aer. Lyme dsease, a sysemc ness caused Clncal Features. he cnca specrum o myocards s broad, rang- by e sprocee Borrea burgdor fer, causes myocards n approx- ng rom a ack o sympoms and compee recover y o precpous maey 5% o paens, wc may resu n se-med conducon onse o ear aure or arryma, somemes causng sudden dea. sysem dysuncon and arrymas a may necessae emporar y Beween ese exremes are modes eves o cardac dysuncon w pacemaker nseron. ague, pan, and ever. Paens may recover compeey or deveop daed cardomyopay. Morphology. In acue myocards, e ear may appear norma Other Causes of Myocardial Disease or may be daed; n advanced sages, e myocardum ypcay Exposures o varous drugs and ceran ormones ave been nked o s daed and s oten moed by pae and emorragc areas. myocye njur y and dysuncon: Mura romb may be presen. Vra myocardts s caracerzed    Cardotoxc drugs. Cardac compcaons o cancer erapy are by edema, nersa ympocyc nraes, and myocye njur y mporan cnca probems. Agens assocaed w cardooxcy (Fg. 8.19A). I e paen sur vves e acue pase o myocards, ncude convenona cemoerapeuc agens, argeed drugs (e.g., esons can resove wou sgncan sequeae or ea by progres- yrosne knase nbors), and mmunoerapeuc agens (e.g., sve bross. In ypersenstvty myocardts, nersa and pervas- mmune ceckpon nbors, wc may nduce severe myocard- cuar nraes ncude numerous eosnops (Fg. 8.19B). Gant s). Doxorubcn and daunorubcn are oten assocaed w oxc ce myocardts, a dsncve eny oug o be medaed by auo- myocarda njur y and may cause ear aure. Recover y s e rue reacve T ces, s caracerzed by wdespread nlammaor y ce oowng e dsconnuaon o suc agens, bu daed cardomy- nraes conanng munuceae gan ces (Fg. 8.19C) and car- opay may occur. res a poor prognoss. In Cagas myocardts, r ypanosomes may be    C atecoamnes. Hg  e ves o c ae co am ne s may  nju re myo - seen n scaered myobers, parcuary n acue dsease, and ere c yes, e adng o o c a  myo c ard a  ne cros s. T  s yp e o  njur y s an nlammaor y nrae o neurops, ympocyes, macro- may be s e en n  e s e  ng o pe o cromo c y oma (a umor pages, and occasona eosnops (Fg. 8.19D) a s cenered on  a e ab oraes c ae co am ne s ; see C aper 16), co c ane us e, areas were ere s soogc or moecuar evdence o parasc auonomc s mu  a  on s e cond ar y o  n r a c ran  a   es  ons , and necon. admns ra on o v as opre ss or agen s suc as d op am  ne. Te A B C D Fig. 8.19 Myocarditis. (A) Viral myocarditis with extensive lymphocytic infiltrate, edema, and associated myo- cyte injury. (B) Hypersensitivity myocarditis, characterized by perivascular eosinophil-rich inflammatory infil- trates. (C) Giant cell myocarditis, with lymphocyte and macrophage infiltrates, extensive myocyte damage, and multinucleate giant cells. (D) Chagas myocarditis. A myofiber distended with trypanosomes (arrow) is present, along with mononuclear inflammation and myofiber necrosis.  CHAPTER 8 Heart 135 me cansm s uncer  a n bu may be re ae d o d re c  ox  c e  e c  s ncreases e vascuar one, and spurs waer and sa reenon. e o c ae co amnes on myo c ye s or o c ae co am ne - nduc e d aer oten s counerproducve, owever, because  ncreases e vas osp asm and s cem a. bood voume and worsens e venous congeson.    Myocarda structura canges, ncudng ypertropy. Cardac myo- cyes adap o ncreased workoads by assembng new sarcomeres, CONGESTIVE HEART FAILURE eadng o myocye yperropy. he ncrease n venrcuar mass Congestive heart failure is the common endpoint for many forms of carres a rsk o possbe scemc njur y because e myocarda cardiac disease, is usually progressive, and carries a poor prognosis. capar y bed does no expand suiceny. In e Uned Saes aone, more an 5 mon ndvduas are hese compensaory mecansms may be efecve or a me, bu e afeced, w we over 1 mon ospazaons per year. Rougy one usua course s one o progressvey worsenng aure. Eary n e course, a o paens de wn 5 years. Overa, ear aure s a conrbu- ear aure oten preerenay nvoves ony one sde o e ear, eadng or y cause n 1 n 9 deas n e Uned Saes. o soaed et- and rg-sded ear aure (dscussed nex). In mos cases o cronc ear aure, ere s bvenrcuar dysuncon w sgns and Pathogeness. C ongesve ear aure usuay occurs wen cardac sympoms o bo rg-sded and et-sded ear aure. damage ms e ear’s aby o mee e meaboc demands o perpera ssues a norma ng pressures. In a mnory o cases, Left-Sided Heart Failure  s a consequence o ncreased ssue demands, as n yperyrod- The effects of left-sided heart failure stem from diminished sys- sm, or a decreased oxygen-carr yng capacy (so-caed g-oupu temic perfusion and elevated back pressures within the pulmonary aure, usuay assocaed w severe cronc anema) e onse circulation. can be abrup, as n e seng o a myocarda narc or acue vave dysuncon, bu n mos cases  deveops nsdousy owng o e Pathogeness. he mos common causes o et-sded aure are sc- cumuave efecs o cronc work overoad or progressve oss o emc ear dsease, sysemc yperenson, mra or aorc vave ds- myocarda uncon. I can be dvded no severa caegores accord- ease, and prmar y dseases o e myocardum (e.g., amyodoss). ng o e underyng cause:    Systoc faure resus rom nadequae myocarda conracy, Morphology. e prncpa morpoogc ndngs are n e ear mos commony as a consequence o scemc ear dsease or and e ungs, as oows: yperenson.    Hear. W e excepon o aure due o mra vave senoss    Dastoc faure reers o an naby o e ear o adequaey reax or resrcve cardomyopaes, e et venrce s yperro- and , as n marked et venrcuar yperropy, resrcve car- ped and may be daed, somemes massvey. Let venrcuar domyopaes, or consrcve percards. Approxmaey a o daon can resu n mra nsuicency and et ara enarge- cases o congesve ear aure are arbuabe a eas n par o men, oten assocaed w ara braon and mura rom- dasoc dysuncon, w a greaer requency seen n obese nd- boss. vduas, oder adus, dabec paens, and women. Aoug we    Lungs. In acue et ear aure, ncreased pumonary ven pres- dsngus beween sysoc and dasoc ear aure, n mos sures are ransmed back o e capares and areres o e cases bo coexs. ungs, resung n congeson, edema, and peura efusons due    Vave dysfuncton (e.g., due o endocards or reumac ear ds- o ncreased ydrosac pressure n peura venues. Mcroscop- ease) can ead o e aure o an oer wse norma ear. Depend- cay, ere are pervascuar and nersa ransudaes, aveoar ng on e afeced vave and e consequence o e vave dsease sepa edema, and nraaveoar edema lud. In cronc et ear (nsuicency versus senoss), aure secondar y o vave dsease aure, red ces exravasae no aveo, were ey are pago- may sem rom pressure overoad (e.g., aorc senoss) or voume cyosed by macropages a become aden w emosdern overoad (e.g., mra vave nsuicency). (ear faure ces). Regardess o e mecansm, e aure o e ear o pump bood eiceny eads o ncreased end-dasoc venrcuar voumes, ncreased end-dasoc pressures, and eevaed venous pressures. hus, Clncal Features. Dyspnea (sorness o brea) on exeron s usuay nadequae cardac oupu, caed forward faure, s amos aways e eares and mos promnen sympom o et-sded ear aure. accompaned by congeson o e venous crcuaon, a s, backward Coug occurs due o ransudaes n ar spaces. As aure progresses, faure. Aoug e roo probem s decen cardac uncon, vru- paens experence dyspnea wen recumben (ortopnea) because e ay ever y oer organ s evenuay afeced by some combnaon o supne poson ncreases venous reurn rom e ower exremes and or ward and backward aure. eevaes e dapragm. Sng reeves oropnea, and paens usu- Once aure appears, compensaor y mecansms ensue: ay seep n a semseaed poson. Paroxysma nocturna dyspnea s a    he Frank-Starng mecansm. Increased end-dasoc ng vo- dramac orm o breaessness, awakenng paens rom seep w a umes dae e ear, srecng cardac myobers; ese eng- eeng o sufocaon. Oer manesaons ncude ear enargemen ened bers conrac more orcby, ereby ncreasng e cardac (cardomegay), acycarda, and ne raes a e ung bases, caused by oupu. I e daed venrce s abe o manan cardac oupu by e openng o edemaous pumonar y aveo. W progressve venrc- s means, e paen s sad o be n compensated eart faure. uar daon, e papar y musces are dspaced, causng mra regur- However, venrcuar daon comes a e expense o ncreased gaon and a sysoc murmur. Subsequen cronc daon o e et wa enson and ncreased oxygen requremens. W me and ds- arum can cause atra ibraon, reducng e ara conrbuon o ease progresson, e paen deveops decompensated eart faure. venrcuar ng, urer reducng e venrcuar sroke voume, and    Actvaton of neuroumora feedback oops. Lack o adequae peru- causng sass, w s aendan rsk o romboss (parcuary n e son o varous ssues nduces e reease o norepneprne by e ara appendage) and embosm. auonomc ner vous sysem and acvaes e renn–angoensn– Sysemcay, dmnsed cardac oupu acvaes e renn–angoen- adoserone sysem. s ncreases e ear rae and conracy, sn–adoserone axs, ncreasng e nravascuar voume and pressures 136 CHAPTER 8 Heart and exacerbang pumonary edema. Reduced rena peruson may ead o so-caed cardac crross. Rg-sded ear aure may aso ead rena faure, and w severe congesve ear aure, dmnsed cerebra o porta ypertenson, congestve spenomegay, and congeson and peruson can manes as ypoxc encepaopaty, w rraby, dmn- edema o e bowe wa, causng maabsorpon. Eevaed venous sed cognon, and resessness a can progress o supor and coma. pressures cause peura, percarda, and peronea efusons and perpera edema n e skn, parcuary n dependen porons Right-Sided Heart Failure o e body. Right-sided heart failure is usually the consequence of left-sided heart failure, because any pressure increase in the pulmonary cir- culation inevitably produces an increased burden on the right side Clncal Features. Pure rg-sded ear aure ypcay s assocaed of the heart. w ew respraor y sympoms. Insead, s manesaons are reaed o sysemc and pora venous congeson, as sed prevousy. In add- Pathogeness. Causes o rg-sded ear aure ncude a o ose on, venous congeson and ypoxa o e kdneys and bran due a nduce et-sded ear aure. Isoaed rg-sded ear aure o rg-sded ear aure can produce decs comparabe o ose (cor pumonae) s nrequen and ypcay s due o dsorders a cause caused by ypoperuson n et-sded ear aure. pumonar y yperenson (e.g., parencyma ung dseases, prmar y pumonar y yperenson, recurren pumonar y romboembosm, CARDIAC TUMORS or condons a cause pumonar y vasoconsrcon suc as obsruc- ve seep apnea). Pumonar y yperenson resus n yperropy and Prmar y umors o e ear are uncommon, and mos are bengn. daon o e rg sde o e ear. In cor pumonae, myocarda Ony myxoma, e mos common prmar y umor o e adu ear, s yperropy and daon generay are conned o e rg venrce descrbed ere. he vas majory o myxomas occur n e et arum. and arum, aoug bugng o e venrcuar sepum can mpede et hey usuay are beween 2 and 6 cm n dameer and may be sesse venrcuar oupu by causng oulow rac obsrucon. or peduncuaed (Suppemena eFg. 8.5). he aer are suiceny mobe o swng no e mra or rcuspd vave durng sysoe, caus- ng nermen obsrucon and damage o vave eales over me (ba Morphology. he major morpoogc eaures o pure rg-sded vave obsrucon). Cnca sympoms arse rom vavuar obsrucon, ear aure dfer rom ose o et-sded ear aure n a embozaon o ragmens, and, n some cases, a sysemc syndrome o engorgemen o e sysemc and pora venous sysems ypcay ever and maase due o e eaboraon o nereukn 6. s pronounced and pumonar y congeson s mnma. he ver usuay s ncreased n sze and weg (congestve epatomegay). A cu secon dspays promnen passve congeson o cenrobuar areas, a paern reerred o as nutmeg ver (see Caper 3). Wen et-sded ear aure s aso presen, severe cenra ypoxa pro- duces centrobuar necross, and w ong-sandng severe rg- sded ear aure, e cenra areas can become broc, creang  CHAPTER 8 Heart 136.e1 A B Supplemental eFig. 8.5 Atrial myxoma. (A) A large pedunculated lesion arises from the region of the fossa ovalis and extends into the mitral valve orifice. (B) Abundant amorphous extracellular matrix contains scat- tered multinucleate myxoma cells (arrowheads) in various groupings, including abnormal vessel-like forma- tions (arrow).