Encyclopedia of Heart Diseases PDF
Preview Encyclopedia of Heart Diseases
Encyclopedia of Heart Diseases Encyclopedia of Heart Diseases M. Gabriel Khan, MD, FRCP [London], FRCP[C], FACC Cardiologist, The Ottawa Hospital, Ottawa, Canada Associate Professor of Medicine, University of Ottawa With a Foreword by Christopher P. Cannon, MD TIMI Study Group, Brigham and Women’s Hospital Harvard Medical School Boston, MA Editor-in-Chief, Cardiosource Science and Quality With255Figuresand70Tables MGabrielKhan UniversityofOttawa Cardiologist TheOttawaHospital Ottawa,ONK1H8L6 Canada ISBN:978-1-60761-218-6 TheelectronicversionwillbeavailableunderISBN978-1-60761-219-3 TheprintandelectronicbundlewillbeavailableunderISBN978-1-60761-220-9 DOI10.1007/978-1-60761-219-3 SpringerNewYorkDordrechtHeidelbergLondon LibraryofCongressControlNumber:2010928184 (cid:1)SpringerScience+BusinessMediaLLC2011 Allrightsreserved.Thisworkmaynotbetranslatedorcopiedinwholeorinpartwithoutthewrittenpermissionofthepublisher (SpringerScience+BusinessMedia,LLC,233SpringStreet,NewYork,NY10013,USA),exceptforbriefexcerptsinconnectionwithreviews orscholarlyanalysis.Useinconnectionwithanyformofinformationstorageandretrieval,electronicadaptation,computersoftware,orby similarordissimilarmethodologynowknownorhereafterdevelopedisforbidden. Theuseinthispublicationoftradenames,trademarks,servicemarks,andsimilarterms,eveniftheyarenotidentifiedassuch,isnottobetaken asanexpressionofopinionastowhetherornottheyaresubjecttoproprietaryrights. Whiletheadviceandinformationinthisbookarebelievedtobetrueandaccurateatthedateofgoingtopress,neithertheauthorsnortheeditors northepublishercanacceptanylegalresponsibilityforanyerrorsoromissionsthatmaybemade.Thepublishermakesnowarranty,expressor implied,withrespecttothematerialcontainedherein. Printedonacid-freepaper SpringerispartofSpringerScience+BusinessMedia(www.springer.com) TomywifeBrigidwhomadethisworkpossible Andtoourchildren Susan Christine Yasmin Jacqueline Stephen Natasha Acknowledgments Peoplewhoneedpeople The vast amount of information provided to readers is indicative of the efforts and perseverance of the numerous investigatorswhose publishedworksIhavehadthepleasureofquoting.Thesetalentedwomenandmenofmedicine deservemyrespect,mythanks,andmycongratulations.Ifeelcertain,however,thatthenamesofmanyresearchershave beenomittedbecauseofmyoversightandbecausereferencesprovideonlythreenames. SandraFabiani: ExecutiveEditor, my Publisher atSpringer,hadtheforesightto acceptmy proposal;without her remarkablevision,thissecondeditionwouldnothaveemerged. ImustexpressmythankstoSusanneFriedrichsen,AssociateEditor,andherteamthatincludes: ● UlrikeEggert-Neben,EditorialAssistant ● Chandramohan Sivasubramanian, Project Manager whofacedthe taskofproduction ofthe book without disap- pointingmewiththeirpatienceforacceptingmynumerousadditionalupdates. The printing style is what I requested – a text that is noncompressed, user friendly, and with well-positioned illustrations.Fewpublishersareabletofollowthewhimsofauthors. Last,ImustthankDoctorsScottSolomonandBernardBulwerforallowingmetouseanimatedechocardiographic imagesfetchedfromtheirbookEssentialEchocardiography. Thereislittledoubt,however,thatwithouttheloveandcommitmentofmywifeBrigid,thisdauntingtaskofthe productionofasingle-authored,96-chapterencyclopediawouldnothavebeenpossible. Preface Cardiovasculardiseasecurrentlyisresponsibleformorethan14milliondeathsworldwideannuallyandisestimatedthat thiswillincreasetomorethan25milliondeathsintheyear2025inapopulationof7.9billionpeople.Thiswidespread diseasecausesmoredeathsthanallformsofcancer,diabetes,infections,andlungdiseases.Thisepidemiccanonlybe curbedbyrelevantandsoundresearch.Suchresearch,however,requiresacquisitionofaccuratecoreknowledge.The buddingresearcherneedstoknowwhatistrulyprovenandwhatneedstobeproven. Cliniciansrequireonlinemedicalupdatesbroughtrapidlytotheircomputerssoastorendermoreefficientcarefortheir patients. ● Thisencyclopedicworkisdirectedatallphysicianswhorendercaretocardiovascularpatientsandtoallwhowishto pursuearesearchcareerinmedicine,pharmacology,biomedicalengineering,andtechnologicinnovations.Hope- fully,practicingclinicianswouldgleancrucialandup-to-dateinformationthatwouldprovideamelioratingbenefits for their patients. At the end of a patient–doctor consultation, it is the prescription handed to the patient that provides a cure or salutary effect. Thus, the text gives considerable amount of information on cardiovascular therapeutics. ● Bothcareerresearchersandthosewhowishtodevoteonlyafewyearsinresearchwillfindtheinformationprovided invaluable.Postgraduatesinscienceandtechnology,includingMDsandPhDs,whowishtopursueresearchinthe medicalsciencesmusthaveareferencesourcethatprovidescoreknowledgeinmedicine,particularly,pathogenesis, pathophysiology,clinicaldiagnosticfeatures,diagnostictechniques,andmanagementstrategies.Thetextprovides thisinformation. ● Inaddition,ourseniorcollegeyouthworldwideareclamoringfornewknowledgethatisnotprovidedbytutorswho preferstudentstoresearchtopics.Muchisprovidedbytheinternetbutinaccuracyabounds.Somematerialinthe textisattimessimplifiedtoreachthecollegeaudience. ● Thetextoftendescribeshistoricaleventsthatleduptocertainhallmarkdiscoveries;thisisdonetoindicatetothose interested in research that simple thoughts and perseverance bring fruits from research. It is my hope that this historicalandrelevantcardiologicinformationwillprovidemotivationandawakeningofnewinterestsinthesolving ofthepathogenesis,pathophysiology,diagnosis,andmanagementstrategiesofavarietyofheartdiseases. ● Often,majordiscoveriesaremadebythosewhopursueonlyafewyearsinresearch,andinnovationsmaybemadeby simple thought processes. A prime example is the one revealed by Reverend Hales, the father of hemodynamic medicine.DuringhisstudiesintheologyatCambridge,hewasfortunatetodomathematicsandscienceandhad conversationswithamedicalstudent.In1733,aftermanyyearsinhisministry,atTeddingtonoutsideLondon,he foundthetimeforthestudyofcirculation.Figure1intheentry▶BloodPressureshowsHalesobservingtheblood pressureinahorse,andheiscreditedtobethefirsttodemonstratethemeasurementofbloodpressure. ● The vascular surgeon Korotokoff, in Russia in 1900, recognizing that a constricted artery makes no sound, used astethoscopetoobservethesoundsmadebythebloodflowingthroughthearteryinthearmconstrictedbyanarm band;heheardsoundsasthebandwasreleased.Thefirstsoundsweretakenasthesystolicbloodpressureandthe sounds are called Korotkoff sounds; the technique is used to this day without change. Korotokoff’s innovative discoveryrequiredonlyhisthoughtofsound;hewasnotaresearcher.Surgeonsdonotnormallyusestethoscopesbut vascularsurgeonsdoso,becausetheylistenoverexpandedarteries,aneurysmsthatemitaloudbruit,asoundmade asthebloodstrikestheexpandedwalloftheartery. ● Manyofthetechnologicadvancesinmedicinehavebeenprovidedforusbythecollaborationofengineers,physicists, biologists,andmedicaldoctors.Einthovenwouldnothaveproducedtheelectrocardiogramin1901,ifAdlerhadnot providedthewirelesstelegraph;also,thestringgalvanometer,anonmedicaldevice,wasthenavailabletoEinthoven. ● TheadventofultrasonographywasaninnovationpromptedbytheTitanicdisasterandtheunderwatersearchfor submarinesin1939.Attheendofthewar,physicistsandmedicaldoctorscollaboratedtoprovidetheultrasoundfor neurologicinvestigations.Echocardiographystemmedfromanengineerwhoworkedincollaborationwithamedical studentandaphysician.In1964,Dr.HarveyFeigenbaumsawtheunsophisticatedmachineattheAmericancollegeof x Preface cardiologyscientificsession.Hewentbacktohislabandborrowedanultrasoundmachinefromtheneurosurgical divisionandusedthistoshowthatpericardialeffusionsaroundtheheartcouldbeobservedbyultrasonictechnique andpresentedhishallmarkpaper(Feigenbaum2008). His research work was not overwhelming and did not require much scientific thought or expertise. He was not amajorresearchscientist.Manyoftheadvancesinechocardiographyduring1965to1990canbeattributedtohiswork andtothesophisticationbytheengineers. ● BernardLowniscreditedintheWesternworldwithinitiatingthemoderneraofcardioversion(Cakulevetal.2009). Lownrecalledthefollowing: " NeverhavingseenanACdefibrillator,Ihadn’ttheremotestideahowtouseone.Ahostofquestionsneededpromptanswers: Was the shock painful? Was the anesthesia required? Was there an appropriate voltage setting to reverse ventricular tachycardia?Iftheshockfailed,howmanyadditionalonescouldbedelivered?(Lown1996) He“fortunately,andquiteaccidentally,metabrilliantyoungelectricalengineer,BaruchBerkowitz,”whohadbeen developing a DC defibrillator while working for the American Optical Corporation. Berkowitz in 1961 had the instrumenttestedinanimalsbyBernardLown(Lown1996). Medicalsciencehasmadehugeprogressinthepastfewdecadesbutfarmoreremainsunresolved.Aprimeexampleis theknowledgethatisavailableonthedevelopmentofatheromaandatherothrombosis,adiseaseprocessresponsiblefor heartattacks,angina,suddendeaths,stroke,intermittentclaudication,andgangreneoftheleg.Thewordatheromais derived from the Greek word “athere,” meaning porridge or gruel. Ancient Greekphysicians removedtheplaques of atheromathatobstructedarteries,andcuttingtheplaqueofatheromarevealedagelatinousporridge-likematerial.At least, we do know that the porridge-like material which exudes from a ruptured atheromatous plaque is highly thrombogenicandpromotestheclottingofcirculatingblood,andthusthearterialocclusionwhichresultsinmyocardial infarction(heartattack)orcerebralinfarctions(strokes). Atheromaisthebasisforheartattacksandstrokeandismainlyresponsiblefortheepidemicdescribedabove.After morethan60yearsofresearch,wedonotknowhowtoeffectivelypreventtheatheromaformationanditsprogressionto vesselocclusion.OurnewdiagnosticarmamentariumincludesCTcalciumscoringandCTcoronaryangiograms,bothof whichgeneratesunjustifiableradiationhazardsandgiveonlycluestothepresenceofvulnerableatheromatousplaques. MRIisoflimitedvalue.Theinformationgleanedfromtheresultsofthesetestsmostoftendonotsignificantlyalterthe therapyforthemillionsaffectedworldwidebytheepidemicofatheromatouscardiovasculardisease. Developmentsoftechnologicinstrumentsthatmayprovidenoninvasivedetectionofatheromatousobstructionin coronaryarteriesthatpresentlycanonlybeobservedwithcertaintybyaninvasivecoronaryangiographyareurgently required.CTcoronaryangiographyprovidesconsiderableinformationbutisnotasubstituteforaninvasivecoronary angiographywhichgivesthecrucialinformationrequiredforapercutaneouscoronaryinterventionorabypasssurgery. Theinformationprovidedinthisreferenceworkismainlyfactualanddoesnotdiscusscontroversies.But,twoentries ofthe96,ofnecessity,discusstworecentandimportantcontroversiesincardiovascularmedicine. 1.Worldwide,therearemorethanonebillionhypertensiveindividualswhorequiredrugtreatment.Sadly,aftermore than 70 years of research, there are only four drugs available: diuretics, beta blockers, calcium antagonists, and ACE inhibitors(angiotensinreceptorblockersaresimilaragents).Otheragents:methyldopaisusedmainlyforhypertension inpregnancyandalphablockerscauseheartfailureandhenceitsuseisrestricted.Thissituationcanonlybecorrectedif pharmaceuticalfirmsandexpertsinthefieldofhypertensionrecognizethatonlyfourdrugsareavailable. Morethan60%ofhypertensivepatientsrequiretwoorthreedrugstoattainbloodpressurecontrol. ● Recently, peer-reviewed journals have provided editorials by notable physicians who state that the beta blockers shouldnotbeprescribedforprimaryhypertensionbecauseoftheirineffectivenessandtheymaycausediabetes.An entry entitled ▶Beta Blockers Hypertension Controversy addresses this topic that is important for clinicians worldwide. 2. Increase in the incidence of diabetes is a concern: Many investigators have reported recently in peer-reviewed journals that diuretics and beta blockers cause diabetes mellitus and their use should be restricted. This information wouldgreatlydecreasetheprescribingoftwooftheonlyfourantihypertensiveagentsavailable.Thesetwoagentsare
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