CV System - Heart Function PDF

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Cardiac output in the atria & ventricles, intrinsic & extrinsic factors, heart failure...

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Sunday ,May2,y

Car di ov asc ul ar v es -Val

•R.AVVal v e=Tr i c us pi dv al v e •L.AVVal v e=Bi c us pi dv al v e( =Mi t r al v al v e) •R.SLVal v e=Pul monar ySemi l unar •L.SLVal v e=Aor t i cSemi l unar •Chor daet endi naeat t ac hedt opapi l l ar ymus c l esonAVv al v es •SLval v ess hoott hebl oodoutoft hev ent r i c l es ;AVv al v esbl oodc omesf r om at r i a i nt ot hev ent r i c l es

i v eCel l s&AP -Conduct

•SAnodei si ni t i at i nganAPataf r equenc yt hatt r ans l at est o75bpm i nanor mali ndi v i dual

•AVnodehasi t sowndepol ar i z at i ont hatl eadst oaf r equenc yof50bpm =enought o s us t ai nl i f ef ors omeonewhoi s n' tac t i v e

•Bundl eofHi s / Pur k i nj efi ber s-30bpm ( t oosl owf orpr operc i r c ul at i on) •Wi t ht hes y s t em,speedofs i gnals pr eadi ngi ss ev er almet er s / sec eadwi t houtc onduct i v es y s t em =s i gni fi cant l ys l ower -Spr

•Ar r hy t hmi a=notas y nc hr oni z edc ont r ac t i on;pat c hl i k ec ont r ac t i ons ,nots moot h ( ec t opi cf oc i ) i t t l el oc at i onpoi nt s -Foci=l

•Toomanyi nt oomanypl ac es— fi br i l l at i on( unc ont r ol l edt wi t c hi ng) ,s pas modi c &uns y nc hr oni z edc ont r ac t i ons

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Sunday ,May2,y fi br i l l at i on:mas sofel ec t r i cal s hoc kf r om paddl ei st owi peoutt heAP, -Deandt henwai tf orconduc t i v ec el l st odepol ar i z e&r epol ar i z ewi t ht heSA nodet os t ar tanor malc ont r ac t i ons equenc e bi — nat r i a -Afi

•Causesbl oodcl ot s ,butnotl et hal bi — nv ent r i c l es -Vfi

•Pot ent i al l yl et hal r act i ons=pooreffic i enc yofmov i ngbl ood -Random cont ot heconduc t i ons y s t em ( us ual l ybyl ac kofoxy genat ed -Causedbyadamaget bl oodt owal l )orc ont r ac t i l ecel l sar edamaged

di acCy c l e -Car

•Cont r act i on=s y s t ol e •Rel ax at i on=di ast ol e •Al t er nat i onofs y s t ol e&di as t ol e=c ar di acc y c l e=~75bpm ( gener al l y ) et ec y c l et ak es~8/ 10ofas ec ond=~800ms -Eachcompl

•St eps : r i al&vent r i cul ardi ast ol e— AVv al v esar eopen&SLv al v esar ecl os ed -1.At

•Bl oodi sc omi ngi nt oR.At r i um t hr oughs uper i or&i nf er i orv enac av as&c or onar yv ei n

•Bl oodi sc omi ngi nt oL.At r i um f r om pul monar yv ei n •70% oft hebl oodt hatwi l lbec al l edEndDi as t ol i cVol ume( EDV)wi l lc omei n dur i ngt hi sphas e r i alsyst ol e&vent r i cul ardi ast ol e -2.At

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Sunday ,May2,y

•Fi nal30% ofwhatwi l l beEDVwi l lbeputi nt ot hev ent r i c l es alEDVi n1v ent r i c l e=~120130ml ofbl ood -Tot r i cul arsyst ol e&at r i aldi ast ol e -3.Vent

•Vent r i c l est ar t sc ont r ac t i ngatapex&c ont r ac t supwar d—>c l os eAVv al v es wi t ht hepapi l l ar ymus c l espul l i ngi tback osi ngAVv al v esc aus est hefi r s thear ts ound“ = -Cl l ub”of“ l ubdub”

•SLval v eshav enotopenedy et •Fi r s ti s ov ol umet r i cphas e=c l os edAVv al v ess obl oodcan’ tgetout ,butenough pr es s ur ehas n' tbeengener at edt oopenSLv al v es

•Amountofbl oodej ec tout=St r ok eVol ume( SV)=~7090mlofbl oodperv ent r i c l e r ongerc ont r ac t i onofv ent r i c l e=mor eSV -St

•Amountofbl oodl ef tbehi nd=EndSy s t ol i cVol ume( ESV)=~ b.EndVent r i cul arSyst ol e -3.

•Vent r i c l ess t ar tt or el ax— notex er t i ngenoughpr es s ur e,s ot hear t er i alpr ess ur es l amst heSLv al v esc l os ed=>2ndhear ts ound,“ dub”

•2ndi s ov ol umet r i cphas e-s t ar t i ngt her el ax at i on( AV&SLv al v esal lc l os ed) ax ess omuc h,t hatt heAVv al v esopen—>St ep1 -Rel

-ECG •PWave=El ec t r i cal ev ent st hatl eadt oat r i al cont r act i on ar i z at i on/ Repol ar i z at i onofat r i al cel l s -Depol

•QRSCompl ex=El ect r i c al ev ent st hati ni t i at ev ent r i c ul arcont r ac t i on( BI G) r i aldi as t ol e/ r epol ar i z at i oni shappeni ngatt hes amet i meast heQRSc ompl ex -At

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Sunday ,May2,y ss ol ar get hati sobs c ur est heev ent st hatar et ak i ngpl aceatt heat r i a( P -QRSi wav e)

•TWave=el ec t r i c al ev ent s( v ent r i c ul arr epol ar i z at i on)t hatl eadt or el ax at i onoft he v ent r i c l es

•Measur es i z e,di r ec t i on,andi nt er v al— t el l swhat ’ sgoi ngoni nt er msofhear tf unct i on,howwel l t hes i gnal i ss pr eadi ng,wher et hehear ti shav i ngdi ffic ul t y gePwav e=enl ar gementoft heat r i a -Lar geQ wav e=i ndi cat i v eofani mpendi nghear tat t ac k -Lar atTwav e=i s c hemi a -Fl QRi nt er v al=s cart i s s ue,es pec i al l yi nt hev ent r i c l e -LongP-

•Abnor mal i t i esi nf r equenc y— I SSUE oc k s-i ndi c at esani s s uec ommuni cat i ngbet weenat r i a&v ent r i c l es( s pr ead -AVbl ofs i gnalf r om SAnodet oAVnodet ov ent r i c l es )

•1stdegr ee:pat t er ni snor mal ,butPRi nt er v ali sl engt hened •2nddegr ee:al way saPwav ebef or eaQRS,butmi ghtnothav eaQRSaf t era Pwav e

•3r ddegr ee:“ compl et ehear tbl oc k”— del ay si nget t i ngs i gnalt ov ent r i c l es ,s o v ent r i c l ess t ar tc ont r act i ngont hei rown( notf as tenoughf orgoodc i r c ul at i on) Vent r i cul ares cape”( St ok esAdamsSy ndr ome) ;i nt er -Cancomeandgo=“ mi t t enthear tbl oc k ,s t ar t supagai ns pont aneous l y ss uess endi ngt hes i gnal downi nt ov ent r i c l es— c -Anyi i r c usmov ement s ,s i gnalgoi ngar oundai ml es s l ybec aus ei t ’ snotonr i ghtpat hway ,l eadi ngt ofi br i l l at i on

tFunc t i on -Hear

•Measur es : 4

Sunday ,May2,y di acout put( CO)=t heamountofbl oodpumpedpermi nut e -Car

•CO =HRxSV •Cont r ol l edbot hi nt r i ns i c al l y( wi t hi nt hehear ti t s el f )andex t r i ns i c al l y( f r om out s i det hehear t— ner v ousorendoc r i ne) nt r i ns i cc ont r ol :i ni t i alc hangei sani nt r i ns i cc hange -I

•At r i a— wheny ous t ar tmov i ngmor e,mor ebl oodfl owc omesi nt oat r i a nc r eas edbl oodfl ow ( -I “ P r el oad” )=>I ncr eas esat r i as i z e( s t r et c hi ngat r i a wal l s )

•St r et c hi ngi r r i t at est hec el l soft heSAnode—>i nc r eas i ngdep. / r ep. f r equenc y—>i nc r eas i ngHR—>i nc r eas i ngCO

•Pr eLoad=EDV •Vent r i c l es— bl oodf r om at r i acont i nuesi nt ot hev ent r i c l es nc r eas edbl oodfl ow( pr el oad ) s —> t r et c hesv ent r i c l es( c ont r act i l e -I mus c l ecel l s )—>s t r et c hessar c omer es—>gi v esact i n&my os i nmor e r unni ngr oom —>al l owsani nc r eas ei nt hes t r engt hofcont r ac t i onof c ont r act i l ec el l s( i nt hev ent r i cl e)—>i nc r eas esSV—>i nc r eas esCO

•“ St ar l i ng’ sLaw”( phenomenon) ;ak a“ Fr ank St ar l i ngLaw” •I nc r eas edpr el oad( ~EDV)=>I ncr eas esHR&SV nt r i ns i c / Ex t r i ns i ccombo— “ Bai nbr i dgeRefl ex ”(=“ At r i alRefl ex ” ) -I

•I nt r i ns i cpar t :i nc r eas epr el oad( ~EDV) ,s t r et c hi ngat r i alwal l •Cont r act i l ec el l si nat r i alwal l hav es t r et c hr ec ept or s ;s t r et c hr ec ept or sar e i nner v at ed&s endi mpul s es( APs )t ot hebr ai n( medul l a-c ar di acs i gnal ) —>medul l as endss i gnalt ohear tt oi nc r eas eHR( s y mpat het i ci nput )

•Ext r i ns i cpar t :c ommandsf r om t hebr ai n r i ns i cc ont r ol :neur al&hor monali nput ;does n' ts t ar tatt hehear t -Ext

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Sunday ,May2,y

•Commandscomi ngf r om br ai norhor mones( l i k er el eas eofEi nt ot he bl ood)

•Neur al as y mpat het i ci nner v at i onoft hehear ti nfl uenc est heat r i a( i . e.t heSA -Par node)

•M2r ec ept or s :i nhi bi t or y ,dec r easeHR •Hear ti sundert oni ci nhi bi t i on-t her e’ sal way sal ev el ofpar a.i nput ( ~75bpm) l yi nc r eas i ngpar a.i nhi bi t i on=>~2530bpm ( c oul dnots us t ai n -Real l i f e) het i ci nner v at i on -Sympat

•NE/ E— B1r ec ept or s( i nconduct i v e&c ont r act i l ec el l s )=>i nc r eas e HR&SV=>i nc r eas eCO s i gni fi cant l y

•Mor ec al ci um i n=>i nc r eas ess t r engt hofc ont r ac t i on •Aver agemal e:CO =5000ml / mi n( atr es t ) ,c ani nc r eas e45xmor edur i nge x er c i s ei nnor mal peopl e,at hl et esc ani nc r eas e7xmor e

•Af t er l oad=t hebac kpr es s ur eex er t edbyar t er i al bl ood eas esCO becaus ei tus ual l ydec r eas esSVc omi ngf r om t hehear t ,or -Decr t hehear t( v ent r i c l es )mustc ont r ac tmuc hmor e enc yofamountofbl oodc omi ngoutofv ent r i c l esperc ont r ac t i on: -Effici

•Nor mal :810mmHg— pul monar yar t er y( r i ghts i deofhear t ) ,80mmHg— aor t a( l ef ts i deofhear t )

•Hyper t ens i v e( hi ghBP) :dec r eas eSV=>dec r eas eamountofo xy genat ed bl ood;dec r eas edSV=>i nc r eas esESV( l es spumpi ngout ,mor es t ay si n) =>c ongest i v ehear tf ai l ur e

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Sunday ,May2,y nc r eas edESV=>s t r et c hesv ent r i c l es( t oomuc h,pas tt heopt i mal -I boundar i esofSt ar l i ng’ sLaw)=>pas tboundar i esofact i n&my os i n=> l esss t r engt hofc ont r act i onduet ot oomuc hbl oods i t t i ngt her e=>bl ood t hatc an’ tgetpumpedoutaswel l asnewbl oodc omi ngi n=>pumpbec omesl es seffic i ent

•Of t en1si deoft hehear tf ai l sbef or et heot her … ft hel ef ts i dehaspr obl ems—>deat h… notpumpi ngenough -I bl oodout ,butt hebl oodr emai ni ngi nLv ent r i c l ei scaus i ngbac k up pr es s ur et owar dst hel ungs=>pul monar yedema( pr es sur ei nc r eas esfl ui d&s epar at esal v eol i&capi l l ar yl i ni ng—>bl oodpumpi ngc an’ tgetenoughO2) ft her i ghts i def ai l s—>s y s t emi cedema;i nc r eas edpr es s ur ei nR -I v ent r i c l e=i nc r eas edpr es sur eonv enouss i de=>s wel l i ngofank l es ,et cduet oi nc r eas edfl ui di ni nt er s t i t i alar eas

•Tr eat mentoft y pesofc onges t i v ehear tf ai l ur es : ur et i c s— ur i nat emor e=>dec r eas eex t r ac el l ul arfl ui d( i . e.i n-1.Di t er s t i t i alfl ui d)=>dec r eas eedema gi t al i s( Di gox i n)— i nc r eas ess t r engt hofc ont r act i on; -2.Di i nt er f er es / k noc k soutt heNa+/ K+pump

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