ventricular pressurevolume loops左心室压力容积环课件_1

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1、LeftVentricularPressure-VolumeLoopsLeftVentricularPressure-VolumeLoopsPressure-volumeloopplotsLVpressureagainstLVvolumethroughonecompletecardiaccycleFactorsaffecting:PreloadAfterloadContractilityIHSSValvularproblemsLeftVentricularPressure-VolumeLoops

2、KNOW:WhenthemitralandaorticvalvesareopenandclosedduringeachphaseWhensystolebegins(B)andends(D)Whendiastolebegins(D)andends(B)DiastolicfillingoccursbetweenpointsAandBEjectionoccursbetweenpointsCandDLeftVentricularPressure-VolumeLoopsAcutechangesinpreloa

3、dIncreasedpreload:FillingincreasesSVincreasesDecreasedpreload:FillingdecreasesSVdecreases*NOTE:theventricleemptiestothesameend-systolicvolumeaftereitheranincreaseordecreaseinpreloadLeftVentricularPressure-VolumeLoopsLeftVentricularPressure-VolumeLoops

4、CardiactamponadeUniqueloopLeftVentricularPressure-VolumeLoopsAcutechangesinAfterloadIncreasedafterload:VentricleemptieslesscompletelySVdecreasesIncreaseinBP(shiftsupandright)Decreasedafterload:VentricleemptiesmorecompletelySVincreasesDecreaseinBP(shift

5、sdownandleft)LeftVentricularPressure-VolumeLoopsLeftVentricularPressure-VolumeLoopsAlteredcontractilityIncreasedcontractility:VentricleemptiesmorecompletelySVincreasesBPincreases(shiftsupandleft)Decreasedcontractility:VentricleemptieslesscompletelySVd

6、ecreasesBPdecreases(shiftsdownandright)LeftVentricularPressure-VolumeLoopsLeftVentricularPressure-VolumeLoopsSummaryofconcepts:Alterationsinpreload:end-diastolicvolumeincreasesordecreases,buttheamountofbloodinthechamberatend-systoledoesnotchangeStroke

7、volumefalls:resultofeitheranincreaseinafterloadoradecreaseincontractility,thevolumeofbloodintheLVchamberincreases(chamberdilates)Strokevolumeincreases:resultofadecreaseinafterloadoranincreaseincontractility,thevolumeofbloodintheLVchamberdecreases(chambe

8、rshrinks)LeftVentricularPressure-VolumeLoopsIHSSUNIQUEP-Vloopisshiftedtosmallervolumesandlargerpressures(duetooutflowtractobstruction)ONLYIHSScausesthistypeofcombinedshiftLeftVentricularPressure-VolumeLoopsChronicAorticStenosis