echocardiography/angiography deepak nandan echocardiography/angiography deepak nandan
TRANSCRIPT
EVALUATION OF SYSTOLIC FUNCTION
ECHOCARDIOGRAPHY/ANGIOGRAPHY
DEEPAK NANDAN
“SYSTOLE”- CONTRACTION
“DIASTOLE”-TO SEND APART
Systolic function is affected by preload afterload,contractility and heart rate.
Asynchronous systolic contraction also may affect systolic function
Quantitative echo◦ LV VOLUME
◦ LV MASS
◦ EJECTION INDICES
STROKE VOLUME EJECTION FRACTION FRACTIONAL SHORTENING VELOCITY OF CIRCUMFERENCIAL FIBRE
SHORTENING
LV SYSTOLIC FUNCTION
Quantify LV function -MODES
M-Mode Modified Simpson’s Method Single plane area-length method Velocity of Circumferential Shortening Mitral Annular Excursion E-point to septal separation Rate of rise of MR jet Index of myocardial performance Subjective assessment
M-Mode Quantification Use Parasternal Short-Axis or Long-Axis
views to measure LVEDD and LVESD
May take several measurements at different levels and calculate average
Assumes that no significant regional wall motion abnormalities are present
Uncorrected (LVEDD)² - (LVESD)² LVEF = ----------------- X 100 (LVEDD)²
If apical contractility is normal
Corrected LVEF = Unc LVEF +(100 – Unc LVEF) X
15%)
5% hypokinetic, 0% akinetic, -5% dyskinetic, -10% aneurysm
Global Myocardial Function
• Fractional shortening (FS)– Assumes symmetric
contraction
• Ejection fraction (EF)
LVED LVESFS
LVED
2 2
2
LVED LVESEF
LVED
M-MODE-LINEAR MEASUREMENTS
EPSS
GRADUAL CLOSURE OF AORTIC VALVE
MEAN Vcf-rate of shortening of LV
INDIRECT M-MODE MARKERS
EPSSNORMAL ≤6mm
EF<50% >7mm
EF≤35% ≥13mm
Mitral Annular Excursion toward LV Apex
M-mode tracings in systole The magnitude of systolic motion is
proportional to the longitudinal shortening of the LV
Normal mitral annular systolic motion is 8mm+ (average 12 +/- 2 on apical4 or apical 2 views)
If motion is < 8 mm, the EF is likely < 50%
Velocity of Circumferential shortening Vcf is the mean velocity of LV shortening
through the minor axis
Vcf = FS/ET
ET is the time between LV isovolumetric contraction and isovolumetric relaxation
Measure by obtaining M-mode of AV opening to AV closure, aortic flow by doppler, or by an external pulse recording of carotid artery
NL values are > 1.0 c/s Slow Vcf may suggest diminished systolic
function
2-D MEASUREMENTS
Ejection Fraction
• Quantitative
- accuracy, reproducibility limited
- assumes shape of LV cavity
- best in symmetric ventricles
SIMPSONS RULE\ RULE OF DISC
Simpson’s Rule – the biplane method of disks
Volume left ventricle
- manual tracings in systole and
diastole
- area divided into series of disks
- volume of each disc(πr2x h )
summed = ventricular volume
LV-ED LV-ES
A4C
A2C
LV-ED LV-ES
LEFT VENTRICULAR MASS
TEICHOLZ /CUBED FORMULA
LV Mass Quantification 2D M-Mode method using parasternal short axis view or
parasternal long axis view
Assumes that LV is ellipsoid (2:1 long/short axis ratio)
Measurements made at end diastole
ASE approved cube formula: LV mass (g) = 1.04 [(LVID + PWT + IVST)3 - (LVID)3] X 0.8 + 0.6 LV mass index (g/m2) = LV mass / BSA
Small errors in M-Mode cause large errors in mass values. Can have off axis/tangential cuts due to motion.
LV Mass Quantification
LV mass = 1.04[(IVS + LVID + PWT)3 – (LVID)3] – 13.6 g
NL LV mass index for males: 93±22g/m2
NL LV mass index for females: 76±18g/m2
LV MASS BY 2-D
RWT = 2(PWT/LVID)
REGIONAL LEFT VENT FUNCTION
Regional Myocardial Function
• Assessment of motion of regions of the myocardium
• Useful for detection of myocardial ischemia– Leads to decreased or
paradoxical motion of the wall in affected areas
• Regions can be roughly mapped to coronary arteries
NONISCHEMIC RWMA
DIFF ISCHEMIC VS NONISCHEMIC
LBBB
DOPPLER EVALUVATION OF GLOBAL LVF
SCHEMATIC REP OF ASSESSMENT OF LV VOL
Stroke Volume and Cardiac Output
Flow = Cross sectional area (CSA) x Average velocity
Average velocity not usually measured directly
VTI = velocity-time integral
Area under the velocity curve for a single beatRepresents ‘stroke distance’
SV = VTI * CSA
Stroke Volume Measurement
Measurement of VTIMeasurement of CSA
Accurate measurement of CSA◦ Weakest link in the calculation◦ VTI very good for assessing change in cardiac
output with therapy, by following changes in VTI, since CSA is largely invariant in an individual
Measures forward flow only◦ Regurgitant fraction not considered◦ May over-estimate systemic cardiac output
Echocardiographic window in mechanically ventilated patients may be poor
Pitfalls in Echo Calculation of CO
WALL STRESS
LEFT VENTRICULAR dp/dt
CW doppler to measure rate of rise of MR jet may correlate to LVEFA slow rate of rise may indicate poor systolic functionMust have MR present, and good doppler study present (more difficult with eccentric jets)
INDEX
OF MYOCARDIAL PERFORMANCE
Index of Myocardial Performance Uses systolic and diastolic time intervals to evaluate global ventricular performanceSystolic dysfunction causes prolonged isovolumetric contraction time (ICT) and a shortened ejection time (ET). IMP = (ICT + IRT)/ET
Index of Myocardial Performance Normal LV: 0.39 +/- 0.05 LV, DCM: 0.59 +/- 0.10 Normal RV: 0.28 +/- 0.04 Primary Pulm Htn: 0.93 +/- 0.34
Use PW of AV inflow signal, or CW to get AV regurgitant signal
Also need to measure interval between AV closure and opening (AVco)
PW or CW to capture semilunar outflow signal to measure ejection time (ET)
IMP = (AVco – ET)/ET
Summary LV Mass Quantification: M-mode, Area-
length method, Truncated ellipsoid method, and Subjective assessment.
LV Volume Quantification: M-mode,
Subjective assessment
LV Function Quantification: Modified Simpson’s and Subjective Assessment by region.Also by M-mode, Single plane area length method, Velocity of Circumferential Shortening, Mitral Annular Excursion, EPSS, Rate of Rise of MR jet, Index of myocardial performance, etc
ANGIOGRAPHIC ASSESSMENT OF LV FUNCTION
Amout of passive tension or strectch on the ventricular walls prior to systole
This load determines end diastolic sarcomere length and force of contraction
This inturn decides stroke volume and cardiac output
LV PRELOAD
Afterload is the wall stress during ejection
Three major components are-peripheral resistance,arterial compliance,& peak intraventricular pressure.
Contractility is the inherent property of the myocardium to contract independent of the changes in pre & afterload
AFTERLOAD AND CONTRACTILITY
CONTRACTILITY INDICES
Isovolumic indices Maximum dp/dt Maximum (dp/dt)/p Vpm or peak([dp/dt]/28p) (dp/dt)/Pd at Pd=40 mm hg
Ejection phase indices LVSW LVSWI EF MNSER(mean normalised syst eject rate) Mean Vcf
EVALUATION OF SYSTOLIC PERFO
Dp/dt-max rate of rise of LV systolic pressure-oldest & widely used
Nl-1610±290 mmHg/sec
Isovolumic indices
EJECTION INDICES
Area within PV diagrams-most accurate
Other methods
LVSW=(LVSP−LVDP)SV(0.0136)LVSP&LVDP=MEAN SYST/DIAST PRSV=STROKE VOL IN ml0.0136=for converting mm Hg-ml into g-m
LVSW
LVSW –good measure in the absence of vol or pressure overload
Nl-90±30g-m
Values ≤25 indicate severe Lv syst failure & <20 prognosis is grave.
But reflects syst performance only when ventricle is homogenous in consistency-DCMP
In ext MI LVSW may be depressed even if contractility is normal
LVSW=(AoSP−PCWP)SV(0.0136)
Lv syst function can be assessed using only volume data from P-V diagram
EF=[(LVEDV−LVESV)/LVEDV]
EF/ Ejection time obtained from Ao pressure tracing =Mean normalised syst ejection rate
MNSER=(LVEDV−LVESV)/(LVEDVхET) NL-EF(angio)=.72±0.08
Nl MNSER(angio)=3.32±0.84EDV/sec
Vcf=velocity of the circumferential fiber shortening
Rate of shortening of lv myo fiber in a circmferential plane at the midpoint of the long axis of the ventricle
MeanVcf=end diast endocardial circum fiber length −end syst length
Vcf=(Ded−Des)/Ded(ET)
Nl-1.83±0.56ED circ/sec
Drawbacks-influenced by preload & afterload
An Lvef≤.40 indicates depressed lv contractility, if there is no loading to account for the reduction.
Interpretation of ejection phase indices are improved by consideration of the preload & afterload.
PRESSURE VOLUME LOOPS
Fundamental principle of end-systolic Pv analysis is that, at end-systole there is a single line relating LV chamber vol to pressure,unique for the level of contractility & independent of loading conditions.
Most reliable index of contractility
Insensitive to changes in pre,afterload& heart rate
Slope of the end syst pr vol curve is called elastance-sensitive parameter
ESPVR
Other indices
LVdp/dt max and EDV Slope of this as an
index of contractility
Inverse relation between the two ↑afterload→↑syst
wallstress→↓myocardial shortening
Stress-shortening relationship
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