Echocardiography for the Surgeons

Echocardiography for the Surgeons
Dr. Rezwanul Hoque Bulbul MS, FCPS, FRCSG, FRCSEd Associate Professor BSM Medical University, Dhaka Bangladesh

General concepts The use of ultrasound to examine the heart- a safe, powerful, non-invasive and painless technique Sound is the disturbance propagating in a material Frequency is the oscillations per second Frequency higher than 20KHz can not be perceived by ear- known as ultrasound Echo uses frequency range 1.5MHz to 7.5 MHz, upto15 MHz for skin lesion.

Basic concepts of US Velocity of sound- in heart 1540m/s, in air 330m/s Velocity divided by frequency gives wave length Shorter the wavelength, higher is the resolution, greater is the penetration Piezoelectric crystals converts electrical oscillation to mechanical oscillation to produce US, opposite occurs when same crystal acts as receiver The repetition rate is 1000/s, transmission 1 micro sec, remaining time spent in receiving mode

Probe-types for 2-D 1. Mechanical sector scanner 2
Probe-types for 2-D 1.Mechanical sector scanner 2.Phased array sector scanner

Machines There are 5 basic components of an ultrasound scanner that are required for generation, display and storage of an ultrasound image. Pulse generator - applies high amplitude voltage to energize the crystals Transducer - converts electrical energy to mechanical (ultrasound) energy and vice versa Receiver - detects and amplifies weak signals Display - displays ultrasound signals in a variety of modes Memory - stores video display

Viewing the Heart Windows allow good penetration by US without too much masking by Lung or ribs Echo may be difficult in those with chest wall deformity, COPD, lung fibrosis, obese person Axis refers to the plane in which the US beam travels through the heart

Echo windows & views Left parasternal window( 2nd-4th ICS, left sternal edge) Long axis view, Short axis view(AV, MV,LV Papillary muscle, LV apex level) Apical window 4 chamber ,5 chamber( aortic outflow) , Long axis & 2 chamber view Subcostal window- useful in lung disease Supracostal window Right parasternal window

Parasternal Long-Axis View (PLAX)
Transducer position: left sternal edge; 2nd – 4th intercostal space Marker dot direction: points towards right shoulder Most echo studies begin with this view It sets the stage for subsequent echo views Many structures seen from this view

Parasternal Short Axis View (PSAX)
Transducer position: left sternal edge; 2nd – 4th intercostal space Marker dot direction: points towards left shoulder(900 clockwise from PLAX view) By tilting transducer on an axis between the left hip and right shoulder, short axis views are obtained at different levels, from the aorta to the LV apex. Many structures seen

Papillary Muscle (PM)level
PSAX at the level of the papillary muscles showing how the respective LV segments are identified, usually for the purposes of describing abnormal LV wall motion LV wall thickness can also be assessed

Apical 4-Chamber View (AP4CH)
Transducer position: apex of heart Marker dot direction: points towards left shoulder The AP5CH view is obtained from this view by slight anterior angulation of the transducer towards the chest wall. The LVOT can then be visualised

Apical 2-Chamber View (AP2CH)
Transducer position: apex of the heart Marker dot direction: points towards left side of neck (450 anticlockwise from AP4CH view) Good for assessment of LV anterior wall LV inferior wall

Apical 5-chamber view

Sub–Costal 4 Chamber View(SC4CH)
Transducer position: under the xiphisternum Marker dot position: points towards left shoulder The subject lies supine with head slightly low (no pillow). With feet on the bed, the knees are slightly elevated Better images are obtained with the abdomen relaxed and during inspiration Interatrial septum, pericardial effusion, desc abdominal aorta

Suprasternal View Transducer position: suprasternal notch
Marker dot direction: points towards left jaw The subject lies supine with the neck hyperextended. The head is rotated slightly towards the left The position of arms or legs and the phase of respiration have no bearing on this echo window Arch of aorta

Echo Techniques 2-D echo M-mode echo Pulsed wave Doppler
Continuous wave Doppler Color flow mapping Stress echo 3-D echo Preoperative Intraoperative Postoperative Transthoracic echo Trans oesophageal echo

Diastole/ Systole in echo

2-D echo Gives a snapshot in time of a cross-section of tissue
Ultrasound is transmitted along several scan lines(90-120), over a wide arc(about 900) and many times per second. The combination of reflected ultrasound signals builds up an image on the display screen. This technique is used to "see" the actual structures and motion of the heart structures at work. Real-time imaging is possible if the scanning and display is rapid Sector imaging is possible either by mechanical rotation of a transducer or phased electric stimulation of array of crystals Anatomy, chamber size, intra & extra cardiac mass, fluid collection Ventricular and valvular movement A 2-D echo view appears cone-shaped on the monitor. Positioning for M-mode and Doppler echo

M-mode echo( 1-D echo) Motion mode echo is produced by transmission and reception of US along only one line An M- mode echocardiogram is not a "picture" of the heart, but rather a diagram that shows how the positions of its structures change during the course of the cardiac cycle. M-mode recordings permit measurement of cardiac dimensions and motion patterns. Also facilitate analysis of time relationships with other physiological variables such as ECG, and heart sounds. More sensitive than 2-D echo in imaging moving object

M-mode at Mitral Valve Distance Time Diastole Systole

M-mode at Mitral Valve d e a d Distance f c Systole Diastole Time

M-mode at Mitral Valve d-e amplitude Diastole Distance Systole Time e

M-mode at Mitral Valve Septum EPSS Distance e Systole Diastole Time

M-mode at Mitral Valve e d-e slope Distance Diastole Systole d Time

M-mode at Mitral Valve e e-f slope Distance f Systole Diastole Time

M-mode at the Mitral Valve
Amplitude Description Normal Value EPSS Measure e point to septal separation < 5 mm d-e Measures the maximum excursion of the mitral valve following diastolic opening. 17 to 30 mm

M-mode at the Mitral Valve
Slope Description Normal Value d-e Measure rate of initial opening of the mitral valve in early diastole. 240 to 380 mm/s e-f Measures the rate of early closure of the mitral valve following diastolic opening. 50 to 180 mm/s

Systolic anterior motion
M-mode at Mitral Valve Systolic anterior motion of the AMVL Distance Time Diastole Systole

M-mode at Mitral Valve MV prolapse posterior leaflet Systole Distance
Time Diastole Systole

M-mode at the Aortic Valve
Non-coronary cusp Anterior aortic root Coronary cusp Posterior aortic root Left Atrium

M-mode at the Aortic Valve
Cusp Separation Aortic root LA dimension

Assessment of Severity
Maximal aortic cusp separation (MACS) on M-mode Vertical distance between RCC and NCC during systole Stenotic Aortic Valve → decreased MACS Limitations Single dimension Asymmetrical AV involvement Calcification / thickness ↓ LV systolic function ↓ CO status AVA MACS N > 2cm2 N > 15 mm < cm2 < 8 mm > 1 cm2 > 12 mm gray area 8 – 12 mm

M-mode at Left Ventricle
RVIDd/RVIDs IVS LVIDd/LVIDs LVPWd

M-mode LV Calculation FS = LVIDd – LVIDs LVIDd EF = LVIDd3 – LVIDs3
IVS % thickening = (IVSs – IVSd) x 100 IVSd LVPW % thickening = (LVPWs – LVPWd) x 100 LVPWd LV Mass = 1.04 {(LVIDd + IVSd + LVPWd)3 – (LVIDd)3} x g

E-F slope The two mitral leaflets move in diastole in M-shaped mirror image pattern. At the onset of systole the two leaflets come together sharply to produce the 1st heart sound. The early diastolic velocity of the leaflets, called the E to F slope is dependent on the rate of LV filling. The velocity may be slowed when the rate of filling is slowed( MS).

LV SYSTOLIC FUNCTION STROKE VOLUME EJECTION FRACTION
Quantitative echo LV VOLUME LV MASS EJECTION INDICES STROKE VOLUME EJECTION FRACTION FRACTIONAL SHORTENING VELOCITY OF CIRCUMFERENCIAL FIBRE SHORTENING

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

LV dimension measurement
Correct positioning of M-mode cursor in the transthoracic parasternal long axis view to obtain the standard left ventricular M-mode tracing as shown above.

Fractional shortening
Fractional shortening (FS) is the fraction of any diastolic dimension that is lost in systole. When referring to endocardial luminal distances, it is EDD minus ESD divided by EDD (times 100 when measured in percentage). Normal values may differ somewhat dependent on which anatomical plane is used to measure the distances, but a range from 30 to 42% is considered normal with 26 to 30% representing a mild decrease in function. Midwall fractional shortening may also be used to measure diastolic/systolic changes for inter-ventricular septal dimensions and posterior wall dimensions. However, both endocardial and midwall fractional shortening are dependent on myocardial wall thickness, and thereby dependent on long-axis function. By comparison, a measure of short-axis function termed epicardial volume change (EVC) is independent of myocardial wall thickness and represents isolated short-axis function.

LV ejection fraction Tests for measuring EF: Echocardiogram MUGA scan
In cardiovascular physiology, ejection fraction (EF) represents the volumetric fraction of blood pumped out of the ventricle (heart) with each heart beat or cardiac cycle. It can be applied to either the right ventricle which ejects via the pulmonary valve into the pulmonary circulation or the left ventricle which ejects via the aortic valve into the systemic circulation. Ejection fraction (Ef) is the fraction of the end-diastolic volume that is ejected with each beat; that is, it is stroke volume (SV) divided by end-diastolic volume (EDV): Measure Typical value Normal range end-diastolic volume (EDV)120 mL[1] 65–240 mL end-systolic volume (ESV) 50 mL 16–143 mL stroke volume (SV) 70 mL 55–100 mL ejection fraction (Ef) 58% 55–70%[2] heart rate (HR) 75 bpm 60–100 bpm cardiac output (CO) 5.25 L/minute 4.0–8.0 L/min Tests for measuring EF: Echocardiogram MUGA scan CAT scan Cardiac catheterization Nuclear stress test Depends on contractility, preload and afterload, heart rate, synchronicity of contractions Global parameter, regional differences in contractility averaged

LVEF Qualitative - visual inspection severity: mild, moderate, severe
focality: global reported as a range in intervals of 5-10% regional: 17 segments Quantitative accuracy, reproducibility limited assumes shape of LV cavity best in symmetric ventricles

Simpson’s Rule – the biplane method of disks
LV-ED LV-ES Volume left ventricle - manual tracings in systole and diastole - area divided into series of disks - volume of each disk ( πr2 * h ) summed = ventricular volume A4C A2C

Simpson’s Rule – the biplane method of disks
Once volumes determined, EF is calculated : LV diastolic volume - LV systolic volume x 100% LV diastolic volume Normal > 50%, 35 to 50% moderately depressed, <35% severely depressed Edge detection software can identify borders

LVEF-other echocardiographic method
Echocardiographic methods included: 1. Cubed M-mode formula 2. Teichholz M-mode formula 3. Subjective estimation of LVEF from two-dimensional videotape 4. Area-length method in one four-chamber view 5. Average of area-length method in three four-chamber views 6. Average of area-length method in four-chamber and two-chamber views (one beat each) 7. Subjective estimation from stored videoloop of four-chamber and two-chamber view

Diastolic Dysfunction
LEFT VENTRICULAR DYSFUNCTION The Basics The heart is a pump: it has to be able to fill up (diastole) and then it has to be able pump the blood out (systole) Systolic dysfunction Pump failure equates to a low Ejection Fraction (EF) - Cardiomyopathy / CAD Heart muscle is damaged and is unable to pump the blood out to the body normally Diastolic dysfunction LV can’t fill normally due to impaired relaxation/or restriction Ventricular systolic function is preserved Incidence increases with age and is seen in some degree in at least 50% of older patients More prevalent in women Signs and symptoms may be the same as in systolic failure

Pathophysiology of Diastolic dysfunction: Normally the LV is passively filled, and then the atria contract and that provides additional “atrial packing.” In diastolic dysfunction the left ventricle cannot fill up with blood normally due to a hard stiff and non compliant LV and the blood has to be forced in Causes of Diastolic Dysfunction Aging - lose general elasticity HTN - general wear and tear on the heart muscle causing it to hypertrophy and become stiff Aortic stenosis - LV becomes stiff because it’s overworked MI - scarring, damaged muscle Ischemic heart disease - damaged muscle Obesity - increases the workload and the muscle hypertrophies and becomes stiff and non compliant

Echo findings that support diagnosis of Diastolic Dysfunction: Abnormal E/A ratio – E/A ratio is the ratio between passive filling and active filling of the LV (normally the E wave is 80% process and A wave is 20%; in diastolic dysfunction this ratio is reversed) Normal E/A ratio First spike = E wave / Second smaller spike = A wave

Equates to reversed E/A ratio (smaller E wave - taller A wave)

Regional wall motion abnormality
Most common form of acquired heart disease in the western world is coronary artery disease with its sequelae of myocardial ischaemia and infarction The LV can be divided into segments which can be described on the basis of coronary artery territories This allows the prediction of the artery involved when a regional wall motion abnormality is detected

Formulas and Calculations
Biplane volume & ejection fraction (Area/length 2D axes ) Left ventricular mass, 2D Circumferential end-systolic wall stress Preload Left ventricular segmental wall motion Left atrial biplane volume Left atrial appendage shear rate of blood Long / short axis ratio Mitral valve percent calcification Mitral score Left ventricular biplane volume (Area/length, Dodge correction) (area planimetry1 x area planimetry2 x 8) / (3 x π x smallest long axis) (ml) Transthoracic parasternal short axis view A1 Red: tracing of pericardial border A2 Green: tracing of endocardial border (papillary muscles are excluded Am = A1 - A2 = area of myocardium t: myocardial thickness (automatically calculated by the software) LV mass index (truncated ellipsoid) normal values: Males: 76±13 gm/m2 Females: 66±11 gm/m2

Valve area calculation
1 Planimetry 2 The continuity equation 3 The Gorlin equation 4 The Hakki equation 5 Real-time three-dimensional echocardiography Gorlin Formula

Doppler echocardiography
Doppler echocardiography is a method for detecting the direction and velocity of moving blood within the heart. Velocity information obtained from Doppler shift ( frequency shift) calculation. Detects valvular stenosis, valvular regurgitation, intracardiac shunt by calculating velocity shift and direction of blood flow. Pulsed Wave (PW) useful for low velocity flow e.g. MV flow Continuous Wave (CW) useful for high velocity flow e.g. aortic stenosis Colour Flow (CF) Different colours are used to designate the direction of blood flow. red is flow toward, and blue is flow away from the transducer with turbulent flow shown as a mosaic pattern.

The Doppler shift (Fd) of ultrasound will depend on
both the transmitted frequency (fo) and the velocity (V) of the moving blood. This returned frequency is also called the "frequency shift" or "Doppler shift" and is highly dependent on the angle of ultrasound beam from the transducer and the moving red blood cells. The velocity of sound in blood is constant (c)

Modes Of Doppler Echocardiography
Blood Flow Pulsed Wave HRF Pulsed Wave Continuous Wave Tissue Motion Tissue Doppler The Doppler Display AUDIO SPECTRAL GRAY SCALE COLOR MAPPING

Schematic diagram showing the importance of being parallel to flow when detecting flow through the aortic valve. A jet of known velocity (2.0 m/s) emerges from the aortic valve in systole. Moving 60 degrees from parallel only allows a peak velocity of 1.0 m/s to be recorded.

Carrier frequency V=Fd(C)/2f0(cos q)
If Fd stays the same, the lower the f0 (carrier frequency), the higher the velocity of the jet that can be resolved. Unlike B-mode imaging where higher frequency transducer gives better resolution, here lower frequency transducers gives better resolution.

Spectral analysis The difference in waveform between the transmitted and backscattered signal is compared. A process called fast Fourier transform (FFT) displays this information into a “spectral analysis” (spectral display of entire range of velocities) Time- x axis Velocity- y axis Toward the transducer is positive, away from transducer negative. Amplitude is displayed as “brightness” of the signal.

Aliasing Corrected by:- Increasing the pulse repetition frequency(PRF)
Decreasing the transmitted frequency

CW Doppler echo PW Doppler echo
Two crystals- one transmitting another receiving continuously are used Measures high velocity but can not localize depth and width precisely Detects severity of valvular stenosis, valvular regurgitation and velocity of flow in shunts A single crystal is used for transmitting and receiving US Depth is measured by multiplying half of time delay with velocity of sound in the tissue Can localize the site of flow disturbance Detects normal valve flow pattern LV diastolic function Measurement of stroke volume and cardiac output Can not measure velocity > 2m/s

Color flow mapping 2-D version of PW Doppler with color coding
Velocity away from transducer is blue, towards it is red( BART), green applied to mosaic flow Higher velocity appears lighter, color reversal occurs above a threshold velocity Used for assessment of shunt or regurgitation CW & PW Doppler allow graphical representation of velocity against time known as spectral Doppler

Color Doppler Displayed as color information-
Amplitude- intensity Direction- red vs. blue (toward or away from transducer) Velocity- brightness (bright blue higher velocity) Variance (turbulence)- coded green to give a mosaic appearance. Overlays this information on 2D images Time consuming (temporal resolution is especially poor with a large sector window) Different vendors have different algorithms for generating color Doppler

Tissue Doppler Imaging
Routine Doppler targets blood flow High velocity Low signal amplitude Tissue Doppler (assessing the movement of the myocardium) targets tissue Low velocity High signal amplitude Different Filters Velocity of tissue along a particular sample volume Color-TDI, Velocity of tissue coded by color superimposed on 2-D image . Can derive information such as strain, strain rate, dyssynchrony…etc.

Trans oesophageal echocardiography
This is an alternative way to perform an echocardiogram. A specialized probe containing an ultrasound transducer at its tip is passed into the patient's oesophagus. This allows image and Doppler evaluation from a location directly behind the heart. Transesophageal echocardiograms are most often utilized when transthoracic images are suboptimal and when a more clear and precise image is needed for assessment.

Complications detected with Intraoperative TEE
Intracardiac air Intracavitary Intercavitary Myocardial Individual targets Ventricular dysfunction Left ventricle Right ventricle Following valvular replacement Paravalvular regurgitation Outflow tract obstruction

3-D Echocardiography Live 3-D imaging
Real-time, 360 degree visualization of cardiac structures and cardiac blood flow Precise measurements superior to cardiac magnetic resonance imaging (MRI) regarding assessment of left ventricular (LV) volume, right ventricular (RV) volume, and hypertrophic cardiomyopathy Rivals cardiac MRI regarding measurements of LV systolic function, LV volume, LV mass, left atrial volume, ASD, VSD, as well as aortic valve and mitral valve area Automatically calculates LV ejection fraction resulting in highly reproducible measurements Markedly reduces the need for invasive testing

Cardiovascular stress  exercise pharmacological agents
Stress echo is a family of examinations in which 2D echocardiographic monitoring is undertaken before, during & after cardiovascular stress Cardiovascular stress  exercise pharmacological agents Exercise Non-exercise stress Treadmill Supine bicycle Upright bicycle Handgrip Stair steps Dobutamine Dipyridamole Dobutamine/Dipyridamole combination Adenosine Ergonovine

Prosthetic Valve Pathology
Prosthetic Valve Regurgitation Aortic Mitral Prosthetic Valve Stenosis

Bioprosthetic valves Mitral Position
2-D ECHOCARDIOGRAPHIC APPEARANCE

Bioprosthetic valves Aortic Position
2-D ECHOCARDIOGRAPHIC APPEARANCE

Special Problems of 2-D Imaging Artificial Valves
Echocardiographs are calibrated to measure distance based on the speed of sound in tissue. Prosthetic valves have different acoustic properties than tissue. Hence, distortion of: Size Location, and Appearance, of the prosthesis.

Prosthetic Valve Stenosis
Determinants of gradients across normal prosthetic valves include: Valve type, i.e., Manufacturer Valve size Flow through the valve Wide range of “Normals”

Gradient as a function of valve type
Normal Doppler data in patients with various types of prosthetic valves in the Aortic Position

Indices of Valve Stenosis which are less flow dependent
Contour of jet velocity Doppler velocity index Effective orifice area Valve resistance

Mismatch Literature identifies the above as a cut-off for mismatch
Minimum Effective Orifice area >0.85cm2/m2 BSA < patient prosthesis mismatch(PPM)

A-Contour of the jet velocity
With prosthetic obstruction there is: Late peaking of the velocity, More rounded contour, Prolonged ejection.

Mitral Prosthesis Stenosis
Parameters used for assessment of function: PHT/Area by PHT Effective Orifice Area by continuity Mean gradient

Mitral Prosthesis Stenosis
C-Mean gradient, function of: Size Type of prosthetic Flow Heart rate (should also be reported when evaluating MVA)

Prosthetic Valve Regurgitation
Physiologic Regurgitation Early onset and brief duration Reflects backflow from closing movement of occluding device Tilting disc and bileaflet valves have additional late backflow leakage Intended to reduce risk of thrombosis

Aortic Prosthesis Regurgitation
Criteria similar to grading native valve AI: Jet width PHT < 350 Holodiastolic flow reversal Regurgitant fraction>40%

Mitral Prosthesis Regurgitation
TTE of limited value in assess MR due to acoustic shadowing of the LA Doppler findings suggestive of severe MR E wave > 1.9 m.s PISA Short isovolumetic relaxation time TVILVOT/TVIPr-MV < 0.4

Normal values for adult
LVIDs End systole cm LVIDd End diastole cm Wall thickness Diastolic Septum Post wall cm Systolic cm FS 30-45% EF 50-85% LAD Aortic root diameter RV diameter cm

Range Mean IVS wall thickness (cm) 0.9 ± 0.4 Aortic root dimension (cm) 2.4 ± 0.4 Aortic cusps separation (cm) 1.9 ± 0.4 Percentage of fractional shortening 34-44% 36% Mitral flow (m/s) 0.9 Tricuspid flow (m/s) 0.5 Pulmonary artery (m/s) 0.75 Aorta (m/s) 1.35

The Bernoulli equation is a complex formula that relates the pressure drop (or gradient) across an
obstruction to many factors For practical use in Doppler echocardiography this formula has been simplified to: p1-p2=4V2

CW Doppler recording of normal aortic
systolic velocity taken from the suprasternal notch. Note that the onset of flow toward the transducer begins after the QRS complex of the electrocardiogram (arrow) and peaks in the first third of systole.

easily obtained from the inspection of the spectral tracing.
The flow profiles are characterized by a peak velocity (in cm/s), the maximum velocity reached during systole. This measurement is easily obtained from the inspection of the spectral tracing. The time to reach peak velocity (or “time to peak”) is another component of the systolic profile which helps to characterize systolic ejection and is measured in seconds. Left ventricular ejection time is the duration of the systolic flow velocity recording. These time durations are also easily measured directly from spectral recording. Thus, rapid peak acceleration and high peak velocities characterize optimum ejection fractions. . When stroke volumes are equal and areas remarkably different, the resultant velocities of flow may be quite different. The velocity for large areas would be less than for small areas.

Echo-Doppler estimates of flow volume are based upon a knowledge of the area of flow (from echocardiogram) and the length (from Doppler). It is assumed that the aorta is a cylinder. Doppler estimates of cardiac output compare quite favourably with those obtained by other methods.

Pulmonary valve disease
Idealized spectral recordings demonstrating that time-to-peak velocity is very rapid in patients with pulmonary hypertension. CW Doppler spectral velocity recording of mild pulmonic stenosis and insufficiency. The abnormal diastolic flow toward the transducer of pulmonic insufficiency is easily recognized. (Scale marks = 1m/s) Flow towards the transducer gives positive waves, away from transducer negative deflection

Aortic valve disease For any given pressure gradient there is a corresponding increase in velocity, as predicted by the simplified Bernoulli equation: p1-p2 = 4V2 where p1 = pressure distal to obstruction p2 = peak velocity of blood flow across the obstruction. The peak aortic velocity of the spectral recording is approximately 5.8 m/s. Using the previous formula p1-p = 4(5.8)2, the pressure gradient is therefore 135 mmHg. Typical CW spectral velocity tracing from the apex in a patient with aortic stenosis and insufficiency. Peak systolic velocity is elevated to almost 6 m/s and peaking is delayed. (Scale marks = 2 m/s)

Aortic stenosis PW Doppler spectral recording of aortic blood flow (arrow) taken from the apical window. Note the laminar appearance of normal flow. (Scale marks = 20 cm/s) CW spectral recording from the apex in a patient with aortic stenosis. The velocity spectrum is broadened and systolic velocity is increased to 4 m/s. (Scale marks = 2 m/s)

The systolic jet of aortic stenosis and diastolic jet of aortic insufficiency often cannot be recorded at the same time. As the transducer beam is angled from the stenotic jet (closed arrow) to intercept the aortic insufficiency, the left ventricular outflow tact velocity is encountered (stippled arrow). Both outflow tract velocities are superimposed during the beam sweep (open arrow). (Scale marks = 1 m/s) CW Doppler spectral recording of aortic outflow from the suprasternal notch with flow toward the transducer (left) and apex with flow away form the transducer (right). The spectral recording from the apex is better formed than the one from the suprasternal notch. Operator experience is important.

The duration of mitral insufficiency is generally longer than that of
aortic stenosis, partly because the time from mitral valve closing to opening is longer than for aortic valve opening to closing. Similarly, the duration of aortic insufficiency is longer than mitral stenosis because the time from aortic valve closing to opening is longer than for mitral valve opening to closing. Similar relationships are true of the pulmonic and tricuspid valve on the right side of the heart. Aortic stenosis (left) should not be mistaken for mitral insufficiency (right). Mitral systole begins before aortic (arrow) and is longer in duration. (Scale marks = 2m/s) Left panel shows an aortic stenotic jet in relation to possible viewing directions using CW Doppler. Right panel shows spectral velocity tracings from each respective window. The best recording is from the right sternal window. (Calibration marks = 2m/s)

Continuity of forward flow. Flow that
The severity of aortic stenosis may also be judged by the relative proportion of total systolic time taken to reach peak velocity (stippled areas). Both time to peak and peak velocity are lower in panel A than in panel B. ((Scale marks = 1m/s) Continuity of forward flow. Flow that enters a cylinder is equal to the flow passing through an obstruction and exiting from the distal side.

PW Doppler spectral recording from the
mitral orifice taken from the apical window. Early diastolic flow is high (closed arrow), followed by a rapid descent and then peaks again after atrial contraction (open arrow)(normally biphasic) (Scale marks = 20cm/s). The secondary increase in diastolic velocity due to atrial contraction is absent in patients with atrial fibrillation. Typical CW spectral velocity recording from a patient with mitral stenosis and insufficiency. From the apex, the diastolic flow of mitral stenosis is toward the transducer. There is a rise in velocity in early diastole followed by a slow diastolic descent. A mitral valve gradient is calculated using the modified Bernoulli equation.E.g. a peak diastolic velocity of 2 m/s that is equivalent to a 16mmHg peak transmittal pressure gradient.

Formula for estimation of mitral valve
The starting point is the time of peak velocity (point 1), which in this case is 2.2 m/s. This corresponds to a peak pressure gradient of 19mmHg by the simplified Bernoulli equation. A line along the diastolic descent of the mitral valve velocity spectrum is drawn (step 2). A point is then found along this line where the pressure has dropped to half of its initial value (point 3) This point is rapidly determined by dividing the initial velocity by 1.4 (square root of 2); that is, 2.2/1.4=1.6 m/s. Thus, when velocity falls to 1.6m/s the pressure is at half of its initial (point 1) value. The pressure half-time is simply the time interval between point 1 and point 3, in this case 400 milliseconds (interval 4). MVA Planimetry Continuity equation Pressure half-times It is defined as the time interval in milliseconds (ms) required for the diastolic pressure gradient across the mitral valve to fall to half of its initial value.( normally msec). Formula for estimation of mitral valve area in cm2 using the pressure half-time. The number 220 is an empiric constant.

Pulmonary stenosis Tricuspid stenosis VSD Coarctation of Aorta HOCM

Congenital Heart Disease

Disclaimer: It is a compilation of information from various sources on the internet and available texts. The references are avoided here for the purpose of brevity and clarity only

Echocardiography for the Surgeons

Similar presentations

Presentation on theme: "Echocardiography for the Surgeons"— Presentation transcript:

Similar presentations

About project

Feedback

Log in

Auth with social network:

Echocardiography for the Surgeons

Similar presentations

Presentation on theme: "Echocardiography for the Surgeons"— Presentation transcript:

Similar presentations

About project

Feedback