Echo I Note Cards Flashcards
The method of choice for the visualization and grading of coronary artery obstruction
Cardiac Catheterization
Ultrasound methods employed to visualize coronary arteries
- Intravascular ultrasound
- TEE
- Intraoperative echocardiography
What is the most significant limitation of ultrasound methods
Its inability to gain reasonable access to the entire coronary anatomy
What is the location of the heart within your body?
It lies slightly off-center in the thoracic, or chest, cavity. Roughly 2/3 of the heart is in the left half of the chest. Tho lower end of the heart, apex cordis, rests on the diaphragm (separates the thoracic and the abdominal cavity.
The heart is enclosed by a loose sac called?
Pericardium
What are the two layers of the pericardium?
- an outer protective covering of strong white fibrous tissue
- an inner layer of smooth, moist serous (fluid secreting) membrane called the visceral pericardium.
What are the 3 layers of the heart?
- Epicardium
- Myocardium
- Endocardium
What is the thickest layer within the heart?
Myocardium
What are the 4 chambers of the heart?
- right and left atrium
2. right and left ventricle
What divides the right and left atrium and ventricle?
Interventricular Septum
What kind of blood passes through the tricuspid valves between the right atrium and right ventricle, then through the pulmonary semilunar valves into the pulmonary arteries toward the lungs?
Nonoxygenated blood
What type of blood returns to the heart from the lungs via the pulmonary veins?
Oxygenated blood
How does oxygenated blood pass through the heart?
through the pulmonary veins, into the left atrium and passes throught he mitral (or bicuspid) valve into the left ventricle and from there out into the aorta.
The Cardiac Cycle composes of 3 phases.
- Relaxation period
- Ventricular filling
- Ventricular systole
When does the relaxation period of the cardiac cycle begin?
At the end of a heart beat when the ventricles start to relax, with all 4 chambers in diastole.
What initiates the Relaxation period?
Repolarization of the ventricular muscle fibers (T wave int he EKG).
What happens as the ventricle relax in the relaxation period?
pressure within the chambers drops and blood flows from the pulmonary artery and aorta back towards the ventricles and forces the semilunar valves to close.
What happens when blood rebounds off of the closed cusps of the semilunar valves in the relaxation period?
It produces a bump called a dicrotic wave on the aortic pressure curve.
What is isovolumetric relaxation time?
It occurs in the relaxation period when the semilunar valves are closed and the volum of the ventricles stays constant.
What happens when the ventricles continues to relax in the relaxation period?
the ventricular pressure drops below the atrial pressure and the AV valves open. This begins Ventricular filling.
When does the major part of Ventricular filling occur?
Just after the AV valves open, where blood that has been flowing into the atria and building up during ventricular systole starts rushing into the ventricles.
What is the first 1/3 of ventricular filling time?
Rapid ventricular filling.
What is the middle 1/3 of ventricular filling?
Diastasis, which is when a smaller volum of blood flows into the ventricles and the pressure starts to equalize in the atria and ventricles.
What happens when the SA node fires during ventricular filling?
Atrial depolarization, which is noted by the P-wave on the EKG.
What happens in the last 1/3 of ventricular filling?
Atrial contraction or systole following the P-wave, which marks the end of diastole.
What percentage of total volume of blood in the ventricles is contributed by Atrial systole during Ventricular filling?
20-30%
What are the stages of Ventricular diastole?
- IVRT
- Early rapid diastolic filling
- Diastasis
- Late diastolic filling due to atrial contraction
What is End-diastolic volume or EDV?
the volume of blood present in the ventricles at the end of ventricular diastole
Throughout the period of Ventricular filling (rapid filling, diastasis, and atrial systole), what is happening to the valves within the heart?
AV valves are open and the semilunar valves are closed
What happens near the end of atrial systole in the Ventricular systole phase?
The impulse from the SA node has passed through the AV node and into the ventricles, causing them to depolarize. This is represented by the QRS complex in an EKG.
What happens in the isovolumetric contraction time period in Ventricular systole?
Ventricular contraction begins and blood is pushed up against the AV valves, forcing them to shut. For about 50 msec, all four valves are closed again. Muscle fibers are contracting, but are not shortening, thus the muscle fibers are isometric (same length) and the ventricular volume stays constant (isovolumic).
What is Ventricular Ejection?
As Ventricular contraction continues, pressure inside the ventricle rushes sharply. When left ventricular pressure surpasses aortic pressure and right ventricular pressure rises above the pulmonary artery pressure, both semilunar valves open and ejection of the blood from the heart begins.
How long does Ventricular Ejection last?
It last until the pressures in the ventricles and great vessels equalize.
What is End-sstolic volume or ESV in the Ventricular Systole phase?
It is when the pressure in the aorta and pulmonary artery rise above the ventricular pressure the semilunar valves close and relaxation of the ventricles begins leaving a volume of blood in the ventricle after ventricular systole, which is the ESV.
What is Stroke volume?
The volume of blood ejected per beat from each ventricle.
What is the end-diastolic volume or ESV number?
130 ml
What is the stroke volume number?
70 ml
What represents the end-systolic volume?
During ejection, the ventricular volume decreases from 130 ml to 60 ml, which represents the end-systolic volume.
What causes the heart sounds?
It comes primarily form blood turbulence caused by closing of the heart valves.
What is the first sound or S1 (Lub)?
It is created by the turbulence associated with the closure of the AV valves (mitral and tricuspid) after ventricular systole begins. It is louder and a bit longer than the second sound.
What is the second sound or S2 (Dub)?
It is created by the blood turbulence associated with the closure of the semilunar valves at the beginning of the ventricular diastole. It is less loud and shorter.
How doe you calculate the cardiac output?
Stroke volume x the heart rate
LA–Left Atrial - End Systolic Dimension
2.2-4.0 cm or 22-40 mm
AoR–Aortic - End Diastolic Diameter
2.1-3.7 cm or 21-37 mm
ACS–Aortic Cusp Separation - Aortic valve systolic separation
1.5-2.6 cm
MV E-F slope
70-150mm/s
MV Excursion – D-E Excursion (Amplitude)
18-28 mm
EPSS - E point septal separation
2-7 mm
RVIDd - Right Ventrical internal diameter in diastole
1.9-2.6 cm
IVSd – Intraventricular septum in diastole
0.6-1.0 cm
LVIDd – Left Ventricle internal Diameter in diastole
3.9-5.9 cm
LVPWd – Left Ventricle Posterior Wall in diastole
0.6-1.0 cm
IVSs – Intraventricular septum in systole
0.8-1.2 cm
LVIDs – Left Ventricle Internal Diameter in Diastole
2.0-3.8 cm
LVPWs – Left Ventricle Posterior Wall in systole
0.8-1.2 cm
Out Flow Tract in Women
1.9
Out Flow Tract in Men
2.0
What are the disadvantages of M-Mode?
- Limited spatial orientation with improper alignment of the measurements in PLAX
- Overestimation of LV dimensions when using a low parasternal window
- Inaccuracy of FS and EF in apical infarction leading to false estimation of LV global performance
What is the normal range of Left ventricular ejection fraction?
50-80%
What hemodynamic informationis provided by Doppler echo?
- Intracardiac pressures and pressure gradients
- Normal blood flow velocities across the valves
- Regurgitant flow velocities and their effect on the cardiac chambers
- Flow velocities across stenotic valves and the effect on the cardiac chambers
What 2 components determine Blood flow or flow volume Q?
- Velocity of the blood
2. Cross sectional area of the orifice or container through which blood is flowing
How do we measure velocity?
By the Doppler signal, which is converted to velocity using the standard Doppler equation, a calculation that requires knowing the angle between the direction of blood flow and the ulltrasound beam
T/F The US beam should be as parallel to the blood flow as it can get in order to have an accurate measurement and calculation of the velocity of the blood flow.
True
VTI–Velocity time integral or TVI–time velocity integral or FVI–flow velocity integral
It represents the actual measurement of flow velocity required obtaining the area under the Doppler signal curve
What What is stroke distance?
Sometimes referred as VTI, is the distance traveled by the sampled volume with each heart beat
What is required when converting velocity to flow volume=Q?
It requires an accurate assessment of the cross sectional area of the vessel or orifice through which the blood is flowing
How do we measure CSA?
It is determined by M-Mode or 2-D measurement, obtaining a diameter or radius converted to area by using the follow formulas:
CSA=r^2 or CAS=0.785 x d^2
Measurements should be accurate because the error can be significant since the value is squared. The CSA location has to be identical to where the Doppler signal is recorded
What is the flow volume Q formula?
Flow volume Q = CSA x VTI
What is the normal Blood Flow profile?
Laminar blood flow using Doppler
What is the abnormal Blood Flow profile?
Turbulent blood flow - peak is increased
What is aortic flow?
The blood that perfuses the systemic circulation; therefore it provides a measure of the cardiac output
How do we calculate the Cardiac output?
CO = SV x HR or A x V x HR
What are the sites for SV measurements?
- LVOT with diameter measured at the annulus and PW sample gate placed at the same level
- ACS - aortic leaflet opening level
- Aortic Root
- Ascending or Descending Aorta
What is the site of choice for aortic flow measurement? Why?
LVOT-Diameter of the LVOT at the annular level is measured in PLAX in midsystole from the septal endocardium to the leading edge of the anterior mitral leaflet annulus. VTI is obtained by tracing the doppler spectral profile of the LVOT flow; PW is done fromthe apical approach: AP5 or AP3 with the sample gate placed at the same site where the 2-D measurement was taken, proximal to the aortic cusps.
What are the 2 distinctive steps when performing the Doppler assessment of the aortic flow?
- LVOT VTI or Vmax with PW
2. AV VTI or Vmax with CW
What is the Doppler Profile?
- Negative or retrograade deflection
- Single V-shaped waveform with rapid acceleration and deceleration reflecting ventricular systolic ejection
- PW - open spectral window characteristic of laminar flow
- CW - absence of the spectral window due to higher velocity
Continuity Equation to find the Aortic valve area
AVA (cm^2) = CSA (cm^2) x V1 (m/sec)/V2 (m/sec) where: CSA = LVOT d^2 x 0.785 V1 = LVOT peak or max velocity V2 = AV peak or max velocity
Using VTI versus V max for LVOT and AV enables measurement of the mean pressure gradient (Pmean) through the aortic valve
AVA = CSA x VTI of LVOT/VTI of AV
How is the pressure gradient determined between the LV and aorta?
By using the Bernoulli’s Principle and Equation. This information is necessary to quantify the severity of valvular stenosis.
^P - 4 x V^2 where V is the peak velocity of the AV (V2)
What is the Mean pressure gradient (Pmean) calculated?
by measuring the velocity at equally spaced points, squaring each velocity, averaging the velocity values and multiplying the average by 4.
What are the 2 phases of mitral flow (LV inflow)?
- Early diastole
2. Atrial systole
What happens in early diastole of LA Flow?
a sudden increase of the lA volume occurs as the MV opens and the blood flows from the LA to the LV; the posterior aortic wall moves downward toward the LA; this phase is known as “rapid emptying phase”
What happens in mid diastole of LA Flow?
the blood flowing from the LA to LV is about equal with the blood flowing into the LA from the pulmonary veins; the posterior aortic wall shows no motion; this phase is called “conduit phase”
What happens in atrial systole of LA flow?
LA actively contracts and the posterior aortic wall moves downward rapidly producing the “systolic phase of atrial emptying”
Mitral Valve Doppler Profile (LV Inflow doppler Provile
- M-shaped configuration
- Positive or antegrade flow
- Velocity curve of PW shows narow band of velocities (envelope) characteristic of laminar flow pattern
- E-wave - first diastolic peak reflects LV passive filling immediately after MV opening
- A-wave - second diastolic peak reflects LV inflow by atrial contraction
How is the mitral valve area calculated?
MVA is calculated using the Pressure-Half Time (PHT) method
MVA = 220/PHT
M-Mode @ LV
evaluates wall contractility by assessing wall thickness, systolic wall thickening and systolic wall motion
End-diastolic dimension
3.7-5.7
End-systolic dimension
2.6-3.6
IVS diastolic thickness
0.6-1.1
PW diastolic thickness
0.6-1.1
Fractional shortening FS
28-41%
FS=LVDd-LVDs/LVDd x 100
Ejection Fraction EF
55-75%
EF=EDV-ESV/EDV x 100
EF <35% - candidate for ICD placement
M-Mode @ MV
evaluates EPSS (E-point septal separation) lest than or equal to 7 mm EPSS > 20 mm is indicative of an EF < 30%
2-D
- qualitative visualization of LV function
- determine segmental wall motion abnormalities WMA
- take linear measurements to determine FS and EF
- trace ara of LV in diastole and systole in 4-Ch and 2Ch and using the Simpson’s method to find the EF
Doppler
- evaluate aortic flow velocity by tracing VTI and using the value to find stroke volume
SV = VTI x CSA normal=75-100 cc
CO = SV x HR normal = 4-8 L/min - determine change in pressure of the LV over time: dP/dT=Isovolumetric phase index of LV systolic performance
- Doppler tissue velocity by Doppler tissue imaging DTI which determines the direction and velocity of wall motion
- Strain Rate Imaging is derived form DTI, form the velocity determination; it provides a high resolution evaluation of regional myocardial function
What is Stress Echocardiography?
It is a non-invasive diagnostic method to detect and asses known or suspected coronary artery disease.
Which data is used in stress echo to formulate a diagnosis?
EKG and echo data
Which tests were used prior to 1986 to non-invasively assess CAD?
Treadmill EKG
An objective of stress echo is?
- to evaluate LV function
- to evaluate known or suspected CAD
- to risk stratify patients before non-cardiac surgery, after myocardial infarction or interventional procedures and prior to starting an exercise/diet program
- to identify viable, hibernating or stunned myocardium with left ventricular dysfunction
- to evaluate let ventricular function and valvular hemodynamics in valvular /cardiomyopathic heart disease.
What are the three main coronary arteries
LAD, LCX, and RCA
What are the essential items for conduction stress echo?
EKG machine, Ultrasound system, and Crash cart
Who should be in attendance for a stress echo?
A diagnostic cardiac sonographer a nurse and/or a physician
What are two types of stress echos?
DSE and XSE
What are the absolute contraindications to stress echo testing?
- Hemodynamic instability
- MI less than 72 hrs old
- outpatients, not fully evaluated, who are suspected to have MI
- unstable angina
- Symptomatic Ventricular arrhythmias
- Patients with acute myocarditis or pericarditis (XSE
- Patients with 2nd degree or 3rd degree HB, or with known severe left main disease or high grade proximal lesion
- Acutely ill patients
- Patients with ambulation problems
- Patients with IHSS and asymmetric septal hypertrophy, aortic stenosis, hypertrophy with outflow obstruction, or history of syncope
- Patients iwth large aortic aneurysm
- Pregnancy
- Combative patients or patients who are otherwise judged uncooperative
- Patients who refuse the procedure and/or consent may not be obtained
What are examples of relative Contraindications to stress echo?
- IHSS
- Unstable angina
- Uncontrolled HTN
- Increaed cardiac enzymes
- Significant EKG findings
- If echo images are sub-optimal, then it should be the cardiologist’s decision to abort, use contrast agents or to continue with stress echo testing
- EF of less than 25% as determined by previous echo or other method
- Pulmonary HTN defined as mean pulmonary artery pressure >50mmHg or maximum pulmonary artery pressure >70mmHg
- History of seizure disorder
- Severe valvular disease
- Idiopathic hypertrophic subaortic stenosis
- Patients with large aortic aneurysms (except for surgery clearances)
The equation 220-age (in years) =
maximal predicted heart rate
The equation MHRx0.85 =
target heart rate
An adjunctive therapy to DSE includes the use of?
Atropine
What is Diastolic Function?
The interval form the AV closure (end-systole) to MV closure (end-diastole)
What is diastole in Diastolic function?
the temporal component of the cardiac cycle which comprises LV filling
What is the normal diastolic function?
the ability of the LV to fill in a competent fashion
What is the abnormal diastolic function or diastolic dysfunction?
changes in LV relaxation, LV compliance or both
Normal Range of IVRT of transmitral and pulmonary veins Doppler flow pattern
65-100 msec
Normal Range of E/A of transmitral and pulmonary veins Doppler flow pattern
> 1
Normal Range of DT (decel time) of transmitral and pulmonary veins Doppler flow pattern
160-240 msec
What is the major determinant of PV systolic forward flow (S)?
LA pressure–when the LA pressure increases, then the S wave of th ePV flow may become blunted or even absent
What is PV diastolic flow(D)?
a reflectionof the transmitral early rapid filling E wave flow (when E wave increases the D wave also increases)
What are the three types of diastolic dysfunction?
- Impaired or delayed relaxation with normal filling pressures
- “Pseudonormalized” pattern of abnormal relaxation with increased LA pressure
- Restrictive Filling pattern
Diastolic Dysfunction–Impaired or delayed relaxation with normal filling pressures
- Inc IVRT–Abnormal myocardial relaxation prolongs the active relaxation process of the LV delaying the opening of the MV resulting in increased IVRT
- Dec E/A–The slower decline of the LV pressure causes a decrease in the pressure gradient or driving pressure across the MV resulting in a decrease in early rapid filling E wave velocity
- Inc D/T >240–As the relaxation process of the LV is prolonged, the time is increased for pressure equalization b/t LV and LA resulting in a n observed increase in the DT
- As a consequence of less early diastolic LV filling (E decreased), there is more LA volume than wave velocity, therefore E/A ratio ears of age)
Isovolumetric relaxation is the first stage of diastole. It represents:
The time from av closure to mv opening
Condition associated with abnormal relaxation are:
CAD,CM, HTN, LVH, and Pulmonary HTN. The patients are asymptomatic unless they have angina associated with CAD.
During diastole, which of the following events occur?
Atrial contraction, tricuspid valves opens, passive filling of ventricles
