Echo - Test 1

location of the heart

lies posterior to sternum within middle mediastinum

where does the heart lie?

45 degree angle, between third and fifth intercostal spaces

apex

constitutes the cone or bottom of the heart and rests on the diaphragm below the seventh rib

what does the apex consist of?

tip of the LV

position of the heart

superior border of the heart

RA & LA

inferior (diaphragmatic) border of the heart

almost entirely RV and portion of the LV

right border of the heart

RA

left border of the heart

LV & small portion of LA

anterior border of the heart

almost entirely RV and small portions of RA & LV

posterior border of the heart

LA & LV

pericardium

thin sac that houses the heart and roots of the great vessels

what are the two layers of the pericardium?

parietal and visceral

pericardial cavity

space between the parietal and visceral layers of the pericardium

pericardium

contains serous fluid that lubricates the 2 layers as the heart beats

IV sulcus

separates RV from LV externally

AV sulcus

separates LA from LV externally

coronary sulcus

separates RA from RV externallys

sulcus terminalis

separates anterior and posterior portions of RA

crux

located at posterior portion of heart where all four chambers come together; determines dominance of heart by which coronary artery feeds this portion; Rt dominate is fed by RCA

epicardium

• outermost layer of the heart

• AKA the visceral layer of the pericardium

• composed of epithelial cells

myocardium

• middle layer

• composed of involuntary muscle fibers and muscle cells

• responsible for contraction

endocardium

• innermost layer of the heart

• lines the inside of the myocardium

• covers the valves and tendons

• composed of simple squamous epithelial cells

• continuous with endothelial lining of the large blood vessels and vascular system

KNOW THIS

interatrial septum

located between LA and RA; prevents mixing of oxygenated and deoxygenated blood

interatrial septum can be divided into 3 regions where defects occur:

• sinus venosus

• septum secundum

• septum primum

sinus venosus

located at the junction of the SVC & IVC with atrium

septum secundum

located at the mid portion

• foramen ovale - prenatal opening to allow for fetal circulation

• fossa ovalis - postnatally the foramen ovale closes and becomes the fossa ovalis

septum primum

located at the endocardial cushion level (AV valves)

interventricular septum

located between the RV and LV and prevents mixing of oxygenated and deoxygenated blood

what are the two portions of the IVS?

membranous portion & muscular portion

membranous IVS

located between outflow tracts; made up of a thin membrane

muscular IVS

from the membranous portion of the apex

coronary sinus

drains blood from the myocardium

coronary artery system

supplies oxygenated blood to heart muscle

coronary artery system

located on external surface of the heart, between the epicardium and myocardium

sinuses of valsalva

RCA & LCA originate here just above the aortic valve; very common to have variations in branching

left coronary artery

begins with left main, arising from the left coronary cusp » branches into left anterior descending (LAD) and left circumflex (LCX)

left anterior descending artery

follows the AV sulcus and feeds the anterior wall of the LV, apex, and portions of the septum, as well as the right and left bundle branches of the conduction system

• has septal perforators of the conduction system

left circumflex artery

follows the coronary sulcus to lateral and posterior portion of LV

• feeds the SA node (45%), AV node (20%), and Bundle of HIS (10%)

• has obtuse marginals

right coronary artery

arises from the RT coronary cusp at the sinuses of valsalva and runs through the coronary sulcus to the RV

RCA

• feeds the RA, RV, inferior portion of the LV, and a portion of the ventricular septum

• feeds the SA node (55%), AV node (80%), and Bundle of HIS (90%)

• has acute marginal branches

RCA

distal portion gives rise to posterior descending artery which feeds crux and runs down posterior portion of the IV sulcus

coronary artery wall distribution

sinoatrial node (SA)

native pacemaker of the heart located within the sulcus terminalis at the confluence of the SVC, RA appendage and the lateral wall of the RA

SA node

initiates the cardiac cycle and has inter-nodal pathways and the Bachman’s bundle feeds the RA

• responsible for initiating and stimulation atria (rate of 60-100 bpm)

atrioventricular (AV) node

located in the medial floor of the RA and delays impulse to allow for ventricular filling (40-60 times per minute)

transducer windows

• suprasternal: suprasternal notch

• subcostal: body midline beneath costal margin

• apical: over cardiac apex

• parasternal: over area bounded superiorly by left clavicle, medially by sternum, inferiorly by apical region

parasternal views

PLAX: LV in sag, RV inflow, LV outflow

PSAX: LV apex, LV mid @ pap muscles, MV, AV/TV/RVOT/PV (basal view)

PLAX

PSAX

apical views

• 4C

• 5C

• 2C

• apical long (3C)

subcostal views

• 4C

• IVC

• PSAX LV

• additional: PSAX MV & PSAX AV

suprasternal notch (SSN)

• ascending aorta

• descending aorta

• right pulmonary artery

phase 0 (depolarization)

channels are opened with stimulation and a rapid influx of sodium enters the cell, making the cell more positive on the inside than on the outside

• happens at the onset of the QRS interval on the EKG

phase 1

gating mechanisms close and the entry of sodium slows down, making the interior of the cell less positive

phase 2

sodium is no longer entering the cell through fast channels » calcium is entering through slow channels, determining the degree of contraction

phase 3 (repolarization)

potassium ions exit the cell making the inside more negative

phase 4 (refractory period)

sodium is transported from inside to outside of the cell and potassium is brought back inside the cell » the cells can be stimulated again once they reach the threshold potential

phases curve

p wave

atrial depolarization

hidden in the QRS complex

atrial repolarization

QRS

ventricular depolarization

t wave

ventricular repolarization

phases of the cardiac cycle

ventricular diastole » isovolumetric relaxation

after ejection of blood through the semilunar valves, they close; for a brief moment, all 4 valves are closed » repolarization of the ventricles initiates relaxation (t wave)

isovolumetric relaxation

ventricles continue to relax, volume is constant and pressure is decreasing

what does 3 on the diagram represent?

isovolumetric relaxation

ventricular diastole - ventricular filling

AV valves open and blood begins to move from LA to LV because ventricular pressure drops below the atrial pressure; semilunar valves are closed

what is 1 on the diagram?

ventricular filling

three phases of ventricular filling

1. rapid ventricular filling (early diastole - MV E wave)

2. diastasis - flow slows because AV pressures have equalized

3. slow filling (atrial kick or contraction - MV A wave): SA node sends impulse and atria contract (P wave)

ventricular systole - isovolumetric contraction

near the end of atrial systole, the impulse from the SA node has passed through the AV node and into the ventricles causing them to depolarize (QRS complex) » contraction begins and blood is pushed up against the AV valves, forcing them to shut » for about 0.05 seconds all 4 valves are closed

isovolumetric contraction

as contraction continues, volume is constant and pressure is increasing

what is 2a on the diagram?

isovolumetric contraction

ventricular systole - ventricular ejection

when LV pressure surpasses the aortic pressure and the RV pressure surpasses the PA pressure, the semilunar valves open and blood is ejected from the heart » lasts about 0.25 seconds

what is 2b on the diagram?

ventricular ejection

end systolic volume (ESV)

the volume of blood remaining in the ventricles after systole (about 50-60 mL)

stroke volume (SV)

the amount of blood ejected per beat » typically around 70 mL

SV

EDV - ESV

preload

the stretch of the heart before it contracts

the greater the preload…

the greater the force of contraction » the more the heart is filled during diastole, the greater the force of contraction during systole (Frank-Starling law of the heart)

contractility

the forcefulness of the contraction

afterload

the pressure that must be exceeded for LV contraction » ejection of blood begins when the pressure in the RV/LV exceeds the pressure of the aorta/PA; dependent on systemic and pulmonary vascular resistance

common indications for an echo - signs & symptoms

• enlarged heart

• murmur

• chest pain

• heart failure

• fever or bacteremia

• shortness of breath

• palpations

• syncope/presyncope

• TIA, stroke or peripheral embolic event

• arrhythmias: A-fib, SVT, VT, etc.

common indications for an echo - known cardiac diagnoses

• valvular heart disease

• hypertension

• heart failure

• cardiomyopathy

• aortic disease

• cardiac masses

• pericardial disease

• congenital heart disease

• coronary artery disease (CAD)

• pulmonary hypertension

doppler equation (fd)

2/c x v x ft x cos angle

c

propagation speed of sound in the medium

v

speed of moving interface (blood)

ft

frequency of transmitted (original) sound wave

cos angle

cosine of the angle of incidence between transmitted sound wave and particle (RBCs or reflector) motion

bernoulli equation

∆p = 4v²

bernoulli equation

pressure gradient across a value is related to velocity

• pressure drop across a stenotic valve, in echo, is calculated using this

color doppler

don’t invert color map

velocity scale

• specifies range of velocities displayed

• adjust to maximize waveform without aliasing

sweep speed

• changes number of cardiac cycles shown

• use 100 mm/sec

sample volume size

• adjusts width of sample volume

• adjust to receive adequate signal while reducing noise

wall filter

• eliminate low-velocity signals near baseline

• adjust to remove unwanted noise without erasing flow information

spectral doppler gain

• amplifies doppler signals before display

• optimize for ability to measure accurately

baseline

• position to optimize the doppler signal as large as possible

• use with doppler scale to eliminate aliasing

peak velocity and pressure gradient

• caliper to measure PV

• PP gradient is calculated based on PV using bernoulli