AE 1.2 - Scope of Practice, Cardiac Anatomy, Optimization

Scope of practice of the cardiac sonographer

- functions as a delegated agent of the physician

- does not practice independently

- sonographers CAN not provide interpretation of exam to patient

-- interpretation comes from physician '

- recognize, evaluate, quantify

ALARA principle

as Low as Reasonably Achievable

- lowest output power & the shortest scan time

-- consistent with acquiring the required diagnostic information

Joint commission patient identification requirements

Name & Date of Birth

ask the patient the date of birth instead of saying it and having them agree

IAC

Intersocietal Accreditation Commission

– the minimum standards and guidelines for echocardiography accreditation

Proper patient positioning

left lateral decubitus

How breathing affects image quality

- sound beam cannot travel through air inspiration

- brings lung artifacts into view expiration

- brings lungs out of view

Basic image optimization principles

Patient Positioning

Patient Breathing

AdJust image/window

Ergonomics

Highest possible transducer frequency

Focus centered at ROI (region of interest)

Don’t rely on auto-optimization

Every image should be re-evaluated for quality and optimized

Frequency

Low frequency = better penetration

High frequency = better resolution

First step in image optimization & why

- positioning, cannot see anything if patient is not in right position

- your goal is to image structures on-axis whenever possible

- on-axis imaging gives the most accurate representation of size, shape, motion, and relationships

- don't accept an off-axis image just because you can see the structure

- go off-axis with purpose, not by accident

Temporal Resolution / Frame Rates

- ability of the ultrasound machine to accurately show the position of moving structures at a particular instant in time

- ↑ Depth = ↑ pulse time

- ↑ Sector size = ↑ the # of scan lines

- narrow sector

- shallow imaging

- above 30 fps in 2D images

- above 18 fps in color images

Cardiac chambers

pulmonic circuit

- right atrium (smallest, thinnest, lowest pressure)

- right ventricle (most anterior)

systemic circuit

- left atrium (most posterior) (conduit, reservoir, pump)

- left ventricle (largest, thickest, highest pressure)

RA vs LA

RA

- anterior

- low pressure

- 3 inlets

- thin walls; coarse pectinate muscles

- chiari network, eustachian valve

LA

- posterior

- high pressure

- 4 inlets

- thick walls; smooth pectinate muscles

- no fetal remnants

Coronary sinus

- lies within a sulcus called the AV sulcus or AV groove (epicardium) and empties into RA

- drains the coronary veins into the RA

- Thebesian valve sits at the opening

Cardiac valves

tricuspid valve

pulmonic valve (most anterior & superior)

mitral valve (2 leaflets)

aortic valve

Tricuspid valve

leaflets

1) anterior

2) posterior

3) septal

Mitral valve

- leaflets

1) anterior

- anchored to aortic root

- larger

- no scallops

2) posterior

- wider attachment to annulus

- divided into 3 scallops

TV vs MV

TV

- 3 leaflets, thinner

- expandable annulus

- sits lower in heart

- 3 commissures

- ant, post, sept = papillary muscles

MV

- 2 leaflets

- D shaped, rigid annulus

- 2 commissures

- AL, PM papillary muscles

Pulmonic valve

- semilunar

- cusps

1) anterior

2) left

3) right

- most anterior & superior valve

Aortic valve

- semilunar

- based on where coronary arteries originate

1. Left coronary cusp (LCC)

2. Right coronary cusp (RCC)

3. Non coronary cusp (NCC)

Sinuses of Valsalva

"hips"

Sinotubular junction

"waist”

Branches off aortic arch

- Innominate Artery

-- splits into right common carotid Artery & right subclavian Artery

- Left common carotid

- Left subclavian

Moderator band

- muscle column that courses from IVS to the base of anterior papillary muscle

- electrical conduction path

- CAN also act as a protective mechanism to resist overdistention of the RV

Subvalvular apparatus (TV, MV

- annulus

- leaflets

- chordae tendineae

- papillary muscle

- commissures

Chordae tendineae

- small, string-like structures

- connect the leaflets of the valve with the papillary muscles

- anchor and support the leaflets

- prevent leaflet prolapse during ventricular systole

Papillary muscles

- contract, pulling the leaflets toward one another, helping valve closure

- connect to the chordae tendineae

Left atrial appendage

- long and narrow, “finger like”

- decompresses LA when atrial pressure is high

- frequent location for blood clots

Right ventricle unique characteristics

- thin walls

- heavily trabeculated

- moderator band

- smaller

- crescent shape

- rough interior

Left ventricle unique characteristics

- thick walls

- no moderator band

- fine trabeculations at apex

- ellipsoid shape

- larger

- smooth interior

Normal intracardiac pressure ranges

right heart - lower pressure

left heart - higher pressure

Oxygen percentage

right heart = 75%

left heart = 98%

Blood composition

plasma, red blood cells, white blood cells, platelets