1. High frequency ultrasound = 2.0 - 7.5 MHz
A. Adults = 2.0 - 2.5 MHz
B. Pediatric = 3.0 - 5.0 MHz
C. TEE = 3.5 - 7.5 MHz
D. M-mode "ice pick view"
E. 2D sector scanning
F. Doppler effect
G. Color flow imaging
2. Standard Transducer Positions
A. Transthoracic long
B. Transthoracic 90o short axis
C. Parasternal long
D. Parasternal short
E. Apical
F. Subcostal 4 chamber
G. Subcostal ventricular septum
H. Suprasternal
I. Transesophageal
3. Doppler Effect
A. Sound frequency increases as sound source moves toward observer; frequency decreases as source moves away.
B. Ultrasound of known frequency is transmitted to heart or blood vessel.
C. Moving RBC's reflect ultrasound waves at altered frequency depending on direction RBC's are moving.
D. Frequency shift is used to estimate blood flow velocity.
4. Color Flow Imaging
A. Doppler flow velocity sampled at multiple sites (gates)
B. Frequency shift converted to color scheme
1) Blood flow toward transducer = RED
2) Blood flow away = BLUE
3) Turbulence (multiple directions) = GREEN
4) High frequency = WRAP AROUND OR ALIASING
5. Hemodynamic Assessment by Doppler
A. Doppler shift measures blood flow velocity
B. Flow velocity converted to pressure gradient by Bernoulli equation
1) DP = 4 x (V2)2
C. Sum of flow velocity during ejection period = time velocity integral (TVI)
1) Used with cross sectional area to calculate flow
D. Valve area
1) Continuity equation
2) Pressure half-time
E. Flow velocity across a regurgitant valve is related to intracardiac pressure
6. Typical 2D ECHO Patterns
A. Normal Anatomy
1) Four Chamber
B. Normal Valve Anatomy
1) Tricuspid
2) Mitral
3) Aortic
C. Pathologic variations
1) Valvular congenital aortic stenosis
2) Subvalvular congenital aortic stenosis
3) Ebstein's Anomaly
4) Tricuspid atresia
5) Atrial septal defect
6) Ventricular septal defect
7) Cor triatriatum
8) Total anomalous pulmonary venous connection
9) Hypoplastic left heart syndrome
10) Single ventricle
11) Transposition of great arteries
12) Aortic endocarditis
13) Mitral endocarditis
14) Hypertrophic obstructive cardiomyopathy
15) Myxoma
16) Aortic dissection
17) Coarctation
18) Congenital mitral stenosis
19) Congenital rheumatic mitral disease
20) Ruptured mitral chordae
7. Intraoperative
A. Ensure optimal result of reconstructive cardiac surgery
1) Cardiac valve
2) Congenital defect repair
B. Minimize CV complications during operation
1) Air embolism
2) Cardiac wall motion (value controversial)
C. Trouble-shooting the hemodynamically unstable patient
