�

asiolo &� Anatomy Course� January 11^th 2018

Advanced Cardiac Physiology and Anatomy course

2026

​

Shanti L Narasimhan, MD,FASE

Professor of Pediatrics

Pediatric Cardiologist

Introduction to Echocardiography

Goals for Today

​

• Introduction to Ultrasound
• Clinical applications
• Live Demonstration: Cardiac anatomy and Physiology

Goals for

1.

​

2. Clinical applications of Cardiac Ultrasound

​

3. Live Demonstration : Cardiac anatomy and Physiology

Echocardiography

Historical Perspective�

1950’s - Physical examination/EKG

1950’s - Physical examination/EKG

1960’s - Cardiac catheterization/angiography

1970’s - Development of echocardiography

1980’s - Routine 2D echocardiography

Doppler

Color

- Development of echocardiography

1980’s - Routine 2D echocardiography

​

Historical Perspective�

1990’s - Fetal echocardiography

Transesophageal echocardiography (TEE)

2000’s - Advanced Imaging

3D echocardiography

Intravascular/Intracardiac ultrasound

Tissue Doppler

Early Fetal cardiac assessment/Transvaginal scan at 12-14 weeks of GA.

​

Basic Ultrasound Principles

• Ultrasound = sound waves of frequencies higher than those audible to the human ear or > 20,000 Hz (cycles/sec)
• λ = c/f
• λ = wavelength; f = cycles/sec ; c = speed of sound in the medium (varies with density and elastic properties)

​

Basic Ultrasound Principles

• Frequencies of 2,000,000 - 10,000,000 (2-12 MHz) used in medical applications

3-12 MHZ Human hearts

• 9-18 MHz large animal imaging
• 18-38 MHz small animal cardiovascular imaging
• 32-55 MHz embryonic imaging
• 30-70 MHz epidermis, ophthalmology, small tumors

​

​

​

Imaging Properties

Images are based on reflection of sound waves from tissue

Sound wave generated by stimulation of a piezoelectric crystal

A portion of the wave is reflected at the interface between tissues (reflected wave) the rest travels forward (refracted wave)

The reflected wave is received by the transducer, turned back into electrical energy, amplified and displayed

​

Imaging Properties

• Too much variance of acoustic density prevents imaging

​

• Distance traveled is proportional to wavelength and inversely related to frequency
• better at low frequency

​

• Resolution is also proportional to wavelength-

therefore better at higher frequencies

(7.5 MHz transducer is 0.4 mm; 3.5 MHz is 0.86 mm)

• Angle of incidence effects reflected wave
• Perpendicular provides best images
• Irregular surfaces can be difficult to image

​

​

​

Doppler

• Doppler Principle - Frequency of sound is altered when the source is moving

​

• Converse is true as well
• stationary source - red blood cells moving
• Frequency shift is measured and velocity of blood flow can be calculated
• f_d = 2(f₀ ) (v) (cos Ø)

c

• Most accurate Doppler recordings are obtained parallel to blood flow

​

​

Doppler

Continuous wave

• picks up high velocities, no spatial resolution
• Pulse wave
• lower velocity limit, spatial resolution guided by 2-D images
• Myocardial performance index (Tei index)
• Color mapping
• computerized “picture” of flow velocities coded by direction and speed
• Tissue Doppler imaging

ssure

Modified Bernoulli equation

Pressure change = velocity squared x 4

∆ P = v² x 4

​

Doppler

• Assessment of Hemodynamic
• Valve obstruction
• Intracardiac shunts
• Chamber pressures
• Modified Bernoulli equation

Pressure change = velocity squared x 4

∆ P = v² x 4

​

​

2D- Echo

• Used for defining cardiac anatomy and analyzing valve motion and myocardial function
• Assess LV function:

Ejection fraction- uses ventricular volume to calculate the amount of blood ejected

EF = LVD volume – LVS volume = 55 - 65%

LVD vol

Cardiac output = stroke volume x heart rate

​

​

Motion or M-Mode

• Rapid sequence analysis of structures in a single plane (300 images/sec plotted as movement vs. time)
• Useful for measurements of chamber size and function and valve motion
• Estimate of LV Function:

Shortening fraction

SF = LVd - LV s = 30 - 40%

LV d

​

Transthoracic Echo

• Three basic plane used to examine the heart
• Long–axis plane, parallel to the major axis of the LV
• Short-axis plane ,perpendicular
• Four-chamber plane, coronal plane through the cardiac apex
• Subcostal imaging
• Aortic arch imaging

​

​

Transthoracic Echo

Transthoracic Echo

4 C

4C

Color

Doppler

Doppler

Aortic arch

Color

M-mode

M-Mode in a Fetus� Complete Heart Block

Myocardial performance index� (MPI) Tei index

Short Axis

Transthoracic

Doppler

Doppler

Strain

Strain

3D Echocardiography

Transesophageal Echocardiography

Imaging from esophagus or stomach

• Eliminates acoustic interference
• Decreases distance from transducer

Used for: Improved resolution

Limited transthoracic windows

Widely used to monitor operative or interventional procedures

​

TEE

TEE

TEE

Clinical Applications� Fetal Echocardiography

Transvaginal

Visualization of cardiac structures from 12-14weeks

​

Transabdominal

Best visualization from 16 -28 weeks

Useful to define anatomy and function

Monitor natural history of cardiac lesions

Diagnose and monitor fetal arrhythmias

​

Fetal Echo Indications

• Abnormal cardiac examination on routine ultrasound
• Parents with congenital heart disease
• Previous child with congenital heart disease
• Family Hx of left sided cardiac lesions (HLHS)
• Identification of other congenital malformation
• Identification of chromosomal abnormalities
• Abnormal fetal growth or evidence of fetal distress
• Exposure to a known Teratogen (Lithium, Alcohol, Anticovulsants,Paxil, Isotretinoin)
• Maternal Hx of Autoimmune disorder (Lupus, Sjogrens)
• Abnormal heart rate or rhythm
• Maternal Hx of Diabetes
• 2 vessel cord
• Heterotaxy
• TTTS

​

​

Fetal

Fetal

Imaging

Stress or exercise echocardiography

Imaging during exercise or pharmacologic stress(dobutamine)

Myocardial perfusion/function

Gradients

Pulmonary artery pressures

Evaluation of exercise related symptoms

​

​

Epicardial Imaging

Multimodality Imaging

VR

• New platforms for patient imaging present opportunities for improved planning in congenital heart disease
• Virtual reality (VR) allows for interactive manipulation of high-resolution representations of patient-specific imaging data, as a supplement to traditional 2D visualizations and 3D printed heart models

​

​

​

VR

VR

Imaging

• Transthoracic Echocardiogram Demonstration

Thank You

​

Questions ?