Pitfalls in Fetal Echocardiography

Jung Yun Choi

Department of Pediatrics

Seoul National Univ. Children’s Hospital

Pitfalls of Fetal Echocardiography

• Pitfalls due to technical factors

• Pitfalls related to interpretation

Pitfalls due to technical factors

Structural Image

Doppler Spectral Image

Color Doppler image

Pitfalls in Structural Image

Echo drop-out

Artifact : Shadowing

Imperfect resolution

Slice thickness

Echo drop-out; Shodowing; Artifact

Pitfalls in Color Doppler image

Low frame rate

Poor range resolution

Poor velocity resolution

Range resolution Velocity resolution

Resolution of color Doppler study

Velocity Scale Change

Transducer Frequency Change

Pitfalls in assessing size

Normal size

Large heart

Small heart

Normal size

• What is normal ? Mean ± 2 SD

• Growth parameters : gestational period,

body weight, head circumference, height, etc

• Heart parameters : dimension, area, volume

Large Heart

• Right or left or both sides

• Causes – cardiac malformation– valvular or ventricular dysfunction– secondary to fetal diseases

• Effects on fetus; long-term effects

Small Heart

• Anatomic definition: diameter / area below - 2 SD ?

• Functional definition : too small to be a ventricle

• Growth parameters : body weight > gestational age

• Any potential of catch up growth ?

How small?

• Too small: hardly seen, no potential of growth

• Questionable

• Not too small: -2 ~ -3 SD, may have a potential

Too Small Heart

• Causes : HLHS, HRHS

• How to assess : PFO, ductus, coronary fistula

• Counsel : single ventricle and Fontan

Not Too Small

• Causes: unknown, COA, AS, MS, PS etc

• How to assess: complete study on heart / vessel

• Counsel : cautious optimism

An example of LV being ‘Not Too Small’

An example of LV being ‘Not Too Small’

Pitfall in Natural History

• Newly diagnosed in the 3rd trimester

• Cardiac malformations become worse

• Cardiac defects / diseases become better

Newly diagnosed in the 3rd trimester

• Cardiac malformation

• Cardiomyopathy

• Cardiac tumor

• Secondary cardiac disease

Natural History

May get worse

May get better

May stay the same

Pitfalls in Arrhythmia

• Technical pitfalls: difficult to obtain signal

• Interpretation: requires thorough knowledge

• Common mistake– transient bradycardia– intermittent premature contraction

M-mode is difficult to obtain

FrequentlyPoor Tracing: difficult to identify wall motion

← Ventricular wall

← Mitral valve

← Atrial wall

Occasionally

Good Tracing : Atrial wall contraction precedes mitral valve closure and ventricular contraction← Ventricular wall← Mitral valve← Atrial wall

Premature Atrial Contraction

Brief bradycardia is common

Intermittent premature contraction is frequent