Cardiac echo is the examination of the fetal heart using ultrasound imaging. This involves different modalities including 2D gray scale, color Doppler, pulsed wave Doppler and M-mode imaging. Fetal echo can detect up to 90% of major cardiac defects if done by an experienced physician. However, there are certain cardiac defects, which cannot be detected prenatally, and therefore a negative test does not preclude entirely the possibility of their existence.
