Same fetus 48 hours later with incessant SVT has developed a larger pericardial effusion and fetal Hydrops.

Same fetus 48 hours after initial fetal echo has remained in SVT and is noted to have a larger pericardial effusion and interval development of ascites.

M-mode through the atria and ventricles in a patient with SVT revealing 1:1 conduction with a rate of ~250 beats/min (atria are on top and ventricles are on bottom).

M-mode through atria and ventricles in patient with SVT revealing 1:1 conduction (ventricles on top and atria are on bottom).

Color m-mode in a patient with SVT revealing 1:1 conduction at a rate of ~250 beats/min.

Another fetus with SVT noted on apical 4 chamber view.

Fetus with SVT.

Ventricular rate of 208 beats/min was obtained by spectral Doppler across the aortic valve.

M-mode through atrium and ventricles (ventricles on top and atria on bottom of screen) revealing 1:1 conduction at a rate of 212 beats/min.