Figure 3.

Case 2. Spectral Doppler images of junctional ectopic tachycardia (JET). A: Ascending aorta (Ao) and superior vena cava (SVC) waveforms. Atrial systole (seen as retrograde SVC flow velocities [arrows]) occurs simultaneously with ventricular systole (antegrade Ao flow velocity). B: A sinus capture beat (arrow) is seen from simultaneous mitral E inflow (MV) and Ao outflow. C: Increased retrograde flow during atrial systole (atrial wave [a] below baseline) is seen in the ductus venosus. Flow toward the heart is biphasic (S and D waves).