What is shown in Figure 1 is the pulse-wave (PW) Doppler through the left ventricular outflow tract (LVOT). The rhythm is regular, but the peak velocities vary from 0.8 m/s to 1.1 m/s.
When there is significant variability in the flow through the LVOT, differential diagnoses include constrictive pericarditis or pericardial tamponade, as well as pulsus alternans, which can be seen in patients with severe LV systolic dysfunction.
Figure 4 (repeated above) is an M-mode through the LV in the parasternal long axis. Note that the septum demonstrates variable filling of the LV; sometimes the LV is smaller than the RV or vice versa. This can be seen in cases of pericardial constriction. The size of the LV and the thickening of the LV segments appears normal, making pulsus alternates very unlikely. However, there is a different explanation here.
Look closely at the M-mode through the mitral valve (Figure 3, repeated above). Do you notice that from beat to beat, the opening of the mechanical leaflets is different (before the fourth QRS complex, the leaflets don't appear to open in early diastole, but only after atrial systole)?
This patient was not compliant with their warfarin prescription, causing thrombosis of the mechanical mitral valve. One can see the variable motion of the mitral discs in the 2D images (Figures 5, 6 below).
Notice that in Figure 7 below, the color flow varies from beat to beat, as does the LV volume (look at the septal motion from beat to beat and correlate it with the amount of flow coming through the mitral valve).
The CW-Doppler through the mitral valve (Figure 8 below) nicely shows the difference in valve "clicks" from beat to beat and the corresponding degrees of flow through the mitral valve (or lack thereof) and the variable timing (sometimes the flow is throughout diastole, at other times, it is mostly in the small period after atrial systole, as in the fourth QRS complex).
Finally, if one looks at Figure 9, despite the regular rhythm, one can see the variability in the ejection period—one final extra subtlety to this case.
Any views expressed above are the author's own and do not necessarily reflect the views of WebMD or Medscape.
Cite this: Ronald H. Wharton. Analyze This Image: Young and Short of Breath - Medscape - Dec 02, 2016.