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Wednesday #EchoFirst #Tweetorial on one of my favorite #FellowsFirst topics, septal motion. Thank you to @ottoecho for the excellent graphic in her textbook ( https://amzn.to/2JIaPYC ) which is an excellent read. @ASE360
2/ Abnormal septal motion can be from multiple etiologies and #EchoFirst, particularly M-mode, is a great way to distinguish among these patterns. Normally, the septum moves anteriorly (towards RV) in late diastole before moving towards the LV during systole.
3/ In LBBB, early activation of the septum causes early rapid inward contraction ("septal beaking"), causing stretch of the posterior wall which (as a result of increased restoring forces) forcefully contracts resulting in anterior displacement of the septum.
4/ Rule of thumb: the septum moves towards the chamber with the larger mass (usually the LV). Thus, with LV volume overload, normal patterns are exaggerated.
5/ In RV pressure overload, RV>LV mass throughout the cardiac cycle and thus the septum flattens throughout the cardiac cycle, especially at end-systole when the effect of LV/RV filling is minimized.
6/ In RV volume overload, RV is > LV mass maximally in ~mid-diastole (when the effect of increased RV filling is maximal) resulting in septal flattening or anterior motion during diastole with reversal of this pattern in systole (when the effect of LV/RV filling is minimized).
7/ After cardiac surgery, the septum can also move paradoxically anterior. Though causes are likely multifactorial ( https://bit.ly/3m8kNQc ), PSM may in part be caused by changes in pericardial restraint within the thorax ( https://bit.ly/2LdFDR8 )
8/ With constrictive pericarditis, there is increased LV/RV interdependence and exaggerated anterior motion of the septum in late diastole from atrial contraction.
9/ In constrictive pericarditis, early rapid filling of the RV causes RV pressure to overtake LV pressure in early diastole with early leftward septal shift. As RV pressure plateaus but the LV fills, the septum rapidly shifts back causing a "bounce." ( https://bit.ly/340787n )
10/ Close attention to the timing/ pattern of these changes can help trigger an evaluation for their etiology and may help discover things that were not identified initially. Using M-mode (due to higher temporal resolution) to evaluate septal motion can be invaluable for dx. FIN.
