1/ #LBBB generates often a classical pattern on #EchoFirst. The pattern is very distinctive in Tissue Doppler of the septum.

The classical pattern arises from the time lapse of the activation and relaxation of the two walls, creating a pattern of interaction due to a sequence temporal imbalances of the tension between the two walls.

2/ As the septum is activated first, it contracts (shortening - septal flash) without activation of the lateral wall, which stretches. This generates slower pressure build up than a normal IVC, which then is prolonged.

3/ During ejection, the LV volume decreases, so both walls shorten. Tension, however, declines first in the septum, as this was activated first. This leads to a tension imbalance, so the lateral wall continues to shorten, the more relaxed septum stretches.

4/ The stretching of the septum builds up an elastic tension in the septum, which is released as recoil, when tension declines in the lateral wall, showing a post systolic shortening in the septum which is due to elasticity.