• Images in cardiology

Atrial stunning occurs in about 20% of patients cardioverted for atrial fibrillation, being characterised by absence of mechanical activity of the atria despite normal activation. We report an unusual example of mechanical dissociation between the left atrium and the appendage. A 67 year old patient underwent DC shock for permanent atrial fibrillation (200 J); the precardioversion transoesophageal echocardiogram (below) shows relatively high velocity emptying (E) and filling (F) waves at the auricular level (LA, left atrium, LAA, left atrial appendage, LV, left ventricle). The images recorded 24 hours following sinus rhythm restoration (upper panel, right) demonstrate a paradoxical auricular flow during atrial systole; in coincidence with the P wave, thus, a filling wave occurs (arrow) instead of the expected emptying wave. In other words, the left atrial appendage does not contract simultaneously with the atrium during systole, so that some blood is forced from the atrial cavity into the appendage. Three weeks later, in contrast (lower panel, right), normal auricular flow is restored, as demonstrated by the expected emptying wave (arrow) simultaneous to the P wave.