Transient ST-segment depression during rapid atrial fibrillation is of uncertain clinical significance (much as is true for ST segment depression in SVTs). A recent study indicates that ST-segment depression in rapid AFib is not consistently associated with positive stress testing or occlusions on cardiac catheterization.
On the other hand, if the ST-segment depression persists after the rate is controlled, then there should be greater concern.
[Androoulakis A. J Am Coll Cardiol 2007;50:1909-1911.]
