<prompt> Electrical alternans in ECG is characteristic ofSevere bronchial asthmaPericardial effusionSevere LVFAR  <response>: Electrical alternans is an electrocardiographic phenomenon defined as an alternating amplitude or axis of the QRS complexes in any or all leads. It is most commonly associated with a large pericardial effusion and impending threat of cardiac tamponade Ref Davidson 23rd edition pg 467 