Transient Recurrent Ventricular Fibrillation due to Hypopotassemia with Special Note on the U Wave

Abstract

IT is very rare that Adams-Stokes syndrome occurs in hypopotassemia and only 2 cases are reported in the literature.1) These cases were caused by atrioventricular block, though in this case the Adams-Stokes syndrome was caused by ventricular fibrillation that was recurrent, transient and reversible. The patient was, moreover, relieved by potassium chloride. Such a case was not reported yet in the literature as far as we know.
The massive fused T and U wave inversion, the postextrasystolic alteration of it, the alternans of the U wave after the cessation of ventricular fibrillation and the postextrasystolic alteration of the U wave were seen in this case. These were very interesting signs in the electrocardiogram to resolve the ionic shift in the myocardium in these occasions.2) The antiarrhythmic drug of ajmalin was effective in the initial stage in this case, though it became ineffective in the further advanced stage of hypopotassemia. This finding is interesting, if we refer the ineffectiveness of quinidine in hypopotassemia which is shown experimentally.3)
Such a rare case is presented with the review of the literature and the mechanisms are discussed.