"Intermittent" and transient ST-segment elevation following direct current cardioversion.

Transient ST-segment elevation immediately following direct current cardioversion is a clearly documented occurrence in a small percentage of cases. Two main explanations have been suggested: myocardial injury or coronary vasospasm. We report two cases of "intermittent" and transient ST-segment elevation after cardioversion. Such intermittent elevation of the ST segment has not been reported previously. We hypothesize that this electrocardiographic observation is explained by a timing difference induced by electroshock in the action potential between the epicardium and endocardium.