Pseudo infarction ECG pattern occurring during intravenous treatment with flecainide acetate.

A 79-year-old woman presented with atrial flutter and anginal complaints, which remitted on nitroglycerin but the flutter did not respond to digoxin and verapamil. Flecainide acetate was given intravenously; administration was stopped because of development of a significant increase in the QRS duration, existence of prominent deep Q waves and marked ST elevation in leads V1 to V4. These abnormalities mimicked the ECG changes seen in myocardial infarction. However, the presence of an acute myocardial infarction could be ruled out. On a second admission intravenous flecainide acetate resulted in comparable marked ECG changes.