Torsade de Pointes and Persistent QTc Prolongation after Intravenous Amiodarone

Abstract

We report a case of torsade de pointes after intravenous amiodarone and concurrent hypokalemia. Despite treatment cessation and correction of electrolyte abnormalities, excessive QTc prolongation was noted, which persisted for 14 days. This prolonged course for QTc normalization may be attributed to the high rate of amiodarone loading and concurrent electrolyte disturbances coupled with possible underlying individual variability in pharmacokinetics.

Figure 1

Baseline QTc. QTc interval was normal prior to amiodarone administration (day 0); after 1.65g intravenous amiodarone, QTc increased progressively.

Figure 2

Torsade de pointes after amiodarone administration.

Figure 3

Time course of QTc prolongation. QTc prolongation persisted for 14 days after cessation of intravenous amiodarone. Note the (marginally) low serum K⁺ on the 4th hospital day.

Figure 4

12-lead ECG at discharge. Prior to discharge, the QTc interval was 470 ms.