QT prolongation and the antiarrhythmic efficacy of amiodarone.
Publication/Presentation Date
1-1-1986
Abstract
Amiodarone is an antiarrhythmic agent known to cause prolongation of action potential duration which is reflected in the electrocardiogram as a prolongation of the QT interval. Prolongation of the QT interval in patients dying suddenly was compared with that in patients who remained alive to determine whether a difference existed between these two groups. The electrocardiogram and amiodarone levels were evaluated in 33 patients who presented with cardiac arrest and symptomatic ventricular tachycardia in whom no other antiarrhythmic agent was found effective in preventing induction of ventricular tachycardia during electrophysiologic studies. There were 30 men and 3 women (mean age 52 +/- 10 years). Twenty-three are alive after a mean follow-up period of 12 +/- 7 months. Ten died: six suddenly, three of non-cardiac causes and one of congestive heart failure. Using a two-way analysis of variance, the percent change in QT, QTc, JT and JTc intervals before and after amiodarone therapy was analyzed. Marked prolongation in the QT interval was present in patients who remained alive with amiodarone therapy. A significant difference in percent QT prolongation was seen between the latter patients and those who died suddenly (p less than 0.005). No difference was observed in the percent change in QRS interval between the two groups. The levels of amiodarone (2.5 versus 3.2 micrograms/ml) and its metabolite (desethylamiodarone) were not significantly different between the living patients and those who died suddenly. These findings suggest that a prolongation of the QT interval may be a marker for the therapeutic antiarrhythmic effect of amiodarone.
Volume
7
Issue
1
First Page
142
Last Page
147
ISSN
0735-1097
Published In/Presented At
Torres, V., Tepper, D., Flowers, D., Wynn, J., Lam, S., Keefe, D., Miura, D. S., & Somberg, J. C. (1986). QT prolongation and the antiarrhythmic efficacy of amiodarone. Journal of the American College of Cardiology, 7(1), 142–147. https://doi.org/10.1016/s0735-1097(86)80272-8
Disciplines
Medicine and Health Sciences
PubMedID
3941202
Department(s)
Department of Medicine
Document Type
Article