Letters Section Editor: Stephen J. Lurie,
MD, PhD, Senior Editor.
To the Editor: Dr McBride and colleagues1 found that a dietary supplement containing ephedra
significantly prolonged the QT interval. The authors reported, though, that
none of the participants who received ephedra was found to have a corrected
QT (QTc) interval greater than 500 milliseconds, a point beyond which drug-induced
torsade de pointes frequently occurs.2 This
is not surprising given the small number of participants in their study and
the absence of structural heart disease among them.
Krantz MJ. Cardiovascular Effects of Ephedra. JAMA. 2004;291(13):1560. doi:10.1001/jama.291.13.1560-a