Transient symptomatic subendocardial ischemia during intravenous magnesium sulfate tocolytic therapy

Although beta-sympathomimetic tocolytic therapy has been associated with transient subendocardial ischemia, magnesium sulfate has rarely been noted to cause acute chest pain and is, in fact, known to improve myocardial perfusion in patients with variant angina. We believe this report represents the first case in which intravenous magnesium sulfate administered as a tocolytic agent caused acute chest pain accompanied by transient electrocardiographic evidence of subendocardial ischemia.