Aizawa Y, Matsubara T, Higuchi K, Washizuka T, Tamura Y, Uchiyama H, Igarashi Y, Shibata A
First Department of Internal Medicine, Niigata University School of Medicine, Japan.
Jpn Heart J. 1994 Sep;35(5):683-8. doi: 10.1536/ihj.35.683.
A 75-year-old female had syncopal episodes from Torsade des Pointes (TdP). Her electrocardiogram showed a prolonged QT interval which was not associated with electrolyte imbalances or drug therapy. Similar electrocardiographic abnormalities were found in three family members. Electrophysiologic study showed a mildly prolonged effective refractory period of 260-290 msec, but no tachyarrhythmia was induced. Coronary arteriography was normal but intracoronary acetylcholine unexpectedly induced a prolongation of the QT interval and TdP. Direct action of acetylcholine on the ventricular muscle was suggested.
