Profound bradycardia after amyl nitrite in patients with a tendency to vasovagal episodes

Abstract

Two patients with mild aortic insufficiency inhaled amyl nitrite during routine echocardiographic examinations. One developed sinus arrest and syncope and the other had pronounced sinus bradycardia. The mechanism of this paradoxical response is unclear. Caution should be exercised when amyl nitrite is administered for diagnostic purposes.