Syncope caused by cardiac asystole during dobutamine stress echocardiography.

Syncope caused by cardiac asystole during dobutamine stress echocardiography occurred in a 60 year old woman presenting with chest pain and a non-diagnostic exercise test. Cardiac asystole was not associated with myocardial ischemia and was attributed to a powerful cardioinhibitory vagal reflex elicited by the stimulation by the drug of cardiac and aortic mechanoreceptors. Cardiac asystole was promptly reversed by the administration of atropine with no significant sequelae.