we used the `` '' upright-tilt test '' '' ( duration , less than or equal to 10 minutes ) with or without an infusion of exogenous catecholamine ( isoproterenol [ 1 to 5 micrograms per minute ] , given intravenously ) to elicit bradycardia , hypotension , or both in 24 patients with recurrent syncope and in 18 control subjects .
C0007412
s catecholami
C0022245
( isoproteren