Use of intravenous esmolol to predict efficacy of oral beta-adrenergic blocker therapy in patients with neurocardiogenic syncope.
The usefulness of esmolol in predicting the efficacy of treatment with an oral beta-adrenergic blocking agent was evaluated in 27 consecutive patients with neurocardiogenic syncope. Seventeen patients had a positive head-up tilt test response at baseline and 10 patients required intravenous isoproterenol for provocation of hypotension. All patients were then given a continuous esmolol infusion (500 micrograms/kg per min loading dose for 3 min followed by 300 micrograms/kg per min maintenance dose) and rechallenged with a head-up tilt test at baseline or with isoproterenol. Of the 17 patients with a positive baseline tilt test response, 11 continued to have a positive response to esmolol challenge. Sixteen patients (including all 10 patients with a positive tilt test response with isoproterenol) exhibited a negative response to upright tilt during esmolol infusion. Irrespective of their response to esmolol infusion, all patients had a follow-up tilt test with oral metoprolol after an interval of greater than or equal to 5 half-lives of the drug. All 16 patients (100%) with a negative tilt test response during esmolol infusion had a negative tilt test response with oral metoprolol. Of the 11 patients with a positive tilt test response during esmolol infusion, 10 (90%) continued to have a positive response with oral metoprolol. It is concluded that in the electrophysiology laboratory, esmolol can accurately predict the outcome of a head-up tilt response to oral metoprolol. This information may be helpful in formulating a therapeutic strategy at the initial head-up tilt test in patients with neurocardiogenic syncope.
Sra
J S
JS
Sinai Samaritan Medical Center, Milwaukee, Wisconsin 53201.
Murthy
V S
VS
Jazayeri
M R
MR
Shen
Y H
YH
Troup
P J
PJ
Avitall
B
B
Akhtar
M
M
D000284:Administration, Oral; D000319:Adrenergic beta-Antagonists; D005260:Female; D006801:Humans; D007024:Hypotension, Orthostatic / Q000150:complications* / Q000175:diagnosis / Q000453:epidemiology; D007545:Isoproterenol; D008297:Male; D008790:Metoprolol / Q000008:administration & dosage / Q000627:therapeutic use*; D011187:Posture; D011237:Predictive Value of Tests; D011412:Propanolamines; D013575:Syncope / Q000188:drug therapy* / Q000209:etiology
D000319:Adrenergic beta-Antagonists; D011412:Propanolamines; D008790:Metoprolol; D007545:Isoproterenol; C036604:esmolol