Inducibility of paroxysmal atrial fibrillation by isoproterenol and its relation to the mode of onset of atrial fibrillation.
BACKGROUND
Isoproterenol has been used to assess inducibility during catheter ablation for paroxysmal PAF. However, no studies have determined the sensitivity and specificity of isoproterenol for the induction of AF. It also is not clear whether isoproterenol is equally effective in inducing AF in the clinical subtypes of vagotonic, adrenergic, and random AF.


OBJECTIVE
To determine the sensitivity and specificity of isoproterenol for the induction of atrial fibrillation (AF).


METHODS
Isoproterenol was infused at 5, 10, 15, and 20 microg/min at 2-minute intervals or until AF was induced in 20 control subjects with no history of AF and in 80 patients with PAF.


RESULTS
Among the 20 control subjects, AF was induced by isoproterenol in one patient (5%). Among the 80 patients with PAF, persistent AF was induced in 67 patients (84%, P < 0.001). Isoproterenol induced AF in 15 of 17 patients (88%) with vagotonic AF, 11 of 11 patients (100%) with adrenergic AF, and 41 of 52 patients (79%) with random episodes of AF (P = 0.2). The yield of AF was 11% (9/80) after 5 microg/min, 28% (22/80) after 10 microg/min, 51% (40/78) after 15 microg/min, and 88% (67/76) after 20 microg/min of isoproterenol (P < 0.01). Isoproterenol had to be discontinued in four patients (5%) before reaching the maximum dose due to reversible chest pain or systolic blood pressure <85 mmHg.


CONCLUSIONS
Isoproterenol at infusion rates up to 20 microg/min has a high sensitivity (88%) and specificity (95%) for induction of AF in patients with PAF, regardless of whether the clinical subtype is vagotonic, adrenergic, or random.
Oral
Hakan
H
Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, Michigan, USA. oralh@umich.edu
Crawford
Thomas
T
Frederick
Melissa
M
Gadeela
Nitesh
N
Wimmer
Alan
A
Dey
Sujoya
S
Sarrazin
Jean F
JF
Kuhne
Michael
M
Chalfoun
Nagib
N
Wells
Darryl
D
Good
Eric
E
Jongnarangsin
Krit
K
Chugh
Aman
A
Bogun
Frank
F
Pelosi
Frank
F
Morady
Fred
F
D000318:Adrenergic beta-Agonists / Q000008:administration & dosage; D000328:Adult; D001281:Atrial Fibrillation / Q000175:diagnosis*; D004305:Dose-Response Relationship, Drug; D004562:Electrocardiography / Q000187:drug effects*; D005260:Female; D006801:Humans; D007262:Infusions, Intravenous; D007545:Isoproterenol / Q000008:administration & dosage*; D008297:Male; D008875:Middle Aged; D011300:Preoperative Care / Q000379:methods*; D011379:Prognosis; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
D000318:Adrenergic beta-Agonists; D007545:Isoproterenol