Head-up tilt test in patients with high pretest likelihood of neurally mediated syncope: an approximation to the "real sensitivity" of this testing.
This study was designed to examine the "true sensitivity" of a specific head-up tilt (HUT) testing protocol using clinical findings. The HUT protocol used 45 minutes at 60 degrees for the baseline portion and intermittent boluses of 2, 4, and 6 micrograms of isoproterenol in the second phase. Eighty-eight patients (40 men and 48 women; mean age of 33.8 +/- 16 years) with recurrent syncope and high pretest likelihood of neurally mediated syncope were included. The following were considerated as high pretest likelihood criteria: (1) at least two syncopal episodes; (2) no structural heart disease and normal baseline ECG; (3) age < 65 years; (4) a typical history of neurally mediated syncope, triggering factors plus premonitory signs; and (5) short duration of symptoms and fast recovery without neurological sequelae. Fifty-four patients (61%) had a positive tilt test (34/88 baseline [39%] and 20/50 with isoproterenol [40%]). The shorter time interval between the last syncopal episode and baseline HUT test was the only predictor for a positive response (P < 0.003). Conversely, this time interval was not predictor of positive responses during isoproterenol-tilt testing.


CONCLUSIONS
(1) we claim a "sensitivity" for this combined protocol of 61%; and (2) our results indicate that patients with syncope of unknown origin must be tilted nearest as possible to the last syncope to increase the positive responses of HUT test.
Pérez-Paredes
M
M
Cardiology Unit, University Hospital Morales Meseguer, Murcia, Spain. mpparedes@doymanet.es
Picó-Aracil
F
F
Florenciano
R
R
Sánchez-Villanueva
J G
JG
Ruiz Ros
J A
JA
Ruipérez
J A
JA
D000293:Adolescent; D000318:Adrenergic beta-Agonists / Q000008:administration & dosage; D000328:Adult; D001794:Blood Pressure; D002648:Child; D002675:Child, Preschool; D015150:Echocardiography, Doppler; D015716:Electrocardiography, Ambulatory; D004569:Electroencephalography; D005260:Female; D005500:Follow-Up Studies; D006339:Heart Rate; D006801:Humans; D007262:Infusions, Intravenous; D007545:Isoproterenol / Q000008:administration & dosage; D016013:Likelihood Functions; D008297:Male; D008875:Middle Aged; D010275:Parasympathetic Nervous System / Q000187:drug effects / Q000503:physiopathology; D012008:Recurrence; D012680:Sensitivity and Specificity; D019462:Syncope, Vasovagal / Q000175:diagnosis* / Q000503:physiopathology; D018667:Tilt-Table Test; D014057:Tomography, X-Ray Computed
D000318:Adrenergic beta-Agonists; D007545:Isoproterenol