Neurocardiogenic syncopeBMJ 2004; 329 doi: https://doi.org/10.1136/bmj.329.7461.336 (Published 05 August 2004) Cite this as: BMJ 2004;329:336
Acceptable tilt test protocols6
Tilt test protocols vary, but a generally acceptable protocol (for evaluating adult patients) involves an initial drug-free tilt at 60-80°, lasting 30-45 minutes. If this is non-diagnostic, then pharmacological provocation is used.6
Laboratory and environment6
- Dim lighting, comfortable temperature, quiet environment.
- Tilt table capable of angles of 60-80°.
- Minimum of three lead electrocardiographic recording.
- Continuous beat to beat blood pressure recording.
- Emergency resuscitation equipment on standby.
- Fasting after midnight or at least several hours before tilt test.
- Intravenous access for fluid replacement.
- Supine period of 20-45 minutes to allow equilibration.
- Initial drug-free tilt for 30-45 minutes at 60-80°.
- Drug-free tilt: low sensitivity in elderly patients (>60 years of age).w2
- Isoproterenol infusion or sublingual nitroglycerin most commonly used.
- Isoproterenol—Exogenous catecholamine used to help identify patients susceptible to neurocardiogenic syncope. Plasma concentrations of adrenaline (epinephrine) and noradrenaline (norepinephrine) increase significantly when patients are gradually tilted.6 Low dose isoproterenol (1-2 µg/min) is well tolerated in elderly patients but has low sensitivityw2; high dose (5µg/min) has high sensitivity but has more adverse side effects such as warmth, diaphoresis, palpitations, nausea, palpitations, and chest discomfort, and is thus poorly tolerated.w2
- Nitroglycerin (400 g sublingual)—Nitrate used to help increase sensitivity of tilt testing in elderly patients, by elimination of the diminished blood pooling and baroreceptor activation associated with postural changesw2; generally well tolerated; main side effect is headache. Compared with isoproterenol, nitroglycerin increases sensitivity of tilt testing in elderly patients.w2
- Positive—If syncopal symptoms with hypotension, bradycardia, or both occur as a consequence of the procedure; if syncope occurs as a result of hypotension, bradycardia, or both.6
- Negative—No response; or bradycardia or hypotension, without presyncopal or syncopal symptoms.6
Diagnostic capability and reproducibility6
- 85% diagnostic specificity3 (90%, with pharmacological provocation2,6).
- Sensitivity ranges from 32% to 85%,6 with 87% sensitivity when pooled data are used.3
- Reproducibility ranges from 65% to 85%.6
** For more extensive reading, refer to ESC and ACC guidelines.**
w1 Ventura R, Maas R, Zeidler D, Schoder V, Nienaber CA, Schuchert A, et al. A randomized and controlled pilot trial of beta-blocker for the treatment of recurrent syncope in patients with a positive or negative response to head-up tilt test. Pacing Clin Electrophysiol 2002;25:816-21.
w2 Mahanonda N, Bhuripanyo K, Kangkagate C, Wansanit K, Kulchot B, Nademanee K, et al. Randomized double-blind, placebo-controlled trial of oral atenolol in patients with unexplained syncope and positive upright tilt table test results. Am Heart J 1995;130:1250-3.
w3 Takata TS, Wasmund SL, Smith ML, Li JM, Joglar JA, Banks K, et al. Serotonin reuptake inhibitor (paxil) does not prevent the vasovagal reaction associated with carotid sinus massage and/or lower body negative pressure in healthy volunteers. Circulation 2002;106:1500-4.
w4 Mitro P, Trejbal D, Rybar AR. Midodrine hydrochloride in the treatment of vasovagal syncope. Pacing Clin Electrophysiol 1999;22:1620-4.
w5 Yu JC, Sung RJ. Clinical efficacy of propantheline bromide in neurocardiogenic syncope: pharmacodynamic implications. Cardiovasc Drugs Ther 1997;10:687-92.
w6 Natale A, Sra J, Akhtar M, Kusmirek L, Tomassoni G, Leonelli F, et al. Use of sublingual nitroglycerin during head-up tilt-table testing in patients >60 years of age. Am J Cardiol 1998;82:1210-3.
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