Comparison of provocative tests for unexplained syncope: isoprenaline and glyceryl trinitrate for diagnosing vasovagal syncope

• Published in: European heart journal 2001-03, Vol.22 (6), p.497-503
• Main Authors: Graham, L.A, Gray, J.C, Kenny, R.A
• Format: Article
• Language: English
• Subjects: Adult; Aged; Biological and medical sciences; Cranial nerves. Spinal roots. Peripheral nerves. Autonomic nervous system. Gustation. Olfaction; Female; head-up tilt testing; Humans; Isoproterenol; Male; Medical sciences; Middle Aged; Nervous system (semeiology, syndromes); Neurology; Nitroglycerin; Sensitivity and Specificity; Sympathomimetics; Syncope; Syncope, Vasovagal - diagnosis; Tilt-Table Test; vasovagal syndrome
• ISSN: 0195-668X; 1522-9645
• DOI: 10.1053/euhj.1999.2007

Aims To compare the sensitivity, specificity and adverse event profile of glyceryl trinitrate head-up tilt with isoprenaline head-up tilt in the diagnosis of vasovagal syncope in patients with unexplained syncope and healthy controls Methods and Results Forty-eight patients with unexplained syncope and negative passive head-up tilt at 70 degrees for 40min, and 14 healthy controls underwent glyceryl trinitrate head-up tilt and isoprenaline head-up tilt (maximum dose 5μg.min−1) one week apart in random order. Outcome measures were production of symptoms (syncope, pre-syncope) with development of hypotension. In those with negative passive head-up tilt, the sensitivity of glyceryl trinitrate for diagnosing vasovagal syncope was 48% and the specificity was 71%. Glyceryl trinitrate was well tolerated. Isoprenaline sensitivity was 21% with specificity 64%. Side-effects prevented completion of the test in 68%. Commonest adverse events were the development of hypertension or tachycardia and intolerable flushing or nausea. Conclusions Glyceryl trinitrate head-up tilt is as effective as isoprenaline head-up tilt as a provocative agent for vasovagal syncope and has a lower incidence of adverse events