Diagnostic Value of Nitrate Stimulated Tilt Testing Without Preceding Passive Tilt in Patients with Suspected Vasovagal Syncope and a Healthy Control Group

Abstract

Nitrate stimulated tilt testing, without a preceding passive tilt phase, and limited to a test duration of 15 minutes, provides an accurate, sensitive, and specific method to provoke vasovagal reactions in subjects with clinically suspected vasovagal syncope.

Teste de inclinação (Tilt-test): do necessário ao imprescindível

“…Likewise, when one analyzes more recent studies, it is possible to notice a significant decrease in specificity when, in sensitized protocols, the duration of the passive phase is equal to or more than 30 minutes. Protocols with shorter passive phases, or even without a passive phase, followed by sensitization with nitrate or isoproterenol, are linked with specificities that range from 84 to 97% 18,28,38 , whereas, in studies that used a more prolonged passive phase, there was a decrease in specificities (48 to 70%) 9,11,15 . Therefore, limiting the total duration of the examination seems to guarantee good specificity.…”

“…Many authors consider that it is enough to stop the HUTT when the doctor believes that the loss of consciousness is imminent -phase called presyncope -, and there is no reason to subject the patient to the huge discomfort resulting from hypotension or bradycardia, which will allow defining the vasovagal response 1,26,27 . More recent studies have considered that the positivity criterion is the induction of syncope or presyncope, when associated with bradycardia or hypotension 11,13,14,18,26,28 .…”

“…More recently, Aerts and Dendale 28 analyzed the accuracy of HUTT without passive phase. The tilt test was carried out with thirty-eight patients and thirty healthy subjects after administration of 400 ug of sublingual nitroglycerin, for a maximum period of 30 minutes.…”

Comparison of short head-up tilt test with conventional protocol after omission of nonmedicated phase in children and young adults

“…Aerts and Dendale[13] performed tilt testing after direct administration of sublingual nitroglycerin spray in an erect posture on 38 patients (mean age 46 ± 16) and 31 control subjects. In the patient group 31 (82%) and in controls 5 (16%) had a positive test.…”

Contribuição dos grandes vasos arteriais na adaptação cardiovascular a ortostase

“…The role of the wave refl ection in the circulatory homeostasis during orthostasis is reinforced by the observation that, when nitroglycerin, utilized in the sublingual route for IT sensitization, generates a peripheral vasodilation, it leads to a delay in the refl ected component of the pulse wave and the consequent reduction in the proximal systolic pressure, resulting in symptoms of low brain fl ow in patients with neuromediated syncope 105,106 . In fact, although a decrease in the coeffi cient of refl ection is verifi ed with the use of nitroglycerin, paradoxically, an increment in aortic stiffness is also observed.…”