Tilt test en sujetos sanos asintomáticos / Tilt test in asymptomatic healthy subjects

RESUMO

The head-up test has demonstrated to be useful in the study of patients with syncope of unknown origin for the diagnosis of neurocardiogenic syncope. Several publications have described different methods, with different results in cases as well as in controls. We performed a prospective study in a group of normal subjects in order to evaluate the methodology used in our population and to establish its specificity. A positive test was defined as the presence of syncope or presyncope and hypotension. The examination was carried out on a tilt table, five minutes at 0º, then at 70º during 20 min at 70º. Twenty one volunteers (14 males and 7 women; mean age 26.7ñ3.5 years; range 21-33 years) and body mass index 23.4ñ2.2 kg/m2 were examined. Mean dose of isoproterenol was 3.1ñ0.9 ug/min (3.4ñ1.1 in men and 2.6ñ0.7 ug/min in women. NS). During the phase without isoproterenol no subject developed hemodynamic alterations neither symptoms. One volunteer (4.8 percent) developed presyncope and systemic hypotension (52/28 mm Hg) accompanied with nodal rhythm after 14 min of isoproterenol at 70º, and his examination was discontinued with immediate recovery. Three other subjects developed asymptomatic transient nodal rhythm during the phase with isoproterenol and recovered spontaneously. No other complications were observed. It is concluded that head-up tilt test with isoproterenol at 70º with the used doases and heart rate increments, is highly specific (95 percent) to stablish the diagnosis of a neurocardiogenic syncope