Clinical usefulness of head-up tilt test in patients with syncope and intraventricular conduction defect.

Head-up tilt test was performed in 99 patients with syncope of unknown origin and intraventricular conduction defect. Twenty-five per cent had a positive response to tilt with reproduction of spontaneous clinical symptoms. Holter recording revealed paroxysmal atrioventricular (AV) block in three patients. Carotid sinus massage was positive in four patients. An electrophysiological study was performed in 76 patients with abnormal findings in 17 (22%). Thus, vasovagal syncope was the discharge diagnosis in 25 patients (25%). Therefore, tilt test should be considered in patients with intraventricular conduction defect presenting with syncope of unknown origin, especially if clinical findings suggest the possibility of a vasovagal mechanism, or if the results of the electrophysiological study are inconclusive.

[The tilt-table test: is it essential for adequate treatment of vasovagal syncope? Arguments in favor]. / Test de mesa basculante: es imprescindible para el tratamiento adecuado del síncope vasovagal? Argumentos a favor.

Head-Up tilt test (HUT) permits the identification of vasovagal syncope in patients with syncope of unknown origin. Several authors have pointed out its usefulness for the therapeutic management of these patients. However, even though it has limitations, this paper discusses those situations in which HUT may be useful. First, as HUT permits the recognition of the etiologic diagnosis of syncope, it may be helpful in the evaluation of its treatment. On the other hand, the characterization of different components of vasovagal reaction, cardioinhibition and/or vasodepressor response, may be helpful in the selection of therapeutic options. It has been suggested that the performance of HUT may even be beneficial for the relapses of vasovagal syncope in patients with recurrent syncope and refractory to other treatments. Finally, further randomized clinical trials in HUT will help to establish the prediction of therapeutic effectiveness in patients with vasovagal syncope. However, there are important limitations to its usefulness for the clinical management of individual patients.

[An analysis of the responses to the tilt-table test depending on the clinical characteristics of the syncopal episodes in patients without apparent cardiopathy]. / Análisis de las respuestas a la prueba en tabla basculante en función de las características clínicas de los episodios sincopales en pacientes sin cardiopatía aparente.

Seventy-six consecutive patients were evaluated to assess whether the response to head-up tilt test was related to the type of clinical presentation in patients with syncope of unknown origin and free from heart disease. The syncopal attacks were clinically characterized in a prospective fashion before the tilt test. In 44 patients (group I) syncope had been preceded by autonomic symptoms or was associated with recent or static sustained orthostatism. In 32 patients (group II), syncope had been sudden, without prodromal or autonomic symptoms. Mean age was 49 +/- 17 years in group I patients and 47 +/- 17 years in group II patients (NS). The degree of tilt was 75 degrees. During 30 min no drugs were administered, and then isoproterenol was infused for an additional 20 min (1-5 micrograms/min until a maximal heart rate of 140 bpm was achieved). Tilt test was considered as positive when the patient developed syncope or presyncope with hypotension. Tilt test was positive in 33 patients from group I (75%) and 12 from group II (37.5%)(p = 0.001). The positive response developed within the 30 initial min of the test (without isoproterenol infusion) in 19 of 33 patients from group I (57%) and in 3 of 12 patients from group II (25%) (p = 0.053). It is concluded that the response to tilt test is related to the clinical features of syncopal attacks.