Tilt Table

Excerpt

Syncope may be caused by inadequate regulation of the heart and vessels function by the autonomic nervous and neuroendocrine systems. A tilt table test is a diagnostic procedure for patients with syncope of unknown origin. During the test, the patient is exposed to orthostatic stress, which may be exaggerated during the negative-passive phase of the test by nitroglycerin, clomipramine, and isoprenaline administration. A negative result tilt table test is characterized by a moderate increase in heart rate and the maintaining of the systolic blood pressure above 90 mmHg without symptoms during the planned duration of the study. The tilt table test may provoke a neurocardiogenic reflex with its vasodepressor and cardioinhibitory components. However, some other positive responses may be distinguished, for example, initial orthostatic hypotension, orthostatic hypotension, delayed orthostatic hypotension, and postural orthostatic tachycardia. The patient may present chronotropic incompetence when their heart rate does not increasemore than 5/min above baseline values. The neurocardiogenic reflex may occur suddenly or may be preceded by orthostatic hypotension or delayed orthostatic hypotension. Today, a tilt table test is believed to reveal susceptibility to reflex hypotension rather than the cause of the syncope.

During the test, the patient may present pseudo-syncope often manifested by a sudden silence, head dropping, and closed eyes, which can not be opened, even with force. In such a case, the patient can maintain an upright position, and blood pressure and heart rate are within normal limits.