PubMed1977
Circulatory regulation in response to postural changes follows mechanical rules, whereby the shifts in volume in the various organs of the body play an essential role. The change from the horizontal to the vertical position is accompanied by a decrease in pressure above the hydrostatic neutral point, i.e. in the cephalic vessels, whereas the capacious vessels in the caudal region are dilated and the venous return becomes sluggish. As a consequence of the different time courses followed by the various circulatory parameters in the wake of counter-regulatory measures, a distinction can be made between an early orthostatic instant regulatory response and a late orthostatic response. Prominent clinical features do not necessarily always consist of non-systemic dizziness, tinnitus, pallor cold sweat and, finally, orthostatic collapse, but general subjective symptoms such as deafness and tingling of the extremities, a chilly sensation and cardiac symptoms may frequently predominante. In the case of development of an autonomic neurotic symptom complex, psychoautonomic symptoms such as general sleep disturbance are observed. Apart from investigations carried out on a surgical tilting table in general practice, other procedures such as the Valsalva manoeuvre, the squatting test and, in most cases, the erect test are performed. Broadly speaking four different reaction types can be distinguished amongst cases of postural hypotension. Drugs with different therapeutic actions are selectively administered according to the pathophysiological characteristics of the individual patient and the sympathetic adrenal counter-regulatory response. Medico-mechanical measures and physical training should not be neglected.
Adrenergic beta-Antagonists↗