[Heart rate variability in the elderly with syncope or falls of uncertain origin].

Presyncope, syncope and falls in undetermined circumstances are frequent among the elderly. They may be caused by orthostatic hypotension secondary to autonomic insufficiency. Tilt-tests and determination of catecholamines in serum and urine may establish the diagnosis, but often may not be feasible in these patients. A simple, indirect, noninvasive technique to assess autonomic insufficiency is analysis of heart rate variability during Holter-monitoring. We present 5 cases in which it proved useful in the investigation of spells of unconsciousness.