A state before syncope
. The patient often has non specific symptoms which may reflect their individual response to the decreasing cerebral perfusion pressure where this comes on gradually over more than a few cardiac cycles. This is the situation with some forms of neurogenic syncope or major haemorrhage, but not usually with malignant arrhythmia or pulmonary embolism
. These often are similar to those with orthostatic hypotension
which most have experienced and include feeling lightheaded, legs weak, dizzy and can progress to other more specific symptoms such as tinnitus
as the blood pressure falls.
For a given individual tilt table studies show a good correlation between a given presyncopial symptom and blood pressure - MLJ -comment on the many tilt table studies he has done