The semiology of tilt-induced psychogenic pseudosyncope

To provide a detailed semiology to aid the clinical recognition of psychogenic pseudosyncope (PPS), which concerns episodes of apparent transient loss of consciousness (TLOC) that mimic syncope.

We analyzed all consecutive tilt-table tests from 2006 to 2012 showing proven PPS, i.e., apparent TLOC had occurred without EEG changes or a decrease in heart rate (HR) or blood pressure (BP). We analyzed baseline characteristics, video data, EEG, ECG, and continuous BP measurements on a 1-second time scale. Data were compared with those of 69 cases of tilt-induced vasovagal syncope (VVS).

Of 800 tilt-table tests, 43 (5.4%) resulted in PPS. The majority (74%) were women. The median duration of apparent TLOC was longer in PPS (44 seconds) than in VVS (20 seconds, p < 0.05). During the event, the eyes were closed in 97% in PPS but in only 7% in VVS (p < 0.0001). A sudden head drop or moving down the tilt table was more common in PPS than in VVS (p < 0.01), but jerking movements occurred more frequently in VVS (p < 0.0001). In PPS, both HR and BP increased before and during apparent TLOC (p < 0.0001).

PPS is clinically distinct from VVS and can be diagnosed accurately with tilt-table testing and simultaneous EEG monitoring. Compared with VVS, eye closure during the event, long periods of apparent TLOC, and high HR and BP are highly specific for PPS. Improved understanding of the semiology of PPS as a clinical entity is vital to ensure accurate diagnosis.