Tilt-induced vasovagal syncope and psychogenic pseudosyncope: Overlapping clinical entities

To describe the combination of tilt-induced vasovagal syncope (VVS) and psychogenic pseudosyncope (PPS) and aid its clinical recognition.

We identified people with tilt-induced VVS/PPS from 2 tertiary syncope referral centers. For each case, 3 controls with tilt-induced VVS were selected at random from the same center. Clinical characteristics were compared between both groups adjusting for multiple comparisons.

Of 1,164 tilt-table tests, 23 (2%) resulted in VVS/PPS; these 23 cases were compared with 69 VVS controls. VVS and PPS coincided more often than chance would predict: 2% vs 0.6%, p < 0.001. Typical VVS prodromes and triggers were reported in all people with VVS/PPS and in controls with VVS. Attack frequency was significantly higher in the VVS/PPS (2 per month, range 0.1-60) than in the VVS group (0.25 per month, range 0.02-4; p < 0.001). Delayed recovery of consciousness was more frequently reported in the VVS/PPS group (likelihood ratio [+LR] 8.14, 95% confidence interval [CI] 3.94-16.84), as well as episodes without prodromes (+LR 5.57, 95% CI 2.53-12.26), atypical triggers (+LR 5.00, 95% CI 2.04-12.24), eye closure (+LR 3.75, 95% CI 1.68-8.35), and apparent loss of consciousness >1 minute (+LR 2.86, 95% CI 1.98-4.13).

VVS/PPS presents with a complex phenotype. High attack frequency, delayed recovery of consciousness, apparent loss of consciousness >1 minute, ictal eye closure, atypical triggers, and the absence of prodromes may serve as indicators that PPS coincides with VVS.