Cited 21 times since 2017 (3.2 per year) source: EuropePMC JACC. Clinical electrophysiology, Volume 3, Issue 13, 13 2 2017, Pages 1592-1598 Temporal Relationship of Asystole to Onset of Transient Loss of Consciousness in Tilt-Induced Reflex Syncope. Saal DP, Thijs RD, van Zwet EW, Bootsma M, Brignole M, Benditt DG, van Dijk JG
Objectives
The purpose of this study was to investigate the relationship between the onset of asystole and transient loss of consciousness (TLOC) in tilt-induced reflex syncope and estimate how often asystole was the principal cause of TLOC.
Background
The presence of asystole in vasovagal syncope (VVS) may prompt physicians to consider pacemaker therapy for syncope prevention, but the benefit of pacing is limited in VVS.
Methods
We evaluated electrocardiography, electroencephalography, blood pressure, and clinical findings during tilt-table tests. Inclusion required TLOC (video), electroencephalographic slowing, accelerating blood pressure decrease, and an RR interval ≥3 s. We excluded cases with nitroglycerin provocation. Asystole after onset of TLOC (group A) or within 3 s before TLOC (group B) was unlikely to cause TLOC, but an earlier start of asystole (group C) could be the cause of TLOC.
Results
In one-third of 35 cases (groups A [n = 9] and B [n = 3]), asystole was unlikely to be the primary cause of TLOC. The median of the mean arterial pressure at the onset of asystole was higher when asystole occurred early (45.5 mm Hg, group C) than when it occurred late (32.0 mm Hg, groups A and B), which suggests that vasodepression was not prominent at the start of asystole in early asystole, further suggesting that early asystole was the prime mechanism of syncope.
Conclusions
In one-third of cases of tilt-induced asystolic reflex syncope, asystole occurred too late to have been the primary cause of TLOC. Reliance on electrocardiography data only is likely to overestimate the importance of asystole.
