Estimated risk of serious harm or death in highly symptomatic vasovagal syncope patients while driving was less than the same risk in the general population, according to an analysis of the Prevention of Syncope Trials (POST).
Researchers sought to determine the likelihood of a motor vehicle accident in patients with vasovagal syncope and compare it to international accident data. The 2 POST trials were multicenter randomized studies conducted from 1998 to 2004 (POST I) and 2006 to 2011 (POST 2) in patients with “at least 3 lifetime vasovagal syncope spells.” POST 1 participants received metoprolol or placebo and POST 2 participants received fludrocortisone or placebo. Accident data were collected from the United States, United Kingdom, and Canada.
The mean age of patients at enrollment was 38 ± 17 years and mean onset of vasovagal syncope was 22 ± 16 years, with a median of 10 lifetime faints and 3 faints in the previous year. In total, 5 patients experienced vasovagal syncope “while on or in a moving wheeled vehicle”—3 were excluded (2 were passengers in cars and 1 was on a bicycle). The other 2 patients, one from each POST trial, fainted while driving. Based on this incidence, the probability of syncope while driving was 0.62% per person-year.
Researchers also conducted a systematic search of available literature and found 444 publications, eliminating 432 based on duplication and lack of relevance. They found that 9 patients fainted while driving during a total observation period of 2945 years with a likelihood of 0.31% faints per driving year. Therefore, the estimated risk of an accident causing injury or death was 0.0017% per driving year, lower than the Canadian Cardiovascular Society (CCS) Consensus Guidelines on Fitness to Drive standard of 0.005%.
“Most of the subjects in the POST studies were Canadian, and advice about driving was informed by the CCS about syncope and driving private vehicles,” researchers wrote. “For private driving, it recommends no restriction for a single episode of typical vasovagal syncope, and a 1-month waiting period for patients with more than 1 faint in 12 months.”
One limitation of this study is that the POST trials were not designed to evaluate the risk of syncope while driving. Therefore, larger and appropriately designed studies are necessary to determine more precise risk estimates for policy makers.
Researchers recommend that despite the relatively low risks associated with vasovagal syncope, clinicians should know and adhere to local guidelines and legislation regarding fainting while driving.
Tan VH, Ritchie D, Maxey C, Sheldon R, on behalf of the Prevention Syncope Trials Investigators. Prospective assessment of the risk of vasovagal syncope during driving. JACC Clin Electrophysiol. 2016. doi: 10.1016/j.jacep.2015.10.006.