Vasovagal syncope: prevalence and presentation. An algorithm of management in the aviation environment.

Vasovagal syncope can occur in any individual, given sufficient provocation, and probably half the population suffers at least one episode during life. Often it occurs in youth and may occur in clusters. Usually there is a history of a previous episode. Prodromal symptoms include nausea sweatiness and a sensation of warmth. Diagnosis is by careful history and tilt testing. The false positive rate for passive tilt is 13% and the true positive rate is about 70% including use of nitroglycerine. A classical history and a positive tilt test obviate the need for further investigation in clinical practice, but in the context of aviation, it is wise to seek the small possibility of intermittent rhythm and/or conduction disturbance as an alternative explanation for the episode. It is, therefore, reasonable to carry out a Holter recording and exercise electrocardiogram, perhaps also echocardiography. No treatment is of much benefit, although many agents, including beta blocking drugs, have been used. Some patients have undergone permanent dual chamber pacing with some favourable results. Explanation and reassurance is important. From the licensing point of view, following investigation after an attack, consideration may be given to restricted certification with regular follow-up. Review with investigation after an event free interval, arbitrarily after 2 years, may permit full certification. Malignant vasovagal syncope with no warning of impending attack should disbar.