Nonsustained ventricular tachycardia in 193 US military aviators: Long-term follow-up

Background: Despite its importance to the aeromedical community, the occupa tional implications of asymptomatic, nonsustained ventricular tachycardia ( VT) are not well described. We sought to clarify this issue via a review of military aviators evaluated for nonsustained VT by defining event rates fo r sudden cardiac death, syncope, presyncope and sustained VT, and by determ ining whether any cofactors predicted a subgroup at increased risk for such outcomes. Methods: We reviewed the records of 193 military aviators evalua ted at the U.S. Air Force Aeromedical Consultation Service for nonsustained VT from September 1960 to December 1992. Follow-up information was availab le on 192 of the 193 aviators over a mean of 10.6 yr. Cofactor analysis foc used on idiopathic VT (no associated underlying cardiac disease) and VT ass ociated with mitral valve prolapse (MVP). Results: There was no documented sustained VT; 9 (4.6%) had events including syncope (1), presyncope (5) and sudden death (3). Of these 9, 4 had idiopathic VT. The 3 deaths were assoc iated with coronary artery disease, MVP and cardiomyopathy. No cofactors pr edicted events in aviators initially presenting with asymptomatic nonsustai ned VT. For asymptomatic nonsustained VT, the maximum predicted annual even t rate was 0.33% for idiopathic VT and 2.3% for VT with MVP (95% confidence limit). Conclusions: Nonsustained VT did not predict future documented sus tained VT. Cofactors failed to predict a subgroup at increased risk for eve nts. Idiopathic nonsustained VT appeared to be a low risk population for wh om expanded waiver criteria are proposed with suggested limits on duration and number of episodes of VT.