RESUMEN
BACKGROUND: Despite its importance to the aeromedical community, the occupational 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 for sudden cardiac death, syncope, presyncope and sustained VT, and by determining whether any cofactors predicted a subgroup at increased risk for such outcomes. METHODS: We reviewed the records of 193 military aviators evaluated at the U.S. Air Force Aeromedical Consultation Service for nonsustained VT from September 1960 to December 1992. Follow-up information was available on 192 of the 193 aviators over a mean of 10.6 yr. Cofactor analysis focused on idiopathic VT (no associated underlying cardiac disease) and VT associated 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 associated with coronary artery disease, MVP and cardiomyopathy. No cofactors predicted events in aviators initially presenting with asymptomatic nonsustained VT. For asymptomatic nonsustained VT, the maximum predicted annual event 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 sustained VT. Cofactors failed to predict a subgroup at increased risk for events. Idiopathic nonsustained VT appeared to be a low risk population for whom expanded waiver criteria are proposed with suggested limits on duration and number of episodes of VT.
Asunto(s)
Muerte Súbita Cardíaca/epidemiología , Personal Militar , Taquicardia Ventricular/patología , Adulto , Medicina Aeroespacial , Electrocardiografía , Femenino , Estudios de Seguimiento , Humanos , Incidencia , Masculino , Persona de Mediana Edad , Pronóstico , Taquicardia Ventricular/mortalidadRESUMEN
BACKGROUND: Little is known about the diagnostic usefulness of 201Tl scintigraphy for detecting asymptomatic coronary artery disease in apparently healthy men. We thus evaluated planar 201Tl exercise myocardial scintigraphy in 845 asymptomatic male military aircrew undergoing coronary arteriography because of abnormal noninvasive tests suggesting possible myocardial ischemia. METHODS AND RESULTS: Patients were stratified by prior disease risk into six subgroups using age (< 45 and > or = 45 years) and ratio of total to high density lipoprotein cholesterol (< 4.5, 4.5-6.0, and > 6.0). Significant coronary artery disease (> or = 50% diameter stenosis in any major coronary artery) was present in 143 (16.9% prevalence). Overall sensitivity and specificity of 201Tl scintigraphy adjusted for verification bias were estimated to be 45 +/- 4% and 78 +/- 1%, respectively. These values are lower than corresponding values accepted for clinical populations. Positive and negative predictive values varied across subgroups. A normal thallium scan indicated low risk of disease, but an abnormal test was likely to be a false-positive result. A logistic equation was retrospectively fit to the data for estimating the probability of disease given age, cholesterol ratio, and thallium results. Within each quintile of estimated risk, the average risk did not differ significantly from the observed disease prevalence. CONCLUSIONS: Exercise 201Tl scintigraphy is limited by the frequent occurrence of false-positive tests in detecting asymptomatic, anatomic coronary artery disease in young men in accordance with Bayesian probability theory.