Nine hundred and fifty CAD patients were recruited for this study from patients hospitalized for elective cardiac catheterization. Anxiety was measured by the Hospital Anxiety Scale, the Spielberger Trait Anxiety Inventory, and the Crown-Crisp Phobic Anxiety Scale. Symptoms of depression were measured by the Montgomery-Asberg Depression Rating Scale, the Hospital Depression Scale, and the Beck Depression Inventory. Vagal control of heart rate was determined using power spectral analysis to measure two indices of vagal control: baroreceptor-mediated vagal reflex cardiac control, and respiratory sinus arrhythmia. Patients were followed at 6 months, l year, 2 years, and 3 years postcatheterization, and cardiac mortality data were obtained, including non-sudden and sudden cardiac death. The data generated by this study were used to examine the involvement of impaired vagal cardiac control in the risk of fatal coronary heart disease and sudden cardiac death associated with anxiety.