ANXIETY AND VAGAL CONTROL OF HEART-RATE

Objective: Prospective studies have demonstrated that anxiety predicts sudden cardiac death, but the mechanism underlying this increased ris k is unclear. This study examined whether anxiety is associated with r eductions in vagal control of heart rate in healthy volunteers. Method : Trait anxiety (T-ANX) was measured, using the Spielbeger State-Trait Anxiety Inventory (STAI), in 93 healthy men and women 25 to 44 years of age. Power spectral analysis was used to measure two indices of vag al control: baroreflex control of heart rate (BRC) and respiratory sin us arrhythmia (RSA). Results: High trait anxiety (T-ANX > 41, N = 23) was associated with significantly reduced vagal control of the heart, compared with low trait anxiety (T-ANC < 31, N = 22), as indicated by a 36% reduction in BRC (p < .001) and an 8% reduction in RSA (p < .05) . Furthermore, T-ANX scores were negatively correlated with levels of BRC (r = -.30, p < .005), and levels of RSA (r = -.26, p < .05). Concl usions: These findings provide evidence that trait anxiety is associat ed with reductions in vagal control of the heart. Additional studies a re needed to examine whether low vagal control is involved in the incr eased risk of sudden cardiac death associated with anxiety.