Decreased heart rate variability in men with phobic anxiety (data from the Normative Aging Study)

Prospective cohort studies suggest that phobic anxiety is a strong risk factor for fatal coronary artery disease, in particular, sudden cardiac death. It has also been established that reduced heart rate (HR) variability can identify patients at high risk for subsequent sudden cardiac death. We therefore hypothesized that persons with symptoms of phobic anxiety may exhibit reduced HR variability. We tested our hypothesis in 581 men, aged 47 to 86 years, enrolled in the Normative Aging Study who were free of coronary artery disease and diabetes. Symptoms of anxiety were assessed using the Crown-Crisp index, an instrument that has been demonstrated in previous prospective studies to strongly predict risk of sudden cardiac death. HR variability was measured under standardized conditions, with paced deep breathing (6 breaths/1 min). Two measures of HR variability were used: the SD of HR and the maximal minus minimal HR over 1 minute. Men reporting higher levels of phobic anxiety had a higher resting HR (p = 0.025 for linear trend). After adjusting for age, mean HR, and body mass index in analyses of covariance, men reporting higher levels of phobic anxiety had lower HR variability, whether measured by the SD of HR (p = 0.03 for linear trend). These data suggest that phobic anxiety is associated with altered cardiac autonomic control, and hence increased risk of sudden cardiac death.